Tag Archives: meteorite

More than 5,000 tons of extraterrestrial dust falls onto Earth every year

Electron micrograph of a Concordia micrometeorite extracted from Antarctic snow at Dome C. Credit: Cécile Engrand/Jean Duprat.

While menacing asteroids occupy the public’s imagination when it comes to extraterrestrial impacts, the reality is that planet Earth is bombarded on a daily basis — it’s just that these cosmic projectiles are so tiny we barely notice them. When we do notice them, it’s because they light up the sky in a beautiful meteor shower. Now, scientists have quantified exactly how much extraterrestrial matter hits the planet’s atmosphere.

For nearly 20 years, researchers at the French National Center for Scientific Research (CNRS), the Université Paris-Saclay, and the National Museum of Natural History in France, have been collecting and analyzing micrometeorites. In a study due to be published on April 15 in the journal Earth & Planetary Science Letters, they concluded that nearly 5,200 tons of these micrometeorites reach the ground.

The few micrometeorites that survive atmospheric entry can fall anywhere on Earth. However, it is damned near impossible to tell them apart from normal, terrestrial dust and soil — unless you’re in Antarctica.

The Franco-Italian Concordia station (Dome C), located about 1,100 kilometers off the coast of Adélie Land in the heart of Antarctica, is virtually devoid of terrestrial dust. So researchers know that any dust they find in the snow has a good chance of being of extraterrestrial origin.

Over the last two decades, six expeditions have collected countless micrometeorite samples, ranging in size from 30 to 200 micrometers — so small they’re invisible to the naked eye.

Scientists collecting micrometeorites in the central Antarctic regions, at Dome C in 2002. Credit: Jean Duprat/ Cécile Engrand/ CNRS Photothèque.

Based on these samples, the researchers first calculated the annual flux of mass accreted on the surface per square meter per year. For the entire planet’s surface, the annual flux of micrometeorites amounts to 5,200 tons per year.

For comparison, the annual flux of larger objects such as meteorites, which typically range between the size of a pebble and a fist, is less than ten tons per year.

The researchers also performed a statistical analysis that showed that 80% of the meteorites come from comets, while the rest from asteroids. While asteroids consist of metals and rocky material, comets are made up of ice, dust, rocky materials, and organic compounds.

In the future, astrophysicists can use this information to model the formation of young Earth, which was greatly influenced by the amount of available interplanetary dust particles.

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.

Meteorites might have helped create life on Earth (and beyond)

Meteorites are usually described as having caused some of the most devastating and destructive events in the history of Earth. Nevertheless, they might have also provided the necessary conditions for life to blossom on the planet, according to a new study, which urged space agencies to pay further attention to craters.

Researchers exploring melt rock at Haughton impact crater in Nunavut. Credit Western University

All non-avian dinosaurs went extinct because of the impact of a massive asteroid 66 million years ago in the Yucatan Peninsula. The same would probably happen with human civilization and most other species if a similar asteroid hit Earth today. But asteroids may not only be responsible for ending lives — they have the power to seed new ones.

“If you ask anyone to imagine what happens when you have kilometer-size chunks of rock hitting the Earth, it’s typically destructive. It’s an extinction event like the one that killed the dinosaurs,” Dr. Gordon Osinski, lead-author, said in a statement. “What we’re trying to do here is turn that idea up on its head and say yes, the impact is initially destructive, but it also delivers the building blocks for life.”

Osinki and his team argued that impact events are not just isolated catastrophic geological events but a fundamental process in planetary evolution that plays an important role in the origin of life and in controlling planetary habitability. Building on previous studies, they provided a modern comprehensive treatise of the role of meteorite impacts in the origin and early evolution of life

Following the impact of an asteroid, conditions would be brutal for any life form that previously existed. Tons of debris would fall into the atmosphere and melted rock would flow from the crater, burning everything it touches and releasing toxic fumes that would remain for a while in the air. But after the rock cools and conditions settle down the conditions would be ideal for microbial life to develop.

While a crater lake forms in the impact basin, the combination of minerals, chemicals, heat and water would create the conditions for microbes to have a safe environment filled with abundant energy. These habitats include hot springs and geysers, such as the one in the Yosemite National Park, and hydrothermal systems, similar to the hydrothermal vents on the ocean floor.

Images of impact craters showing the change in morphology with increasing size. Credit Western University

But that’s not all. Other habitats include rock pools created in cooling volcanic flows where water can collect, so-called splash pools, as well as endolithic habitats (inside rocks). Life can develop inside the pores and fissures of rocks and inside floating islands of porous pumice rock, protected from ultraviolet radiation, the researchers said.

“There are a lot of hypotheses for where life started on Earth and where we should look for life on Mars, but we are actually overlooking a major geological force and a key habitat in understanding the origin of life and that’s meteorite impacts and their resulting craters,” said Osinski, who is the Director of Western’s Institute for Earth and Space Exploration.

Earth sweeps up hundreds of tons of material from space when it passes around the Sun, mostly dust, a few meteoroids and sometimes even an asteroid. The B612 Foundation identified over two dozen impacts around the world between 2000 and 2013. Most of them weren’t significant to produce a crater. An exceptional impact would be required to produce an environment where life could develop.

The findings showed that a crater of about 5 kilometers wide is needed to generate hydrothermal environments. For that, we would need a relatively massive asteroid. Besides the size, the type of object involved in the impact is also important.

For the researchers, understanding the beginnings of life on Earth might not only shed light on our origins but also aid our search for life elsewhere. Mars, for example, has been hit by many asteroids and most of the impact craters are intact and available for exploration. NASA’s Perseverance rover is scheduled to land on the red planet next year to look for signs that life once existed on Mars.

“Perseverance is going to land in Jezero Crater and there is evidence of minerals such as clays formed through hydrothermal activity. It’s a good place to start to explore the role of meteorite impacts in the origin of life, as long as they look out for the habitats, nutrients, and building blocks for life that we outlined in our study,” said Osinski.

The study was published in the journal Astrobiology.

Massive 800-million-year-old asteroid shower on Earth left dozens of huge craters on the moon

Artist’s illustration of the asteroid shower on the Earth-Moon system. Credit: Murayama/Osaka Univ.

Around 800 million years ago, Earth was bombarded by meteorite fragments belonging to a huge, disintegrated 100-km-wide asteroid. The collective force of impact is believed to have been 30 to 60 times more than the Chicxulub impact — the asteroid that hit our planet off the coast of Mexico and wiped out the dinosaurs in one swift blow at the end of the Cretaceous.

However, you wouldn’t have any way of knowing this, as any crater older than 600 million years has been erased by the relentless grinding and sweeping of erosive forces. But the moon, which has such a minimal atmosphere it virtually doesn’t exist, still bears the pockmarks of this ancient onslaught that affected both Earth and its satellite.

In a new study published in Nature Communications, Japanese researchers at Osaka University describe the age and formation of 59 lunar craters with a diameter greater than 20 kilometers.

The humongous craters were imaged by the Terrain Camera (TC) onboard the lunar orbiter spacecraft Kaguya, built by the Japanese Space Agency (JAXA). But in order to determine their age, the researchers led by Kentaro Terada, professor at the Department of Earth and Space Science at Osaka University, had to examine the density of relatively small craters in the ejecta of the larger craters.

I said “relatively small” because some of the craters could be as large as 1 km in diameter. But that pales in comparison to the Copernicus crater, which is 93 km in diameter. For the Copernicus crater alone, the researchers were able to identify 860 smaller craters with a diameter of 0.1-1 km.

“In this study, we used the Moon as “a witness to the history of the solar system”, because the moon surface has no erosion and well preserves the impact history of Earth-Moon system. This is a “quite new idea”, shedding light on the veiled impact history of the Earth before 600 million years,” Terada told ZME Science.

The density of 0.1-1 km-diameter craters (green) in ejecta of the Copernicus crater was examined to derive chronological information (Terrain Camera image). Credt: Osaka University.

Overall, 8 of 59 craters that the researchers examined were formed simultaneously. Based on crater scaling laws and collision probabilities, Terada and colleagues estimate that up to 5 trillion tones worth of meteoroids impacted the Earth-Moon system immediately before the Cryogenian (720-635 million years ago).

