Christopher Moore is an Assistant Professor of Physics at Coastal Carolina University. He lives in Myrtle Beach, SC with his wife and two children.So it turns out there is an asteroid coming our way in 2029. No worries, though. There is practically zero chance that the asteroid will actually hit Earth. That should be comforting. The problem is, these things eventually come back around, and in 2036 …
SPLAT!
In 2004, NASA said there was a chance an asteroid named Apophis could strike the Earth in 2029. However, once more was known about the trajectory of Apophis, they revised their estimates and now the chances of a 2029 strike are practically zero.
A Russian scientist is now claiming that Apophis will strike in 2036 when it swings back around in its orbit. Should we be alarmed?
According to NASA’s Near-Earth Object Program Office, we shouldn’t be. There is apparently only a 1-in-250,000 chance that Apophis will strike Earth in 2036.
Oh. OK.
Wait.
1 in 250,000? That’s a hell of a lot better odds than hitting the lottery. As far as doomsday scenarios go, that’s easily the greatest chance of Earth-killing disaster I’ve seen.
Here is some perspective: The odds of you as an individual being killed in a terrorist attack on a commercial airliner is 1 in 10,408,947. Hopefully Apophis will pass through airport security before attempting a collision. Note to the TSA: if you notice during one of your pat-downs that the traveler appears to be a giant rock the size of three football fields, then please detain it.
Shark attack? 1 in 11.5 million.
It is more likely that I will date a supermodel sometime in my life (1 in 88,000). It’s still a little disconcerting that NASA thinks a 1 in 250,000 chance of world destruction is “small”.
Admittedly, it IS more likely that this asteroid will strike Earth than that one specific individual on Earth will win the lottery / get eaten by a shark / date a super model / get taken hostage by a terrorist, but the reason these sound bite stats seem to make the prospect of Earth-ending asteroid impact probable, is that we’re used to considering the chances of such freak occurences over very large populations – i.e. we know that people DO win the lottery – every week, and that some people are eaten by sharks / dating super models / taken hostage by terrorists from time to time.
However, in order to have such improbable events taking place (kudos by the way for your eight significant figure estimate of terrorist hostage probabilities), the possibility of such events needs to be repeated millions of time; i.e. millions of people each week play the lottery without winning; millions of swimmers are NOT eaten by sharks; millions of airline passengers fly safely home without the afront of their journey being interuppted by terrorists and tens of thousands of hapless individuals (inculding many physicists no doubt!) go each week either without dates or at least with dates of less than supermodel stature.
If I went to the doctor with a worry about some tropical disease I contracted and he informed me I had a 0.01% chance of the disease developing into something life threatening I think I’d still sleep pretty well (aside from worries of sharks and terrorists). To be told by NASA that there is a 0.0004% chance of impending doom or to put it in a slightly more positive light: a 99.9996% chance that this asteroid will pass by uneventfully, I think I will sleep even better.
The distinction you are making is between probability and statistics, and it is a very good one. Apparently, it’s very difficult for many to see the tongue within my cheek in my writing. I may need to work on that.
You should note, however, that I made sure to be technically correct in wording as much as possible. The exception being the sig. figs. on the terrorist attack, which I just copied from someone else. Good catch there.
Two main points:
(1) The asteroid strike probability is exceedingly small, but it looks a lot larger than other potential strikes have been in the past, as far as I can remember. It’s also large enough to hope the NASA Near-Earth Object Program Office is paying close attention, which I assume they are. It’s also a date far enough ahead that something could actually be done if necessary. The real concern should be the bazillion objects they haven’t observed.
(2) There is a subtle political point concerning the TSA. Only 674 passengers have been on board planes involved in terrorist incidents over the past decade. Not all of those passengers have even died. Of course, many more have been killed (on the ground) due to airborne terrorist incidents, but that number is also exceedingly small. Responses to single incidents (like the shoe bomber), where the millions of yearly passengers now must remove their shoes at security, are borne from some of the same reasoning concerning improbable events. It would be interesting to compare the budgets of the TSA and the Near-Earth Object Program Office.