... So I hear March 2 was a close call...

[Inactive Account]

This book wasn't by Anne McCaffrey was it?

[Freohr Datia]

This book wasn't by Anne McCaffrey was it?

XD have you read it?

oui oui, it was =)

[Inactive Account]

Aha. Thought so. Dragonriders of Pern--which one?

[Junkhead]

Did anyone else hear of that asteroid that almost hit Earth? It came closer to us than the moon is. I also heard it was the size of a... idk... I think it was a 45 story building?... idk...

discuss!!! =o

So? Iy wasn't going to destroy Earth, only a few landscapes, but that's it.

[California Mountain Snake]

Well considering a 10 meter diameter asteroid can create an air blast with the same explosive force as the nuclear bomb dropped on Nagasaki, it doesn't take a very big asteroid to do a lot of damage.

[GKSB]

Think about gravity, and you'll understand why this was a difficult asteroid to spot and why it really was low threat.

So, things orbit in ellipses, right? The Earth's orbit is slightly elliptical around the sun. Now, since we don't know the origin of the asteroid, it could either be in an elliptical orbit around the sun or have entered into a hyperbolic orbit (where it enters orbit, is angled by it, and then escapes orbit again) around it. Either way, it's orbit's path was probably extraordinarily elliptical; and since it passed near earth, presumably on the same plane. That means, then, that looking at this asteroid as it approached was like watching a car at night approach on a flat road. The headlights obscure everything, and you can't really tell its approach or speed or much by it. Now, since it was so small this asteroid probably reflected very little light; now imagine a car with its headlights off and a bunch of cars in front of it with headlights on. Picking out this asteroid among everything else was very unlikely.

That elliptical/hyperbolic orbit is also important, because it means the asteroid probably would not veer off course. It is already propelled by the sun's gravity and its own inertia, the Earth and Moon's gravity are unlikely to have altered it significantly. That's why a hit chance is so low; these asteroids need to enter orbit around the sun in such a manner as to rotate on the same plane as the Earth, as well as having perfect timing. That perfect angle and orbit is further exacerbated by one very important specimen; Jupiter. Jupiter has much, much more gravity than Earth. It, therefore, alters the course of asteroids much more significantly; away from the Earth's orbit. Thus, it's no exaggeration to say that a significant, large impact is very, very, very unlikely.

I'd be skeptical about going off of laws based on observations made some hundreds of years ago, except they keep finding new ways to prove that the laws are sound. I don't think they screwed this up per se; they probably didn't have the equipment to detect the asteroid any earlier (it was detected in the end of Feb). And of course, there didn't used to be any such equipment at all, and we're all still here.

Those laws weren't right, just generalizations. Relativity, a discovery of the previous century, makes a significant distance in the vastness of space; and physicists have plenty of equations to deal with them. We would have had a lot of trouble landing the Rovers on Mars if we had used classical physics. It was a difficult asteroid to detect.

As for the sun dying, you don't have to worry about that, they've managed to figure out from actual observations of other stars and such that that won't be for a good long time. They haven't found anything about our sun that would make it behave differently from other stars.

The sun will become a red giant; but like any stellar process, it'll take millions of years. Several billion, in fact. Even I don't plan to be around that long. There's no reason to fret about the health of our sun, it's going to be almost exactly the same from when we are born to when we die except its magnetic fields' cycle.

Edited March 5, 2009 by Crepe Knight

[Bohemund]

Interesting bit of news.