“Since I have looked at the data that indicated asteroid shower on the Earth-Moon system, I have been excited, and I wanted to publish this exciting new insight to all over the world as soon as possible. But it took two years since my first submit until publish. My biggest challenge was to persuade the reviewers,” Terada said as he remembered the struggles of publishing such an innovative technique.

The age distribution of lunar craters based on the 800 Ma spike model. Credit: Osaka University.

According to Terada, the meteoroid shower was generated by the collision and disruption of two big asteroids with a diameter greater than 100 kilometers. For comparison, the devastating Chicxulub impact that led to the extinction of 75% of all animal and plant species more than 65 million years ago was generated by an asteroid 10 to 15 km in diameter.

Some of these fragments fell on Earth and the Moon, but also other terrestrial planets in the solar system, as well as the sun itself. Other fragments strayed into the asteroid belt, where they still roam today as part of the Eulalia family. Other remnants entered an orbital evolution as near-Earth asteroids, like Ryugu and Benny, which show rubble-pile structures. In 2018, JAXA landed two small rovers and a probe on the surface of Ryugu — marking an unprecedented feat.

Snowball Earth and life thereafter

After this massive meteorite shower bombed the Earth-Moon system, around 700 million years ago, the planet turned into a snowball. Virtually all of Earth’s surface became engulfed in polar ice sheets and the oceans turned to slush. Massive volcanic eruptions then spewed so much greenhouse gases into the atmosphere that Earth became so hot oceans were near their boiling point. Then, the ash-darkened skies triggered global cooling again, and Earth returned to its snowball form yet again.

It’s rather difficult to imagine a more inappropriate time for the tiny single-celled and multicellular organisms that came into existence. But oddly enough, this difficult geological period, known as the Cryogenian, coincides with the moment complex animal life evolved. Out of the alternating ice and inferno sprang the first complex creatures that would eventually evolve into jellyfish and corals, snails, fish, dinosaurs, birds, and, at some point, humans.

Where do these 800-million-year-old impacts fit into all of this? The study suggests that the meteorites deposited 100 billion tonnes of phosphorus on Earth, “which is one order of magnitude higher than the total phosphorus amount of the modern sea (assuming that the volume of modern seas is 13.5×10^8 km3 and the concentration of P is approximately 3 μg/litre),” Terada told ZME Science.

“Interestingly, Reinhard et al. (Nature 2017) found that the average P content of late Tonian samples is more than four times greater than that of pre-Cryogenian samples and noted that a fundamental shift in the phosphorus cycle may have occurred during the late Proterozoic Eon after 800 Ma (until 635 Ma),” the Japanese researcher added.

While there’s no way of telling at this point how the course of life was impacted by this ancient meteorite shower, the extraterrestrial phosphorus may have seeded enough nutrients to kick start the evolution of complex life.

“In general, large-scale changes in marine biogeochemical cycles are undoubtedly forced by tectonic and magmatic processes and chemical weathering of the continental crust, but our new finding suggests that the flux of extra-terrestrial bioavailable elements might also have influenced marine biogeochemical cycles,” Terada said.

“I am glad that this research will lead to the advancement of earth science from the point of view that environmental changes 800 million years ago may have been caused by extraterrestrial factors,” he concluded.

Mineral never before seen in nature is discovered in a meteorite from 1951

Working on a meteorite first discovered in 1951, a group of researchers has now found a rare form of an iron-carbide mineral never before seen in nature. The finding is the key prerequisite for the new mineral to later be officially recognized as such by the International Mineralogical Association (IMA).

Wedderburn Meteorite. Source: Victoria Museum

The Wedderburn meteorite was found in a small town with the same name in Australia. Researchers have been working on it for decades to figure out the secrets behind it. Now, a group lead by mineralogist Chi Ma has decoded another one with the new mineral.

Only a third of the original meteorite remains intact at the Museum Victoria in Australia. The rest was divided into a series of slices and used to analyze the content of the meteorite. The analysis showed traces of gold and iron, as well as other rare minerals such as kamacite, taenite and troilite.

Now we can add a new mineral to that list, known as ‘edscottite’ in honor of meteorite expert and cosmochemist Edward Scott from the University of Hawaii. It’s a significant discovery as never before researchers had been able to confirm that this atomic formulation of iron carbide mineral occurs naturally. Previously, only the synthetic form of the iron carbide mineral was known.

“We have discovered 500,000 to 600,000 minerals in the lab, but fewer than 6,000 that nature’s done itself,” Museums Victoria senior curator of geosciences Stuart Mills, who wasn’t involved with the new study, told The Age.

There’s not much clarity yet on how the natural edscottite ended up outside of Wedderburn in Australia. But the first theories are already available. Planetary scientists Geoffrey Bonning, a researcher at Australian National University, believes the mineral could have formed in the core of an ancient planet.

A long time ago, this planet could have produced a big cosmic collision that involved another planet or moon or asteroid. The blast would have led to fragmented parts of the world travel across time and space, according to Boning. This would explain the finding of the fragment in Wedderburn.

The findings were published in American Mineralogist, part of the Journal of Earth and Planetary Materials.

Mars.

Some Martian clouds are made of ground-up meteors

Mars has clouds too — but some are formed by falling meteorites, not rain.

Mars.

Rendering of Mars produced using MOLA altimetry data.
Image credits Kevin Gill / Flickr.

Researchers from the University of Colorado at Boulder have obtained new insight into the clouds that dot the Red Planet. While these clouds have long been documented in Mars’ middle atmosphere (which begins about 18 miles or 30 kilometers above the surface), little was known about how they form in the thin, dry ‘air’ there.

New research shows that these wispy bodies are actually accumulations of “meteoric smoke”, the icy dust thrown up when meteorites or space debris break up in the planet’s atmosphere.

Dust rain

“We’re used to thinking of Earth, Mars and other bodies as these really self-contained planets that determine their own climates,” said Victoria Hartwick, a graduate student in the Department of Atmospheric and Ocean Sciences (ATOC) and lead author of the new study.

“But climate isn’t independent of the surrounding solar system.”

The most peculiar fact about Mars’ clouds is that they exist. The Big Bang notwithstanding, you can’t make something out of nothing, and clouds subscribe to this rule as well. Down here on Earth, low-lying clouds form on the backs of tiny particles — things like grains of sea salt or dust that get blown high into the air. These act as anchors of sorts for water vapor to condense on, growing into larger and larger drops, forming the large puffs of white or gray you can see from the ground.

To the best of our knowledge, however, that same mechanism doesn’t exist on Mars. There’s no sea salt to be blown up, and even if there was, the atmosphere is less dense so it’s less able to hold particles aloft. So Hartwick’s team turned their attention to meteors.

Around two to three tons of space debris rain down on Mars, on average, every single day, the authors explain. As this material, ranging from meteorites to space dust, comes into contact with the planet’s atmosphere, it starts to burn and break apart. In essence, a torrent of space dust ‘rains’ down on Mars.

So far, the theory seemed plausible — now the team needed to test it. To find out if this dust could generate Mars’ mysterious clouds, the team employed massive computer simulations that attempt to mimic the flows and turbulence of the planet’s atmosphere. After introducing meteors into the simulations, clouds started to appear.

“Our model couldn’t form clouds at these altitudes before,” Hartwick said. “But now, they’re all there, and they seem to be in all the right places.”

The findings are supported by previous research showing that a similar mechanism may help seed clouds near Earth’s poles (where the magnetic shield is weakest), the team explains. However, we shouldn’t expect to see enormous, roiling thunderstorms of cosmic dust above Mars: the clouds Hartwick’s team studied are very thin, “cotton candy-like clouds” explains Space.

“But just because they’re thin and you can’t really see them doesn’t mean they can’t have an effect on the dynamics of the climate,” Hartwick said.

Depending on the area, these clouds could cause temperature swings of up to 18 degrees Fahrenheit (10 degrees Celsius), the team’s model shows. The findings flesh out our understanding of Martian clouds and could help us better understand how ancient Mars regulated its climate, and how it was able to hold liquid water on its surface.

