Tag Archives: asteroid

Astronomers spot second Trojan asteroid trailing Earth’s orbit

Artist impression of 2020 XL5, shown in the foreground in the lower left. The two bright points above it on the far left are Earth (right) and the Moon (left). The Sun appears on the right. Credit: OIRLab/NSF/AURA/J. da Silva/Spaceengine.

Astronomers have just confirmed the existence of only the second-known Earth Trojan. This isn’t some mythical wooden horse or pesky computer virus, but actually a massive, 1-km-wide asteroid that shares an orbit with the planet, clustered around special gravitationally balanced areas known as Lagrange points.

Trojan asteroids trail ahead or behind the orbit of a planet at approximately 60°, in the Lagrange points L4 and L5. These are gravitational “sweet spots” where the influence of two large bodies, such as the Sun and a planet, cancel each other out, so a relatively tiny body isn’t drawn towards any particular object. Instead, objects stay put in the same orbital point relative to the two large bodies, which is why NASA recently sent Hubble’s successor, the powerful James Webb Telescope, to L2, where it remains in a stable orbit with its back constantly facing the sun in order to perform infrared observations of some of the most distant objects in the universe with minimal disturbances.

This diagram shows the five Lagrange points for the Earth-Sun system (distances not at scale). There are only two known Earth Trojan asteroids, the newly found 2020 XL5 and 2010 TK7. Credit: NOIRLab/NSF/AURA/J. da Silva.

The first official Trojan was discovered in a Lagrange point around Jupiter on February 22, 1906, by German astronomer Max Wolf. Two other Trojans were found quickly after, and the three were named Achilles, Patroclus, and Hektor. By 2017, more than 6,400 Trojans had been spotted:  4,184 at Jupiter’s L4 point and 2,326 at L5. In order to track them, Austrian astronomer Johann Palisa, a prolific discoverer of asteroids, came up with the naming convention where asteroids near the L4 point were named for Greek heroes from Homer’s Iliad (The Achean camp) and those near L5 for Trojan heroes (the Trojan camp). However, 617 Patroclus (at L5) and 624 Hektor (at L4) were named before this convention took root, so each camp has a “spy” in its midst!

Although Jupiter and its swarm of Trojans comprise by far the lion’s share of Lagrangian asteroids in the solar system, astronomers have identified Trojans near other worlds, such as Mars (4 to date, 1 at L4 and 3 at L5) and Neptune (8 Trojans, 6 at L4 and 2 at L5) and even Earth.

The first Earth Trojan, called 2010 TK7, was found a decade ago. It’s estimated to be less than 400 meters across. The second, newly found Trojan, known as 2020 XL5, is nearly three times larger, with an estimated diameter of 1.2 kilometers (0.7 miles). It was discovered on 12 December 2020 by the Pan-STARRS1 telescope in Hawai‘i during a routine survey of the sky. A preliminary analysis suggests the asteroid’s orbit may be compatible with L4 and after some convincing work by researcher Toni Santana-Ros, the director of the 4.1-meter SOAR (Southern Astrophysical Research) Telescope on Cerro Pachón in Chile was persuaded to allocate more observation time to confirm this hypothesis.

Armed with new precise measurements of 2020 XL5 of movements in the sky, the astronomers could then access archival images taken since 2012 by the Víctor M. Blanco 4-meter Telescope located at the Cerro Tololo Inter-American Observatory (CTIO), in Chile.

“The day we discovered the precovery data was an explosion of emotions. Suddenly, out of the blue, we had 10 years of observations of our object! Santana-Ros,” an astronomer with the Institut de Ciències del Cosmos (ICCUB) at the Universitat de Barcelona and lead author of the new study, told ZME Science.

This second Earth Trojan is likely a C-complex type asteroid, a designation for asteroids predominantly composed of carbon. Based on its orbital analysis, 2020 XLwill remain in its orbit for at least 4,000 years. The asteroid could have been ejected from the main asteroid belt between Mars and Jupiter, following an interaction with Jupiter.

Further research would be needed to confirm the origins of 2020 XL5. What’s certain is that both Earth Trojans were captured after the planet formed, unlike primordial Jupiter Trojans that orbit L4 and L5 points since the time of the gas giant’s formation. That’s why Jupiter Trojans are much more important and interesting to study, as they may lock secrets pertaining to the formation of Jupiter and the solar system as a whole. In late 2021, NASA launched the Lucy spacecraft, which is now on route to rendezvous with 3548 Eurybates, 15094 Polymele, 11351 Leucus, and 21900 Orus in the L4 Greek Camp, plus 617 Patroclus and its binary companion, Menoetius, in the L5 Trojan Camp. During its 12-year mission, Lucy is tasked with gathering data on the surface composition, surface geology, and the interior and bulk properties of the Trojan targets.

“Primordial Trojan asteroids (i.e. those orbiting the L4/L5 points of a planet from the time of its formation) can provide us information about the formation of its host planet and, in turn, keys to better understand the evolution of the Solar System by adding constraints to its evolution models. We have studied the primordial Jupiter Trojans for several years and we will soon have the opportunity to investigate them with in situ observations taken by NASA’s space mission Lucy,” Santana-Ros said.

“Unfortunately, both Earth Trojans known have been confirmed to be transient objects, meaning that they have been captured in the L4 stability point many years after the Earth formation (actually quite recently! Only 600 years ago for 2020 XL5). Nevertheless, the discovery of 2020 XL5 as an Earth Trojan, confirms that 2010 TK7 is not a rare exception and that there are probably more bodies populating L4 and probably L5 of the Earth-Sun system. This encourages us to keep enhancing our survey strategies to find, if it exists, the first primordial Earth Trojan,” he added.

Due to its huge mass, Jupiter has cleared its neighboring region of objects, gathering 79 moons and a swarm of Trojans. Earth and other rocky planets in the solar system have more delicate environments, hence they have far fewer Trojans. Even so, the researchers estimate that Earth probably has tens or hundreds — but certainly not thousands — of Trojans waiting to be discovered. But it won’t be easy.

“It is a pain for astronomers to point to the L4 and L5 points of the Sun-Earth system while being on our planet! Any asteroid orbiting around these points will only be visible during a short time window close to twilight, at very low elevations above the horizon,” Santana-Ros said.

The findings appeared in a study published today in the journal Nature Communications.

Space rocks: the difference between asteroids, comets, and meteors

Some objects in our solar system don’t orbit the Sun as neatly as planets do. Instead, rocky objects of different sizes and shapes float around our solar system, and sometimes, get really close to Earth and even enter our atmosphere. We give these objects names like shooting stars, asteroids, or comets, but which is which?

Asteroids vs Comets

Image credits: Giulia Forsythe.

Asteroids are essentially rocks that orbit the Sun. Most are small, but some can be pretty big — like Vesta, which measures 525 kilometers across, or Ceres the largest asteroid in our solar system, with a whopping 946-kilometer diameter. Overall, though, asteroids are usually quite small, and their combined mass is approximately equal to (or perhaps even smaller than) that of the Earth’s moon.

Most asteroids can be found in or nearby the Main Asteroid Belt — an area between Mars and Jupiter whose gravitational field keeps the dangerous rocks trapped and keeps them from flying about in the solar system (thanks for that, by the way). There are over a million asteroids larger than 1 kilometer (0.6 miles) in diameter, and millions of smaller ones in the asteroid belt. However, it’s hard to study them because they are basically small rocks with nothing to light them up.

Comets, on the other hand, have ice in their interior, and when they get close enough to the Sun, some of that ice starts melting away. The melting helps form the comet’s tail, along with ionized particles from gas molecules that are excited by the solar radiation. The orbits of comets are abnormal, typically very elongated ellipses that make them come really close to the Sun and then go away for a long time. This is what happens to Halley which can be seen every 75 years from Earth. 

Image Credit & Copyright: Rolando Ligustri (CARA Project, CAST) and Lukas Demetz.

So the main difference between asteroids and comets is in their composition: asteroids are made of metals and rock, whereas comets also contain ice and dust. This can be traced back to where they formed (asteroids generally formed closer to the Sun, where it was impossible to keep their ice).


Trojans are a special group of asteroids that share a planet’s orbit. They are so-called co-orbital objects found near the Lagrange points (points of gravitational equilibrium) of planets or larger moons — the Lagrange points, L4 and L5, to be precise. These regions of equilibrium make it so that a collision with neighboring planets is nearly impossible.

Jupiter has two large groups of trojans, the Trojan Camp and the Greek Camp — yes, astronomers really like wordplay.  The system is in a constant astronomical dance: Jupiter’s gravity pulls the trojans towards it, the Sun (which is much larger but also much farther away) also pulls the trojans, and the result is the swarm rotating in the Lagrange point and never leaving the area.

The time-lapsed animation above shows the movements of the inner planets, Jupiter and both swarms of Trojans (green) during the time period of the Lucy mission. The L4 Trojans lead Jupiter in its orbit and the L5 Trojans follow. Credits: Astronomical Institute of CAS/Petr Scheirich

Believe it or not, Earth has its own trojans as well. One was studied by astronomers, although it doesn’t have a charming name. It’s called 2010 TK7 and it was detected by the Wide-field Infrared Survey Explorer (WISE). 2010 TK7 is thought to be 300 meters wide, but thankfully it is in a stable position not threatening us.

Edgeworth-Kuiper Belt and Oort Cloud

Now, let us focus on the comets’ “home”. Comets are found both in the Edgeworth-Kuiper Belt and the Oort cloud. Those are both very distant regions in the Solar System that are far enough from the Sun to allow solid ice to exist. 

Kuiper Belt and Oort Cloud. Credits: JPL/NASA.

The doughnut-shaped Edgeworth-Kuiper Belt is located beyond Neptune’s orbit. Scientists believe the region is what was left of material to make a planet, but Neptune was more efficient and got the larger stuff to form itself, so the smaller rocks remained there without being massive enough to coalesce.

Pluto and many comets can be found in the Edgeworth-Kuiper Belt. In fact, being beyond Neptune’s orbit and in resonance with it is one of the reasons why it Pluto has lost its classification of a planet. As a consolation prize, Pluto is the largest object in this region.

