The red phone on my desk went off again, flashing and
beeping urgently. What was it this time? Another super-villain escaped from
prison, threatening the safety of Oakland City again? I pick up the phone to
find out. Ben Burrress writes: ah, it was Apophis again, back in the public eye
and causing concern for one of our citizens.
At Chabot Space & Science Center, I'm the one who
answers the science help line, which is why I keep my cape and cowl close at
hand. Ah, Apophis, that thousand-foot
chuck of rock plotting to buzz the Earth. The citizen on the phone has called
about Apophis before, so I figured it was time to back up my response with the
word from a resident asteroid expert, Gerald, one of Chabot's asteroid tracking
team—like Alfred passing the phone to Bruce.
Gerald's report on Apophis: After 3.8 years of observations,
we project that Apophis will pass by (and miss) the Earth by about 23,600 miles
on April 13 (yeah—Friday the 13th) 2029 (in case you want to plan a party).
Then, Apophis will revisit the Earth's vicinity on April 13th (not a Friday)
2036. And here's the meat of the deal with Apophis: if its trajectory on the
2029 flyby is anywhere near what is predicted, then there is no chance at all
that it will hit us in 2036. There is only a small chance that within the range
of uncertainty the 2029 passage will aim Apophis for a 2036 impact with
Earth–but the probability of that are calculated at less than 0.002%. That's
roughly the same probability as drawing a straight flush right off the top of
the deck (to you non-poker-players, the odds of that are about 72,000 to 1).
Though astronomers are planning to observe Apophis next year
using the giant radio telescope at Arecibo to give us a more refined impact
probability for the 2036 passage (still 24 years out!), the consensus among
scientists is that the refinement should further diffuse concerns, not raise
them.
Just can’t get enough?
Check out http://science.kqed.org/quest/stations/northern-california/
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