meteorite Archives

June 2, 2015April 8, 2018 by Nancy Atkinson

What Is The Difference Between Asteroids and Meteorites?

Various meteorites from 2008 TC3. Credit: P. Jenniskens, et. al. Click image for full description

Asteroids, meteors, and meteorites … It might be fair to say these rocks from space inspire both wonder and fear among us Earthlings. But knowing a bit more about each of them and how they differ may eliminate some potential misgivings. While all these rocks originate from space, they have different names depending their location — i.e. whether they are hurtling through space or hurtling through the atmosphere and impacting Earth’s surface.

In simplest terms here are the definitions:

Asteroid: a large rocky body in space, in orbit around the Sun.

Meteoroid: much smaller rocks or particles in orbit around the Sun.

Meteor: If a meteoroid enters the Earth’s atmosphere and vaporizes, it becomes a meteor, which is often called a shooting star.

Meteorite: If a small asteroid or large meteoroid survives its fiery passage through the Earth’s atmosphere and lands on Earth’s surface, it is then called a meteorite.

Another related term is bolide, which is a very bright meteor that often explodes in the atmosphere. This can also be called a fireball.

Let’s look at each in more detail:

Asteroids

*An artists impression of an asteroid belt. Credit: NASA*

Asteroids are found mainly in the asteroid belt, between Mars and Jupiter. Sometimes their orbits get perturbed or altered and some asteroids end up coming closer to the Sun, and therefore closer to Earth. In addition to the asteroid belt, however, there have been recent discussions among astronomers about the potential existence of large number asteroids in the Kuiper Belt and Oort Cloud. You can read a paper about this concept here, and a good article discussing the topic here.

The asteroid Vesta as seen by the Dawn spacecraft. Credit: NASA/JPL-Caltech/UCAL/MPS/DLR/IDA

Asteroids are sometimes referred to as minor planets or planetoids, but in general, they are rocky bodies that do not have an atmosphere. However, a few have their own moons. Our Solar System contains millions of asteroids, many of which are thought to be the shattered remnants of planetesimals – bodies within the young Sun’s solar nebula that never grew large enough to become planets.

The size of what classifies as an asteroid is not extremely well defined, as an asteroid can range from a few meters wide – like a boulder — to objects that are hundreds of kilometers in diameter. The largest asteroid is asteroid Ceres at about 952 km (592 miles) in diameter, and Ceres is so large that it is also categorized as a dwarf planet.

Most asteroids are made of rock, but as we explore and learn more about them we know that some are composed of metal, mostly nickel and iron. According to NASA, a small portion of the asteroid population may be burned-out comets whose ices have evaporated away and been blown off into space. Recently, astronomers have discovered some asteroids that mimic comets in that gas and dust are emanating from them, and as we mentioned earlier, there appears to be a large number of bodies with asteroid-like compositions but comet-like orbits.

How Often Do Asteroids Hit Earth?

Meteor Crater near Winslow, Arizona. Image credit: NASA.

While we know that some asteroids pass very close to Earth’s orbit around the Sun, we’ve been lucky in the history of humanity that we haven’t had a large asteroid hit Earth in the past several thousand years. It wasn’t until satellite imagery of Earth became widely available that scientists were able to see evidence of past asteroid impacts.

One of the more famous impact craters on Earth is Meteor Crater in Arizona in the US, which was made by an impact about 50,000 years ago. But there are about 175 known impact around the world – a few are quite large, like Vredefort Crater in South Africa which has an estimated radius of 190 kilometers (118 miles), making it the world’s largest known impact structure on Earth. Another notable impact site is off the coast of the Yucatan Peninsula in Mexico, and is believed to be a record of the event that led to the extinction of the dinosaurs 65 million years ago. You can see images of some of the most impressive Earth impact craters here.

These days, asteroid impacts are less of a threat. NASA estimates that about once a year an automobile-sized asteroid enters Earth’s atmosphere, creates an impressive fireball and disintegrates before ever reaching the surface. Studies of Earth’s history indicate that about once every 5,000 years or so on average an object the size of a football field hits Earth and causes significant damage. Once every few million years on average an object large enough to cause regional or global disaster impacts Earth. You can find more information about the frequency of impacts in this article from NASA.

Meteors, Meteoroids and Bolides

A bright meteor from September 21, 1994. Credit: John Chumack.

Space debris smaller than an asteroid are called meteoroids. A meteoroid is a piece of interplanetary matter that is smaller than an asteroid and frequently are only millimeters in size. Most meteoroids that enter the Earth’s atmosphere are so small that they vaporize completely and never reach the planet’s surface. When they burn up during their descent, they create a beautiful trail of light known as a meteor, sometimes called a shooting star.

Mostly these are harmless, but larger meteors that explode in the atmosphere – sometimes called bolides — can create shockwaves, which can cause problems. In February 2013 a meteor that exploded over Chelyabinsk, Russia shattered windows with its air blast. This meteoroid or bolide was estimated to be 18 meters (59 feet) in diameter. In 1908, a rocky meteoroid less than 100 meters in diameter is believed to have entered the atmosphere over the Tunguska region of Siberia in 1908 and the resulting shockwave knocked down trees for hundreds of square kilometers

How often is Earth hit by meteroids?