Meanwhile, the Oort Cloud is much bigger and even more distant. You can think of it as a sort of shell for the solar system, like how a traditional Chinese paper lantern surrounds a candle. The cloud is technically just a theory because astronomers can’t observe it directly yet, but there is a lot of indirect information that supports its existence. Based on this evidence, the Oort cloud appears to be populated mainly by comets, but there are some asteroids as well. Like the other rocky/icy objects regions, the Oort Cloud is thought to be a remnant of the early Solar System.

The only man-made objects to ever reach distances beyond Neptune are the Voyagers and Pioners spacecraft. Voyager 1 reached over 14,480,000,000 miles from Earth, over 155 times the distance between the Earth and the Sun (called an “astronomical unit”) — and yet this is not even close to the Oort cloud. The 44-year mission would still need to move another 1,845 astronomical units to get there, which will take nearly another 44 years based on its current speed.

New Horizons is the fifth spacecraft to traverse the Kuiper Belt, but the first to conduct a scientific study of this mysterious region beyond Neptune. Credit: NASA/JHUAPL/SwRI/Magda Saina

Shooting stars

So what about shooting stars? These are small bodies called meteors entering Earth’s atmosphere and heating up to the point they become bright. When some of their minerals survive entering the air, the meteorite is the piece of rock left that reaches the ground. 

“Shooting star” is a pretty vague term, and astronomers don’t really like to use it. Instead, they class these objects as either meteors or meteorites. Meteors are rocks that burn up completely before reaching the planet’s surface, whereas a meteorite reaches the surface intact (or at least some part of it does). Meteorites are also smaller than asteroids.

Whenever Earth moves closer to certain asteroids, or when a comet comes near us, the debris can form a meteor shower. When the asteroid or comet passes near us, the debris enters the atmosphere and burns. Most of the debris is as tiny as blueberries, in fact, Earth is bombarded by 5,200 metric tons of micrometeorites (smaller than 1 millimeter) a year, but because they are so small they aren’t a threat.

Since we are orbiting the Sun, we get close to the same location every year, so we have periodic meteor showers like Orionids, Geminids, and many others named after the constellation they will appear at. It is easier to see the showers under a dark sky, without city lights to interfere. Also, depending on whether the phenomenon will happen near the horizon or not, you may find trouble with buildings blocking your view.

Perseid meteor shower, Wednesday, Aug. 11, 2021, in Spruce Knob, West Virginia.

In the end, the differences between the rocks aren’t so difficult, right? The comet is icy different from the asteroids. Comets are periodic and can be seen every 80 years or so. Many asteroids are near Jupiter who keeps most of them there – phew. Meteors are small objects that enter the atmosphere and if some of them survive, the remains are meteorites.

Ryugu asteroid rocks brought back by Japanese spacecraft get their first look

Japan’s Hayabusa2 spacecraft snapped pictures of the asteroid Ryugu while flying alongside it two years ago. The spacecraft later returned rock samples from the asteroid to Earth. Credit: JAXA

In December 2020, a small piece of an asteroid was found in the middle of the Australian desert. This was no meteorite, however, but rather the result of one of the most well-choreographed operations in aerospace history. During its six-year-long mission, the Japanese Hayabusa 2 probe rendezvoused with the Ryugu asteroid, chipped and collected a sample from its surface, then launched a capsule containing pieces of the space rock back to Earth for analysis.

The engineering challenge of landing on a fast-moving asteroid in the middle of the solar system was immense, but it was all worth it. Now, Japanese scientists have shared the first results of Ryugu, providing clues about the formation of the early solar system, as well as how water and other basic building blocks made their way to Earth.

The Ryugu sample-containing capsule was retrieved after it was gently dropped in Australia. Credit: JAXA.

Ryugu is a carbon-rich, diamond-shaped, near-Earth asteroid that is about one kilometer in diameter. The distant space rock is classed as a C-type asteroid, where ‘C’ stands for carbon due to these asteroids’ coal-like appearance. These carbonaceous objects are the most common variety, forming around 75% of known asteroids.

The asteroid poses no threat of colliding with our planet — instead, it offers a fantastic opportunity to study carbon-rich space rocks in situ. When pieces of asteroids arrive on Earth, their chemical composition can be heavily altered by the high atmospheric entry temperature and the shock of impact, whereas the 5.4-gram Ryugu sample arrived on Earth unadulterated, protected by a special shielding capsule.

The mass of the sample actually greatly exceeded the Japanese researchers’ expectations, who were prepared to do work with no more than 100 mg. In order to keep physical alterations to the Ryugu samples to a minimum, some of the asteroid pieces were removed from the capsule in vacuum so as to not expose the space rock fragments to terrestrial nitrogen conditions.

After analyzing the sample, Toru Yada and colleagues at the Japan Aerospace Exploration Agency in Sagamihara, Japan found that Ryugu is very dark, reflecting only 2% of the light that hits its surface. Ryugu also has a high porosity of 46%, much greater than any meteorite found thus far, the astronomers reported in Nature Astronomy. C-type asteroids like Ryugu are believed to be possible parent bodies for dark, water- and carbon-bearing meteorites found on Earth known as carbonaceous chondrites, and the analysis suggests that this is indeed the case.

“Curatorial works of returned samples from asteroids are very essential to not only sample return missions themselves, but related science communities like meteorites and asteroids sciences, as well as planetary sciences to reveal the evolution of the solar system. In this sense, our preliminary studies on Ryugu returned samples give us direct proof to connect C-type asteroids to carbonaceous chondrites, which are enriched in water and organics,” Yada told ZME Science.

In a second study published in the same Nature Astronomy, Cédric Pilorget and colleagues at the Université Paris-Saclay in France used special microscopes on Ryugu samples that can acquire images at different wavelengths of light, both in the visible and infrared spectrums.

According to the researchers in France, Ryugu is rich in clay and other organic minerals, linked in a hydrated matrix. However, it also contains carbonates and volatile compounds, making its composition rather heterogeneous.

Since Ryugu’s rocks are thought to be around 4.6 billion years old, their composition reflects the primordial materials found at the dawn of the solar system’s formation, offering a unique opportunity to study the origin and evolution of Earth and other rocky planets.

“Because Ryugu is an asteroid enriched in water and organics, its original body(ies) should be possible sources of water and building blocks of life on ancient Earth,” said Yada.

Yada added that D-type asteroids, which are the main populations in the outer asteroid belt and are thought to be ‘extinct’ comet nuclei, as well as M-type asteroids, which are mainly made of iron, are great targets for future sample return missions, helping fill in the blanks in our understanding. In fact, next year will launch a spacecraft that will do just that, targeting the M-type asteroid Psyche.

Dinosaur-killing asteroid may have hit Earth during spring

Credit: Pixabay.

About 66 million years ago, one of the worst disasters in history happened after a large asteroid struck Earth offshore Mexico’s Yucatan Peninsula. The cosmic impact unleashed the force of 10 billion Hiroshima A-bombs and released gigatons of sulfur and carbon dioxide, which could have lowered surface air temperatures by a staggering 26 degrees Celsius (47 degrees Fahrenheit). This global winter lasted for years, enough to devastate plant life and everything else along the food chain. Around 75% of all animals and plant species went extinct, including the iconic dinosaurs (except for birds).

To say this was bad luck would be a huge understatement. If the asteroid’s course was just a tiny fraction of a degree different, it would have missed Earth. Were the impact site in a different place, things could have been different too. The time of the year may have also made a difference in which species were wiped out or spared.

This latter point was partly the subject of a new study that found the asteroid impact likely took place in the spring or early summer in the Northern Hemisphere. The findings are based on controversial fossils from Tanis, a site in North Dakota where paleontologists found a huge trove of fish fossils. The freshwater creatures are believed to have all perished just hours after the asteroid impact.

Robert DePalma, a doctoral student at the University of Manchester in the UK, was in charge of analyzing the fossils, which still preserved growth lines in their skeletons. These growth lines can trace the life history of the fish, not all that different from how growth rings record a tree’s history of drought and rainfall. Like barcodes, they enable scientists to deduce unique details like whether or not the fish had plenty of food during a particular season of their lives.

During spring and summer, the bones of fish grow a darker layer while lighter bands form in fall and winter. Previously, DePalma and colleagues published a study in 2019 that found a massive surge of water fell upon Tanis as a result of a vast earthquake triggered by an asteroid impact, rapidly depositing sediments that locked in the fish remains. The last growth lines observed in the bones of the fish were light, suggesting the asteroid impact occurred in the spring or early summer.

This line of reasoning is supported by isotopic analysis of the growth lines, since the two types of growth lines have different ratios of carbon.

“This project has been a huge undertaking but well worth it. For so many years we’ve collected and processed the data, and now we have compelling evidence that changes how we think of the KPg event, but can simultaneously help us better prepare for future ecological and environmental hazards,” DePalma said in a statement.

“Extinction can mark the end of a dynasty, but we must not forget that our own species might not have evolved if it weren’t for the impact and the timing of events that saw the end of the dinosaurs”.

Robert DePalma (L) and Professor Phil Manning at the Iridium-bearing KPg boundary clay layer capping Tanis. Credit: University of Manchester.

In addition, the team of researchers also analyzed fossils of leaves that were damaged by insects, as well as fossilized adult mayflies found at the site, which also match the seasonal timing.

“They all matched up…everything points to the fact that the impact happened during the northern hemisphere equivalent of Spring to Summer months,” said co-author Loren Gurche.

Scientists looking to reconstruct the aftermath of the asteroid impact that caused the fifth mass extinction need every bit of evidence they can gather to paint a more accurate picture. Knowing which season of the year the asteroid struck may prove very important. Certain animals, for instance, are more vulnerable during certain times of the year, such as periods of growth and reproduction.

The data could also be applied today, helping scientists better understand how contemporary life responds to global-scale hazards.

The findings appeared in the journal Scientific Reports 

Why did birds survive the asteroid impact that wiped out the dinosaurs?