The paper “High-altitude water ice cloud formation on Mars controlled by interplanetary dust particles” has been published in the journal Nature Geoscience.

The oldest known meteorite in the UK struck about 1.2 billion years ago

The meteorite crater was discovered near Ullapool, Scotland.

Britain might be a green place that’s full of life today, but 1.2 billion years ago, it was a completely different place — the whole world was. Plants hadn’t migrated onto land yet, and all macroscopic life was still in the sea. Judging by its dry land, Earth was a barren planet. At that time, Scotland was around the equator, making it an arid, Mars-like landscape.

When the meteorite struck, the change in landscape wouldn’t have been observed by anyone, although the impact was probably felt by any microorganisms unfortunate enough to lie too close to the impact site. For geologists, however, the site of the impact was quite lucky: it was quickly covered by sediment favoring its preservation.

At about 1 km across, it wasn’t a huge meteorite, but it came down at 40,000mph, striking the Earth with a force 940 million times greater than that of the Hiroshima bomb. Although it created a 40 km-wide crater, the fact that it was preserved was quite lucky. Lead author Dr. Ken Amor explains:

“The material excavated during a giant meteorite impact is rarely preserved on Earth, because it is rapidly eroded, so this is a really exciting discovery. It was purely by chance this one landed in an ancient rift valley where fresh sediment quickly covered the debris to preserve it”.

“It would have been quite a spectacle when this large meteorite struck a barren landscape, spreading dust and rock debris over a wide area,” he adds.

World map with the largest discovered meteorite craters.

The site was discovered near Ullapool, in northwest Scotland and it’s the oldest meteorite impact ever recorded in the UK. The largest ever meteorite was discovered in Free State, South Africa, and it’s called the Vredefort crater. Vredefort crater has an estimated radius of 118 miles (190 kilometers), making it the world’s largest known impact structure. This crater was declared a UNESCO World Heritage Site in 2005.

Meteorite impacts were a bit more common back then due to all the leftover debris from the formation of the solar system still floating around. Even now, it’s unclear how common and likely this sort of impact was at the time. A commonly used estimate states that collisions with an object of about 1 km in size occur once every 100,000-1,000,000 years. However, these estimates can vary quite a bit — one of the reasons we don’t have better estimates is because these impact sites aren’t often preserved. Meanwhile, smaller impacts (where the meteorite is only a few meters across) are much more common, occurring about once every 25 years on average. In December 2018, a meteorite exploded in the atmosphere above the Kamchatka Peninsula in Russia and we barely even noticed.

Journal Reference: ‘The Mesoproterozoic Stac Fada proximal ejecta blanket, NW Scotland: constraints on crater location from field observations, anisotropy of magnetic susceptibility, petrography, and geochemistry’ is available to view in Journal of the Geological Society here: https://doi.org/10.1144/jgs2018-093

Asteroid Lutetia.

NASA and partners will be holding an asteroid impact exercise at conference next week

At next week’s 2019 Planetary Defense Conference, NASA, ESA, and the International Asteroid Warning Network will stage a “tabletop exercise” of an asteroid flying towards Earth.

Asteroid Lutetia.

Asteroid Lutetia seen by Rosetta spacecraft.
Image credits European Space Agency / Flickr.

Media outlets are always abuzz when an asteroid ‘near-misses’ our planet, and it’s easy to see why — there’s just something very exciting about a narrowly evading extinction. However, space agencies and governments around the world take the risk of impact with a near-Earth object (NEO) quite seriously. Given the potential for widespread panic such a scenario poses, any preparations are generally carried out discreetly, out of the public’s view.

The NEO threat

In the spirit of better communication, however, NASA’s Planetary Defense Coordination Office (PDCO), the European Space Agency’s Space Situational Awareness-NEO Segment and the International Asteroid Warning Network (IAWN) want to make the hazards posed by NEOs clearer for us laymen. Towards that end, they will organize — along with other U.S. agencies and space science institutions around the world — a “tabletop exercise” that will play out a fictional-but-realistic scenario for an asteroid on an impact trajectory with Earth at the conference, NASA announced.

NEOs are bodies such as asteroids or comets that come within 30 million miles (50 million kilometers) of Earth’s orbit. NASA and its international partners have been monitoring NEOs for over two decades now, keeping an eye out for any that might be gunning for Earth. However, preparations for such an impact have very rarely involved the public at large. The proposed exercise aims to address this shortcoming.

A tabletop exercise is basically a simulated emergency, used to accustom participants to the possible outcomes of such a disaster and help them see what needs to be done to mount a successful response. NASA plans to have attendees at the conference play out a NEO impact scenario developed by the NASA Jet Propulsion Laboratory’s Center for NEO Studies (CNEOS).

This type of exercise was specifically identified as part of the National Near-Earth Object Preparedness Strategy and Action Plan developed over a two-year period and published by the White House in June 2018. They’re not tightly scripted, aiming to let people ‘run wild’ and observe their response in conditions that mirror real life. This can then help us predict how NEO observers, space agency officials, emergency managers, decision-makers, and citizens might respond to an actual impact prediction.

Next week’s exercise events will occur over the five days of the conference. The scenario begins with the premise that on March 26th, a potentially-hazardous NEO dubbed 2019 PDC is discovered. After a ‘few months’ of tracking, observers predict that it has a 1% chance of impacting the earth in 2027. A 1% impact chance has been decided upon by the international space community as the threshold for action.

Exercise leaders will be briefing participants on the status of the scenario at the end of each day and soliciting response ideas and feedback, based on the latest fictional data. They will be asked to discuss potential preparations for reconnaissance and deflection missions, as well as plans to mitigate the effects of a potential impact.

“These exercises have really helped us in the planetary defense community to understand what our colleagues on the disaster management side need to know,” said Lindley Johnson, NASA’s Planetary Defense Officer. “This exercise will help us develop more effective communications with each other and with our governments.”

NASA has participated in six NEO impact exercises so far: three at Planetary Defense Conferences (2013, 2015, 2017) and three jointly with the Federal Emergency Management Agency (FEMA). The three NASA-FEMA exercises included representatives of several other federal agencies, including the Departments of Defense and State. Each exercise builds on lessons learned in the previous exercise. These exercises have shown that emergency management officials aren’t focused on the scientific details regarding the asteroid, but on more practical concerns.

“What emergency managers want to know is when, where and how an asteroid would impact, and the type and extent of damage that could occur,” said Leviticus Lewis of the Response Operations Division for FEMA.

However, NASA is a bit concerned with this approach. It’s those ‘scientific details’ that determine the outcome of an impact. So, while they’re working on developing new methods to determine asteroid characteristics, they also want to engage the public in these tabletop exercises to raise awareness of the hazards posed by NEOs.

“NASA and FEMA will continue to conduct periodic exercises with a continually widening community of U.S. government agencies and international partners,” said Johnson. “They are a great way for us to learn how to work together and meet each other’s needs and the objectives laid out in the White House National NEO Preparedness Action Plan.”

Lena Okajimac.

Japan start-up planning to sell “shooting stars on demand” launched their first satellite

A Tokyo-based startup offering “shooting stars on demand” just launched their first satellite into space this Friday.

Lena Okajimac.

Lena Okajimac.
Image credits

An Epsilon-4 rocket launched from the Uchinoura space center earlier today carries on board a micro-satellite that aims to put on a show on the night sky. The device is intended to release tiny balls of material through the atmosphere, simulating a meteor shower. A Japan Aerospace Exploration Agency (JAXA) spokesperson confirmed that all satellites on board the rocket successfully reached Earth’s orbit.

Flames in the sky

The microsatellite is the brainchild of Japanese start-up ALE Co. Ltd, which plans to deliver its first meteorite show over Hiroshima in the spring of 2020.

“I was too moved for words,” said Lena Okajima, the company’s president, for the Jiji Press agency. “I feel like now the hard work is ahead.”

The satellite is equipped with 400 such tiny balls — whose chemical formula is a closely-guarded company secret. As each meteorite show should take up around 20 such balls, the satellite should have enough ‘ammunition’ for 20 to 30 events, the company adds.