Chelyabinsk fireball recorded by a dashcam from Kamensk-Uralsky north of Chelyabinsk where it was still dawn.

Because of the Chelyabinsk meteor in 2013, astronomers have acquired more information about the frequency of larger meteors that hit Earth, and there is now a growing consensus that the Earth gets hit by bigger space rocks more often than we previously thought. You can read more about that concept here.

This video from the B612 Foundation shows a visualization of the location of 26 space rocks that hit Earth between 2000 and 2013, each releasing energy equivalent to some of our most powerful nuclear weapons. The B612 foundation says that a Hiroshima-scale asteroid explosion happens in our atmosphere on average once a year, but many are not detected because they explode high in the atmosphere, or because most of the Earth’s surface is water and even a large percentage of land is fairly uninhabited by humans.

Estimates vary of how much cosmic dust and meteors enter Earth’s atmosphere each day, but range anywhere from 5 to 300 metric tons. Satellite observations suggest that 100-300 metric tons of cosmic dust enter the atmosphere each day. This figure comes from the rate of accumulation in polar ice cores and deep-sea sediments of rare elements linked to cosmic dust, such as iridium and osmium.

But other measurements – which includes meteor radar observations, laser observations and measurements by high altitude aircraft — indicate that the input could be as low as 5 metric ton per day. Read more about this here.

For a documented list of bolide events, you can check out this page from JPL.

Meteorite

If any part of a meteoroid survives the fall through the atmosphere and lands on Earth, it is called a meteorite. Although the vast majority of meteorites are very small, their size can range from about a fraction of a gram (the size of a pebble) to 100 kilograms (220 lbs) or more (the size of a huge, life-destroying boulder). Meteorites smaller than 2mm are classified as micrometeorites.

Meteorites have traditionally been divided into three broad categories, depending on their structure, chemical and isotopic composition and mineralogy. Stony meteorites are rocks, mainly composed of silicate minerals; iron meteorites that are largely composed of metallic iron-nickel; and, stony-iron meteorites that contain large amounts of both metallic and rocky material.

Meteorites have also been found on the Moon and Mars and conversely, scientists have traced the origination of the meteorites found here on Earth to four other bodies: the Moon, Mars, the asteroid 4 Vesta, and the comet Wild 2. Meteorites are the source of a great deal of the knowledge that we have have about the composition of other celestial bodies.

How Often Do Meteorites Hit Earth?

On Feb. 28, 2009, Peter Jenniskens (SETI/NASA), finds his first 2008TC3 meteorite after an 18-mile long journey. "It was an incredible feeling," Jenniskens said. The African Nubian Desert meteorite of Oct 7, 2008 was the first asteroid whose impact with Earth was predicted while still in space approaching Earth. 2008TC3 and Chelyabinsk are part of the released data set. (Credit: NASA/SETI/P.Jenniskens) — On Feb. 28, 2009, Peter Jenniskens (SETI/NASA), finds his first 2008TC3 meteorite after an 18-mile long journey. “It was an incredible feeling,” Jenniskens said. The African Nubian Desert meteorite of Oct 7, 2008 was the first asteroid whose impact with Earth was predicted while still in space approaching Earth. 2008TC3 and Chelyabinsk are part of the released data set. (Credit: NASA/SETI/P.Jenniskens)

According to the Planetary Science Institute, it is estimated that probably 500 meteorites reach the surface of the Earth each year, but less than 10 are recovered. This is because most fall into water (oceans, seas or lakes) or land in remote areas of the Earth that are not accessible, or are just not seen to fall.

Summary

In short, the difference between asteroids and meteors all comes down to a question of location. Asteroids are always found in space. Once it enters an atmosphere, it becomes a meteor, and then a meteorite after it hits the ground. Each are made of the same basic materials – minerals and rock – and each originated in space. The main difference is where they are when they are being observed.

We have many great articles on the subject of asteroids and meteorites here at Universe Today, such as this general information article on asteroids, this article and infographic about the difference between comets, asteroids and meteors, and these articles that deal with Ceres and Vesta. And here are some recent articles about the Chelyabinsk meteor that landed in Russia, as well as a 2 billion-year old Martian meteorite that contains evidence of water on Mars.

There is some good information on a NASA page as well as some great information here on Universe Today and Astronomy Cast.

Sources:
JPL’s Near Earth Asteroid Office
Planetary Science Institute
NASA: Asteroids
NASA: Meteors

February 9, 2015December 23, 2015 by Matt Williams

What Could Explain the Mysterious Ring in Antarctica?

