Posted on by Ian O'Neill

Bad Idea: Blowing Up Asteroids with Nuclear Missiles

On 4 July 2005, NASA collided a projectile with comet Tempel 1. Should a nuclear warhead be used in the future to deflect asteroids? (NASA)

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The first thing that comes to mind when someone asks: “How do we deflect a near Earth asteroid?” is “Fire some nuclear missiles at it.” However, this might not be the best course of action. Akin to opening a walnut with a sledgehammer, there might be a better, less messy option. This is what Apollo astronaut Rusty Schweickart thinks at least. Last year, NASA issued a report suggesting they were seriously considering a nuclear option should an asteroid threaten Earth. However, the ex-lunar module pilot believes this decision was manipulated by political pressure, possibly indicating the asteroid threat was being used to speed up nuclear proliferation in space…

When ex-Apollo astronauts express an opinion, people tend to sit up and listen. After all, the astronauts throughout the space race years in the latter half of the 20th Century (from the USA and Russia) were the ultimate explorers, going above and beyond the call of duty, putting their lives on the line for their countries. Several of the retired Apollo astronauts have come forward over the years with their opinions on modern NASA, concerns for the future of the US position in space exploration and their belief in extraterrestrial cover-ups (!). And last Wednesday, during a public lecture in San Francisco, legendary astronaut Rusty Schweickart voiced his opinion about NASA’s decision to use nuclear technology when faced with an asteroid threat.

Schweickart has expressed concern with the possibility of using nuclear weapons to destroy, or deflect Earth-bound asteroids, pointing out there are many other less harmful ways of dealing with the asteroid threat. At the moment he points out that we are completely unprepared to deal with asteroids, but by 2015, we should have developed a gentler means of deflection. Simply blowing asteroids up have many knock-on implications. First and foremost, Schweickart believes that NASA may be open to manipulation to put forward the proliferation of space-based nuclear weapons under the guise of international “safety.” Another problem I can see is blowing up a large piece of rock only to create many smaller (but just as deadly) pieces of rock, doesn’t really extinguish the destructive power of an asteroid on collision course, in fact, it might increase it.

Schweickart’s organization, the B612 Foundation examines other, more subtle ways of deflecting dangerous asteroids are examined (nuclear warheads not included). Decisions such as when to take action, how to better track asteroids and how to deflect them should be an international effort and not one nation’s decision to detonate a nuclear bomb in space.

Source: Wired

Posted on by Nancy Atkinson

Where Do Meteorites Come From?

If you’ve ever held a real meteorite in your hand, you probably wanted to know, “Where has this rock been in space and where did it come from?” Until now, no one has been able to definitively establish where the majority of meteorites found on Earth came from because of the changes that occur in meteorites after they are ejected from the asteroids they were originally part of. The most common type of meteorite found on Earth, about 75% of those identified, are chondrites, stony bits of space rocks that didn’t undergo any melting while out in space. Two astronomers say have determined that most of these meteorites come from the asteroid belt between Mars and Jupiter. Using the GEMINI telescope, they found that asteroids in that region are similar to chondrites found on Earth.

This discovery is the first observational match between the most common meteorites and asteroids in the main belt. It also confirms the role of space weathering in altering asteroid surfaces.

To find the parent asteroid of a meteorite, the astronomers compared the spectra of a meteorite specimen to those of asteroids. This is a difficult task because meteorites and their parent asteroids underwent different processes after the meteorite was ejected. In particular, surfaces of asteroids are known to be altered by a process called “space weathering”, which is probably caused by micrometeorite and solar wind action that changes the surface and spectra of asteroid surfaces.

Meteoroids are created, usually when there is a collision between asteroids. When an impact of a large asteroid occurs, the fragments broken off can follow the same orbit as the primary asteroid. These groups of fragments are called “asteroid families.” Until recently, most of the known asteroid families have been very old (they were formed 100 million to billions of years ago), and younger families are more difficult to detect because asteroid fragments are closer to each other.

In 2006, four new, extremely young asteroid families were identified, with an age ranging from 50,000 to 600,000 years. The astronomers, Thais Mothé-Diniz from Brazil and David Nesvorný from the US observed these asteroids, obtaining visible spectra. They compared the asteroids spectra to the spectra of an ordinary chondrite (the Fayetteville meteorite, shown in the top photo) and found they matched.

