Image via Universe Today

Image via Universe Today

You may have heard about the killer asteroid aptly named Apophis, which had a chance of hitting earth in 2036 and potentially devastating a good chunk of the human population. Thankfully, scientists have now made more accurate observations of Apophis and ruled out the possibility of it hitting earth.

The asteroid has been on a watch list for many years because in 2029 it will pass very VERY close to earth. So close that it will actually be inside the orbit of some of our satellites! The fear was that if the asteroid passed through a very specific spot as it passed us, the earth’s gravity would tug on it just right so that its orbit would be altered and it would hit earth on its next pass in 2036. Due to limited observations of Apophis, astronomers didn’t know its exact orbit accurately enough to determine if it would pass through this very specific gravitational “keyhole.” Even before this latest observation, which occurred during its latest flyby of earth, the odds of Apophis passing through that keyhole were very slim (about 1 in 100,000 if I remember correctly, but don’t quote me on that) but significant enough to worry. Further observations a few years ago lessened the odds considerably to about 1 in 1,000,000. Now, astronomers are absolutely positive the rock will not pass through that gravitational keyhole, and the rock will never hit earth. They also learned from these latest observations that Apophis is actually larger than originally thought- about 325 meters in diameter, vs. 270. So it’s a really good thing that this rock won’t hit us!

This does not mean we can sit back and relax, however. There are probably thousands of asteroids flying around out there that we haven’t even seen yet, and any of them could be on a collision course with us. It’s a very real threat, and based on our knowledge of past extinctions and impacts, statistically it’s only a matter of time before we get smacked by another one. We just have be able to detect it before it hits us, and have the technology in place to deflect it.

More detailed info can be found at Bad Astronomy and Universe Today.