Aerial photo of the crater site, taken with the Polar 6 board camera, while the aircraft was flying 7000 feet above the ice shelf. Credit: Alfred-Wegener-Institut

Ever since its discovery was announced earlier this year, the 3 km-wide ring structure discovered on the of Antarctica has been a source of significant interest and speculation. Initially, the discovery was seen as little more than a happy accident that occurred during a survey of East Antarctica by a WEGAS (West-East Gondwana Amalgamation and its Separation) team from the Alfred Wegener Institute.

However, after the team was interviewed by the Brussels-based International Polar Foundation, news of the find and its possible implication spread like wildfire. Initial theories for the possible origin of the ring indicated that it could be the result of the impact of a large meteor. However, since the news broke, team leader Olaf Eisen has offered an alternative explanation: that the ring structure is in fact the result of other ice-shelf processes.

As Eisen indicated in a new entry on the AWI Ice Blog: “Doug MacAyeal, glaciologist from the University of Chicago, put forward the suggestion that the ring structure could be an ice doline.” Ice dolines are round sinkholes that are caused by a pool of melt water formed within the shelf ice. They are formed by the caving in of ice sheets or glaciers, much in the same way that sinkholes form over caves.

“If the melt water drains suddenly,” he wrote, “like it often does, the surface of the glacier is destabilised and does collapse, forming a round crater. Ice depressions like this have been observed in Greenland and on ice shelves of the Antarctic Peninsula since the 1930s.”

However, in glaciers, these cavities form much more rapidly, as the meltwater created by temperature variations causes englacial lakes or water pockets to from which then drains through the ice sheet. Such dolines have been observed for decades, particularly in Greenland and the Antarctic Peninsula where the ice melts during the summertime.

Initial analysis of satellite images appear to confirm this, as they indicate that the feature could have been present before the supposed impact took place around 25 years ago. In addition, relying on data from Google Maps and Google Earth, the WEGAS (West-East Gondwana Amalgamation and its Separation) team observed that the 3 km ring is accompanied by other, smaller rings.

Such formations are inconsistent with meteorite impacts, which generally leave a single crater with a raised center. And as a general rule, these craters also measure between ten to twenty times the size of the meteorite itself – in this case, that would mean a meteorite 200 meters in diameter. This would mean that, had the ring structure been caused by a meteorite, it would have been the largest Antarctic meteor impact on record.

It is therefore understandable why the announcement of this ring structure triggered such speculation and interest. Meteorite impacts, especially record-breaking ones are nothing if not a hot news item. Too bad this does not appear to be the case.

Location of the ring formation on the ice shelf off the Antarctic continent. The site is on the King Baudouin Ice Shelf. (Map Credits: Google Maps, NOAA) — *Location of the ring formation on the* *King Baudouin Ice Shelf* *off the Antarctic continent. Credit: Google Maps, NOAA*

However, the possibility that the ring structure is the result of an ice doline raises a new host of interesting questions. For one, it would indicate that dolines are much more common in East Antarctica than previously thought. Ice dolines were first noticed in the regions of West Antarctica and the Antarctic Peninsula, where rapid warming is known to take place.

East Antarctica, by contrast, has long been understood to be the coldest, windiest and driest landmass on the planet. Knowing that such a place could produce rapid warming that would lead to the creation of a significant englacial lake would certainly force scientists to rethink what they know about this continent.

“To form an ice doline this size, it would need a considerable reservoir of melt water,” Eisen said. “Therefore we would need to ask, where did all this melt water come from? Which melting processes have caused such an amount of water and how does the melting fit into the climate pattern of East Antarctica?”

In the coming months, Eisen and the AWI scientists plant to analyze the data from the Polar 6 (Eisen’s mission) measurements thoroughly, in the hopes of getting all the facts straight. Also, Jan Lenaerts – a Belgian glaciologist with AWI – is planning an land-based expedition to the site; which unfortunately due to the short Antarctic summer season and the preparation time needed won’t be taking place until the end of 2015.

AWI's Polar 6 aircraft takes off from the runway at the Princess Elisabeth Antarctica research station. © International Polar Foundation / Jos Van Hemelrijck — *AWI’s Polar 6 aircraft takes off from the runway at the Princess Elisabeth Antarctica research station.*
*Credit: International Polar Foundation / Jos Van Hemelrijck*

But what is especially interesting, according to Eisen, is the rapid pace at which the debate surrounding the ring structure occurred. Within days of their announcement, the WEGAS team was astounded by the nature of the debate taking place in the media and on the internet (particularly Facebook), bringing together glaciologists from all around the world.

As Eisen put it in his blog entry, “For the WEGAS team, however, our experience of the last few days has shown that modern scientific discussion is not confined to the ivory towers of learned meetings, technical papers, and lecture halls, but that the public and social media play a tremendous role. For us, cut off from the modern world amongst the eternal ice, this new science seems to have happened at an almost breathtaking pace.”

This activity brought the discussion about the nature of the ring structure forward by several weeks, he claims, focusing attention on the true causes of the surprise discovery itself and comparing and contrasting possible theories.