The actual fossil (top) and the digital brain reconstruction of Ichthyornis, an ancient bird that lived during the Cretaceous. Credit: Torres et al, Science Advances.

You might have heard that birds are essentially living dinosaurs, just like humans are mammals. Dinosaurs actually represented a huge group spanning countless species of reptiles that held the top carnivore and top herbivore spots. But out of all these different dinosaur groups, it was only birds that survived the disastrous asteroid impact from 65 million years ago, which killed 80% of all life on Earth.

A new study tried to demystify what helped birds to survive when all other dinosaurs failed. According to the findings reported in the journal Science Advances, many ancient species of birds also perished in the wake of the damning asteroid impact off the coast of Mexico’s Yucatan Peninsula. However, the scientists found that the lineages of birds that did endure must have had larger forebrains. Turns out, you want to pick brains over brawn during an apocalypse.

Who you calling bird brain

The fossil record hasn’t been kind to bird bones, which are more often than not too delicate and fragile to endure over millions of years. What few bird fossils paleontologists know about though are enough to firmly place birds in the same group as dinosaurs, having evolved from a group of meat-eating dinosaurs known as theropods. It’s the same group that the famous Tyrannosaurus rex belonged to, although birds evolved from much smaller theropods.

After a long reign spanning more than 140 million years, the age of the dinosaurs came to an abrupt end. Only puny birds remained, which rapidly expanded and filled vacant ecological roles. Some 150 million years ago, the oldest birds looked like feathered dinosaurs and had sharp teeth. Over time birds lost their teeth and evolved beaks.

Not very much is known though about the brains of early birds since their braincases (the interior of the skull) rarely fossilized. This is why scientists are very excited by a partial skull belonging to Ichthyornis, an ancient bird that lived about 85 million years ago in Kansas.

In a new study, researchers at the University of Texas at Austin have completed an X-ray CT scan of the fossil, digitally reconstructing the Cretaceous bird’s facial skeleton and braincase in 3D without having to invasively alter the fossils in any way.

The analysis showed that Ichthyornis‘ brain was surprisingly similar to that of other dinosaurs, in contrast to living birds that have disproportionately large forebrains relative to the rest of their brain regions. However, the ancient bird’s brain did have an ace up its sleeve: a wulst. This brain structure was previously observed only in bird species that appeared after the mass extinction event caused by the asteroid impact. The wulst is thought to have played a major role in visual and sensory processing that could have played a critical role in flight.

Ancient birds had brains more closely resembling those of dinosaurs rather than the birds of modern birds. The ancestors of modern birds likely later developed a larger cerebrum, helping them survive the mass extinction. Credit: Science Advances.

Finding a wulst in the brain of a Cretaceous dinosaur shows that ancient birds had brains that were more complex than previously thought. And since Ichthyornis is very closely related to modern birds but still lacked the massive forebrain we’re used to seeing in living birds, the researchers inferred that “those big brains evolved in the ancestor of living birds,” Chris Torres, a National Science Foundation postdoctoral research fellow in the Heritage College of Osteopathic Medicine at Ohio University, told Live Science. Torres was a graduate student at the University of Texas when he participated in the fossils’ CT scanning.

Ichthyornis exhibited a wulst and segmented palate, previously proposed to have arisen within extant birds. The origin of Aves (extant birds) is marked by larger, reshaped brains indicating selection for relatively large telencephala and eyes but not by uniquely small body size. Sensory system differences, potentially linked to these shifts, may help explain avian survivorship relative to other dinosaurs,” the authors wrote in their study.

The combination of bigger brains, small size, their ability to eat a wider palate of foods, and their ability to fly ultimately may have helped birds survive the last mass extinction. Today, there are at least 11,000 bird species. 

NASA wants to deflect an asteroid to test our planetary defences

Although there’s no imminent threat, NASA wants to make sure we’re ready to deflect an asteroid should this problem ever arise. Next year, they want to accelerate an unmanned spacecraft to a speed of 15,000 miles per hour (24,000 kph) and crash into an asteroid to see if they can deflect it.

In the 1998 blockbuster Armageddon, an unlikely team sets out to deflect an asteroid on a collision course with Earth and save everyone on the planet. The movie is riddled with scientific inaccuracies, but the central premise is not absurd. Although there’s no imminent threat, the possibility of an asteroid crashing down on Earth is enough to keep NASA concerned.

“Although there isn’t a currently known asteroid that’s on an impact course with the Earth, we do know that there is a large population of near-Earth asteroids out there,” said Lindley Johnson, NASA’s Planetary Defense Officer.

Last month, NASA announced plans to deflect an asteroid to see if it can be done, and now, they’ve provided more details on the mission. The Double Asteroid Redirection Test (DART) will carry a price tag of $330 million and will determine whether crashing a ship into an asteroid is an effective way to deflect it.

The DART spacecraft is scheduled to be launched aboard a SpaceX Falcon 9 rocket on November 23. The rocket launch will take place at the Vandenberg Space Force Base in California. The shuttle will fly to the target asteroid Dimorphos, which measures 160 meters (525 feet) in diameter, and is one of the smallest celestial objects that has its own name. The asteroid is not considered to pose a threat to Earth, it’s just a test.

Two different views of the DART spacecraft. The DRACO (Didymos Reconnaissance & Asteroid Camera for OpNav) imaging instrument is based on the LORRI high-resolution imager from New Horizons. The left view also shows the Radial Line Slot Array (RLSA) antenna with the ROSAs (Roll-Out Solar Arrays) rolled up. The view on the right shows a clearer view of the NEXT-C ion engine. Image credits: NASA.

The collision will take place 6.8 million miles (11 million km) from Earth, sometime between September 26 and October 1 of next year. The mission won’t destroy the asteroid — it’ll just nudge it a bit and deflect it from its current trajectory, says Nancy Chabot of the Johns Hopkins Applied Physics Laboratory, which built the DART spacecraft.

“It’s only going to be a change of about one percent in that orbital period,” Chabot said, “so what was 11 hours and 55 minutes before might be like 11 hours and 45 minutes.”

In the case of an asteroid on a trajectory to Earth, a small nudge would also be enough — provided that we detect the asteroid quickly enough. This is the key to planetary defense, researchers say: detecting threats early on.

“The key to planetary defense is finding them well before they are an impact threat,” Johnson said. “We don’t want to be in a situation where an asteroid is headed towards Earth and then have to test this capability.”

“If there was an asteroid that was a threat to the Earth, you’d want to do this technique many years in advance, decades in advance,” Nancy Chabot, a planetary scientist and the DART coordination lead at Johns Hopkins Applied Physics Laboratory in Maryland, said during a prelaunch news conference held on Thursday (Nov. 4). “You would just give this asteroid a small nudge, which would add up to a big change in its future position, and then the asteroid and the Earth wouldn’t be on the collision course.”

DART team members carefully lower the DART spacecraft onto a low dolly in SpaceX’s payload processing facility on Vandenberg Space Force Base. Image Credits: NASA/Johns Hopkins APL/Ed Whitman.

The main focus of this experiment is to understand how much momentum is needed to deflect an asteroid, just in case one would be found to be on a collision course with Earth. Dimorphos is a great target for such an experiment. It’s the most common type of asteroid — a chondritic (stony, non-metallic) meteorite that has been floating about the solar system for around 4.5 billion years.

Researchers aren’t exactly sure just how much Dimorphos will be deflected because there are still uncertainties regarding how dense and porous it is, but they will target the impact to cause the biggest possible deflection, Chabot said.

NASA’s Asteroid Watch program is keeping track of near-Earth asteroids. So far, NASA has identified over 27,000 such asteroids, with 30 new ones being added each week. While no known asteroid larger than 140 meters in size has a significant chance to hit Earth over the next century, NASA estimates that only 40% of those asteroids have been found to date. This is why the space agency is also building an infrared telescope that could detect dangerous asteroids.

The most dangerous asteroid NASA has identified so far is called Bennu. Bennu is 500 meters across (1650 feet), and it’s estimated to pass relatively close to the Earth (within half the distance of the Earth to the Moon) in 2135. The probability of a collision is very low.

A small asteroid just grazed past Antarctica. Why didn’t anyone see it coming?

Credit: Max Pixel.

NASA usually does a pretty good job at tracking relatively close asteroids whose paths might cross Earth’s orbit. However, over the weekend a small asteroid about the size of a refrigerator traveled just 3,000 km past Earth — much lower than most communications satellites. No one was hurt and no damage was reported, but the problem is that the entire thing went unnoticed until later after the fact.

The asteroid in question, known as 2021 UA1, represents the third closest asteroid flyby with no impact in recorded history. The two closest asteroid flybys were 2020 QC and 2020 VT4, both of which occurred in the latter half of 2020.

Astronomers estimate that 2021 UA1 has a diameter of only two meters and during its closest approach above Antarctica, it came more than 100 times closer to Earth than the moon. Luckily, it was still much farther away than the manned International Space Station, which orbits Earth at around 400 km above the surface.

Given its small size, if 2021 UA1 had entered a collision path with Earth it would surely have been disintegrated and vaporized by the atmosphere. The last known significant asteroid event happened on February 15, 2013, when a 17-meter-wide asteroid exploded above Chelyabinsk, sending a shock wave that shattered windows across six cities and injuring more than 1,500 people. The Chelyabinsk asteroid was about 20 times larger than 2021 UA1.

But although 2021 UA1 proved to be harmless, the fact that it zipped past us undetected is highly concerning and reveals a huge blind spot in our asteroid monitoring system.

Most of the objects tracked by NASA and other space agencies are in the “front”, meaning their direction of travel is towards Earth and the sun. However, 2021 UA1 came from close to the inner solar system, from the sun towards Earth. Due to the sun’s glare, it is very difficult to spot these asteroids, especially if they approach during the daytime, which was the case in this situation as well.