Identifying the parent asteroid of a meteorite is a unique tool when studying the history of our solar system because one can infer both the time of geological events (from the meteorite that can be analyzed through dating techniques) and their location in the solar system (from the location of the parent asteroid).

Meteorites are also a major tool for knowing the history of the solar system because their composition is a record of past geologic processes that occurred while they were still incorporated in the parent asteroid.

Original News Source: Astronomy and Astrophysics

Posted on by Ian O'Neill

Binary Asteroid Glides Past Earth

Asteroid 2008 BT18 (Aricebo)

A rare event has given astronomers a great view of a binary asteroid system. Tonight, asteroid 2008 BT18 passed 1.4 million miles from Earth, shining like a 13th magnitude star. Before July 7th, astronomers believed 2008 BT18 was “just another” near-Earth asteroid, but then the Arecibo radio telescope obtained a “delay-Doppler” image of the asteroid and found it in fact had a binary partner. Although binaries are fairly common in the Solar System, this was a rare opportunity for a ground-based telescope to capture such a clear view…

Only last week, Nancy wrote about binary asteroids and double craters found on Earth may be evidence that our planet has been hit by binaries in the past. As the article was being written, the Arecibo radio telescope in Puerto Rico was taking a detailed look at a binary asteroid approaching Earth. Although asteroid 2008 BT18 posed no threat to Earth, astronomers are very keen to learn more about binary asteroids to understand how they form and how they may be deflected from a collision course with Earth should a binary get too close.

About 16% of asteroids in the Solar System are thought to be binaries, so this event was a great opportunity for Arecibo to image 2008 BT18 and it could be seen by amateur astronomers as a 13th magnitude star. The Arecibo observatory has discovered 53% of all near-Earth binaries, so this seasoned radio telescope is an important component in the observation of these objects.

The orbit of 2008 BT18 (JPL)

The asteroid binary was fairly sizeable but passed about six times the Earth-Moon distance from us. “The sizes of the two components are 600m for the primary and >200m for the secondary,” said Lance Benner, a scientist from NASA’s Jet Propulsion Laboratory (JPL). “The primary looks spheroidal, but we don’t yet know about the shape of the secondary.”

Other telescopes are analyzing the binary orbit, asteroid masses and density of the two objects, such as NASA’s Goldstone radar in the Mojave Desert, California. Although Goldstone is smaller than Arecibo, there is a strong echo for scientists to analyze the data collected from the passage of the asteroid pair. According to spaceweather.com, observers in the Southern Hemisphere had the opportunity to see 2008 BT18 pass through the constellation of Canis Major, heading south.

Source: Spaceweather.com

Posted on by Nancy Atkinson

The Sunny Side of Asteroids

Asteroids with moons, called binary asteroids, are fairly common in the solar system. But scientists haven’t been able to figure out the dynamics of these asteroids, especially how the moons form. But a group of astronomers studying binary asteroids say the surprising answer is sunlight, which can increase or decrease the spin rate of an asteroid. The researchers also say that since there are a number of “double craters” on Earth – side-by side craters that appear to have formed at about the same time — these binary asteroids may have hit our planet in the past. The image above is of twin circular lakes in Quebec, Canada, formed by the impact of an asteroidal pair which slammed into the planet approximately 290 million years ago. Similar double craters also can be found on other planets, as well.

Derek Richardson, of the University of Maryland, and Kevin Walsh and Patrick Michel at the Cote d’Azur Observatory, France outline a model showing that when solar energy “spins up” a “rubble pile” asteroid to a sufficiently fast rate, material is slung off from around the asteroid’s equator. This process also exposes fresh material at the poles of the asteroid.

If the spun off bits of asteroid rubble shed sufficient excess motion through collisions with each other, then the material coalesces into a satellite that continues to orbit its parent.

Link to an animated model of the spin-up and binary formation from two views, on the left is an overhead view. The right pane of the movie looks at the equator of the primary body, which is also the plane in which the asteroid’s satellite is formed (courtesy of the authors of the study).

