Tag Archives: Asteroid Belt

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.

Astronomers scout metal-rich asteroid thought to be worth 10,000 quadrillion dollars

Most asteroids are made of plain rock or ice — but not ’16 Psyche’.

Representation of the Psyche asteroid. Image credits: Arizona State University.

According to recent observations perform using NASA’s Hubble Space Telescope, the chunky asteroid from the solar system’s main asteroid belt between Mars and Jupiter is mostly made of nickel and iron. This makes it an extremely atypical asteroid and a very valuable one — it’s worth as much as $10,000 quadrillion in raw resources by some estimates, or almost 70,000 times the value of the global economy in 2019.

Billionaires: ‘hold my beer’

Psyche spans 140 miles (225 km) in diameter, making it one of the largest objects in the main asteroid belt. In fact, Psyche is so large it was easily discovered using 19th-century technology in 1852.

The novelty is that now scientists have reported in The Planetary Science Journal the asteroid’s composition.

Scientists previously had some hints that Psyche is a dense, largely metallic object. This assumption has now been confirmed thanks to observations at two specific points in the asteroid’s rotation that offered a view of both sides of Psyche at ultraviolet wavelengths.

For the first time, astronomers have recorded iron oxide ultraviolet absorption bands in any asteroid. This is a clear indication that oxidation is occurring on the surface of the asteroid. Its high density suggests that the oxidated metals are nickel and iron. In fact, the entire asteroid might be the leftover core of a failed planet that never succeeded in forming into one.

“We’ve seen meteorites that are mostly metal, but Psyche could be unique in that it might be an asteroid that is totally made of iron and nickel,” Dr. Tracy Becker, Southwest Research Institute planetary scientist and co-author of the new study, said in a statement. “Earth has a metal core, a mantle and crust. It’s possible that as a Psyche protoplanet was forming, it was struck by another object in our solar system and lost its mantle and crust.”

The oxidation is believed to be caused by the solar wind. This flow of charged particles from the sun’s corona is responsible for the beautiful tails of comets, the formation of auroras in Earth’s atmosphere, and, in this case, the space weathering of Psyche.

Such metal asteroids are extremely rare, which is why Psyche was shortlisted in 2017 for a mission to study it closely using a spacecraft. The mission, which will be operated by NASA, is slated for a 2022 launch on a SpaceX Falcon Heavy rocket. The unmanned spacecraft would become the first to visit a body almost entirely made of metal, learning more about the asteroid as well as the solar system.

Since Psyche is believed to be as old as the solar system itself, findings from the mission could enrich our understanding of how planets form. Besides the scientific value of the mission, if you take into account the size of the asteroid and its metal composition, its total economic value could add up to $10,000 quadrillion, or $10 million trillion. That’s quite the incentive to visit the asteroid — provided, of course, we one day develop the technology to mine and retrieve metals from such asteroids.

“To understand what really makes up a planet and to potentially see the inside of a planet is fascinating,” Becker said.

“Once we get to Psyche, we’re really going to understand if that’s the case, even if it doesn’t turn out as we expect … any time there’s a surprise, it’s always exciting,” he added.

Arrokoth--or as it was previously known Ultima Thule--may reveal secrets about the formation of the solar system (NASA, JOHNS HOPKINS UNIVERSITY APPLIED PHYSICS LABORATORY, SOUTHWEST RESEARCH INSTITUTE, ROMAN TKACHENKO)

Arrokoth, the ‘Space Snowman’, sheds new light on how the solar system formed

Arrokoth--or as it was previously known Ultima Thule--may reveal secrets about the formation of the solar system (NASA, JOHNS HOPKINS UNIVERSITY APPLIED PHYSICS LABORATORY, SOUTHWEST RESEARCH INSTITUTE, ROMAN TKACHENKO)
Arrokoth–or as it was previously known Ultima Thule–may reveal secrets about the formation of the solar system (NASA, JOHNS HOPKINS UNIVERSITY APPLIED PHYSICS LABORATORY, SOUTHWEST RESEARCH INSTITUTE, ROMAN TKACHENKO)

Located beyond the orbit of Neptune and within the Kuiper Belt — a massive circumstellar disc of small remnants left over from the formation of the solar system — Arrokoth (previously known as ‘Ultima Thule’) represents the most distant and primitive object ever to visited by a man-made space probe. 