NASA is learning, though. This recent close shave, as well as other recent asteroid close encounters, are helping scientists to fine-tune their monitoring tech and software. NASA is also planning to launch the Near-Earth Object (NEO) Surveyor space telescope in 2026, which is supposed to orbit between Earth and the Sun. That’s the perfect vantage point to monitor asteroids coming from the sun towards the outer solar system.

Nevertheless, it’s safe to say that asteroid monitoring and deflection are still in their infancy. Mistakes like these are valuable lessons that will help scientists get better with time — as long as it’s not too late and we get sucker-punched by some giant rock.

Even if we detect an asteroid, our technology and response capabilities are woefully lacking. That is why on November 24, NASA plans to perform the Double Asteroid Redirection Test (DART), humanity’s first-ever mission that will test a planetary defense method. The DART spacecraft, which will launch from a SpaceX Falcon 9 rocket, is supposed to travel more than 11 million kilometers and slam into Dimorphos, a 150-meter wide asteroid. Dimorphos is just target practice since it poses no threat to Earth. The idea is to impact the asteroid with enough energy to divert its course by a fraction of a degree, but just enough to make a huge difference millions of kilometers later.

“DART will be the first demonstration of the kinetic impactor technique, which involves sending one or more large, high-speed spacecraft into the path of an asteroid in space to change its motion,” NASA said.

“We’re going to make sure that a rock from space doesn’t send us back to the Stone Age,” Thomas Statler, a NASA scientist, said during a NASA podcast.

NASA will crash a spacecraft into an asteroid to practice ‘planetary defense’

The DART mission will involve crashing a satellite into the asteroid Didymos and its moonlet. Credit: NASA/Johns Hopkins Applies Physics Lab.

With all our day-to-day struggles, it’s easy to forget just how fragile all life on Earth really is. Our planet is essentially one giant rock zipping through nothingness, with only a thin blanket of atmosphere and magnetic fields separating us from total annihilation. What’s more, our blue rock isn’t alone. We’re surrounded by other smaller rocks called asteroids, some of which have trajectories dangerously bordering our own.

Of all existential threats, an asteroid impact seems the most distant — at least compared to climate change and nuclear war. But NASA is taking it very seriously, which is why next month it will be launching a spacecraft tasked with crashing into a pair of asteroids and changing their paths. The mission, called Double Asteroid Redirection Test (DART), is humanity’s first-ever test for a planetary defense method.

The launch is scheduled for November 24, when a SpaceX Falcon 9 rocket will take off from the Vandenberg Space Force Base in northwestern California. Once in orbit, the DART spacecraft will detach from the Falcon 9 and cruise through space for about a year until it encounters a pair of small asteroids — a larger one, known as Didymos, and its orbiting ‘moonlet’, called Dimorphos — that will come as close as 11 million kilometers from Earth at the time of the rendezvous.

These two asteroids pose no threat to Earth. The idea is to slam DART into Dimorphos with just enough energy to move it off course. It’s a test that will provide valuable lessons for when we need to avert a collision with an asteroid that may pose an actual threat. The entire interaction will be recorded by a small Italian satellite launching from the DART spacecraft and will be live-streamed on NASA TV.

“We’re going to make sure that a rock from space doesn’t send us back to the Stone Age,” Thomas Statler, a NASA scientist, said during a NASA podcast.

Didymos is about 800 meters (0.5 miles) in diameter, while the smaller Dimorphos measures just 150 meters (500 feet) across. NASA scientists chose Dimorphos as their target because these smaller asteroids are the most common and most likely to pose a significant threat to Earth.

By their calculations, NASA scientists estimate that the DART spacecraft will crash into Dimorphos at a speed of 24,000 km/h (15,000 mph). That’s enough energy to nudge its orbit by a fraction of one percent. That’s a small but very significant difference that adds up when you consider an orbit millions of kilometers across.

Researchers inspecting the spacecraft that will slam into Dimorphos. Credit: NASA/Johns Hopkins APL/Ed Whitman.

Sorry to break the news, but there will be no Armageddon-style nukes (not this time at least). Regardless, this will be one heck of an entertaining live stream. Be sure to bring popcorn.

“DART will be the first demonstration of the kinetic impactor technique, which involves sending one or more large, high-speed spacecraft into the path of an asteroid in space to change its motion,” NASA said.

Astronomers take best pictures of Kleopatra’s ‘portrait’

This processed image, based on observations taken in July 2017, shows the two moons of the asteroid Kleopatra (the central white object), AlexHelios and CleoSelene. Credit: ESO.

A team of astronomers has seemingly obtained the best pictures and data to date of the peculiar asteroid, Kleopatra. Using the European Southern Observatory’s Very Large Telescope (VLT), observers from the SETI Institute in Mountain View, California, and the Laboratoire d’Astrophysique de Marseille, France, captured images to help two teams of scientists answer some interesting questions.

“Kleopatra is truly a unique body in our Solar System,” says Franck Marchis, who led a study on the asteroid published in Astronomy & Astrophysics. “Science makes a lot of progress thanks to the study of weird outliers. I think Kleopatra is one of those and understanding this complex, multiple asteroid system can help us learn more about our Solar System.”

The asteroid, which orbits in the central region of the asteroid belt between Mars and Jupiter, was initially discovered on April 10, 1880. However, it wasn’t until just 20 years ago that radar observations revealed it had two lobes which were connected by a thick “neck.” In 2008, Marchis and his colleagues discovered that the asteroid was orbited by two moons, named AlexHelios and CleoSelene, after the Egyptian queen’s children.

Using the telescope’s Spectro-Polarimetric High-contrast Exoplanet Research (SPHERE) to obtain several images from 2017-2019, Marchis’s team determined the celestial body to be 168 miles (270 kilometers) across. That is nearly half the length of the English Channel. The VLT allowed them to produce a 3D rendering of the dog-bone-shaped body where they found one end of the dog-bone shape to be larger than the other.

Eleven images are of the asteroid Kleopatra, viewed at different angles as it rotates. Astronomers have called it a “dog-bone asteroid” ever since radar observations around 20 years ago revealed it has two lobes connected by a thick “neck”. Credit: ESO.

Astronomers were also resolved to find the answer to another curious question. What was up with Kleopatra’s moons? A second study, also published in Astronomy & Astrophysics, used SPHERE observations to find the correct orbits of the moons. Previous studies had estimated their trajectories, however, these new readings surprised the team a bit, showing that the satellites were not where they were previously thought to be. The new data revealed that the positions of the moons’ orbits were actually 35% lower than they formerly thought. 

“This had to be resolved,” said Miroslav Broz of Charles University in Prague, Czech Republic, who led the study. “Because if the moons’ orbits were wrong, everything was wrong, including the mass of Kleopatra.”

Combining the new estimates for volume and mass, the astronomers were able to estimate a new value for the density of Kleopatra. This also ended up being different than expected, when results concluded that the asteroid was less than half the density of iron. The low density, which is believed to have a metallic composition, suggests that the asteroid has a porous structure and could be little more than a “pile of rubble.” These conclusions mean it likely formed when material reaccumulated following a giant impact.

This rubble-pile structure – along with the way it rotates — gives indications as to how its two moons could have developed. The Kelopatra asteroid rotates almost at a critical momentum, the speed above which it would start to fall apart, and even small impacts may kick pebbles off its surface. Marchis and his team believe that those pebbles could subsequently have formed AlexHelios and CleoSelene, meaning that Kleopatra has truly birthed its own moons.

The upcoming (and originally named) Extremely Large Telescope (ELT) promises to hold more surprises for the researchers.

“I can’t wait to point the ELT at Kleopatra, to see if there are more moons and refine their orbits to detect small changes,” exclaimed Marchis.

Astronomers discover the fastest orbiting asteroid

Astronomers have discovered a one-kilometre wide asteroid orbiting the Sun at a distance of just 20 million km (12 million miles). Not only does this make the asteroid–currently designated 2021 PH27–the Sun’s closest neighbour, but it also means that as it completes an orbit in just 113 days, it is also the solar system’s fastest-orbiting asteroid. 2021 PH27 skirts so close to the Sun that its discoverers say its surface temperature is around 500 degrees C–hot enough to melt lead.

An artist’s rendition of the asteroid 2021 PH27 inside Mercury’s orbit. (CTIO/NOIRLab/NSF/AURA/J. da Silva)

Scott S. Sheppard of the Carnegie Institution of Science first spotted asteroid 2021 PH27 in data collected by the Dark Energy Camera (DECam) mounted at the prime focus of the Victor M. Blanco 4m Telescope at Cerro Tololo Inter-American Observatory (CTIO), Chile. Brown University astronomers Ian Dell’antonio and Shenming Fu took images of the asteroid on 13th August 2021 at twilight–the optimum time for hunting asteroids that lurk close to the Sun. Just like the inner planets–Mercury and Venus–asteroids that exist within the Earth’s orbit become most visible at either sunrise or sunset.

The discovery was followed by measurements of the asteroid’s position conducted by David Tholen of the University of Hawai‘i. These measurements allowed astronomers to predict asteroid 2021 PH27’s future position, leading to follow-up observations on the 14th of August by DECam and the Magellan Telescopes at the Las Campanas Observatory in Chile.

The Víctor M. Blanco 4-meter Telescope at the Cerro Tololo Inter-American Observatory (CTIO) home to the Dark Energy Camera (DECam) (CTIO/NOIRLab/NSF/AURA/R. Sparks)

These observations were then subsequently followed on August 15th by imaging made with the Las Cumbres Observatory network of 1- to 2-meter telescopes located in Chile and South America by European Space Agency (ESA) researcher  Marco Micheli.

The findings were so significant that many astronomers cancelled their scheduled projects to use telescope time with a variety of sophisticated instruments to further observe the asteroid. “Though telescope time for astronomers is very precious, the international nature and love of the unknown make astronomers very willing to override their own science and observations to follow up new, interesting discoveries like this,” explains Sheppard.

What makes the discovery of asteroid 2021 PH27 so special, and of great interest to astronomers, is the fact that it belongs to a population of solar system bodies that have been, thus far, notoriously difficult to spot.