Because the team’s model closely matches observations from binary asteroids, it neatly fills in missing pieces to a solar system puzzle. And, it could have much more down-to-earth implications as well. The model gives information on the shapes and structure of near-Earth binary asteroids that could be vital should such a pair need to be deflected away from a collision course with Earth.
The authors say that their current findings also suggest that a space mission to a binary asteroid could bring back material that might shed new light on the solar system’s early history. The oldest material in an asteroid should lie underneath its surface, explained Richardson, and the process of spinning off this surface material from the primary asteroid body to form its moon, or secondary body, should uncover the deeper older material.

“Thus a mission to collect and return a sample from the primary body of such a binary asteroid could give us information about the older, more pristine material inside an asteroid,” Richardson said.

Original News Source: PhysOrg

Posted on by Nancy Atkinson

Exploding Asteroid Theory Gains Evidence

About 13,000 years ago, woolly mammoths roamed the North American continent and the first known human society in that region, known as the Clovis civilization, lived there as well. But geologic and archeological evidence shows they both suddenly disappeared, and scientists have long debated the mystery of the mass extinction of both animals and humans about 12,900 years ago. At that time, climatic history suggests the Ice Age should have been drawing to a close, but instead rapid climate change initiated an additional 1,300 years of glacial conditions. But scientists couldn’t agree on the cause of the sudden change in climate. However, about two years ago geophysicist Allen West proposed that an asteroid or comet exploded just above the earth’s surface at that time over modern-day Canada, sparking a massive shock wave and heat-generating event that set large parts of the northern hemisphere ablaze, setting the stage for the extinctions. Another scientist set out to prove West wrong, but ended up finding evidence to support the exploding asteroid/comet theory.

Ken Tankersley, Anthropology professor at the University of Cincinnati studied sites in Ohio and Indiana that offers the strongest support yet for the exploding comet/asteroid theory. Samples of diamonds, gold and silver found in the region have been conclusively sourced through X-ray diffractometry to have come from the diamond fields region of Canada.

Tankersley and West both believe the best scenario to explain the presence of these materials this far south is the kind of cataclysmic explosive event described by West’s theory. “We believe this is the strongest evidence yet indicating a comet impact in that time period,” says Tankersley.

Previously, geologists believed the deposits of the gems and precious metals were brought south from the Great Lakes region by glaciers. But they are found at a soil depth consistent with the time frame of the comet/asteroid event.

“My smoking gun to disprove (West) was going to be the gold, silver and diamonds,” Tankersley says. “But what I didn’t know at that point was a conclusion he had reached that he had not yet made public – that the likely point of impact for the comet wasn’t just anywhere over Canada, but located over Canada’s diamond-bearing fields. Instead of becoming the basis for rejecting his hypothesis, these items became the very best evidence to support it.”

Additional work is being done at the sites looking for iridium, micro-meteorites and nano-diamonds that bear the markers of the diamond-field region, which also should have been blasted by the impact into this region.

As Tankersley, West and additional scientists compile more data, they’ll be looking for more clues to help explain the history of our planet and its climate.

“The kind of evidence we are finding does suggest that climate change at the end of the last Ice Age was the result of a catastrophic event,” Tankersley says. “The ultimate importance of this kind of work is showing that we can’t control everything,” he says. “Our planet has been hit by asteroids many times throughout its history, and when that happens, it does produce climate change.”

Original Source: Science Daily

Posted on by Nicholos Wethington

Canada to build World’s First Asteroid-hunting Satellite

Just yesterday (June 30th) was the 100-year anniversary of the Tunguska event, when a small piece of ice or rock exploded in the air near the Podkammenaya Tungus river in Siberia, flattening trees and scaring the heck out of people in the surrounding area. Thankfully, the blast didn’t happen in a populated area and nobody was killed, but there are many more pieces of debris floating around out there in space. If we want to do something about an asteroid headed our way, or keep astronauts safe from space debris, knowing is half the battle. Thanks to a new microsatellite being built by the Canadian Space Agency, we will soon have a better map of the objects surrounding the Earth’s orbit.

The Near Earth Object Surveillance Satellite (NEOSSat) is a small satellite, about the size of a suitcase and weighing 143 pounds (65 kilograms). This puts it in a class of satellites known as “microsatellites”. Canada has already launched a successful microsatellite mission – Microvariability and Oscillation of STars (MOST) – that measured the light oscillation of stars to determine their age.