Revealed in a small amount of data collected during a January 2019 flyby conducted by the New Horizons probe, the double-lobed contact binary— or Kuiper Belt object 2014 MU69 to give it its formal name — is the subject of three new papers due to be published in the journal Science. The key findings of these studies were revealed at a press briefing held in Seattle, Washington, on 13th February 2020.

The research provides us with a stunningly detailed picture of the compact binary’s composition and origins and suggests a rethink of how planetary building blocks–planetesimals form.

“Data from Arrokoth has given us clues about the formation of planets and our cosmic origins,” says Marc Buie, of the Southwest Research Institute, who was part of the New Horizons team that first discovered the object. “We believe this ancient body, composed of two distinct lobes that merged into one entity, may harbour answers that contribute to our understanding of the origin of life on Earth.”

New Horizons Path of Exploration (NASA)

The authors believe that their results could help rule out a hierarchical formation model of planetesimal formation, in which objects from different areas of the nebula of gas and dust violently collide to create larger bodies.

The shape of Arrokoth, with its two distinctive lobes, seems to favour a much more delicate formation process, that of local cloud collapse. This would involve regions of the nebula collapsing with smaller particles gradually accumulating together.

If planetesimals form differently then previously modelled, the fact that they are the building blocks of the planets means that we may also have to revise our ideas of how the planets themselves form.

As the planetesimal is composed of pure and unchanged material, its detailed study could answer long-standing questions about the elements which were present during the solar system’s planet-formation phase.

“The mission of the New Horizon probe was to explore the solar system’s ‘third zone’,” Alan Stern, the principal investigator of the New Horizons mission says describing the Kuiper Belt where icy planetesimals and dwarf planets lurk. “It is the best-preserved region of the solar system, important for understanding its origins.”

Each of the three separate papers focuses on different aspects of Arrokoth’s formation and composition, offering new insights into planetesimals and the conditions and composition of the early solar system. 

Three papers, three lines of evidence pointing to a new paradigm of planetesimal formation

William McKinnon and his team investigated how Arrokoth got its unique binary shape discovering that its two ‘lobes’ were once separate independent bodies. 

McKinnon and his team believe that the two separate objects which comprise Arrokoth formed in the same vicinity joined together in a surprisingly gentle process. As hierarchical accretion, is anything but gentle McKinnon and his team think that Arrokoth formed as a result of a local collapse of the nebula. 

“They’re just touching, it’s almost as if they’re kissing,” McKinnon, Professor of Earth and Planetary Sciences at the California Institute of Technology about the two lobes of Arrokoth. “There’s no evidence that the merger of these two lobes was violent. There’s no sign of catastrophic disruption.

“The merger speed must have been very low.”

The two dominant methods of planetesimal formation. Observations of Arrokoth may have ruled out high-velocity model. (McKinnon)

Whilst McKinnon and his team focused on the formation of Arrokoth’s distinctive shape, researchers led by John Spencer were studying that shape in painstaking detail. 

Spencer and his colleagues reveal that Arrokoth’s binary lobes are flattened in shape with a greater volume than originally believed. They are also almost perfectly aligned. “This tells us these are not objects that just blundered together,” Spencer “They have orbited each other for a long time, gently drifting together.”

The team have also been able to ascertain details about the surface of the contact binary, describing in their paper a smooth face with only slight cratering. This means that Arrokoth stands out from previously visited bodies within the solar system, having been struck by very few other objects. The greater consequence is that Arrokoth’s composition is unpolluted and thus may represent our best chance of studying the building blocks of the solar system.

Other comets that form closer to the Sun evolve very quickly as a result of the intense environments they find themselves in. In comparison, planetesimals that form far away from the Sun remain relatively unchanged, in Arrokoth’s case, for 4 billion years.

Will Grundy and the research team he worked with were charged with investigating the composition, colour, and temperature of Arrokoth’s surface. They found that the planetesimal’s distinctive and uniform red hue is a result of the presence of unidentified complex organic molecules — molecules formed from carbon, nitrogen, oxygen amongst other elements–present with methanol ice.

Grundy’s paper puts forward several suggestions as to how this frozen methanol could have formed on the Kuiper Belt object, including formation by irradiation of mixed water and methane ice by cosmic rays. The team was unable to detect the presence of water on Arrokoth, but they believe it could yet be present, currently ‘masked’ or hidden from view. 

The uniformity of the compact binary’s surface colour and composition provide the third line of evidence in support of the theory that it formed as a result of local nebula collapse. 