Hunting For Inner Solar System Asteroids

Interior asteroids that exist close to the Sun tend to be difficult for astronomers to spot because of the glare from our central star. This difficulty is amplified by the fact that as they get close to the Sun these objects experience intense gravitational, tidal, and thermal forces that breaks them up into smaller–thus tougher to spot–fragments.

The fastest orbital period asteroid in the Solar System has been discovered at NOIRLab’s CTIO using the powerful 570-megapixel Dark Energy Camera (DECam) in Chile — the Sun’s new nearest neighbour. The asteroid was imaged inside Mercury’s orbit and has been coloured red and blue to show the two different times where it was imaged on the discovery night of 13 August 2021 — just three minutes apart. (CTIO/NOIRLab/NSF/DOE/DECam/AURA/S.S. Sheppard (Carnegie Institution of Science)

That means tracking an intact interior asteroid could have benefits for our understanding of these objects and the conditions they experience. In particular, if there are few asteroids experiencing a similar orbit to asteroid 2021 PH27 it may indicate to astronomers many of these objects were loose ‘rubble piles.’ This may, in turn, give us a good idea of the composition of asteroids on a collision course with Earth, and crucially, how we could go about deflecting them.

“The fraction of asteroids interior to Earth and Venus compared to the exterior will give us insights into the strength and make-up of these objects,” Sheppard continues. “Understanding the population of asteroids interior to Earth’s orbit is important to complete the census of asteroids near Earth, including some of the most likely Earth impactors that may approach Earth during daylight and that cannot easily be discovered in most surveys that are observing at night, away from the Sun.”

In addition to this, asteroid 2021 PH27’s orbit is so close to the Sun that our stars exerts considerable gravitational effects upon it, something that could make it a prime target for the study of Einstein’s geometric theory of gravity–better known as general relativity.

This close proximity to the Sun may actually be a recent development for asteroid 2021 PH27.

Asterod 2021 PH27 is on the Move

Planets and asteroids don’t move around their stars in perfectly circular orbits, but in ellipses–flattened out circles. The ‘flatter’ the circle the greater we say its eccentricity is. The widest point of the ellipse is the semi-major axis and for an orbit, this represents the point at which a body is farthest from its parent star.

Asteroid 2021 PH27 has a semi-major axis of 70 million kilometres (43 million miles or 0.46 au) which gives it a 113-day orbit crossing the orbits of both Venus and Mercury. But it may not have always existed so close to the Sun.

The fastest orbital period asteroid in the Solar System has been discovered at NOIRLab’s CTIO using the powerful 570-megapixel Dark Energy Camera (DECam) in Chile — the Sun’s new nearest neighbour. The illustration shows the locations of the planets and asteroids on the discovery night of 13 August 2021, as they would be seen from a vantage point above the Solar System (north). (CTIO/NOIRLab/NSF/AURA/J. da Silva)

Astronomers believe that the asteroid may have started life in the main asteroid belt between Mars and Jupiter, with the gravitational influence of the inner planets drawing it closer to the Sun. This would make it similar to the Near-Earth Object (NEO) Apophis, which has only recently been ruled out as a potential Earth impactor, which was also dragged closer to the Sun by gravitational interactions.

There is also some evidence arising from 2021 PH27’s high orbital inclination of 32 degrees that the asteroid may have a slightly more exotic origin, however. This could imply that the asteroid is actually an extinct comet that comes from the outer edge of the solar system pulled into a close orbit as it passed an inner-terrestrial–rocky–planet. Astronomers will be looking to future observations to determine which of these origins is correct, but unfortunately, this will have to wait. 2021 PH27 is about to enter solar conjunction which means that from our vantage point on Earth it is about to move behind the Sun. That means the asteroid will only become available for further observations in 2022.

These follow-up observations will allow astronomers to better determine its orbit. And with this better determination will come a new official name that is hopefully a bit less of a mouthful than 2021 PH27. But what is certain is that this asteroid is not set to become any less interesting.

Odds of asteroid Bennu hitting the Earth are greater than we thought. Here’s why you shouldn’t worry

Using more precise calculations of the asteroid’s trajectory, NASA updated the likelihood of Bennu hitting Earth within the next 300 years, and it’s a bit higher than the initial estimate. This shouldn’t keep you up at night though: there’s still a 99.94% probability that Bennu won’t hit Earth.

A mosaic image of Bennu compiled from 12 photos from the OSIRIS-REx mission. Image credits: NASA/Goddard.

NASA’s OSIRIS-REx mission spent more than two years orbiting Bennu, and then landing a probe on it. With the orbit data and the sample obtained directly from the asteroid (which is currently heading back to Earth and will arrive in September 2023), we can understand Bennu better than ever before.

NASA considers Bennu and another asteroid called 1950 DA to be the most hazardous asteroids in our solar system. Discovered in 1999, Bennu has a mean diameter of 490 m (1,610 ft) and was studied extensively using telescopes. Bennu is a “rubble pile” asteroid — it’s not made of one single rock (or monolith), but rather consists of numerous bits that have coalesced under the influence of gravity.

Still, even though it’s not the biggest or toughest asteroid out there, if Bennu were to hit the Earth, it could cause quite a lot of damage.

If it were to hit the Earth, Bennu would produce a crater around 6 miles wide, devastating everything some 600 miles around it. But the odds of this happening are still very low.

Using new data from the OSIRIS-REx mission and integrating it with existing data on Bennu’s trajectory, researchers have predicted its path with unprecedented accuracy. They included the gravitational effect of not just the sun, the planets, and their satellites, but also the gravitational pull of tiny asteroids and the drag caused by interplanetary dust.

When they put everything together, they concluded that the asteroid has a 1 in 1,750 chance of impacting Earth through 2300 — so there’s no particular reason for concern, the researchers say.

An image showing Bennu’s boulder-covered surface. Image credits: NASA/Goddard.

The researchers have published their predictions in the journal Icarus, and they say the asteroid will make a close approach to Earth in 2135. Bennu will pose no danger at that time, but Earth’s gravity will alter the asteroid’s path around the sun and affect its possibility of coming back and going splat.

However, we’ve only discovered half of the potentially hazardous asteroids NASA expects to find in our solar system. The recently approved Near-Earth Object Surveyor Mission is expected to help us find the others.

In the meantime, NASA is also testing our asteroid planetary defense systems: in November, it will launch the first mission to see if a spacecraft can deflect a space rock and change its trajectory — a technology that could become useful should asteroids like Bennu actually hurdle their way towards Earth.

The study has been published in the journal Icarus.

Several city- and state-sized asteroids impacted young Earth. Probably.

Early Earth might have caught some significantly larger asteroids than we assumed, a new paper reports. These could have ranged from a city to a small province in size, the authors explain. Still, in the end, these impacts could have helped to shape Earth into what it is today.

Rendering of Mars’ Victoria Crater. Image credits Alexander Antropov.

Take someone living today back to the days when our Earth was young, and they probably wouldn’t recognize it. Even after its crust cooled and solidified, the blue planet wasn’t particularly blue, but rather, a bit barren. It was also pockmarked by asteroid impacts and, occasionally, impacted by asteroids.

Most traces of this past have slowly been ground away by tectonics, erosion, and weathering. So we don’t have much in the way of direct evidence (i.e. craters) to study. Still, researchers are pretty confident that the Earth was hit by a significant number of large asteroids, rocks over 10 km (6.2 mi) in diameter, in the past, and that this helped shape its chemical properties, eventually culminating in the appearance of life. But new research presented at the 2021 Goldschmidt Geochemistry Conference proposes that these large asteroids were much larger than we believed.

Big Rock

While our planet slowly grinds away traces of asteroid impacts unlike, say, the Moon or Mars, we can still find evidence of them happening in the shape of spherules. These are round, glassy beads that are produced by super-heated material ejected during an asteroid impact. As they’re propelled away from the impact through the air, they cool to form a spherical shape and eventually land back on the surface. Over geological time, they become encased by rocks. The greater the impact, the more of these particles it would produce, and the wider they would spread around the crater.

A large enough impact could even spread spherules across the world.

The team developed a statistical model to analyze our records of spherule layers so far. Their model suggests that the number of known impacts in the past “severely underestimates” the real number of impacts. According to the results, there were likely 10 times more impacts between 3.5 and 2.5 billion years ago than we assumed. That’s equivalent to one Chicxulub-sized impact (the one that wiped out the dinosaurs) once every 15 million years.

The authors add that although we have very little information regarding their number and magnitude, these impacts had a profound effect on how the Earth’s surface and atmosphere evolved throughout the ages. For example, they explain that atmospheric levels of oxygen likely varied significantly during these impacts. They could help account for the dips we see in oxygen levels throughout history, before they stabilized around 2.5 billion years ago, for example.

Given how important oxygen eventually became for the evolution of both the Earth and the life upon it, a better understanding of ancient impacts could help us better understand how we came to be here.

Naturally, the impacts also caused widespread disruption and destruction, but we don’t really have enough evidence to estimate their true effect; very few rocks survive from that period. This lack of direct data is what prompted the team to develop a statistical model to study these impacts in the first place.

China wants to practice deflecting an asteroid with rockets

A government-funded study from China says that by using 23 Long March 5 (CZ-5) rockets (the largest China has in its fleet), we could break up rocky objects in our solar system and save the Earth from potentially catastrophic asteroids. The country wants to put the hypothesis to the test.

Asteroid Bennu: a carbonaceous asteroid in the Apollo group discovered by the LINEAR Project on 11 September 1999. It is a potentially hazardous asteroid. Image credits: NASA / Goddard / University of Arizona.

Asteroids come in many shapes and sizes. Many are as small as pebbles, while others are kilometers or even hundreds of kilometers across. A kilometer-wide asteroid strikes the Earth on average once every 600,000 years, and would have global consequences, but even a 500-meter asteroid, which hits the Earth once every 10,000 years, can easily kill millions.

If there’s anything we’ve learned from science fiction, it’s that having an insurance policy against such an asteroid could come in handy. At China’s National Space Science Center, researchers simulated just that.

