Tag: Leonid Sokolov

Repeat after me: Apophis is not a danger!

By Phil Plait | January 31, 2011 7:00 am

What is it with all the bad media reports of cosmic doomsdays? Betelgeuse last week, giant spaceships before that, and now Apophis. Sigh.

Here’s the scoop: I was tipped off about this by Jesse Emspak, who writes for the International Business Time (and who wrote a great article about the real opportunities represented by Apophis), and who told me about a Russian news site which, a few days ago, posted an article about the asteroid Apophis with the very menacing title, "Russian astronomers predict Apophis-Earth collision in 2036".

Sounds scary, right? One problem: it’s 100% utter crap.

Rock will roll on by

This guy won’t help.

First, the reality: Apophis is what’s called a near-Earth asteroid; it currently swings near our planet roughly every seven years. In April 2029 it will have an extremely near pass, getting so close it will actually be below our geosynchronous satellites! It will definitely miss us, but there’s a catch: if it passes us at just the right distance, Earth’s gravity will warp its orbit just enough that seven years later, Apophis will hit the Earth.

Let me be very, very clear: the odds of this happening are incredibly low, something like one in a 135,000. I fret about asteroid impacts, as you might imagine, but this one doesn’t worry me at all. The odds are so low I worry more about Snooki getting her own three-movie contract.

The reason the impact odds are so low, but not zero, is that we don’t precisely know Apophis’s orbit. There is a tiny region of space above the Earth called the keyhole, and Apophis has to pass right through it to have its orbit modified enough to hit us on the next path. We can’t know for sure if the rock will pass through the keyhole or not in 2029, but we can apply statistics and calculate that minuscule 0.0007% chance. And maybe it’s better to think of it as a 99.9993% chance it’ll miss.

Feel better?


OK, so what’s with that Russian news article? Besides the breathless — and totally wrong — headline, here’s the first line:

Russian astronomers have predicted that asteroid Apophis may strike Earth on April 13, 2036.

Bzzzzzt. While technically correct, this gives the strong impression that the odds of impact are high. That’s irresponsible journalism at best. Yet things quickly get worse:
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