Gecksteroids! Asteroids and Geckos May Share Common Force

The asteroid Itokawa (as imaged by the Japanese Hayabusa probe) and a gecko tattoo. Bear with me, it'll make sense soon (JAXA)
The asteroid Itokawa (as imaged by the Japanese Hayabusa probe) and a gecko tattoo. Bear with me, it'll make sense soon (JAXA)

What do asteroids and geckos have in common? Not a lot, as you’d expect, but they may share a common force.

This rather strange notion comes from research being done by a team of University of Colorado scientists who have been studying the odd nature of the asteroid Itokawa. When the Japanese Hayabusa mission visited the space rock in 2005 (Hayabusa’s sample return capsule is set to return to Earth on June 13th by the way), it noticed the asteroid was composed of smaller bits of rubble, rather than one solid chunk. Although this isn’t a surprise in itself — indeed, many asteroids are believed to be floating “rubble piles” — the rate of spin of the asteroid posed a problem.

Itokawa spins rather fast and if only the force of gravity was keeping the lumps of rock together, they would have been flung out into space long ago. In short, the asteroid shouldn’t exist.

Although plenty of theories have been bandied around, one idea seems to stick.

More commonly found as a force that holds molecules together, the van der Waals force may bind the individual components of the asteroid together, acting against the centripetal force caused by its spin.

But where do the geckos come in?

Geckos are highly skilled in the “climbing up walls” department, and it’s the van der Waals force that makes this happen. Should the body of a gecko be tilted in such a way against a perfectly smooth, “impossible” to climb surface, the gravity acting on the little creature will trigger the force into action. Therefore geckos have evolved to exploit the practical application of van der Waals.

This has some rather interesting ramifications for asteroid evolution too. During early stages of asteroid formation, the larger fragments of rock are flung off; the centripetal force exceeds that of gravity. In the latter stages of development, only the smallest rocks remain behind, their mass small enough to allow van der Waals forces to overcome the spin.

So, there you have it, asteroids do have something in common with geckos. It seems only right to call these space rubble piles “Gecksteroids.”

Thanks to my Discovery News colleague Jennifer Ouellette for drawing the comparison between asteroids and geckos!

Source: Discovery News, arXiv.org

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Deflecting Doomsday Asteroids… and Plundering Them

A metorite impact would be very bad, but using asteroid deflection techniques could provide mankind with a lucrative opportunity (©Discovery Channel)
A metorite impact would be very bad, but using asteroid deflection techniques could provide mankind with a lucrative opportunity (©Discovery Channel)

I’ve always found asteroids to be fascinating. They are often surprisingly big, they contain a wealth of information about the history of the Solar System… and, let’s be honest, they’re frightening.

There are thousands of asteroids out there, often collecting in clearly defined belts or gravitationally stable regions known as Lagrangian points. However, many are not so well behaved; they seem to have their own agenda, flying around the Solar System in their own orbits, sometimes buzzing the Earth.

Fortunately, the vast majority of these rocks are harmless; if they hit our atmosphere they might create a dazzling light show, burning up, possibly even exploding as a fireball. Sometimes though, a big asteroid might be observed and astronomers become a little concerned. The next known threat that might hit us is the famous asteroid named Apophis that is expected to make an uncomfortably close encounter with Earth on April 13th, 2036. The odds of Apophis hitting us in 2036 (not 2029 as quoted in the above video) are 45,000:1, which may sound fairly unlikely, but if you start comparing those odds with dying in a plane crash, or being hit by a car, you’ll see that actually, a one in 45,000 chance are the kind of odds you’d happily quote when placing a bet in a Vegas casino. I have a chance!

Yes, and there’s also a chance of a 350 metre-wide asteroid hitting us in 2036, so perhaps we should start planning for the worst?

Fortunately, we have some lead time on Apophis, and we’ll learn more about the chunk of rock when it flies past the Earth in 2029. And that’s what it’s all about: lead time. If mankind spots a potentially deadly asteroid approaching us, we’ll need as much time as possible to nudge it off course.

In a video I just stumbled across on Discovery.com, Joseph A. Nuth III from NASA Goddard Spaceflight Center shares his views on what we could do to prevent a potential asteroid catastrophe. By developing asteroid deflection techniques, we’ll also be presented with an opportunity. As pointed out by Nuth, if we have the ability to deflect an asteroid, perhaps we can steer it into lunar orbit, so we can carry out mining operations…

Meteor Explodes Over Canada

Only a month ago, a series of all-sky cameras in the Canadian region of southern Ontario captured a long-lasting meteorite fireball as it streaked across the skies. Last night it was the turn of the central province of Saskatchewan to see the spectacular fireball of a meteroid dropping through the atmosphere. According to eye witnesses, the intense light lit up the dark skies and a series of thunderous booms shook the ground.