The researchers analyzed how Long March rockets could help deflect such an asteroid on a course for our planet. They found that 23 such rockets hitting simultaneously could deflect a large asteroid from its original path by a distance of 1.4 times the Earth’s radius — more than enough to avoid catastrophic damage.

The technology is at our doorstep “[It is] possible to defend against large asteroids with a nuclear-free technique within 10 years,” said author Li Mingtao and colleagues in a June paper published in Icarus

According to Reuters, China would also test the idea by turning away a sizable asteroid, although details on this are still scarce at this point.

China is far from the only country looking at this type of technology. In less than two years’ time, NASA will also look at asteroid-deflecting technology. The space agency will launch a robotic spacecraft to intercept two small asteroids relatively close to the Earth and see how much their trajectory changes. This will be humanity’s first attempt at deflecting the course of a celestial body.

However, while it’s encouraging that several countries are working on asteroid-deflecting programs, whether or not space powers would collaborate in a potential doomsday scenario is anyone’s guess.

“The problem is, when the doomsday threat comes, politics may override science and lots of time may be wasted on debates to decide which country should take the lead,” said an unnamed space researcher at Beijing’s Tsinghua University for SMCP. The researcher did not want to be named because of the sensitivity of the issue.

China’s CZ-5 rockets are also a bit concerning. Due to their size, their descent back onto the Earth can become quite hazardous and difficult. In May, one such rocket crashed traveling at thousands of miles an hour. While the debris didn’t hit any human settlement, it showcased that China needs to up its game as a responsible space power.

A new study provides our best-yet prediction of what a metallic volcano might look like

If you like volcanoes, Earth isn’t a bad place to live on. After all, our planet is quite geologically active, and that also translates into a respectable level of volcanism. But when it comes to having a variety of flavors, the Earth can be a bit lacking.

 a) Metallic flow (yellow) emerging from underneath the silicate flow (orange-black) before cooling and b) metallic flow appears gray/silver, with the silicate flow black, after cooling. Image credits A. Soldati et al., (2021), Nature.

A new paper, however, comes to estimate what one type of not-yet-seen volcanic activity might look like. Called ‘ferrovolcanism’, it is likely a hallmark of geologically active worlds whose composition is mainly metallic. The study, although still purely theoretical, could help us better understand some of the more peculiar alien landscapes out there. And even though ‘metal volcanoes’ sounds like something pretty jagged and oppressive-looking, the team’s findings suggest that they’re actually quite mellow.

Metal volcanoes

“Cryovolcanism is volcanic activity on icy worlds, and we’ve seen it happen on Saturn’s moon Enceladus,” says Arianna Soldati, assistant professor of marine, earth and atmospheric sciences at NC State and lead author of a paper describing the work. “But ferrovolcanism, volcanic activity on metallic worlds, hasn’t been observed yet.”

The study, published by researchers at the North Carolina State University, aimed to give us an idea of how volcanic activity would look on a planet made predominantly of metal.

Volcanoes are born when magma, the partially-molten material found beneath a planet’s surface, erupts. The exact nature and behavior of this magma is closely related to the chemical composition of the planet. On Earth, therefore, magmas tend to be mostly molten rock (i.e. silica molecules). On icy worlds, however, magma is in fact a mixture of fluids such as water, ammonia, or methane, all super-chilled.

What the team wanted to find out, however, is how volcanism would look on 16 Psyche, a 140-mile diameter asteroid floating merrily in the asteroid belt between Mars and Jupiter. Infrared and radar analysis of its surface suggests that 16 Psyche is formed mainly of iron and nickel. Even better, though, it’s also the target for an upcoming NASA mission. This inspired Soldati to try and determine what volcanism would look like on the asteroid.

“When we look at images of worlds unlike ours, we still use what happens on Earth—like evidence of volcanic eruptions—to interpret them,” Soldati says. “However, we don’t have widespread metallic volcanism on Earth, so we must imagine what those volcanic processes might look like on other worlds so that we can interpret images correctly.”

The team defined two types of ferrovolcanism that they believe are possible. Type 1, or ‘pure’ ferrovolcanism, occurs on bodies made entirely of metal. Type 2, or ‘spurious’ ferrovolcanism, is what we’re likely to see on bodies that have both rocky and metal elements in their chemical mix.

Together with members of the Syracuse Lava Project, the researchers then simulated the second type, in which metal separates from rock as the magma melts down, in the lab.

“The Lava Project’s furnace is configured for melting rock, so we were working with the metals (mainly iron) that naturally occur within them,” Soldati says. “When you melt rock under the extreme conditions of the furnace, some of the iron will separate out and sink to the bottom since it’s heavier.”

“By completely emptying the furnace, we were able to see how that metal magma behaved compared to the rock one.”

Metallic lava (magma becomes lava once it reaches the surface) can flow up to 10 times faster, and spreads more thinly, than rock lava, the team found. As it flows, this material also separates into an abundance of braided channels, they add. Furthermore, metal lava tended to flow largely beneath the rock one, and emerged at the leading edge of the lava body.

Another important finding of the study is that the thin, braided layers of metallic lava, once cooled, give a distinctive appearance to a planet’s surface. This is very different in nature from those produced by rocky lava flows, Soldati explains, meaning that the two types of volcanism should be easy to spot from afar.

“Although this is a pilot project, there are still some things we can say,” Soldati says. “If there were volcanoes on 16 Psyche—or on another metallic body—they definitely wouldn’t look like the steep-sided Mt. Fuji, an iconic terrestrial volcano. Instead, they would probably have gentle slopes and broad cones. That’s how an iron volcano would be built—thin flows that expand over longer distances.”

The paper “Imagining and constraining ferrovolcanic eruptions and landscapes through large-scale experiments” has been published in the journal Nature Communications.

The oldest meteorite ever found is older than the Earth itself

The meteorite, which was discovered in the Algerian part of the Sahara Desert, dates from 4.6 billion year ago — before the Earth was truly formed. It’s one of the first building blocks of our solar system. It’s not just any old meteorite: analysis shows it formed volcanically so it was once part of a proto-planet, maybe even one that never really made it.

A piece of the meteorite. Image in public domain. Credits: A. Irving.

“Numerous stones containing distinctive large greenish crystals were found in May 2020 near Bir Ben Takoul, southern Algeria, within the Erg Chech sand sea,” reads a rather dull entry regarding the meteorite. But right from the get-go, researchers knew something was unusual.

No known asteroid looks like EC 002 (the official name of the meteorite) — because almost none of these ancient relics still exist. Since they were formed so long ago, they’ve been either reintegrated into planets or smashed to bits. Meteorites like EC 002 are also very rare, due to its composition.

Most meteorites we’ve found so far are chondritic: stony (non-metallic) meteorites that haven’t been melted. Meanwhile, EC 002 is essentially an igneous rock — an andesite, to be more precise, which is also unusual. Out of the over 50,000 meteorites discovered so far, just 3,179 are not chondrites. Out of these, most are basalts, which makes EC 002 very rare.

Basalt is a common igneous rock not just on Earth but also elsewhere in the solar system. It’s formed by the rapid cooling of basaltic lava, often at the surface (or very close to the surface).

Andesite shares some similarities to basalt, but it has a different chemical make-up and is characteristic of areas where tectonic plates are either sliding by each other or being destroyed one under another. This makes it even rarer because it takes a very special set of circumstances for andesite to reach meteorites. But the surprises kept coming in.

The rock was once molten, and it solidified some 4.565 billion years ago, in a parent body that accreted 4.566 billion years ago. The Earth is 4.54 billion years old, so it’s already older than the Earth. We’re not sure where it formed, but whatever celestial body it formed on, it must have been in its very early days, a part of its primordial crust.

“This meteorite is the oldest magmatic rock analysed to date and sheds light on the formation of the primordial crusts that covered the oldest protoplanets,” the researchers wrote in their paper.

Further analysis also showed that it took the lava over 100,000 years to solidify, indicating that the lava must have been unusually viscous. A lava’s viscosity is given by its temperature, chemical composition, and volatile gas content, so already, geologists can infer certain properties.

It’s always difficult when studying something so old, but finds like this can help shed new light on how our corner of the universe formed and evolved.

The study was published in PNAS.

The dinosaurs may have been wiped out by a comet fragment, not an asteroid

Artist’s reconstruction of Chicxulub Crater soon after impact, 66 million years ago. Image via Detlev Van Ravenswaay/ Science Source.

Around 66 million years ago, a giant asteroid struck our planet off the coast of Mexico. The devastating impact, whose force was equivalent to 10 billion Hiroshima A-bombs, unleashed huge tsunamis hundreds of feet tall, global wildfires, and sent molten rock hurtling all the way to the moon. About 75% of all life on Earth was killed almost instantly, including all non-avian dinosaurs. But according to a controversial Harvard astronomer, the culprit wasn’t an asteroid, but rather a comet fragment from the outer reaches of the solar system.

Since geophysicists first identified the huge impact crater in Chicxulub, Mexico, the site has been the subject of important research probing into the nature of the impactor in order to reconstruct the devastating timeline of the mass extinction that would follow.

We now know, for instance, that the impactor must have been very large, measuring between 10 and 80 kilometers in diameter, judging from the staggering 180-kilometer-wide crater, most of which is submerged in the Pacific Ocean. The impact then shrouded the planet into a decades-long winter, which decimated the suitable environments for dinosaurs.

This leading theory is that this impact arrived from the asteroid belt between Mars and Jupiter, but Harvard’s Professor Avi Loeb and astrophysics graduate student Amir Siraj have published a new study proposing an alternative source.

Loeb is no stranger to controversial theories. Previously, he claimed that the first-ever interstellar object Oumuamua may actually be an alien spaceship. He’s actually being a lot more conservative with his most recent paper published Monday in the journal Scientific Reports.

The pair of researchers performed the statistical analysis and gravitational simulations to essentially reverse-engineer the path the Chicxulub impactor took, showing that the impact actually originated from the Oort cloud — a shell of icy objects that exist in the outermost reaches of the solar system, more than a trillion miles away from Earth.