Right now, however, the satellite isn’t really in place. It’s currently orbiting the Earth at around 500 kilometers (310 miles) altitude. It will descend to roughly 400 kilometers as it orbits the planet over the coming year — which should put it close enough to the surface to safely launch its meteorites.

ALE says it is marketing its shows to “the whole world”, and plans to build up a stockpile of their shooting stars/balls in space that can be later transported wherever they’re needed. Further chemical tinkering with these balls should allow the company to create new colors as they burn up in the atmosphere to create more spectacular shows.

Each of these shooting stars is expected to last for several seconds before burning up completely. As such, they won’t have any chance of reaching the surface, ALE adds. However, they would be bright enough to be seen even over light-polluted areas, such as metropolises.

The company also plans to launch a second satellite on a private-sector rocket in mid-2019. After the second satellite reaches orbit, they will be used either separately or in tandem, depending on individual customer wants.

If all goes according to plan since then, the 2020 event could be visible to millions of people, according to the company. Hiroshima was chosen for the first display, because of its good weather, landscape, and cultural assets, Okajima explains.

So far, ALE  has not disclosed the price for an artificial meteor shower.

The rocket that brought ALE’s microsatellite to orbit also carried six other ultra-small satellites. These will be used to demonstrate various “innovative” technologies, JAXA spokesman Nobuyoshi Fujimoto told AFP.

3D meteorite level.

What’s the difference between an asteroid and a meteorite?

On June 30th, 1908, the boreal forests of Tunguska, Siberia, were shaken (and subsequently flattened) by a massive explosion. It wasn’t man-made — an asteroid pierced our planet’s atmosphere and exploded before hitting the surface.

3D meteorite level.

Artistic rendering of a meteorite.
Image via Pixabay.

This explosion, known as the Tunguska event, would make history. It was the largest impact event humanity has ever witnessed first-hand and would lead the UN to declare June 30th the International Asteroid Day.

While definitely awe-inspiring, the event didn’t lead to the massive loss of life that, say, the Chixulub Impactor caused (that’s the pebble that killed the dinosaurs). So why did one space-rock kill off the largest beasts to ever roam the Earth, while another merely flattened 2,000 square kilometres (770 square miles) of forest without causing a single human death? Well, the secret is all in the definition. Today, we’ll take a look at that simple yet oh so important distinction between an asteroid and a meteorite.

What is an asteroid?

The word itself gives us a glimpse into the nature of asteroids. “Aster” is the ancient Greek word for ‘star’, and the suffix “-oid” is used to show an incomplete or imperfect resemblance to the root word. “Asteroid”, therefore, means ‘star-like’ or, taken more literally, ‘star-like, but not quite’.

Keep in mind that for the ancient Greeks looking up into the night sky, planets and stars all looked the same; ‘aster’, therefore, can be understood as both ‘star’ and ‘planet’.

Vega asteroids.

Artist’s concept of an asteroid belt around the star Vega. Oumuamua, the first object to pass through our solar system that was confirmed to come from outside it — originates from this system.
Image credits NASA / JPL-Caltech.

Asteroids are chunks of space rock ranging from one meter to almost a thousand kilometers in diameter. The larger ones may rightfully be considered minor planets (or dwarf planets/planetoids). Ceres is a good example of this latter category, and the largest known asteroid. These large ones closely resemble planets: they’re roughly spherical and have at least partly-differentiated core structures. They’re generally considered baby planets that didn’t quite make it to adult status.

Most asteroids, however, are quite petite. They also don’t seem to prefer a particular shape. To the extent of our knowledge, they either formed from the primordial matter of a stellar system or via subsequent impacts between its first rocky bodies. Most asteroids in our neighborhood today make a home in the asteroid belt (surprising, I know).

So, to recap: asteroids are chunks of rock or metal (or both) in space. They’re mostly made up of telluric elements (such as carbon, metals, and silica), which tend to be quite resilient. They’re either planets that couldn’t grow large enough or their shattered remnants. Most known ones hang out in the asteroid belt between Mars and Jupiter, but they can take on all sorts of orbits (or none at all!)

What is a meteorite?

Hoba meteorite.

The Hoba meteorite in Grootfontein, Namibia, is the largest meteorite known to have landed on Earth. Estimated to weigh around 60 tonnes, it has never been moved from the spot it was discovered in. Hoba is currently a very visited touristic attraction.
Image credits Sergio Conti / Wikimedia.

A meteorite is any space-borne body that enters a planet’s or moon’s atmosphere, survives the violent trek through it, impacts the surface, and leaves behind solid pieces of material. The name comes from the ancient Greek words “meta” and “aerio”, which put together roughly translate to ‘something hanging up in the air’.

Meteorites start their life as meteoroids (small meteors) or asteroids. On contact with an atmosphere, meteorites experience immense friction, causing them to spontaneously combust (at up to 3,000 degrees Fahrenheit, or 1,649 degrees Celsius). These fireballs — colloquially called shooting or falling stars — are meteors.

The life of a meteor is short — and hellish. The friction they experience is enough to raise surface temperatures beyond the material’s boiling point, vaporizing it layer by layer. In fact, it’s enough to break apart its (and the atmosphere’s) constituent molecules into ionized particles (basically plasma), which then recombine, releasing energy as light. This is the tail you see on a shooting star.

Meteor over Sardinia.

Meteor over Sardinia, seen on the 8th of May 2016.
Image credits Migebuff / Wikimedia.

The extreme violence of the final impact generally shaves off much of a meteor’s mass — the remaining kernel is our meteorite. Keep in mind that geologists generally call impactors large enough to create a crater ‘bolides’, while astronomers tend to prefer ‘meteorite’.

Depending on chemical composition, angle and speed of atmospheric entry, as well as sheer happenstance (whether it breaks apart or not), a meteor needs to range in size between a marble and a basketball for even a tiny portion of it to reach our planet’s surface.

Meteorites under 2mm (0.07in) in diameter are called micrometeorites. Meteorites that impact celestial bodies apart from Earth (and thus don’t necessarily pass through an atmospheric layer, such as those hitting the Moon) are called extraterrestrial meteorites.

As a side note, these burning chunks also spawned the associated term ‘meteorology’, or ‘the knowledge of things happening up in the air’, the branch of atmospheric sciences involved heavily in the study and forecasting of weather events.

So… what’s the difference between them?

As a general guideline, most meteorites are asteroids — but very few asteroids are meteorites.

Ceres.

Ceres, for example, is a moon and an asteroid. We do NOT want it to be a meteorite, too!
Image credits NASA / JPL-Caltech / UCLA/ MPS / DLR / IDA.

The definitions tend to overlap a little. Let’s take size, for example. An astronomer will call any of these space projectiles ranging between a molecule and a chunk several hundred feet wide (usually up to 100m / 330ft in diameter) a meteoroid. Anything larger than that, generally, is considered an asteroid.

However, that leaves out chemistry, which is also a hard delineator for what is (and isn’t) an asteroid. Comets are globs of ice and dust formed in the freezing corners of the cosmos (i.e. outside of solar systems). They also have a little pocket of atmosphere around them (a distinctive feature for comets), generated by evaporation from this ice. Their interaction with heat and particles generated by stars is what creates those long, elegant plumes that are quintessentially comet-y.

Comets can and do fly towards planets and moons. The beefier ones also generally make it through any atmospheric layer and impact the surface. What makes comets generally fall short of being termed ‘meteorites’ is that they’re made up of volatile materials that don’t survive post-impact. However, some do — and also leave behind traces of their impact in the form of impact glass or diamonds. While definitely traces of impact, it can be seen as a technicality to consider such elements remnants of the impacting body itself. I personally do. So, following the impact-and-debris definition, I’d consider comets impacting the surface to be meteors as well.

And herein lies the difference. To be a meteorite, one needs to impact a planet or moon and leave behind solid debris. To paraphrase Iain Banks (my favorite author) the meteorite only lives as it is falling. For asteroids, it’s sufficient to be. Have the right chemical make-up, don’t be too tiny, don’t sublime too much when around stars, and voila! You’re an asteroid.