Further Reading: Helmholtz Gemeinschaft, AWI

January 31, 2015December 23, 2015 by Jason Major

Moroccan Meteorite May Be a 4.4-Billion-Year-Old Chunk of Dark Martian Crust

Mars! Martian meteorites make their way to Earth after being ejected from Mars by a meteor impact on the Red Planet. Image: NASA/National Space Science Data Center.

Mars is often referred to as the Red Planet. But its signature color is only skin-deep – or, I should say, dust-deep. Beneath its rusty regolith Mars has many other hues and shades as well, from pale greys like those found inside holes drilled by Curiosity to large dark regions that are the result of ancient lava flows. Now, researchers think we may have an actual piece of one of Mars’ dark plains here on Earth in the form of a meteorite that was found in the Moroccan desert in 2011.

Classified as NWA 7034 (for Northwest Africa) the meteorite is a 320-gram (11 oz.) piece of Martian basaltic breccia made up of small fragments cemented together in a dark matrix. Nicknamed “Black Beauty,” NWA 7034 is one of the oldest meteorites ever discovered and is like nothing else ever found on Earth.

According to a new study on a fragment of the meteorite by researchers from Brown University in Providence, Rhode Island and the University of New Mexico, Black Beauty is a 4.4-billion-year-old chunk of Mars’ dark crust – the only known piece of such to have landed on Earth.

While other meteorites originating from Mars have been identified, they are of entirely different types than Black Beauty.

The researchers used a hyperspectral imaging technique to obtain data from across the whole fragment. In doing this, the measurements matched what’s been detected from Mars orbit by NASA’s Mars Reconnaissance Orbiter.

“Other techniques give us measurements of a dime-sized spot,” said Kevin Cannon, a Brown University graduate student and lead author of a new paper published in the journal Icarus. “What we wanted to do was get an average for the entire sample. That overall measurement was what ended up matching the orbital data.”

In addition to indicating a truly ancient piece of another planet, these findings hint at what the surface of many parts of Mars might be like just below the rusty soil… a surface that’s been shattered and reassembled many times by meteorite impacts.

“This is showing that if you went to Mars and picked up a chunk of crust, you’d expect it to be heavily beat up, battered, broken apart and put back together,” Cannon said.

HiRISE image of dark terrain near Ganges Chasma (NASA/JPL/University of Arizona)

Source/read more at Brown University news.

January 14, 2015December 23, 2015 by Tim Reyes

Did a House-Sized Meteorite Create This Mysterious Circle in Antarctica?

Endless blinding white ice as far as the eye can see. This is the common scene from the window of planes delivering researchers to Antarctica. However, this is not always the case. While there are mountain ranges and valleys, for a recent research expedition, a large ringed structure came into view on the King Baudouin ice shelf as they were beginning aerial surveys.

Geophysicist Christian Mueller with the Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) in Germany, was looking out the window of an instrument laden plane when the previously unknown ringed formation, 2000 meters (1.24 miles) in diameter, came into view. Looking into research publications, he found evidence that this may be a meteorite impact event from 2004.

Research team members from Alfred Wegener Institute in Germany embark from a landing site at Princess Elisabeth, Antarctica. They discovered something totally unexpected - a large ringed formation on a nearby ice shelf. (Credit: AWI) — Research team members from Alfred Wegener Institute in Germany embark from a landing site at Princess Elisabeth, Antarctica. They discovered something totally unexpected – a large ringed formation on a nearby ice shelf. (Credit: AWI)

The discovery occurred on December 20th from the AWI Polar 6 aircraft as they were flying over the Princess Ragnhild Coast. The formation is located on the King Baudouin Ice Shelf not far from their landing site at Princess Elizabeth station.

Two studies were found in the literature by the researchers which pointed to a possible impact event over east Antarctica in 2004. Triangulation of infrasound monitoring data pointed to the area where the ringed formation is located. The infrasound monitoring sites are located worldwide and primarily used to detect nuclear testing events. On February 15, 2013, the same type of data was used to better understand the asteroid explosion over Chelyabinsk, Russia.

The second study involved local observations. A separate set of researchers, located at Davis Station, an Australian base off the coast of east Antarctica, reported seeing a dust trail in the upper atmosphere during the same time.

Researcher Mueller stated in the AWI provided video, “I looked out of the window, and I saw an unusual structure on the surface of the ice. There was some broken ice looking like icebergs, which is very unusual on a normally flat ice shelf, surrounded by a large, wing-shaped, circular structure.” Altogether, the AWI researchers said that they make the claim “without any confidence.” They intend to request funding to make followup studies to determine its origin.

Cheryl Santa Maria, of the Digital Reporter, also reported that there are survey images showing this structure that date back 25 years. Furthermore, a story by LiveScience quoted Dr. Peter Brown of Centre of Planetary Science and Exploration at the University of Western Ontario as stating that the size of a meteorite is roughly 5 to 10% of the impact crater’s diameter. This would indicate an impactor about 100 meters in size and much larger than the estimated size of the event as estimated by infrasound data from 2004.