NEOSSat will monitor asteroids, comets and space junk in near-Earth orbit – within 100 – 1240 miles (160 – 2000 km) – to create a detailed survey of objects close to the Earth. It will also track other satellites, such as geosynchronous satellites, which orbit further out at 22,400 miles (~36,000 km).

NEOSSat wont’ orbit the way many satellites do – around the equator of the Earth – but will rather follow a polar orbit, circling from pole to pole every 50 minutes. This allows it to observe near the Sun where asteroids that orbit uniquely inside the Earth’s orbit are to be found. It will use a sunshade to observe with 45 degrees of the Sun. The polar orbit also gives the spacecraft the ability to use parallax to determine the distance to asteroids, comets and debris

Because of its location outside the Earth’s atmosphere, NEOSSat can also be small – it will use only a 15cm (6 inch) telescope. The small size will make the satellite easy to pack in with another, larger satellite for launch, thus reducing the cost of the mission.

Satellites are much better at making observations because they don’t have to look through the Earth’s thick atmosphere. NEOSSat will provide a huge advantage in surveying the hundreds of thousands of objects surrounding the Earth.

Dr. Alan Hildebrand the Canada Research Chair in Planetary Science in the University of Calgary’s Department of Geoscience said,”NEOSSat being on-orbit will give us terrific skies for observing 24-hours a day, guaranteed. Keeping up with the amount of data streaming back to us will be a challenge, but it will provide us with an unprecedented view of space encompassing Earth’s orbit.”

The mission is funded by as a joint project between the Canadian Space Agency and Defense Research Development Canada.

Source: EurekAlert, NEOSSat

Posted on by Ian O'Neill

Rare Asteroid Studied by Hawaiian Scientists

A huge impact with the asteroid Vista created a lot of debris. Credit :Don Davis)

Asteroid 10537 (1991 RY16) is a rarity. It is composed of basaltic rock (i.e. rock that cooled quickly after formation from a molten state) and appears to have evolved independently from the large asteroid Vesta. Vesta suffered a huge impact billions of years ago, and the debris from this collision litters the inner asteroid belt. These “Vestoids” make up the majority of the basaltic asteroids apart from three known isolated bodies including asteroid 1991 RY16. Scientists are therefore very interested to understand the evolution of 1991 RY16, possibly helping us understand the formation of the Solar System and why there aren’t more basaltic asteroids out there…

The asteroid belt occupies the volume of space roughly between the orbits of Mars and Jupiter. There are thousands of known rocky bodies in the belt, but half of the mass can be found in four major asteroids; Ceres, 4 Vesta, 2 Pallas, and 10 Hygiea. Ceres is actually classified as a minor (or dwarf-) planet as it is over 900km (560 miles) in diameter and is roughly spherical, unlike other asteroids that are irregular in shape. Large asteroid Vesta suffered a huge impact during the formation of the Solar System some 3.5 billion years ago and the debris (about 1% of its total mass) from this collision can be found scattered around the orbit of Vesta (~2.4 AU). These Vestoids usually explain many of the basaltic asteroids in this region of the asteroid belt.

So where does 1991 RY16 come in? Researchers at the Institute for Astronomy (IfA), University of Hawaii, carried out an analysis of the object after a previous study that utilized the Sloan Digital Sky Survey Moving Object Catalog. The IfA astronomers then used optical and near-infrared observations to derive spectroscopic data for 1991 RY16 to see whether it can be related to any of the asteroid groups in the asteroid belt. It turns out that its basaltic surface composition doesn’t appear to match up with any of the large groups of asteroids, and if its orbital radius is worked into the equation, it is highly unlikely that it could have travelled from any of the groups. 1991 RY16 appears to be an asteroid loner… or does it?

Asteroid semi-major axis plotted against inclination - orbital resonances are obvious (Moskovitz et al. 2008)

Firstly, the 5-15 km wide asteroid had to be ruled out from being a more common Vestoid. For a start 1991 RY16 isn’t even a remotely close spectroscopic match to any of the known Vestoids. Its orbit beyond the 3:1 Jupiter orbital resonance (at a distance of 2.5 AU) suggests that it could not have travelled from 2.4 AU, through the resonance and to its present orbit of 2.85 AU. The orbital resonances of the larger planets cause separation in the asteroid belt populations, confining them to their orbits. So, 1991 RY16 doesn’t originate from the Vesta impact event 3.5 billion years ago. Looking at the positions of the known asteroids (chart pictured), the IfA group ruled out the association of 1991 RY16 with any of the neighbouring asteroid groups (such as Gefion and Eos) as there is little spectroscopic evidence and it isn’t possible that the asteroid simply drifted (even after considering the strange Yarkovsky effect that predicts small rocky bodies experience a small deflection in trajectory due to anisotropic emission of thermal photons).