Stern does not downplay the significance of this evidence supporting a new paradigm of planetesimal formation–local cloud collapse. Comparing it to the discovery of the Cosmic Background Radiation which finally settled competition between different models of the origin of the universe he says: “This is a wonderful scientific present. It is truly a watershed moment.”

Stern concludes that every one of the attributes of Arrokoth observed point towards the cloud collapse model. As for the future, he says that the New Horizons mission has inspired other researchers to revisit another occupant of the Kuiper Belt– the dwarf planet Pluto.

Stern also points out that even though the New Horizons probe has “plenty of gas left in the tank,” the ideal mission would study Pluto for a period of a few years before moving off and investigating other bodies in the Kuiper Belt.

“We’re pretty excited, but it’s going to take a lot of work.”

“Exiled” asteroid shouldn’t be where it is

In the dark, frozen wasteland that lies just beyond Neptune, few things really stand out — and now, astronomers have found one of them: a carbon-rich asteroid, the first asteroid of its kind to be discovered at the outskirts of our solar system.

Artistic depiction of the exiled asteroid 2004 EW95, the first carbon-rich asteroid confirmed to exist in the Kuiper Belt and a relic of the primordial solar system. Image credits: ESO/M. Kornmesser.

It really shouldn’t be there, and as it so often happens in such studies, researchers first thought it was a mistake. Astronomers would have expected this kind of space rock in the asteroid belt between Mars and Jupiter but instead, it was drifting along just beyond Neptune.

The asteroid, which was named 2004 EW95, might be the first of a new class of space objects lurking the frigid area we call the Kuiper belt — the circumstellar disc in the outer Solar System, extending outward from the orbit of Neptune.

So how did the asteroid, which likely originated in the inner parts of our solar system, migrate so much?

It probably has a lot to do with our solar systems’ gas giants, which, in their infancies, caused quite a ruckus in the solar systems. During their early days, the gas giants probably orbited much closer to the Sun than they do today. But they started their outwards migration not long after the solar system was formed, and as they did so, they created all sorts of chaos.

Among this chaos, chunks of ice and rock such as 2004 EW95 were hurled away, which explains how it could have gotten there — and it also supports previous theoretical models of early planetary evolution. But even more interestingly, this means that the asteroid (and others of its kind) could provide insight as to how the solar system looked in its earlier days.

A lone rock far away from home

It’s not the first time objects that originated in the inner solar system were found so far away, but none were confirmed to the level of quality of 2004 EW95. It all started when Tom Seccull, a doctoral student at Queen’s University Belfast in Northern Ireland, used the European Southern Observatory’s Very Large Telescope to look at the light signatures of icy objects in the Kuiper Belt. When they found a 90-mile-long object, located 2.5 billion miles from Earth, something just wasn’t right — the object wasn’t exhibiting the same properties as its neighbors. Further analysis revealed that the object did not share the same icy past as other rocks drifting nearby. Instead, it appeared to have formed in a hotter environment, closer to the Sun.

“When we first looked at this, we thought it was wrong,” said Mr. Seccull, the lead author of the paper published in The Astrophysical Journal Letters. “The rock had been altered by the presence of liquid water.”

The team also determined the asteroid’s chemistry, using a technique called spectrometry. Since Kuiper Belt Object 2004 EW95 has a strong spectrum, its light can be broken down into different wavelengths, enabling researchers to determine what the asteroid is made of. However, identifying the chemical composition of such a distant object is extremely difficult.

The dramatic distance and the asteroid’s relatively small size make it an extremely difficult target to track, and the fact that it features carbon molecules, which makes it appear darker in color, doesn’t make it any easier.

“It’s like observing a giant mountain of coal against the pitch-black canvas of the night sky,” said Thomas Puzia, an astronomer at the Pontificia Universidad Católica de Chile and co-author of the research paper.

Still, the team was able to overcome these difficulties, finding that the asteroid contains carbon, iron oxides, and phyllosilicates (sheet-like silicate minerals). This is the first object ever found in the Kuiper belt containing these elements, all of which indicate that the asteroid formed in the inner parts of the Solar System.

With all this information, the research team concluded that 2004 EW95 probably formed between Mars and Jupiter, and was dragged along as the gas giants moved to their current orbits, thus offering important information about the dynamics of the early solar system.

We should also probably be thankful for this migration of the gas giants. Astronomers have found strong evidence that in many cases, these planets don’t move outwards, and stay in very close orbit to the Sun, creating what is called Hot Jupiters. Hot Jupiters are believed to deter the formation of rocky planets such as the Earth.