Most asteroids are nice and never impact any planets or moons. The overwhelming majority of them, actually, are content to orbit around in their asteroid belts or on whatever path they’re set on. But we should never take their absence for granted; it only takes one to come visiting for humanity to become a thing of the past.

Just ask the dinosaurs.

Illustration of newly discovered immense crater in Greenland. Credit: Nasa/Cryospheric Sciences Lab/Natural History Museum of Denmark.

Scientists find huge 19-mile impact crater under Greenland’s ice sheet

Researchers recently identified a huge bowl-shaped crater measuring a staggering 19 miles (31 km) across under half a mile of Greenland ice. The immense crater was likely formed by the impact of a mile-wide iron meteorite, which must have unleashed 47,000,000 times the energy of the nuclear bomb dropped on Hiroshima at the very end of WWII. The biggest question on everybody’s mind right now is when it all happened.

Illustration of newly discovered immense crater in Greenland. Credit: Nasa/Cryospheric Sciences Lab/Natural History Museum of Denmark.

Illustration of the newly-discovered immense crater in Greenland. Credit: Nasa/Cryospheric Sciences Lab/Natural History Museum of Denmark.

Kurt Kjær, a Professor at the Natural History Museum of Denmark in Copenhagen, suspected an impact crater might be hidden away under Greenland’s ice after NASA radar images showed a massive depression of the bedrock beneath the Hiawatha glacier, in the northwestern part of the island.

In May 2016, one year after the satellite images were released, scientists flew over the glacier pointing a cutting-edge ice-penetrating radar onto the glacier to map the underlying rock. The 3-D images clearly show all the hallmarks of an impact crater — a 19.3-mile-wide circular feature with a rim around it and an elevated central region.

The crater’s basin is about 300 meters deep, suggesting it was perhaps made by a one-mile-wide meteorite. This immediately classes the impact site among the top 25 largest known craters on Earth. According to the researchers, the impact would have melted and vaporized approximately ~20 km3 of rock.

“There would have been debris projected into the atmosphere that would affect the climate and the potential for melting a lot of ice, so there could have been a sudden freshwater influx into the Nares Strait between Canada and Greenland that would have affected the ocean flow in that whole region,” co-author John Paden, Associate Professor of electrical engineering and computer science at Kansas University, told the AFP.

Kurt Kjær collecting sediment samples from the crater's dranage system. Credit: Natural History Museum Denmark.

Kurt Kjær collecting sediment samples from the crater’s drainage system. Credit: Natural History Museum Denmark.

The meteorite was likely mostly made of iron, judging from geochemical tests performed on particles of shocked quarts collected from a nearby floodplain.

“Beyond the grains in the sediment sample that we interpret to be possible ejecta, no ejecta layer associated with this structure has yet been identified. Despite the absence of such additional evidence, an impact origin for the structure beneath Hiawatha Glacier is the simplest interpretation of our observations,” the authors wrote in their new study.

Black triangles represent elevated rim picks from the radargrams, and the dark purple circles represent peaks in the central uplift. Credit: Science Advances.

Black triangles represent elevated rim picks from the radargrams, and the dark purple circles represent peaks in the central uplift. Credit: Science Advances.

When exactly did the impact actually takes place is not at all certain. Kjær and colleagues are confident that the crater is no older than 3 million years, the time when ice began to cover Greenland.

“The age of this impact crater is presently unknown, but from our geological and geophysical evidence, we conclude that it is unlikely to predate the Pleistocene inception of the Greenland Ice Sheet,” the authors wrote in the journal Science Advances

As for the lower limit, radar images show that the deepest layers of the glacier that are older than 12,000 years are very deformed compared to upper layers and are filled with lumps of rock. To be sure, researchers will have to use radiometric dating techniques on material from the crater — that means drilling through half a mile of ice. It might take a few years before this happens, however.

 

Northwest Africa (NWA) 11119 is the oldest igneous meteorite recorded. Credit: University of New Mexico.

Unique 4.6-billion-year-old meteorite is a remnant of the early solar system

A never-before-seen space rock — older than Earth itself! — stands out among the 40,000 meteorites researchers have recovered so far. Scientists claim this is the oldest igneous meteorite found thus far and by studying it they hope to learn more about how the solar system formed and evolved.

Northwest Africa (NWA) 11119 is the oldest igneous meteorite recorded. Credit: University of New Mexico.

Northwest Africa (NWA) 11119 is the oldest igneous meteorite recorded. Credit: University of New Mexico.

About 4.6 billion years ago, a massive cloud of gas and dust collapsed under its own gravity, forming a spinning disk with a proto-sun at its center. Under the influence of gravity, material accreted into small chunks that got larger and larger, forming planetesimals. Many such objects likely broke back apart as they collided with each other, but others would have coalesced — eventually becoming planets and moons. However, the journey to building a planet was quite messy. One study published in Nature concluded that Earth lost nearly 40 percent of its mass as vapor during collisional growth.

The weird meteorite described by Carl Agee, the Director of the University of New Mexico’s Institute of Meteoritics, and colleagues provides chemical evidence that silica-rich crustal rocks were forming on planetesimals at least 10 million years before the assembly of the terrestrial planets.

At first, however, the space rock looked pretty unassuming. The researchers initially thought that the rock — called Northwest Africa 11119, as it was discovered in the sand dunes of Mauritania — was terrestrial in origin due to its light appearance and silica-rich content.

The rock, which was originally found by a nomad and later sourced by Agee via a meteorite dealer, was handed over to graduate student and lead author Poorna Srinivasan to study its mineralogy. Using an electron microprobe and a CT (computed tomography), Srinivasan started noticing unusual details in NWA 11119 and concluded it is extraterrestrial in origin, judging from its oxygen isotopes. What’s more, the silica-rich achondrite meteorite contains information involving the range of volcanic rock compositions (their ‘recipes’) within the first 3.5 million years of solar system creation.

“The age of this meteorite is the oldest, igneous meteorite ever recorded,” Agee said in a statement. “Not only is this just an extremely unusual rock type, it’s telling us that not all asteroids look the same. Some of them look almost like the crust of the Earth because they’re so light colored and full of SiO2. These not only exist, but it occurred during one of the very first volcanic events to take place in the solar system.”

Artist impression of NWA) 11119, seen in right bottom corner. Credit: University of New Mexico.

Artist impression of NWA) 11119, seen in right bottom corner. Credit: University of New Mexico.

According to Srinivasan, the mineralogy of the rock is unlike anything the researchers have worked on before. One of its most striking characteristics is that large silica crystals of tridymite — which are similar to quartz — comprise about 30 percent of the total meteorite. This kind of composition is unheard of in meteorites — which typically have ‘basaltic’ compositions with much lower abundances of silica — and can only be found in certain volcanic rocks from Earth.

Subsequent investigations using inductively coupled plasma mass spectrometry determined the precise formation age of the meteorite: 4.565 billion years.

But where exactly NWA 11119 formed is still a mystery.

“Based on oxygen isotopes, we know it’s from an extraterrestrial source somewhere in the solar system, but we can’t actually pinpoint it to a known body that has been viewed with a telescope,” said Srinivasan. “However, through the measured isotopic values, we were able to possibly link it to two other unusual meteorites (Northwest Africa 7235 and Almahata Sitta) suggesting that they all are from the same parent body – perhaps a large, geologically complex body that formed in the early solar system.”

It’s possible that this larger parent body was torn to pieces through the collision with some other asteroid or planetesimal, ejecting fragments that would eventually hit Earth at a yet unknown time in the past.

“The meteorite studied is unlike any other known meteorite,” says co-author and ASU School of Earth and Space Exploration graduate student Daniel Dunlap. “It has the highest abundance of silica and the most ancient age (4.565 billion years old) of any known igneous meteorite. Meteorites like this were the precursors to planet formation and represent a critical step in the evolution of rocky bodies in our solar system.”

The findings published in the journal Nature Communications are important because they help scientists piece together how the building blocks of planets formed in the early solar system. Specifically, this “missing part of the puzzle that we’ve now found that tells us these igneous processes act like little blast furnaces that are melting rock and processing all of the solar system solids,” Agee said.