The possible remaining explanation could lie with a large asteroid near the orbital vicinity of 1991 RY16. The spectroscopic analysis of 1991 RY16 reveals that it could be a large chunk from another, differentiated asteroid. Although more analysis is required, 349 Dembowska (of ~140km in diameter) could be the parent asteroid 1991 RY16 was chipped from during an impact in the young Solar System. The IfA researchers are keen to point out that more observations are required to see if there is any other debris from this possible collision matching the surface composition of 1991 RY16.

For more detail into this very interesting research, check out the paper below.

Source: “A Spectroscopically Unique Main Belt Asteroid: 10537 (1991 RY16)” (arXiv pdf)

Posted on by Ian O'Neill

What is the Fastest Spinning Object in the Solar System? Near-Earth Asteroid 2008 HJ

The asteroid Eros, it might be big but it doesnt spin as fast as 2008 HJ (NASA)

A British astronomer has discovered a strange spinning object. The fact that it is spinning in itself is not strange, but the speed it is doing so has raised some eyebrows. The near-Earth asteroid 2008 HJ has been spotted spinning at a rate of one rotation every 42.7 seconds, breaking the record for the fastest rotating natural object in the Solar System. It is so fast that it has been designated as a “super-fast rotator”. What makes this discovery even more interesting was that it was spotted by an amateur astronomer when using the Australian Faulkes Telescope South observatory, operating it remotely over the Internet, in his Dorset home in the south of the UK…

Asteroid 2008 HJ smashes the previous record for fastest rotating object by 35 seconds. The previous record holder was asteroid 2000 DO8 (discovered eight years ago) with a rotational period of 78 seconds. This new discovery comes from a new project funded by the Science and Technology Facilities Council (STFC), which gives UK schools and colleges access to the world-class Faulkes Telescopes based in Australia and Hawaii. This finding is one of four recent successes in the search for small near-Earth asteroids under 150 meters in diameter. In April this year, the first significant discovery by the project was of asteroid 2008 GP3 with a measured rotation period of 11.8 minutes.

The orbit of NEO 2008 HJ (NASA/JPL Small Body Database)

Perhaps even more exciting than the discovery itself is who spotted asteroid 2008 HJ in the first place. This isn’t a news release from the Australian observatory, it isn’t even an announcement from an academic institution; the discovery was made by retiree Richard Miles from the comfort of his own home. Miles is an amateur astronomer and vice-president of the British Astronomical Association (BAA). He was able to carry out his research via a remote connection to the Faulkes Telescope South on the other side of the planet, in the UK. This charity based program enables enthusiasts and students to control the research-grade two-metre diameter telescopes, and the discoveries are coming thick and fast.

“A discovery like this demonstrates the capabilities of amateur astronomers and school students to produce exciting scientific results if given the right tools. By providing Richard with access to a big telescope we have smashed the previous record, and opened up the search for even faster objects to UK amateur astronomers and school students. This helps to put all that classroom science, maths and IT to real use!” – Dr Paul Roche, Director of the Faulkes Telescope Project at Cardiff University, Wales

The finding of the 12×24 metre asteroid appears to be consistent with near-Earth asteroid theory, and many sub-minute period asteroids can be expected. It’s just that not very many have been discovered as yet, so with the help of UK schools and amateur astronomers, more can be expected to be found.

Near-Earth asteroids are a concern for the future of the planet as there are many Earth-crossing rocky bodies that could cause significant damage to us on the ground should one come our way. Although the skies appear clear for now, our knowledge of these rogue objects is very limited. It is generally understood that these spinning pieces of rock (often weighing in at thousands of tonnes) are fragments from ancient collisions in the early Solar System. Projects such as Faulkes have an obvious advantage in increasing our knowledge in that it opens up observation time to a vast number of astronomers.