The infrasound data estimated that the asteroid was probably the size of a house, about 10 meters (33 feet) across. In contrast, the asteroid that exploded over Chelyabinsk, Russia, had an estimated size of 20 meters. Dr. Brown was quoted as expressing doubt that the formation is an impact site. The effects of a 100 meter object would have been much more distinctive and likely more readily detected by researchers located in eastern Antarctica. Thus, reporting of the ring formation by the AWI researchers is bringing to light additional information and comments from experts that raises doubts. Follow up studies will be necessary to determine the true origins of the ringed structured.

December 3, 2014December 23, 2015 by Matt Williams

Meteorite May Contain Proof of Life on Mars, Researchers Say

The idea that Mars could have supported life at one time is the subject of ongoing debate. Image credit: NASA

Mars is currently home to a small army robotic rovers, satellites and orbiters, all of which are busy at work trying to unravel the deeper mysteries of Earth’s neighbor. These include whether or not the planet ever had liquid water on its surface, what the atmosphere once looked like, and – most importantly of all – if it ever supported life.

And while much has been learned about Martian water and its atmosphere, the all-important question of life remains unanswered. Until such time as organic molecules – considered to be the holy grail for missions like Curiosity – are found, scientists must look elsewhere to find evidence of Martian life.

According to a recent paper submitted by an international team of scientists, that evidence may have arrived on Earth three and a half years ago aboard a meteorite that fell in the Moroccan desert. Believed to have broken away from Mars 700,000 years ago, so-called Tissint meteorite has internal features that researchers say appear to be organic materials.

The paper appeared in the scientific journal Meteoritics and Planetary Sciences. In it, the research team – which includes scientists from the Swiss Federal Institute of Technology in Lausanne (EPFL) – indicate organic carbon is located inside fissures in the rock. All indications are the meteorite is Martian in origin.

“So far, there is no other theory that we find more compelling,” says Philippe Gillet, director of EPFL’s Earth and Planetary Sciences Laboratory. He and his colleagues from China, Japan and Germany performed a detailed analysis of organic carbon traces from a Martian meteorite, and have concluded that they have a very probable biological origin.

Artist's conception of an fragment as it blasts off from Mars. Boulder-sized planetary fragments could be a mechanism that carried life between Mars and Earth, UA planetary scientist Jay Melosh says. (Credit: The Planetary Society) — *Artist’s conception of an fragment as it blasts off from Mars as a result of a meteor impact. Credit: The Planetary Society*

The scientists argue that carbon could have been deposited into the fissures of the rock when it was still on Mars by the infiltration of fluid that was rich in organic matter.

If this sounds familiar, you may recall a previous Martian meteorite named ALH84001, found in the Allen Hills region in Antarctica. In 1996 NASA researchers announced they had found evidence within ALH84001 that strongly suggested primitive life may have existed on Mars more than 3.6 billion years ago. While subsequent studies of the now famous Allen Hills Meteorite shot down theories that the Mars rock held fossilized alien life, both sides continue to debate the issue.

This new research on the Tissint meteorite will likely be reviewed and rebutted, as well.

The researchers say the meteorite was likely ejected from Mars after an asteroid crashed on its surface, and fell to Earth on July 18, 2011, and fell in Morocco in view of several eyewitnesses.

Upon examination, the alien rock was found to have small fissures that were filled with carbon-containing matter. Several research teams have already shown that this component is organic in nature, but they are still debating where the carbon came from.

Chemical, microscopic and isotope analysis of the carbon material led the researchers to several possible explanations of its origin. They established characteristics that unequivocally excluded a terrestrial origin, and showed that the carbon content were deposited in the Tissint’s fissures before it left Mars.

This research challenges research proposed in 2012 that asserted that the carbon traces originated through the high-temperature crystallization of magma. According to the new study, a more likely explanation is that liquids containing organic compounds of biological origin infiltrated Tissint’s “mother” rock at low temperatures, near the Martian surface.

A piece of the Tissint meteorite that came to Earth via Mars. Credit: EPFL/Alain Herzog — *A piece of the Tissint meteorite that landed on Earth on July 18th, 2011. Credit: EPFL/Alain Herzog*

These conclusions are supported by several intrinsic properties of the meteorite’s carbon, e.g. its ratio of carbon-13 to carbon-12. This was found to be significantly lower than the ratio of carbon-13 in the CO2 of Mars’s atmosphere, previously measured by the Phoenix and Curiosity rovers.

Moreover, the difference between these ratios corresponds perfectly with what is observed on Earth between a piece of coal – which is biological in origin – and the carbon in the atmosphere.

The researchers note that this organic matter could also have been brought to Mars when very primitive meteorites – carbonated chondrites – fell on it. However, they consider this scenario unlikely because such meteorites contain very low concentrations of organic matter.

“Insisting on certainty is unwise, particularly on such a sensitive topic,” warns Gillet. “I’m completely open to the possibility that other studies might contradict our findings. However, our conclusions are such that they will rekindle the debate as to the possible existence of biological activity on Mars – at least in the past.”