“Ultimately, this is how planets are forged,” he added.

Illustration of an asteroid belt. Credit: NASA.

Most objects in the asteroid belt come from a handful of wrecked ancient planets

Most people think of asteroids as scary, cold, and lifeless blobs of rock hurtling around the solar system. That’s a pretty accurate description, but that doesn’t mean that asteroids don’t get to have families. According to a new study, 85% of all objects in the asteroid belt can trace their origin to five or six planetoids (small planets) that turned to smithereens in the early days of the solar system. Accordingly, there are five to six families of asteroids tracing their lineage back to these larger parent bodies.

Illustration of an asteroid belt. Credit: NASA.

Illustration of an asteroid belt. Credit: NASA.

About four to five billion years ago, the solar system was a chaotic, crowded mess. Many of today’s planets had yet to form in their current configuration and collisions between massive planetary bodies were quite routine. Eventually, all this colliding gave rise to many of the solar system’s moons and to the countless asteroids that litter the outskirts of the system. For instance, the main asteroid belt — located between the orbits of Mars and Jupiter — is estimated to contain millions of objects, although only hundreds of thousands have actually been observed.

While these parent bodies fragmented into thousands of smaller bits and pieces, it is possible to piece them back together based on their trajectories. In 1918, Japanese astronomer Kiyotsugu Hirayama was the first to notice that asteroids had similar elements, such as eccentricity and inclination, to their orbit. Suddenly, asteroids were no longer randomly zipping through the solar system but rather groups sharing orbital elements.

Based on Hirayama’s ideas, for the past 100 years, astronomers have grouped asteroids into families and non-families, with only half of all the asteroids that we know of being classed in families. However, this division into families and non-families is not productive, according to researchers led by Stanly Dermott, a Professor of Astronomy at the University of Florida.

Dermott and colleagues found that there’s a relationship between the orbital elements of asteroids and their sizes. By analyzing the dimensions of asteroids and their distribution within the inner asteroid belt, the team was able to classify 85% of the asteroid into about six families, each named after the biggest object in the family. They are Vesta, Flora, Nysa, Polana, Eulalia, and Hungaria. In 2011, NASA’s Dawn spacecraft visited Vesta.

“I wouldn’t be surprised if we eventually trace the origins of all asteroids in the d, not just those in the inner belt, to a small number of known parent bodies,” Dermott said.

The other 15 percent may also trace their origins to the same group of primordial bodies. What astronomers had previously thought of as ‘non-family’ asteroids were likely part of one of the six families, as well — just that they had become estranged due to the gravitational pull of Jupiter or Saturn, which changed their orbits ever so slightly.

The team only analyzed 200,000 asteroids, all found in the inner asteroid belt, which is closer to Earth and more studied than the middle or outer asteroid belt. A NASA survey tracked over 780,000 asteroids in the belt as a whole. This means there’s a lot of room to learn about asteroids. Perhaps there are more families, for instance. What’s more, there’s a similar ongoing analysis, only this time of meteorites, which are the bits of asteroids that survive atmospheric entry and reach Earth. This kind of information could prove essential to protecting the Earth and ourselves from killer asteroids of the kind that wiped out the dinosaurs. 

 “These large bodies whiz by the Earth, so of course we’re very concerned about how many of these there are and what types of material are in them,” Dermott said. “If ever one of these comes towards the Earth, and we want to deflect it, we need to know what its nature is.”

Scientific reference: The common origin of family and non-family asteroids, Nature Astronomy (2018). DOI: 10.1038/s41550-018-0482-4.

Life bounced back quickly at the famed dinosaur-ending asteroid impact site

Some 66 million years ago, a massive asteroid crashed into the Earth, wiping out the dinosaurs and changing all life on the planet. A new study found that life around the impact site bounced back surprisingly quickly.

Plankton repopulate the Chicxulub Crater in the first years after the impact of the asteroid that caused the end-Cretaceous mass extinction. Credit: John Maisano and University of Texas.

During the late 1970s, a team of geophysicists was prospecting the area around the Yucatan Peninsula in Mexico when they made a startling discovery: way beneath the surface, the equipment revealed what appeared to be a dramatic impact crater. After thorough study, the crater turned out to be slightly less than 66 million years old — the missing puzzle piece that explained why the dinosaurs went extinct. They called it Chicxulub, after a nearby town.

Today, we know the Chicxulub event mostly for wiping the dinosaurs, but the impact killed off out 75% of plant and animal species on Earth, striking with the energy with an estimated energy of 10 billion Hiroshima A-bombs. Eventually, life started to recover after the event, but not at the same pace. Generally speaking, the closer to the meteorite impact site, the longer it took to recover. Geologists estimate that it took about 300,000 years in the Gulf of Mexico and the North Atlantic — much slower than in other regions further from the impact crater. There are several theories as to why life recovered slower around the impact crater, including potentially toxic metal seeping from the meteorite.

But a new study challenges that theory and reports that life re-emerged faster than previously believed. Christopher Lowery and colleagues analyzed rock samples drilled up from beneath the crater, tracking variations in micro-fossils after the impact. They also looked at traces of biological activity and the abundance of various elements (such as extra-terrestrially derived helium-3, the flux of which can be used to infer sedimentation rates) — together, all these can be used as a proxy to assess the presence of life at the site.

The results were surprising: mere years after the impact, the first microscopic life forms started appearing. Just 30,000 years later — far faster than other sites farther from the impact — a productive ecosystem was already in place. This strongly suggests that the impact did not delay recovery.

If the impact crater itself would be preventing life from re-emerging, a pattern would have been present around the crater. However, this was not observed, and no such geographic pattern exists, the best explanation for the observed heterogeneity is a combination of ecological factors and ‘chance,’ according to researchers.

This study highlights that we don’t really know much about how life — particularly marine ecosystems — recovers after such a dramatic extinction.

Journal Reference: Lowery et al. Rapid recovery of life at ground zero of the end-Cretaceous mass extinction. https://www.nature.com/articles/s41586-018-0163-6. DOI 10.1038/s41586-018-0163-6

A Martian puzzle: is this a supervolcano or an impact crater?

Images from the European Space Agency’s Mars Express mission revealed an extraordinary feature, but the feature poses more questions than it answers: is it the remnant of an ancient supervolcano, or the crater of a meteorite crash?

Perspective view of Ismenia Patera. Image credits: ESA.

Back in 2003, the European Space Agency (ESA) launched Mars Express — a mission with the goal of exploring Mars. More than 14 years later, the orbiter is still providing valuable insight into the Red Planet. Now, it has sent astronomers on Earth pictures of an intriguing feature called Ismenia Patera.

Patera means ‘flat bowl’ in Latin, and it’s as accurate a name as any. Measuring some 75 km across, it has a flat central area, surrounded by a ring of hills, blocks, and lumps of rock which seem to have been ejected from the center. The feature lies in a transition area which lies between Mars’ southern mountains and its northern plains.

Supervolcano or meteorite crater? We don’t really know. The Mars Express view of Ismenia Patera.

The Martian topography is split into two parts: the northern lowland and the southern highlands — the latter being a few kilometers higher. This clear split is an extremely interesting puzzle for researchers, as the cause of this split isn’t really clear. It could be a massive impact, several smaller impacts, tectonic activity, or even supervolcanoes — whatever the reason may be, it remains hidden for now.

Understanding Ismenia Patera could be a much-needed puzzle piece that would allow astronomers to understand the transition area, and ultimately, the geological history of Mars.

Topographic view of Ismenia Patera. Image credits: ESA.

However, things are not very clear. There are two competing theories: the first one is that it’s a volcano — a supervolcano to be more precise. At some point, the supervolcano would have undergone a massive eruption, which would eject huge quantities of material outwards, collapsing after the magma was thrown out.