The Oort cloud is where most of the comets in the solar system are flung from. However, the Chicxulub impact wasn’t produced by a comet, but rather by comet fragments.

According to the researchers’ simulations, many Earth-crossing events were also directly preceded by very close encounters with the Sun. Astronomers call these comets “sun-grazers”.

Due to the gravitational interactions with the Jupiter-Sun system, large comets are torn apart into a large number of smaller fragments. Since the number of fragments large enough to account for the Chicxulub crater was about an order of magnitude greater than the background asteroid or comet population, the researchers simply conclude that it was far more likely that the crater was produced by a comet fragment.

“The solar system acts as a kind of pinball machine,” Siraj said. “Jupiter, the most massive planet, kicks incoming long-period comets into orbits that bring them very close to the sun.”

“And crucially, on the journey back to the Oort cloud, there’s an enhanced probability that one of these fragments hit the Earth,” the scientist added.

The comet fragment hypothesis may explain the unusual composition of the Chicxulub crater, which suggests the impactor was made of carbonaceous chondrite. These minerals are rare amongst main-belt asteroids, but rather widespread among long-period comets that make rounds between the sun and the Oort cloud.

A similar mineral composition was also encountered at the 2-billion-year-old Vredefort crater in South Africa, which is the largest confirmed crater in Earth’s geological history, as well as the Zhamanshin crater in Kazakhstan, which is the largest confirmed crater within the last million years. This is why the researchers plan to use the same approach on these craters as well.

These insights may be important in the future as the new Vera Rubin Observatory in Chile is scheduled to come online next year. The observatory can measure both the composition and tidal disruption of long-period comets, so it should be able to provide data that may confirm the researchers’ model.

“We should see smaller fragments coming to Earth more frequently from the Oort cloud,” Loeb says. “I hope that we can test the theory by having more data on long-period comets, get better statistics, and perhaps see evidence for some fragments.”

Ultimately, these investigations may be crucial in our efforts to mitigate catastrophic cosmic impacts and avoid the same fate as the dinosaurs.

“It must have been an amazing sight, but we don’t want to see that again,” Loeb said.

Six asteroids to pass close to Earth tomorrow, says NASA

The 2020 US Presidential election was really a wild ride, huh? Well, strap in because it’s not over yet.

Artist’s impression of the double asteroid Antiope. Image credits ESO via Wikipedia.

NASA’s Center for Near Earth Object Studies reported that six pieces of space rock will be passing by our planet tomorrow, 20th Jan., when the US celebrates Inauguration Day — the day when the new president-elect is vested with the powers of his office.

The agency says everything should be alright and that these meteorites will zip past harmlessly. Still, after 2020 and this election’s history, we can all be forgiven some wallowing in skepticism and despair at the thought that they might not. We’ve earned it.

Friends in high places

Inauguration Day marks the transition of power from one administration to the next — this year, that means from the Trump administration to the Biden team. It also marks the occasion on which four meteorites will do a close fly-by of Earth, hopefully missing us entirely.

According to NASA’s estimates, the closest one (asteroid 2021 BK1) will fly by Earth at around the same distance the Moon orbits at. So they should be pretty harmless. The largest of them is around 93 meters in width, which is the height of the Statue of Liberty.

All in all, we should be fine and well-missed by the space rocks. Still, this is close enough to be considered a “close approach” by NASA, and the agency will keep a close eye on the asteroids and their trekking. So let’s all hope for an uneventful Inauguration Day.

More information on these asteroids here (all six asteroids listed for 2021-Jan-20 in the table).

2020: A Year in Space

It’s difficult to mention the year 2020 without referencing COVID-19, but as more human beings than ever before were wishing they could take a break from the surface of the planet, space research continued to push our knowledge of the stars. Whilst much of the scientific community was consumed with combating a pandemic, physicists, astronomers, cosmologists, and other researchers were further pushing our understanding of space and the objects which dwell there.

These are some of my personal favourite space-related breakthroughs and research that have come about this year. The list is by no means exhaustive. 

Black Holes go silent

In terms of black hole science, 2019 was always going to be a difficult year to top being the year that brought us the first direct image of a supermassive black hole (SMBH). That doesn’t mean that 2020 has been a slow year for black hole developments, however.

One of the most striking and memorable examples of black hole research announced this year was the discovery of a ‘silent’ black hole in our cosmic ‘back yard.’ An international team led by researchers from European Southern Observatory (ESO) including found the black hole in the system HR 6819, located within the Milky Way and just 1,000 light-years from the Earth.

A silent and thus invisible black hole discovered lurking in our ‘solar backyard’ could be an indicator of a much larger population. (ESO/L. Calçada) Background: This wide-field view shows the region of the sky, in the constellation of Telescopium, where HR 6819 can be found. (ESO/Digitized Sky Survey 2. Acknowledgement: Davide De Martin)

The observation marks the closest to Earth a black hole has ever been discovered and Dietrich Baade, Emeritus Astronomer at ESO in Garching believes that it is just ‘the tip of the Iceberg’. 

“It’s remarkable because not only is it the first of its kind found, but it’s also so nearby,” said Baade. “Discovering a first only an astronomical stone’s throw away is the biggest surprise one can probably imagine.”

The black hole was described as ‘silent’ by the team because it is not current accreting material — the destructive process that creates powerful x-ray emissions and makes these light-trapping objects observable. 

Close-up screen capture image of the LB-1 which, like HR 6819, could also host a silent black hole (Hubble/Public Domain)

“If there is one, there ‘must’ be more,” Baade remarked in May. “If the Earth is not in a privileged position in the Universe — and all available evidence suggests without a doubt it is not — this means that there must be many more silent black holes.”

Baade also remarked that as current cosmological models suggest that the number of stellar-mass black holes is between 100,000,000 to 1,000,000,000 and we have observed nowhere near this many objects, more quiet black holes are “badly needed” to confirm current models. “HR 6819 is the tip of an iceberg, we do not yet know how big the iceberg is.”

Silent black holes weren’t the only examples of this hind of science making noise in 2020, however. Long-missing Intermediate Mass Black Holes were discovered. And just like a proverbial bus, you wait decades for one and then two turn up at once.

Intermediate mass black holes found and found again

Missing black holes were the subject of another piece of exciting space science in September 2020, when researchers from the VIRGO/LIGO collaboration discovered the tell-tale signal of an intermediate-mass black hole (IMBH) in gravitational-wave signals. To add to the excitement, the signals originated from the largest black hole merger ever observed.

An artistic interpretation of the binary black hole merger responsible for GW190521. The space-time, figured by a fabric on which a view of the cosmos is printed, is distorted by the GW190521 signal. The turquoise and orange mini-grids represent the dragging effects due to the individually rotating black holes. The estimated spin axes, or self-rotations, of the black holes, are indicated with the corresponding coloured arrows. The background suggests a star cluster, one of the possible environments where GW190521 could have occurred. Credits: Raúl Rubio / Virgo Valencia Group / The Virgo Collaboration.)

The merger — identified as gravitational wave event GW190521 —was detected in gravitational waves and is the first example of a ‘hierarchical merger’ occurring between two black holes of different sizes, one of which was born from a previous merger.

“This doesn’t look much like a chirp, which is what we typically detect,” Virgo member Nelson Christensen, a researcher at the French National Centre for Scientific Research (CNRS) said when announcing the team’s observation. “This is more like something that goes ‘bang,’ and it’s the most massive signal LIGO and Virgo have seen.”

The black hole birthed in the detected merger appears to have a mass of between 100–1000 times that of the Sun — most likely 142 solar masses — putting it in the mass range of an IMBH — a ‘missing link’ between stellar-mass black holes and much larger SMBHs. 

Earlier in 2020, another team had used the Hubble Space Telescope X-ray data collected in 2018 to identify what they believed to be an IMBH with a mass 50,000 times that of the Sun named 3XMM J215022.4−055108 (or J2150−0551 for short). 

This Hubble Space Telescope image identified the location of an intermediate-mass black hole (IMBH), weighing over 50 000 times the mass of our Sun (NASA, ESA, and D. Lin (University of New Hampshire))

Whether GW190521 or J2150−0551 will go down in history as the first discovered IMBH is currently a little muddy, but what is less questionable is that 2020 will go down as the year in which these ‘missing link’ black holes were first discovered, bringing with them exciting implications for the future investigation of black holes of all sizes. 

“Studying the origin and evolution of the intermediate-mass black holes will finally give an answer as to how the supermassive black holes that we find in the centres of massive galaxies came to exist,” said Natalie Webb of the Université de Toulouse in France, part of the team that found J2150−0551. And IMBHs weren’t the only missing element of the Universe that turned up in 2020.

Discovering the Universe’s missing mass

In May astronomers, including Professor J. Xavier Prochaska of UC Santa Cruz, announced that they had found the missing half of missing baryonic matter demanded by cosmological models. 

“The matter in this study is ‘ordinary’ matter — the material that makes up our bodies, the Earth, and the entirety of the periodic table. We refer to this matter as ‘baryonic’–matter made up of baryons like electron and protons,” Prochaska said when he spoke exclusively to ZME Science earlier this year. “Of particular interest to astronomers is to ascertain the fraction of the material that is tightly bound to galaxies versus the fraction that is out in the open Universe — what we refer to as the intergalactic medium or cosmic web.”

The matter the team discovered isn’t ‘dark matter’ — which accounts for roughly 85–90% of the Universe’s matter content — but rather ‘ordinary’ matter that has been predicted to exist by our models of universal evolution but has remained hidden.

The team made the discovery using mysterious Fast Radio Bursts (FRBs) and the measurement of the redshift of the galaxy from which they originate as a detection method. FRBs can be used as a probe for baryonic matter because as they travel across the Universe, every atom they encounter slows them down by a tiny amount.

This means that they carry with them a trace of these encounters along with them in the spectral splitting as seen above. This allowed the team to infer the presence of clouds of ionised gas that are invisible to ‘ordinary’ astronomy because of how diffuse they are. 

