OMG Asteroid!

Everybody run to your backyard concrete bomb-shelters and grab your can opener to be ready to break the seal on all those baked beans that you’ve been stocking in anticipation of this moment, because an asteroid is on its way!

YU55 at about 3 lunar distances from earth, or about 1384000 km, on Nov. 7, 2011. Image: NASA/JPL-Caltech

YU55 at about 3 lunar distances from earth, or about 1384000 km, on Nov. 7, 2011.
Image: NASA/JPL-Caltech

t has been given the loveable name of 2005 YU55and has been on many astronomer’s radars for quite a while. In fact, the orbit path of the asteroid is so well-known that we can besure that it is neither going to strike the earth or the moon, which in my opinion is a bit unfortunate because imagine how exciting it would be if it did! (Ignoring all the death, mayhem and destruction). So you can ignore my opening hype-inducing paragraph. But on that topic, if it did hit the earth, what would happen?

The asteroid itself is approximately 400m wide, which in practical terms is about twice as wide as a sporting stadium or about as big as an aircraft carrier. It is also carboniferous (meaning that it contains lots of carbon), which in terms of asteroids is not all that common (although one of the theories about how earth got so much carbon is because of these sorts of asteroids impacting over a large timescale, possibly even bringing life to earth). Basically, if such a big lump of rock were to impact the earth at the speed that this thing is travelling, it wouldn’t cause armageddon, but it would be enough to level a city if it impacted land. If it were to land in water, it would create a 70m high tsunami, but wouldn’t significantly change to orbit or orientation of our planet. The crater that it would create would be 518m in diameter. In comparison, the meteor that impacted just off the Yucatan peninsula in Mexico, (you know, the one that wiped out the dinosaurs) was about 15km wide and 8000 times the mass.

Animation of the trajectory for asteroid 2005 YU55 – November 8-9, 2011. Image credit: NASA/JPL-Caltech

Despite the fact that 2005 YU55 is not going to hit the earth or the moon, it is still pretty interesting. It is passing closer to the earth than the distance to the moon (~325000km, or about 20x the distance from Sydney to London), which in space terms is pretty freakin’ close. The last time a rock this size got this close was in 1976, and it won’t be until 2028 that is happens again, but with a different asteroid.

Scientists are revelling in the opportunity to see an asteroid up close and find our more about it before they visit one themselves. Or bring one closer to earth. They will be able to study the physical characteristics of a massive asteroid; whether it is solid, porous, made up of many smaller asteroids and possibly even why it is so shiny. During this passing we could find quite a bit about the physics, chemistry, geology (possibly even biology) of near-earth-orbit asteroids, which is essential information if we want to land on one by 2025. This is NASA’s plan! US President Barrack Obama laid out his hopes for NASA last year, which included a manned mission to Mars by the mid 2030s.

Ex- Adelaidean astronaut Andy Thomas (now working for the exploration branch of the Astronaut Office) said: ‘”Long outbound and inbound trip times are going to be very challenging … These missions are going to be very, very risky … They are going to be as much risk as the Apollo missions were. To try and sell it to the public purely on the basis of the scientific return … would probably not work.” Which is probably why one of the reasons that they want to do it is to figure out how they can divert an asteroid if it’s on a collision course with earth; surely the public would agree with that, right?

Andy Thomas listens intently as I explain to him the mechanics of asteroid orbits, while Noby laughs as I stumble over my words.

Andy Thomas listens intently as I explain to him the mechanics of asteroid orbits, while Noby laughs as I stumble over my words. Image credit: The University of Adelaide

Our friend 2005 Yu55 is going to pass our way  again in 2075, but again there is very little chance of a collision. The other one that I mentioned that’s going to come around in 2028? It’s called 1997 XF11 and is even bigger than 2005 YU55, but still collision is not very likely. Asteroid Apophis, however, will come around in 2029 and 2036, and the latter passing has a chance (1 in 250000) of giving us a bit of a headache.

If an asteroid struck earth and devastated civilisation as we know it, what would you do? Convert your backyard into a veggie patch? Buy a shotgun? Curl up in a ball and cry? Let us know!

About Tristan O'Brien

My passions are in environmental science and conservation, but scientific interests extend into other fields. At The Other Side of Science I work behind-the-scenes, but write when I feels creative! Read his wise words @TristanAvella

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