Be sure to check out these videos from EPFL News, which include an interview with Philippe Gillet, EPFL and co-author of the study:

And this video explaining the history of the Tissint meteor:

Further Reading: EPFL

November 21, 2014February 9, 2021 by Fraser Cain

Weekly Space Hangout – Nov. 21, 2014: New Images of Europa

Host: Fraser Cain (@fcain)

Guests:
Morgan Rehnberg (cosmicchatter.org / @cosmic_chatter)
Brian Koberlein (@briankoberlein)
Ramin Skibba (@raminskibba)
Dave Dickinson (@astroguyz / www.astroguyz.com)

Continue reading “Weekly Space Hangout – Nov. 21, 2014: New Images of Europa”

August 22, 2014December 23, 2015 by Jason Major

Stolen Meteorite Found at a Tennis Court

The Meteorite of Serooskerken (Source: Sterrenwacht Sonnenborgh)

Here’s a bit of good news: the Serooskerken meteorite, which was stolen from the Sonnenborgh Museum and Observatory in Utrecht, Netherlands on Monday night, has been recovered. It was found in a bag left in some bushes alongside a tennis court and turned in to the police.

It’s not quite “game, set, match” though; unfortunately the meteorite was broken during the theft. (See a photo here via Twitter follower Marieke Baan.) Still, the Sonnenborgh Museum director is glad to have the pieces back, which he said will remain useful for research and can still be exhibited. (Source)

The Serooskerken meteorite was recovered from a fall in the Dutch province of Zeeland on August 28, 1925. Classified as a diogenite (HED) it is thought to have originated from the protoplanet Vesta, the second most massive object in the main asteroid belt between the orbits of Mars and Jupiter (and the previous target of NASA’s Dawn mission.) It is one of only five meteorite specimens ever recovered in the Netherlands.

The meteorite was one of several items reported stolen from the Sonnenborgh Museum on the night of August 18-19, 2014.

Find out more about the recovery (in Dutch) and see photos here.

HT to Google+ Space Community member Andre van der Hoeven for the update on this story.

August 20, 2014December 23, 2015 by Jason Major

A Piece of Vesta Has Been Stolen!

Calling all meteorite collectors and enthusiasts! There’s a hot space rock at large and, as Indiana Jones would say, it belongs in a museum. Perhaps you can help put it back in one.

Mosaic synthesizes some of the best views the spacecraft had of the giant asteroid Vesta. Dawn studied Vesta. The towering mountain at the south pole - more than twice the height of Mount Everest - is visible at the bottom of the image. The set of three craters known as the "snowman" can be seen at the top left. Credit: NASA/JPL-Caltech/UCAL/MPS/DLR/IDA — Mosaic of the asteroid Vesta made from images acquired by NASA’s Dawn spacecraft. Credit: NASA/JPL-Caltech/UCAL/MPS/DLR/IDA

On Aug. 19 a burglary was reported at the Sonnenborgh Museum and Observatory in Utrecht, Netherlands, and one of the items missing is a meteorite that is thought to have originated from the asteroid Vesta.

Seen above in a photo from the museum’s collection, the Meteorite of Serooskerken was recovered from a rare fall in 1925 in the province of Zeeland. Only five meteorites have ever been found in the Netherlands, making the Serooskerken specimen somewhat of a national treasure – not to mention a valuable piece of our Solar System’s history!

About 5–6% of all the meteorites found on Earth are thought to be from Vesta, the second-largest world in the main asteroid belt. (Source)

It doesn’t sound like the meteorite was the target of the burglary, but rather it just happened to be included with other things taken from the museum’s safe.

If you have any information on the burglary or see this meteorite offered up for sale anywhere, please report it to the Sonnenborgh Museum here.

If you are a Dutch-speaker, audio of the news can be found here. (Any translations would be welcome in the comments!)

HT to Google+ Space Community member Andre van der Hoeven.

August 18, 2014December 23, 2015 by Tim Reyes

One That Fell to Earth: Researchers Reveal 2012 Novato Meteorite Took a Beating

End of flight fragmentation of the Nov. 18, 2012, fireball over the San Francisco Bay Area (shown in a horizontally mirrored image to depict the time series from left to right). The photographs were taken from a distance of about 40 miles (65 km). Image Credit: Robert P. Moreno Jr., Jim Albers and Peter Jenniskens

What’s the chance of that thump you just heard in your house was a meteorite hitting your roof? That was the case for one family in Novato, California during a fireball event that took place in the north bay area near San Francisco on October 17, 2012.

Researchers have now released new results from analysis of the meteor that fell to Earth, revealing that the “Novato meteorite” was part of numerous collisions over a span of 4 billion years.