The other theory is that it’s actually the site of a meteorite that collided with Mars at some point. So far, the visual data and our limited knowledge of Martian geology are our only clues regarding the nature of this feature. The transitional area shows signs of being the location of an ancient and long-inactive volcanic province. Ismenia Patera does have an irregular shape, low topographic relief, and relatively uplifted rims, which would suggest a volcanic nature. But then again, Mars is also riddled with numerous impact craters, so this remains an open question.

Hopefully, future missions will offer more surface and subsurface data, allowing scientists to finally untangle the planet’s complex and fascinating history.

NASA is taking a Martian meteorite back home — for calibration purposes

A piece of Mars is going home — NASA engineers want to use a chunk of Martian meteorite to calibrate a future science mission.

A piece of Martian rock is returning home. Image credits: NASA / JPL.

An unlikely lift

In 2002, a rather odd-looking rock was found in the Uhaymir region of Oman. Weighing no more than 206 grams (0.45 pounds), it drew the attention of geologists and astronomers. Based on its chemical and isotopic composition, they dated the impact at around 9,700 years ago and traced its origin back to Mars. Now, the meteorite named Sayh al Uhaymir 008 (SaU008) will be going back home, hitching a ride on NASA’s Mars 2020 rover mission.

Mars 2020 is an ambitious mission: not only does it plan to collect samples from the Red Planet’s surface and save them for a future retrieval mission, but it also wants to carry out chemical analyses on rock features as fine as a human hair.

However, working with such fine details is no easy task, and it requires a lot of fine-tuning and calibration. This isn’t necessarily a new thing, as previous NASA missions have used calibration before — but if you’re calibrating things, why not use the real thing as a scale?

“We’re studying things on such a fine scale that slight misalignments, caused by changes in temperature or even the rover settling into sand, can require us to correct our aim,” said Luther Beegle of JPL. Beegle is principal investigator for a laser instrument called SHERLOC (Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals). “By studying how the instrument sees a fixed target, we can understand how it will see a piece of the Martian surface.”

Rohit Bhartia, a member of NASA’s Mars 2020 mission, holds a slice of a meteorite, which scientists have determined came from Mars. One of two slices will be used for testing a laser instrument for NASA’s Mars 2020 rover while it’s still on Earth; the other slice will go to Mars onboard the rover. Image Credit: NASA/JPL-Caltech.

The plan is to study the meteorite on Earth, measure it thoroughly and write down its physical parameters. Then, when the new rover will settle down on Mars, it will re-scan the meteorite and see if it gets the same results. If something went wrong along the way, then at least researchers will be able to compensate the error. You can perform this sort of calibration with any viable sample, but having one that’s similar to your intended target (in this case, Martian rocks) can add that extra bit of precision — but there’s a catch.

Martian meteorites are quite rare, with only 200 being confirmed by The Meteoritical Society, which has a database of these meteorites. So they’re quite precious and difficult to come about. To make things even more difficult, not any meteorite would do — it needs to be one which features certain chemical features to test SHERLOC’s sensitivity. These features need to be reasonably easy to detect, in order to easily ensure repeatability. The sample also needs to be sturdy, as flaky pieces can break off and damage or destroy the equipment.

Ultimately, they found the right sample at the Natural History Museum of London, where it was made available by courtesy of Caroline Smith, principal curator of meteorites at the museum.

“Every year, we provide hundreds of meteorite specimens to scientists all over the world for study,” Smith said. “This is a first for us: sending one of our samples back home for the benefit of science.”

Aside from the meteorite, Mars 2020 will also carry materials that could be used to make spacesuit fabric, gloves, and a helmet’s visor. Seeing how they hold up in the rugged Martian environment will be key for the planning of manned missions to the Red Planet.

“The SHERLOC instrument is a valuable opportunity to prepare for human spaceflight as well as to perform fundamental scientific investigations of the Martian surface,” said Marc Fries, a SHERLOC co-investigator and curator of extraterrestrial materials at Johnson Space Center. “It gives us a convenient way to test material that will keep future astronauts safe when they get to Mars.”

light-flash-in-Michigan.

Find a 2.2-pound-chunk of the Michigan meteorite and you can win $20,000

If you’re out hunting pieces of the meteorite that shook Michigan on Tuesday 16, Darryl Pitt, curator of the Macovich Collection of Meteorites, has an offer you can’t refuse: be the first to bring him a 2.2 pound (1 kilogram) chunk of the space rock, and he’ll pay you $20,000.

light-flash-in-Michigan.

Dashboard picture of the meteorite over Michigan.
Image via WeekFacts.

Pitt is taking inspiration from video games and sending Michiganians out on a quest for fame, glory — and fortune. Pitt, who’s also a meteorite consultant for auction house Christie’s and one of the largest private collectors of meteorites in the world, is putting up a reward of $20,000 for the first man, woman, or child who can bring him a 2.2-pound or more of the meteorite that crashed in Michigan three days ago.

He described the yet-to-be-retrieved space rock as a “winning extraterrestrial lottery ticket,” adding that the time is now for would-be treasure hunters to turn their efforts into a handsome profit.

Starter quest

“It’s better to go out there and find them sooner, because the longer they’re on the ground, the more they tend to blend in with Earth rocks,” said Pitt. “I really want this to be found and the only way that’s going to happen is if there are more boots on the ground.”

Preliminary NASA estimates place the meteorite that struck Michigan at around 6 feet in diameter (1.8 meters), and the force of its impact roughly around 10 tons of TNT. However, until we get our hands on a sample of the rock, we won’t be able to refine these estimates or determine exactly where it came from.

That’s the main reason Pitt issued his reward for the meteor. Furthermore, he’s a Michigan native who grew up in Southfield and studied at the University of Michigan and has a strong interest in space rocks. He remarked how unique it is for bystanders to witness an impact firsthand, saying that the event heightened public awareness and helped make central lower Michigan a hotbed for meteorite hunters.

He adds that it isn’t very common for him to offer a reward for meteorites, simply because there aren’t many known meteor events where the public is aware of its specific trajectory and location.

“Earth is bombarded regularly by materials, but two-thirds of those materials end up in the ocean, and a very large percentage lands in uninhabited areas and places where you can’t find it,” Pitt said.

The fate of this meteorite is still far from settled, however. William Cooke, the head of NASA’s Meteoroid Environment Office in Huntsville, Alabama, says that the meteorite was spotted after 8 p.m. on Tuesday. He estimates that the meteor fragmented about 20 miles (32 kilometers) above the surface “give or take 5 miles.” You can see it happening here:

Those are about the only clear answers we have so far. NASA couldn’t reliably track the rock after that, as the material released as it broke apart screened the rock from radar.

On Wednesday, the agency released a narrowed-down impact area to the west of Hamburg Township in Livingston County (which seems to be pretty accurate). A better-defined search area would give residents a relatively solid chance of finding meteorite material, Pitt says, although the likelihood, as usual, remains fairly small.

Aspiring questees should take heart, however, and not falter in the face of unfriendly odds. We don’t know what the Michigan meteorite is made of, Pitt explains, but it could teach us a lot about the universe.

“We know that there are many meteorites that contain amino acids or building blocks of proteins of life that have never been seen before on Earth. They’re very important, fascinating objects.”

In the end, both Pitt and Cooke would like to remind everybody they must always ask permission from the owners if their search leads them to private properties. You can contact Pitt via his email or at 917-213-8265.

Blue crystal.

Meteorites carrying both water and organic compounds point to an ocean world “seeding life” in the universe

New research raises an intriguing possibility — that of an alien ocean world seeding life throughout space.

Blue crystal.

One of the meteorites’ tiny crystals bearing organic compounds.
Image credits Queenie Chan / The Open University.

In 1998, a group of friends had to cut their basketball game short for a somewhat unexpected reason — a meteorite decided to crash just yards away from the hoop.

Seeds of life

But that seems to have been fortune’s plan all along, as the rock seems to be a harbinger of life rather than death. Initial analysis of the chunk of meteorite, along with another that fell in Morocco the same year, revealed traces of liquid water and other organic components that underpin life. Now, an in-depth chemical analysis points to an ancient ocean world as the likely cradle of these organic compounds. It’s possible that such material could seed life on planets they land on, including the early Earth.