Another day living in the interplanetary shooting gallery I suppose
Continue reading “Meteor Explodes Over Canada”

Got It! Aftermath of Asteroid 2008 TC3 Impact Spotted

The long-lasting persistent train of the 2008 TC3 re-entry on October 7th (NASA)
The long-lasting persistent train of the 2008 TC3 re-entry on October 7th (NASA)

At long last, we have visual evidence of the 2008 TC3 impact over the remote Sudanese skies. Admittedly, it’s not a video of the dazzling fireball ploughing though the upper atmosphere, before detonating with the energy of a small nuclear weapon, but it is a great picture of the smoky remnant after the explosion.

A noctilucent cloud after the launch of a Delta rocket (<a href='http://www.flickr.com/photos/cocoabeachjoe/1300892840/'>Flickr</a>)
A noctilucent cloud after the launch of a Delta rocket (Flickr)

The meteorite train seen in the image above has been sheared and twisted by high altitude winds, leaving the snake-like pattern suspended in the air. The tenuous debris reflects the dawn sunlight, in a not-so-dissimilar way to the noctilucent cloud produced after a rocket launch (pictured left).

For more on today’s uncovering of the October 7th image (above), check out my Universe Today article. For more information on the first ever predicted asteroid impact, check out my collection of articles on Astroengine.com (tag: “2008 TC3”).

First Image of Asteroid TC3 Impact Fireball… From Space

2008 TC3 generates a huge fireball according to weather satellite Meteosat 8 (Zdenek Charvat, Czech Hydrometeorological Institute)
2008 TC3 generates a huge fireball according to weather satellite Meteosat 8 (Zdenek Charvat, Czech Hydrometeorological Institute)

There may not be any ground-based imagery of the 1.1-2.1 kT fireball after asteroid 2008 TC3 hit the Earth’s upper atmosphere above Sudan, but we now have the first satellite observation of the impact. 2008 TC3 (a.k.a. “Brian” as I lovingly named it in my previous post) hit at 02:43am (UTC) yesterday morning, three minutes before the predicted re-entry. This is a huge moment for asteroid hunters: 2008 TC3 is the first ever asteroid to be discovered and accurately forecast to hit our planet.

The above image was taken by the weather satellite Meteosat 8, as Jiri Borovicka of the Czech Academy of Sciences explains: “The explosion was visible in all 12 of the satellite’s spectral channels, covering wavelengths from 0.5 to 14 microns,” he said. “The satellite takes pictures every five minutes; the fireball appeared at 0245 UTC and had faded away by 0250 UTC.”

It’s great to finally see the explosion of the first ever predicted asteroid impact. I think we all feel a little safer now

Source: Space Weather

Historic Asteroid 2008 TC3 Hits Earth as Predicted

Predicted region of atmospheric impact according to infrasound observations (Peter Brown, University of Western Ontario)
Predicted region of atmospheric impact according to infrasound observations (Peter Brown, University of Western Ontario)

2008 TC3 wasn’t a particularly interesting asteroid. It wasn’t very big (only 1-5 metres wide) and it didn’t really stand out as being special (if it was special, we didn’t have any time to realise it anyway). If 2008 TC3 was in a crowd of other asteroids you wouldn’t have picked it out. In fact, it was that “normal” that it wasn’t named, it just kept its original asteroid designation number. 2008 TC3 was an ordinary piece of space rock in an extraordinary situation.

This was the first ever asteroid that astronomers were able to track and predict (with high precision) where and when it was going to hit Earth. Sure enough, astronomers using the Mt. Lemmon telescope in Arizona as part of the NASA-funded Catalina Sky Survey for near-Earth objects discovered 2008 TC3 before it hit Earth, enabling us to be forewarned a whole six hours before impact. If the object was any larger, astronomers will have (for the first time) been able to warn people on the surface, thus saving lives.

In fact, asteroid 2008 TC3 is so special that I’m going to give it an unofficial name: Asteroid Brian*.
Continue reading “Historic Asteroid 2008 TC3 Hits Earth as Predicted”

Small Asteroid 2008 TC3 Will Hit Earth Tonight

Artist impression of a meteorite entering the Earth's atmosphere (©Leonard Wikberg III)
Artist impression of a meteorite entering the Earth's atmosphere (©Leonard Wikberg III)

A newly discovered asteroid called 2008 TC3 will (with a 99.8-100% probability) hit the atmosphere over northern Sudan at 2:46 UTC (Oct 7th). The piece of rock will not threaten people or structures on the surface, it is likely to burn up during re-entry as a magnificent “air burst.” Estimates suggest that as 2008 TC3 burns up, it will detonate with an energy of a kiloton of TNT.

2008 TC3 is between 1-5 meters in diameter, so it’s not a threat by any means, but it should create a spectacular display. Usually the bright meteors we observe are generated by debris no bigger than a grain of sand, so this will be a huge astronomical event in comparison. The giant meteor will be visible from eastern Africa travelling very quickly from north-east to south-west and it is expected to create a very long trail as it will enter the atmosphere at a very shallow angle.
Continue reading “Small Asteroid 2008 TC3 Will Hit Earth Tonight”