There is nothing ordinary about a meteorite whether it just spent 4.4 billion years all alone or spent such time in a game of cosmic pinball, interacting with other small or large bodies of our Solar System. On any given night one can watch at least a couple of meteors overhead burning up, lighting up the sky but never reaching the Earth below. However, in less than two years, Dr. Peter Jenniskens, SETI Institute’s renowned meteor expert was effectively host to two meteorites within a couple hours drive from his office in Mountain View, California.

The first was the Sutter Mill meteorite, a fantastic carbonaceous chondrite full of organic compounds. The second was the Novato meteorite, identified as a L6 chondrite fragmental breccia. which is the focus of new analysis, to be released in a paper in the August issue of Meteoritics and Planetary Science. Early on, it was clear that this meteorite had been a part of a larger asteroidal parent body that had undergone impact shocks.

Analysis of the meteorite was spearheaded by Jenniskens who initially determined the trajectory and orbit of the meteoroid from the Cameras for Allsky Meteor Surveillance (CAMS) which he helped establish in the greater San Francisco bay area. Jenniskens immediately released information about the fireball to local news agencies to ask for the public’s help with the hopes of finding pieces of the meteorite. One resident recalled hearing something hit her roof, and with the help of neighbors, they investigated and soon found the first fragment in their backyard.

Finding fragments was the first step, and over a two year period, the analysis of the Novato meteorite was spread across several laboratories around the world with specific specialties.

Novato N04, found by Bob Verish. The fourth of 6 fragments of the Novato fireball recovered. (Image Credit, B. Verish) — Novato N04, found by Bob Verish. The fourth of six fragments of the Novato fireball recovered. Fusion crust from entry into the Earth’s atmosphere is clearly evident. A 1 centimeter cube is shown for size comparison. (Image Credit, B. Verish, cams.seti.org)

Dr. Jenniskens, along with 50 co-authors, have concluded that the Novato meteorite had been involved in more impacts than previously thought. Dr. Qingzhu Yin, professor in the Department of Earth and Planetary Sciences at the University of California, Davis stated, “We determined that the meteorite likely got its black appearance from massive impact shocks causing a collisional resetting event 4.472 billion years ago, roughly 64-126 million years after the formation of the solar system.”

The predominant theory of the Moon’s formation involves an impact of the Earth by a Mars-sized body. The event resulted in the formation of the Moon but also the dispersal of many fragments throughout the inner Solar System. Dr. Qingzhu Yin continued, “We now suspect that the moon-forming impact may have scattered debris all over the inner solar system and hit the parent body of the Novato meteorite.”

Additionally, the researcher discovered that the parent body of the Novato meteorite experienced a massive impact event approximately 470 million years ago. This event dispersed many asteroidal fragments throughout the Asteroid Belt including a fragment from which resulted the Novato meteorite.

The Novato meteorite strewn field determined by Dr. Jenniskens team's analysis of CAMS allsky images. (Illustration Credit, P. Jenniskens, NASA/SETI) — The Novato meteorite strewn field determined by Dr. Jenniskens team’s analysis of CAMS allsky images. (Illustration Credit, P. Jenniskens, NASA, SETI – cams.seti.org)

The trajectory analysis completed earlier by Dr. Jenniskens pointed the Novato meteorite back to the Gefion asteroid family. Dr. Kees Welten, cosmochemist at UC Berkeley, was able to further pinpoint the time, drawing the conclusion, “Novato broke from one of the Gefion family asteroids nine million years ago.” His colleague at Berkeley, cosmochemist Dr. Kunihiko Nishiizumialso added, “but may have been buried in a larger object until about one million years ago.”

There was more that could be revealed about history of the Novato meteorite. Dr. Derek Sears a meteoriticist working for the Bay Area Environmental Research Institute in Sonoma, California and stationed at NASA Ames Reserach Center applied his expertise in thermoluminescence. Dr. Sears was involved in the analysis of Lunar regolith returned by the Apollo astronauts using this analysis method.

“We can tell the rock was heated, but the cause of the heating is unclear,” said Dr. Sears, “It seems that Novato was hit again.” As stated in the NASA press release, “Scientists at Ames measured the meteorites’ thermoluminescence – the light re-emitted when heating of the material and releasing the stored energy of past electromagnetic and ionizing radiation exposure – to determine that Novato may have had another collision less than 100,000 years ago.”

From this apparent final collision one hundred thousand years ago, the Novato meteoroid completed over 10,000 orbits of the Sun and with its final Solar orbit, intercepted the Earth, entering our atmosphere and mostly burning up over California. The meteoroid is estimated to have measured 14 inches across (35 cm) and have weighed 176 pounds (80 kg). What reached the ground likely amounted to less than 5 lbs. (~ 2 kg). Only six fragments were recovered and many more remain buried or hidden in Sonoma and Napa counties.

Besides the analysis that revealed the series of likely impact events in the meteoroids history, a team led by Dr. Dan Glavin from NASA Goddard Space Flight Center undertook analysis in search of amino acids, the building blocks of life. They detected non-protein amino acids in the meteorite that are very rare on Earth. Dr. Jenniskens emphasized that the quick recovery of the fragments by scores of individuals that searched provided pristine samples for analysis.