Whatsmore, as they migrate, they can destroy everything in their path, including the proto-Earth. So we should be grateful that they moved in just the right way to allow our planet to be formed, and ultimately, enable a species of primates we call humans emerge and evolve on this blue dot we claim as home.

The study “2004 EW95: A Phyllosilicate-bearing Carbonaceous Asteroid in the Kuiper Belt” by T. Seccull et al., which appeared in The Astrophysical Journal Letters.

asteroid-belt

Main asteroid belt might be a dump for planetary leftovers, new theory proposes

A duo of French scientists at the Université de Bordeaux is proposing a radically different theory that explains the origin of the asteroid belt. According to their new model, the main asteroid belt that orbits between Mars and Jupiter could have formed from ejected material from various neighboring planets.

asteroid-belt

Credit: NASA.

The main asteroid belt is a circumstellar disc in the solar system that draws an imaginary frontier between the rocky and gas planets. It’s comprised of billions (perhaps trillions) of asteroids and minor planets which lie more than two-and-a-half times as far as Earth does from the Sun.

You’ll sometimes see Hollywood movies show a stressed commander trying to navigate his spaceship through dangerously close asteroids. Inside our solar system at least, that’s a non-issue, as the asteroids are spaced too far apart to warrant a close call. From Voyager to the more recent New Horizons mission to Pluto, none of our spacecraft had any issue crossing the asteroid belt. According to NASA, the total mass of the belt is less than the moon, far too small to weigh in as a planet.

A different take on the birth of the asteroid belt

The currently accepted theory that explains the belt’s formation suggests that early in solar system’s history, some five million years after the sun formed, Jupiter and Saturn moved inward toward the sun before changing direction and heading back to the outer solar system, scattering the asteroid belt in the process.

It’s thought that about 99 percent of the original asteroid belt is now gone, flung away by Jupiter’s massive gravitational pull. The gravitational effect is also thought to prevent the material from coalescing into a large planet.

Sean Raymond, the lead author of the study and an astronomer at the University of Bourdeaux, has a different take on the matter. He and colleague Andrei Izidoro propose a new, very different explanation for the asteroid belt’s formation. According to their calculations, it’s quite possible that the asteroid belt was initially almost empty, but was only later filled with S – and p-type asteroids, which form the inner and outer edges of the belt, respectively.

Asteroids closer to the rocky planets, the S-type, most frequently contain silicate, just like the inner planet. C-type asteroids tend to contain more carbon, similarly to the gas giants. This distribution suggests the material these asteroids are made of comes from early planets. Essentially, the asteroids could be excess material that was ejected into the asteroid belt where it remains to this day.

To test these assumptions, the researchers built a model of the early solar system where the space occupied by today’s asteroid belt is empty. Running the model forward revealed that it is indeed possible, though not necessarily likely, that material from the outer planets contributed the material required for the belt, the authors reported in Science Advances.

Raymond and colleagues are now seeing to improve their model on the lookout for more tangible evidence that supports their view.

Dawn spacecraft will soon figure out what Ceres actually is

NASA’s Dawn spacecraft has set sail to Ceres – one of the most intriguing objects in our solar system. Ceres is the largest object in the asteroid belt between Mars and Jupiter, containing a third of all the mass in the asteroid belt. The unmanned Dawn spacecraft is scheduled to arrive at Ceres in early 2015, and will hopefully shed provide new insights not only on Ceres itself, but also the asteroid belt and the solar system.

Ceres as seen by Hubble Space Telescope (ACS). The contrast has been enhanced to reveal surface details.

The asteroid belt is a very accurate name – it represents the place between  the orbits of the planets Mars and Jupiter, occupied by numerous irregular bodies, called asteroids. But among all these asteroids, Ceres alone is considered a dwarf planet – an object the size of a planet (a planetary-mass object) but that is neither a planet nor a moon or other natural satellite. Ceres has a diameter of about 950 km, and to put it bluntly… we don’t really know what it is.

Ceres is probably a surviving protoplanet (planetary embryo), which formed 4.57 billion years ago in the asteroid belt – this is the main theory. In 2014, Ceres was found to have an atmosphere with water vapor, confirmed by the Herschel space telescope, which adds even more mystery to Ceres. Vesta, the second largest object in the asteroid belt is also a point of interest.