Initial analysis revealed that the main elements inside the meteorites include liquid water and amino acids. Taken together, that’s not really news — we’ve found such compounds in meteorites and in space before. They might not be as rare as we tend to believe. However, we’d never seen them together in a single alien sample before these two bits of space rock were first analyzed.

That made the meteorites really special, so they were preserved at NASA’s Johnson Space Center. Keen to find out more, an international team of researchers has recently sampled the organic compounds locked away in these meteorites’ 2-mm long salt crystals using an X-ray beamline and microscope, as well as other chemical experiments.

Along with traces of liquid water, they report finding organogenic elements like carbon, oxygen, and nitrogen, along with more complex organic compounds such as hydrocarbons and amino acids. In other words, we’ve found the fundamental building blocks of life as we know it right next to water — in a space rock.

“This is really the first time we have found abundant organic matter also associated with liquid water that is really crucial to the origin of life and the origin of complex organic compounds in space,” says study lead author Queenie Chan.

“We’re looking at the organic ingredients that can lead to the origin of life.”

After discovering this exciting chemical cocktail, the next step was to see where the meteorites came from, and where they inherited their organic matter. Their complex chemistry (in comparison to other meteorites) makes it unlikely that they’re simply left-over bits from the creation of the Solar System. Instead, the team narrowed their search to an ancient ocean world — similar to today’s Enceladus or Ceres. Water and ice plumes (which are relatively commonly-seen on such bodies) shooting out into space could have doused the meteorites, locking the planet’s organic compounds in the salt crystals.

According to co-author Yoko Kebukawa, the organic matter seen in these samples is “somewhat similar” to what we’ve previously found in primitive meteorites. The results of the analysis support the idea that the “organic matter originated from a water-rich, or previously water-rich parent body”, she explains, adding that it’s “possibly Ceres“.

Encased in the salt crystals, such biomolecules could safely make it across the cosmos. Even microscopic life could survive on a space-cruise within a similar system, the team says. Once in space, all kinds of things could happen to help spread these seeds of life around — collisions between asteroids, for example, would push them along or shatter them into even more ‘seeds’. After making it to a planet, such rocks could jump-start life on the surface.

“Everything leads to the conclusion that the origin of life is really possible elsewhere,” Chan adds. “There is a great range of organic compounds within these meteorites, including a very primitive type of organics that likely represent the early solar system’s organic composition.”

Next, the team plans to look at other crystals embedded in the meteorites that haven’t yet been analyzed. Who knows what we may find? Maybe a tiny alien bacterium swimming around?

The paper “Organic matter in extraterrestrial water-bearing salt crystals” has been published in the journal Science.

Fragments from the Hypatia stone, which was discovered in th esouth-west Egypt in the Libyan Desert Glass Field. Credit: Dr Mario di Martino, INAF Osservatorio Astrofysico di Torino.

Strange interstellar stone discovered in Egypt is like nothing else found in the solar system

Fragments from the Hypatia stone, which was discovered in th esouth-west Egypt in the Libyan Desert Glass Field. Credit: Dr Mario di Martino, INAF Osservatorio Astrofysico di Torino.

Fragments from the Hypatia stone, which was discovered in south-west Egypt in the Libyan Desert Glass Field. Credit: Dr. Mario di Martino, INAF Osservatorio Astrofysico di Torino.

A unique stone discovered in 1992 in Egypt’s Sahara desert has quite the story. Scientists think that the Hypatia stone, named after an ancient astronomer from Alexandria, predates the formation of our solar system and may well be interstellar in nature.

Hypatia is, in fact, the first “comet nucleus” – the solid, central part of a comet, popularly termed a dirty snowball or an icy dirtball – found on Earth. Previously, tests run on Hypatia samples suggested it has a mineral composition like no other known meteorite.

Now, the same team of researchers at the University of Johannesburg that carried out the initial mineral analysis reports even wilder characteristics. Unlike chondritic meteorites, which formed in the cloud of dust and gas (a.k.a. the nebula) from which the rest of the solar system formed, Hypatia is very rich in carbon with trace amounts of silicon. Typically, the opposite is true for chondritic meteorites, which are rich is silicon and poor in carbon.

According to lead-author Prof. Jan Kramers, the Hypatia stone’s internal structure is somewhat like a fruitcake that has fallen off a shelf into some flour and cracked on impact.

“We can think of the badly mixed dough of a fruitcake representing the bulk of the Hypatia pebble, what we called two mixed ‘matrices’ in geology terms. The glace cherries and nuts in the cake represent the mineral grains found in Hypatia ‘inclusions’. And the flour dusting the cracks of the fallen cake represent the ‘secondary materials’ we found in the fractures in Hypatia, which are from Earth,” he said in a statement.

The carbon-silicon matrix of Hypatia is also comprised of polyaromatic hydrocarbons (PAH), commonly found in interstellar dust, “which existed even before our solar system was formed,” Kramers added. It’s these PAH molecules in Hypatia’s matrix that allowed the peculiar cosmic pebble to survive weathering over millions of years. Upon impact with Earth, the released energy was high enough to instantly convert the carbon-rich molecules into micro-diamonds, forming a crust that shielded Hypatia against the elements.

Hypatia is also dotted with inclusions — material trapped within the body of a crystal which is different from the primary elements, and which in our analogy represent the nuts and cherries of a fruitcake that comprised of surprising elements. For instance, aluminum was found in pure metallic form and not in a compound with other elements as one would expect.

“We also found silver iodine phosphide and moissanite (silicon carbide) grains, again in highly unexpected forms. The grains are the first documented to be found in situ (as is) without having to first dissolve the surrounding rock with acid,” adds co-author Georgy Belyanin. “There are also grains of a compound consisting of mainly nickel and phosphorus, with very little iron; a mineral composition never observed before on Earth or in meteorites,” he adds.

All of these characteristics suggest that Hypatia is an unchanged pre-solar system material. The inclusions themselves, however, likely formed in a post-solar system age, which makes this extraterrestrial puzzle even more complex. If Hypatia doesn’t predate the sun, then its features indicate that the solar nebula, from which all planets, moons, and the sun itself formed, was not homogenous, challenging the generally accepted idea of how the solar system was formed.

Kramers adds that the Hypatia pebble likely formed in a cold environment at extreme freezing temperatures — below that of liquid nitrogen on Earth (-196 Celsius). Most comets we’ve identified come from the Kuiper Belt, located well beyond Neptune’s orbit some 40 times farther from the Sun than Earth is. Other comets come from the Oort Cloud, which is even farther out. Hypatia might also come from the Oort Cloud, which contains objects whose mineral composition we know little about. Hypatia might one day help clear the fog around this nebulous region.

Scientific reference: Georgy A. Belyanin, Jan D. Kramers, Marco A.G. Andreoli, Francesco Greco, Arnold Gucsik, Tebogo V. Makhubela, Wojciech J. Przybylowicz, Michael Wiedenbeck. Petrography of the carbonaceous, diamond-bearing stone “Hypatia” from southwest Egypt: A contribution to the debate on its originGeochimica et Cosmochimica Acta, 2018; 223: 462 DOI: 10.1016/j.gca.2017.12.020

A bright green meteor lit up the US’ skies on Monday, and security cameras picked it up

At 1:31 AM on Monday morning, Wisconsin’s skies lit up green as a falling meteor burned up through the atmosphere.

Thankfully, a host of security and dashboard cams have witnessed the event. So here’s how a meteorite falls in that horrible image quality only security cams can boast:

The footage was recorded from the University of Wisconsin campus. It’s black and white so you can’t see much of what’s happening.

Here’s the meteorite from another angle — the dashboard of a police car in Glendale:

The flash was big enough to be seen all the way over in Chicago.

Later, the Milwaukee National Weather Service released some weather radar readings which they suspect captured the meteorite.

And finally, this video the American Meteor Society put together shows the meteorite’s estimated trajectory and visibility range. It also places the rock’s final resting place in the middle of lake Michigan.

If there’s any bit of the meteorite that didn’t burn, that’s most likely where it ended up. But considering it was probably really small to begin with (not much larger than a baseball or a football), there’s slim chances anything survived the burn and the crash.