The impact dent on the rooftop of the Webber home in Novato. Luis Rivera points to the dent. (Image Credit, P.Jenniskens, L.Rivera, cams.seti.org)

Robert P. Moreno, Jr. in Santa Rosa, CA photographed the fireball in greatest detail with a high resolution camera. Several other photos were brought forward from other vantage points. Dr. Jenniskens stated, “These photographs show that this meteorite – now one of the best studied meteorites of its kind – broke in spurts, each time creating a flash of light as it entered Earth’s atmosphere.”

An animated gif of the series of photographs taken by Robert Moreno Jr. (Credit, R. Moreno Jr., NASA, SETI) — An animated gif of the series of photographs taken by Robert Moreno Jr. Click on the image to animate in full resolution. (Credit, R. Moreno Jr., NASA, SETI)

Numerous individuals and groups undertook the search for the Novato meteorite. Dr. Jenniskens trajectory analysis included a likely impact zone or strewn field. People from all walks of life roamed the streets, open fields and hillsides of the north bay in search of fragments. Despite organized searches by Dr. Jenniskens, it was the footwork from other individuals that led to finding six fragments and was the first step which led to these studies that add to the understanding of the early Solar System’s development.

For Dr. Jenniskens, Novato was part of a trifecta – the April 22, 2012, Sutter Mill meteorite in the nearby foothills of the Sierras, the Novato meteorite and the massive Chelyabinsk airburst event in Russia on February 15, 2013. Throughout this period, Dr. Jenniskens all-sky camera network continued to expand and record “falling stars” – meteors. The number of meteors recorded with calculated trajectories is now over 175,000. The SETI Institute researcher has been supported by NASA and personnel at the institute and ordinary citizens including amateur astronomers that have refined the methods for meteor orbital determination and estimating their size and mass. Several websites have compiled images and results for the Novato meteorite with Dr. Jenniskens’ – CAMS.SETI.ORG being most prominent.

July 16, 2014December 23, 2015 by Jason Major

What Created This Huge Crater In Siberia?

An 80-meter-wide crater recently discovered in northern Siberia (Video screenshot)

What is it with Russia and explosive events of cosmic origins? The 1908 Tunguska Explosion, the Chelyabinsk bolide of February 2013, and now this: an enormous ~~80-meter~~ 60-meter wide crater discovered in the Yamal peninsula in northern Siberia!

To be fair, this crater is not currently thought to be from a meteorite impact but rather an eruption from below, possibly the result of a rapid release of gas trapped in what was once frozen permafrost. The Yamal region is rich in oil and natural gas, and the crater is located 30 km away from its largest gas field. Still, a team of researchers are en route to investigate the mysterious hole further.

Watch a video captured by engineer Konstantin Nikolaev during a helicopter flyover below:

In the video the Yamal crater/hole has what appear to be streams of dry material falling into it. Its depth has not yet been determined. (Update: latest measurements estimate the depth of the hole to be 50-70 meters. Source.)

Bill Chappell writes on NPR’s “The Two-Way”:

“The list of possible natural explanations for the giant hole includes a meteorite strike and a gas explosion, or possibly an eruption of underground ice.”

Dark material around the inner edge of the hole seems to suggest high temperatures during its formation. But rather than the remains of a violent impact by a space rock — or the crash-landing of a UFO, as some have already speculated — this crater may be a particularly explosive result of global warming.

According to The Siberian Times:

“Anna Kurchatova from Sub-Arctic Scientific Research Centre thinks the crater was formed by a water, salt and gas mixture igniting an underground explosion, the result of global warming. She postulates that gas accumulated in ice mixed with sand beneath the surface, and that this was mixed with salt – some 10,000 years ago this area was a sea.”

The crater is thought to have formed sometime in 2012.

Read more at The Siberian Times and NPR.

UPDATE July 17: A new video (in Russian) of the hole from the research team has come out, and apparently it’s been made clear that it’s not the result of a meteorite. Exactly what process did produce it is still unknown, but rising temperatures are still thought to be a factor. Watch below (via Sploid).

(If any Russian-speaking UT readers would like to translate what’s being said, feel free to share in the comments below.)

Also check out the latest photos from the research expedition at The Siberian Times here.

UPDATE Nov. 13: Once the water in these holes froze solid scientists were able to enter and explore the bottoms. According to an article published on The Guardian, “eighty percent of the crater appears to be made up of ice and there are no traces of a meteorite strike.”

Researchers descend into an ice-covered Yamal Crater in Siberia. Credit: Vladimir Pushkarev/Russian Centre of Arctic Exploration (via Siberian Times)

“As of now we don’t see anything dangerous in the sudden appearance of such holes, but we’ve got to study them properly to make absolutely sure we understand the nature of their appearance and don’t need to be afraid about them.”

– Vladimir Pushkarev, Director, Russian Center of Arctic Exploration

See more photos from inside the crater from the Russian Center of Arctic Exploration on The Siberian Times here.