Asteroid Samples Returned by Hayabusa2

Japan’s Hayabusa2 probe and its continued investigation of the asteroid Ryugu has been the gift that has just kept giving in 2020. Just this month the probe returned to Earth samples collected from an asteroid — which has an orbit that brings it between Earth and Mars — for the first time.

Though probes have landed on asteroids and collected samples before, these samples have been examined in situ. Thus this is the first time researchers have been able to get ‘up close and personal’ with matter from an asteroid.

Artist’s impression of the Hayabusa2 probe achieving touchdown on Ryugu. Image credit: JAXA

Hayabusa2 arrived at Ryugu in late June 2018, making its touch-down on the surface of the asteroid in February of the following year after months careful manoeuvring conducted by the Japan Aerospace Exploration Agency (JAXA) and the selection of an optimal region from which to collect samples. 

Ahead of the return of samples on December 5th, the probe sent back some stunning images of the asteroid’s surface. These images were more than purely aesthetic, however. Examination of dust grains on the surface of Ryugu gave the team, including Tomokatsu Morota, Nagoya University, Japan, indications of a period of rapid heating by the Sun. 

The surface of near-Earth carbonaceous asteroid 162173 Ryugu, as observed by the Hayabusa2 spacecraft just before its landing. This image was produced from images obtained by ONC-W1 at the bottom and ONC-W2 on the side of the spacecraft. The spacecraft’s solar ray paddle casts a shadow on Ryugu’s surface. Image credit: JAXA/U. Tokyo/Kochi U./Rikkyo U./Nagoya U./Chiba Inst. Tech./Meiji U./U. Aizu/AIST

“Our results suggest that Ryugu underwent an orbital excursion near the
Sun,” said Morota in May. “This constrains the orbital transition processes of asteroids from the main belt to near-Earth orbit.”

Impressive though this achievement is, its the collection of samples from the asteroid and their subsequent safe return to earth that is the ‘main course’ of the Hayabusa2 mission. “The most important objective of the touchdown is sample collection from Ryugu’s surface,” Morota explained. 

Animation created from CAM-H and ONC-W1 data obtained during the 1st touchdown operation (Feb. 21, 2019). Image credit: JAXA/U. Tokyo/Kochi U./Rikkyo U./Nagoya U./Chiba Inst. Tech./Meiji U./U. Aizu/AIST

It is hoped that access to these samples will help answer lingering questions about asteroid composition as well as assisting researchers to confirm Ryugu’s suspected age of 100 million years old — which actually makes it quite young in terms of other asteroids. 

Asteroids like Ryugu can act as a ‘snapshot’ of the system’s in which they form at the time of that formation. This is because whereas planets undergo a lot of interaction with other bodies, asteroids remain pretty much untouched. 

Whilst researchers will no doubt be elated by the return of the Ryugu samples and the continuing success of the Hayabusa2 mission, 2020 wasn’t all good news for fans of asteroid research. 

Goodbye to Arecibo

The iconic radio telescope at the Arecibo Observatory in Puerto Rico collapsed at the beginning of December, ahead of its planned demolition. The telescope which will be familiar to moviegoers as the setting of the climactic battle in Pierce Brosnan’s first outing as James Bond, 1995’s Goldeneye, had been in operation up until November, playing a role in the detection of near-Earth asteroids and monitoring if they present a threat to the planet.

An image of the radio telescope before its December 1st collapse (NSF)

The collapse of the radio telescope’s 900-tonne platform which was suspended above the telescope’s 305-metre-wide dish, on December 1st, followed the snapping of one of its main cables in November.

The US National Science Foundation (NSF), which operates the observatory had announced that same month that the telescope would be permanently closed citing ‘safety concerns’ after warnings from engineers that it could collapse at any point.

Following the collapse, the NSF release heart-wrenching footage of the radio telescope collapsing recorded by drones. The footage shows cables snapping at the top of one of the three towers from which the instrument platform was suspended. The platform then plummets downward impacting the side of the dish. 

Video shows the radio telescope’s instrument platform fall and collision into the side of the dish (NSF)

The observatory had played a role in several major space-science breakthroughs since its construction in 1963. Most notably, observations made by the instrument formed the basis of Russell A. Hulse and Joseph H. Talyor’s discovery of a new type of pulsar in 1974. The breakthrough would earn the duo the 1993 Nobel Prize in Physics. 

Some good could ultimately come out of the collapse of Arecibo. Questions had been asked about the maintenance of the radio telescope for some time and the fact that the cable which snapped in November dated back to the instrument’s construction 57 years ago has not escaped notice and comment.

As a result, various space agencies are being encouraged to make efforts to better maintain large-scale equipment and facilities so that losses like this can be avoided in the future.

This aerial view shows the damage at the Arecibo Observatory after one of the main cables holding the receiver broke in Arecibo, Puerto Rico, on December 1, 2020. – The radio telescope in Puerto Rico, which once starred in a James Bond film, collapsed Tuesday when its 900-ton receiver platform fell 450 feet (140 meters) and smashed onto the radio dish below. (Photo by Ricardo ARDUENGO / AFP) (Photo by RICARDO ARDUENGO/AFP via Getty Images)

For most of us, 2020 is going to be a year that we would rather forget. Whilst very few of us come honestly comment that we have had anything approaching a ‘good year’ space science has plowed ahead, albeit mildly hindered by the global pandemic.

Our knowledge and understanding of space science are better off at the end of 2020 than it was twelve months earlier, and that is at least something positive that has emerged from this painful year.

Water could be a natural byproduct of rocky planets forming — so it could be almost everywhere

Water might be a byproduct of the formation of all rocky planets, a new study proposes.

The Curiosity rover on Mars. Image credits NASA / JPL-CALTECH.

From all we know of life today, water seems to be a key ingredient. Life on our planet spawned and lived its early years in water. So our efforts to find extraterrestrial life focused heavily on identifying planets with liquid water. However, a new study suggests that water may be much more bountiful in the universe than we’d expect. In fact, it may be a byproduct of the formation of any rocky planet.


“There are two hypotheses about the emergence of water. One is that it arrives on planets by accident, when asteroids containing water collide with the planet in question,” says Professor Martin Bizzarro from the Centre for Star and Planet Formation at the Faculty of Health and Medical Sciences, University of Copenhagen.

“The other hypothesis is that water emerges in connection with the formation of the planet. Our study suggests that this hypothesis is correct, and if that is true, it is extremely exciting, because it means that the presence of water is a byproduct of the planet formation process”.

Together with Assistant Professor Zhengbin Deng, Bizzarro performed an analysis of a black meteorite known as “Black Beauty”. This meteorite is 4.45 billion years old and found its way to Earth from the original crust of Mars. As such, it contains unique insight into the ancient history of the solar system. They explain that the findings showcase that water may be much more common in the universe than we’ve assumed up to now.

The duo found that Mars harbored water for the first 90 million years of its existence. This would be long before the planets in the inner Solar System (like Earth and Mars) were bombarded by water-rich asteroids, as per our previous hypothesis. In other words, it couldn’t have been asteroids seeding water onto planets (or, at least onto Mars).

Black Beauty was first discovered in the Moroccan desert, and soon found its way to the market — for around USD 10,000 dollars per gram. The team gathered the funds to buy some 50 grams of the meteorite back in 2017 and started working on it in the lab. They crushed and dissolved some 15 grams of the meteorite and processed them with a new technique they developed.

“We have developed a new technique that tells us that Mars in its infancy suffered one or more severe asteroid impacts. The impact, Black Beauty reveals, created kinetic energy that released a lot of oxygen. And the only mechanism that could likely have caused the release of such large amounts of oxygen is the presence of water,” Zhengbin Deng says.

“It suggests that water emerged with the formation of Mars. And it tells us that water may be naturally occurring on planets and does not require an external source like water-rich asteroids,” Bizzaro adds.

The dry river and lake beds visible on Mars today are undeniable proof that the planet once harbored liquid water. However, its surface is quite cold — so the authors wanted to understand how this could be. Their analysis suggests that asteroid impacts likely released a lot of greenhouse gases into its atmosphere. Their warming effect on the planet’s climate led to the conditions that allow for liquid water to exist on its surface.

Going forward, the team plans to examine microscopic water-bearing minerals in the asteroid, which have remained unchanged since they first formed.

The paper “Early oxidation of the martian crust triggered by impacts” has been published in the journal Science Advances.

NASA’s asteroid sampling mission ran into a problem: they sampled too much asteroid

Two days ago, NASA’s OSIRIS-REx mission landed on and sampled an asteroid barreling through space. We now have confirmation that the craft retrieved enough material for the mission to be considered a success — in fact, it may have sampled a bit too much.

An image captured by the SamCam camera on the OSIRIS-REx spacecraft showing the sampler head with the flap wedged open. Image credits NASA.

OSIRIS-REx‘s target was to bring back home at least 2 ounces (60 grams) of material from the asteroid’s surface. One of the ways NASA planned to check if this was met was to weigh the sample over the coming few weeks by spinning the spacecraft around (there’s no gravity out there, so we have to simulate it). However, images beamed back by the probe show that enough material has been recovered.

A handful of dirt

The craft’s Touch-And-Go Sample Acquisition Mechanism, or TAGSAM, which was tasked with actually retrieving the asteroid sample, appeared to be full of particles, according to ground control. It’s actually overflowing to an extent, as the mylar flap which acts as a lid for the collector is wedged slightly open by larger rocks in the sample.

Right now, they’re working on stowing the sample as quickly as possible to avoid losing material into space. They fear that any additional movement of the instrument or the craft as a whole could dislodge additional dust, or otherwise lead to further loss of the sample.

“Although we may have to move more quickly to stow the sample, it’s not a bad problem to have. We are so excited to see what appears to be an abundant sample that will inspire science for decades beyond this historic moment,” said Thomas Zurbuchen, NASA’s associate administrator for science at the agency’s headquarters in Washington, D.C.

In order to preserve the sample, NASA decided to not start measuring the sample’s mass (which included a braking burn on Friday) as was originally planned. Instead, they will focus on transferring it to the return capsule, where any loose material will be kept safe.