For more information on the Faulkes Telescopes, go to the project website »

Source: SpaceRef.com

Posted on by Ian O'Neill

NASA Considers Manned Asteroid Mission

Low gravity on an asteroid would be a big issue (NASA)

What would happen if we spot a Near-Earth Asteroid (NEO) heading straight for us? Assuming we had enough time, we might be able to pull together a group of brave astronauts (or oil drillers) and send them to the asteroid just in the nick of time to destroy it… oh hold on, that sounds like the storyline for a Hollywood blockbuster. Actually, NASA is planning a mission to an NEO, but not because it’s aimed at us. An asteroid named 2000SG344 (which threatened the Earth in the year 2000) is being considered as the destination for the first manned asteroid mission. The asteroid astronauts will travel there, chasing the 28,000 mi/hr (45,000 km/hr) speeding body and then carry out experiments, living on it for up to two weeks. Why? To briefly establish a manned outpost, advancing science and technology toward the ultimate goal: Mars.

The 1.1 million tonne asteroid was once thought to be a serious threat Earth. Back in 2000, there was a significant chance that asteroid 2000SG344 may have been on a collision course for Earth (with an explosive power of approximately 1 megatonne). Obviously it wasn’t, but it is expected to make an astronomically close flyby in 2030. Before then, NASA hopes to use this 40 meter-wide asteroid as the destination of a three to six month manned mission.

The asteroid mission would act as a “stepping stone” for future planetary missions to Mars and beyond. This three-month trek would provide vital technological, psychological and practical clues to what a manned deep space mission would face. Landing on an asteroid will be very difficult (due to the tiny influence of gravity on such a low-mass body), but it would provide an opportunity for astronauts to mine for water ice, use it for consumption and convert it into its component hydrogen and oxygen (for fuel and breathing). These tests would be essential before sending man on a long-term mission to Mars.

Under the current US administration, NASA has been instructed to send man back to the Moon by 2020. It is hoped that a more permanent base will be established soon after. Once the Moon base has been established, missions to Mars will become much easier to carry out. However, manned trips to near-Earth asteroids allow us to learn more about this potentially catastrophic hazard as well as developing deep space technology for the human presence on Mars.

In a study to be published in June, scientists at NASA’s Johnson Space Centre in Houston and Ames Research Centre in California will provide a rundown of their plans to use the future Orion spacecraft for this task, with a stop over of one- or two-weeks. I’m looking forward to seeing their recommendations for this ambitious development…

Source: The Guardian (UK)

Posted on by Fraser Cain

Comet Strikes Increase as We Pass Through the Galactic Plane

There are just so many ways the Universe is out to get us. Astronomers have already considered the threat from our Sun’s orbit around the center of the Milky Way. When our Sun rises up out of flat plane of the Milky Way, it appears we might be less protected from intergalactic radiation and cosmic rays. Well, it looks like passing through the middle of the galactic plane might have its own share of risks: an increased number of comets might be hurled towards the Earth because of gravitational interaction with the densest parts of our galaxy.

Researchers at the Cardiff Centre of Astrobiology have built a computer model of the Solar System’s journey around the Milky Way. Instead of making a perfectly flat orbit around the galaxy’s centre, it actually bounces up and down. At times it can rise right up out of the galactic plane – getting 100 light years above – and then dip down below it. They calculated that we pass through the plane every 35 to 40 million years.

And this time period seems to match dangerous periods of impacts on Earth. According to the number and age of craters on Earth, we seem to suffer increased impacts every 36 million years. Uh oh, that’s a match.

In fact, one of these high points of comet activity would have been 65 million years – the same time that an asteroid strike wiped out the dinosaurs.

And here’s the bad news. According to their calculations, the Solar System will be passing through the galactic plane in the near future, and should see an increased risk of impact. Our risk of impact could increase 10-fold.

There might be a silver lining to the bounce, though. The impacts might have helped life spread across the galaxy.

While the “bounce” effect may have been bad news for dinosaurs, it may also have helped life to spread. The scientists suggest the impact may have thrown debris containing micro-organisms out into space and across the universe.

Centre director Professor Chandra Wickramasinghe said: “This is a seminal paper which places the comet-life interaction on a firm basis, and shows a mechanism by which life can be dispersed on a galactic scale.”

Here’s more info on the story from Bad Astronomy.

Original Source: Cardiff News Release