Missing the target

Lately I've been seeing a lot of buzz on social media apropos of the Earth being hit by a killer asteroid.

Much of this appears to be wishful thinking.

Most of it seems to focus on the asteroid 2007 FT3, which is one of the bodies orbiting the Sun that is classified as a "near-Earth object" -- something with an orbit that crosses Earth's, and could potentially hit us at some point in the future.  It bears keeping in mind, however, that even on the scale of the Solar System, the Earth is a really small target.  This "deadly asteroid," we're told, is "on a collision course with Earth" -- but then you find out that its likelihood of its actually striking us on the date of Doomsday, March 3, 2030, is around one in ten million.

Oh, but there's "an altogether more sinister estimate" that 2007 FT3 could hit us on October 5, 2024, but the chances there are one in 11.5 million.  Why this is "altogether more sinister," I'm not sure.  Maybe just because it's sooner.  Or maybe the author of the article doesn't understand how math works and thinks that the bigger the second number, the worse it is.  I dunno.

Then there's the much-hyped asteroid 99942 Apophis, which was first thought to have a 2.7% chance of hitting the Earth in April of 2029 (more accurate observations of its orbit eliminated that possibility entirely), and then gets a second shot at us in April of 2036.  The 2036 collision depends on it passing through a gravitational keyhole during its 2029 close approach -- a tiny region in space where the pull of a much larger planet shifts the orbit of a smaller body in such a way that they then collide on a future pass.  Initially, the keyhole was estimated to be eight hundred kilometers in diameter, and this caused the physicists at NASA to rate Apophis at a four out of ten on the Torino Impact Scale -- the highest value any object has had since such assessments began.  (A rating of four means "A close encounter, meriting attention by astronomers.  Current calculations give a 1% or greater chance of collision capable of regional devastation.  Most likely, new telescopic observations will lead to reassignment to Level 0.  Attention by public and by public officials is merited if the encounter is less than a decade away.")  If it hit, the impact site would be in the eastern Pacific, which would be seriously bad news for anyone living in coastal California.

The close approach in 2029 [Image licensed under the Creative Commons Phoenix7777, Animation of 99942 Apophis orbit around Sun, CC BY-SA 4.0]

This, of course, spurred the scientists to try to refine their measurements, and when they did -- as the scale suggested -- they found out we're not in any danger.  The gravitational keyhole turns out to be only a kilometer wide, and Apophis will miss it completely.

In fact, there are currently no known objects with a Torino Scale rating greater than zero.

It's always possible, of course, that we could be hit out of the blue by something we never saw coming.  But given that we're talking about an unknown risk from an unknown object of unknown size hitting in an unknown location at an unknown time, I think we have more pressing things to worry about.  Sure, something big will eventually hit the Earth, but it's not going to happen in the foreseeable future.  NASA and the other space monitoring agencies in the world are doing a pretty good job of watching the skies, so maybe we should all just turn our attention on more important matters, like trying to figure out how nearly half of Americans think the best choice for president is a multiply-indicted, incompetent compulsive liar who shows every sign of incipient dementia.

In any case, I'm not concerned about asteroid impacts, and all the hype is just more clickbait.  So if you live on the West Coast and were planning on moving inland, or are considering cancelling your plans for a big Halloween bash this year, you probably should just simmer down.

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