“These two bodies are much more massive than any body yet visited in this region of space and are truly small planets,” the Dawn mission team, at NASA’s Jet Propulsion Laboratory (JPL), wrote in their mission statement.

Studying these objects could also tell us more about our solar system – no matter what’s there, it’s almost certainly unchanged since the early days of the planetary formation.

Ceres (bottom left), the Moon and the Earth, shown to scale. Image via Wiki Commons.

“When Dawn visits Ceres and Vesta, the spacecraft steps us back in solar system time,” the JPL team said.

In 2007, Dawn paid a short visit to Vesta, and found a dry and metallic wasteland. Astronauts are expecting quite a different story with Ceres – maybe even some water under the icy surface, though that’s highly debatable. Whatever it is, the good thing is that we’ll have a chance to study.

“Now, finally, we have a spacecraft on the verge of unveiling this mysterious, alien world,” Marc Rayman, chief engineer and mission director of the Dawn mission, said in a statement. “Soon it will reveal myriad secrets Ceres has held since the dawn of the solar system.”

Three possible scenarios for the evolution of asteroid belts. Top: A Jupiter-size planet migrates through the belt, scattering material and inhibiting the formation of life on planets. Middle: A Jupiter-size planet moves slightly inward but is just outside the belt (this is the model proposed for our solar system). Bottom: A large planet does not migrate at all, creating a massive asteroid belt. Material from the hefty asteroid belt would bombard planets, possibly preventing life from evolving.

Asteroid belts may be crucial to intelligent life formation – alien life could be rarer than thought

When you think of asteroid impacts, the last thing that might come to mind is life. Contrary to popular belief, a team of researchers have recently presented their theory that holds intelligent life on our planet spurred with the help of asteroid impacts. As cosmic cold rock hit Earth, the impacts allowed for a shift in environment that pressured life to adapt and make rapid changes. Also, during the planet’s early days, frozen water, which came along with asteroids, might have had a crucial role in birthing life.

Asteroids aren’t enough though. For intelligent life to foster on an exoplanet, these space rocks need to be in a certain position, according the hypothesis formulated by astronomers Rebecca Martin of the University of Colorado in Boulder and Mario Livio of the Space Telescope Institute in Baltimore. Out solar system’s asteroid belt – between Jupiter and Mars – is not an accident,  according to the researchers, and was indispensable for life formation.

Alien life needs just the right asteroid belt

The researchers claim that for a planet to harbor alien life, chances are that it needs an asteroid belt of its own, similar to that of our solar system, positioned in the so-called “snow line”. At this certain orbit, frozen materials like water ice will remain in this state; any closer to the sun will melt them, and any farther would lead to the asteroids being gobbled by the gravitational pull of some giant planet, like Jupiter in our case.

“To have such ideal conditions you need a giant planet like Jupiter that is just outside the asteroid belt [and] that migrated a little bit, but not through the belt” Space Telescope Science Institute astronomer Mario Livio said. ”If a large planet like Jupiter migrates through the belt, it would scatter the material. If, on the other hand, a large planet did not migrate at all, that, too, is not good because the asteroid belt would be too massive. There would be so much bombardment from asteroids that life may never evolve.”

Three possible scenarios for the evolution of asteroid belts. Top: A Jupiter-size planet migrates through the belt, scattering material and inhibiting the formation of life on planets. Middle: A Jupiter-size planet moves slightly inward but is just outside the belt (this is the model proposed for our solar system). Bottom: A large planet does not migrate at all, creating a massive asteroid belt. Material from the hefty asteroid belt would bombard planets, possibly preventing life from evolving.

Three possible scenarios for the evolution of asteroid belts. Top: A Jupiter-size planet migrates through the belt, scattering material and inhibiting the formation of life on planets. Middle: A Jupiter-size planet moves slightly inward but is just outside the belt (this is the model proposed for our solar system). Bottom: A large planet does not migrate at all, creating a massive asteroid belt. Material from the hefty asteroid belt would bombard planets, possibly preventing life from evolving. (C) NASA

The scientists analyzed data from NASA’s Spitzer telescope, which has so far found infrared signals around 90 different stars which can indicate the presence of an asteroid belt. Of the 520 gas giants found orbiting other stars, in only 19 cases were they outside of where that star’s snow line would be expected to be. This suggests that fewer than four percent of exoplanet systems will be equipped to support the evolution of advanced, intelligent life in accordance with the punctuated equilibrium theory.

Their research isn’t a bash at alien life research, but on the contrary. It suggests hints and gives a pertinent starting point for scientists to better channel their efforts, and have a better chance at getting results.

“Our study shows that only a tiny fraction of planetary systems observed to date seem to have giant planets in the right location to produce an asteroid belt of the appropriate size, offering the potential for life on a nearby rocky planet. Our study suggests that our Solar System may be rather special,” said Martin.

Findings were presented in the Monthly Notices of the Royal Astronomical Society. 

Rainbow-like map of meteor shows planet like features

This rainbow map of the Vesta asteroid was obtained using NASA’s Dawn spacecraft and it shows that it has much more planet-like features than its mates from the asteroid belt.

Vesta is a pretty special place, with lots of surprises; it has a weird history, a mountain 3 times bigger than the Everest, and now, as it turns out, an interesting mineralogy. The colors you see in this image are practically different types of rock; the image was taken with the probe’s framing camera, which was built by the Max Planck Institute for Solar System Research and the German Aerospace Center. It basically picks up different wavelengths emitted by different minerals.

The green colored areas for example suggest wavelengths of iron-rich pyroxen, a silicate found mostly in igneous rocks. This all goes to show Vesta is a diverse object, unlike most other asteroids, and it has well-separated layers – all of which point at it being a protoplanet, an embryonic world which might have become a regular planet, if it hadn’t had the misfortune of being trapped in the lethal asteroid belt.

“The distinct compositional variation and layering that we see at Vesta appear to derive from internal melting of the body shortly after formation, which separated Vesta into crust, mantle and core,” said Carol Raymond, Dawn’s deputy principal investigator at NASA’s Jet Propulsion Laboratory, in a press release. “Vesta’s iron core makes it special and more like terrestrial planets than a garden-variety asteroid.”

The $466-million Dawn spacecraft has been studying Vesta since July this year, and will continue to do so until the summer, when it will move on to Ceres – another protoplanet, and the largest body in the asteroid belt.

Via Wired

Hubble Space Telescope images of Vesta and Ceres show two of the most massive asteroids in the asteroid belt, a region between Mars and Jupiter. Credits for Vesta: NASA, ESA, and L. McFadden (University of Maryland) Credits for Ceres: NASA, ESA, and J. Parker (Southwest Research Institute)

NASA spacecraft set to visit giant asteroid this weekend

Hubble Space Telescope images of Vesta and Ceres show two of the most massive asteroids in the asteroid belt, a region between Mars and Jupiter. Credits for Vesta: NASA, ESA, and L. McFadden (University of Maryland) Credits for Ceres: NASA, ESA, and J. Parker (Southwest Research Institute)

Hubble Space Telescope images of Vesta and Ceres show two of the most massive asteroids in the asteroid belt, a region between Mars and Jupiter. Credits for Vesta: NASA, ESA, and L. McFadden (University of Maryland) Credits for Ceres: NASA, ESA, and J. Parker (Southwest Research Institute)

After a four year journey, NASA’s Dawn spacecraft will finally reach the orbit of Vesta, the second largest asteroid in our solar system.

The object, located 117 million miles from Earth and spanning across a circumference of 329 miles, will be visited in premiere by Dawn this weekend when the latter will hover over on July 16. For whoever’s interested, the exact time is 1:00 a.m. EDT.

“It has taken nearly four years to get to this point,” said Dawn project manager Robert Mase of NASA’s Jet Propulsion Laboratory in a press release. “Our latest tests and check-outs show that Dawn is right on target and performing normally.”

The target in question is located in an asteroid- rich filled zone, in between the  solar system’s inner and outer planets. Propulsion and navigation had been powered by Mars’ gravitational force and Dawn’s own ion-powered thrusters. Once the spaceship reaches Dawn, it’s scheduled to hover about 9,900 miles above the asteroid’s surface for a whole year and, in this time, use two different cameras, a gamma-ray detector and a neutron detector to study and map the object. After this part of the mission is over, next July, Down’s ion thrusters will catapult the spaceship out of orbit and towards the dwarf planet Ceres, the largest object in the Asteroid Belt.

Meanwhile, NASA has another asteroid mission running, spearhead by the Osiris-Rex spacecraft, which is supposed to land and collect samples from a near-Earth asteroid, before returning home to Houston by 2023.

Very little is know about both Vesta and Ceres, although a lot of theories are currently emitting suppositions. Vesta maybe once had a molten core before going cold after a few million years, while Ceres, some believe, may have an icy mantle and active mud volcanoes.

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