Throwback Thursday: Are asteroids dangerous? (Synopsis)

Image credit: The Day, via http://theday.co.uk/science/astronauts-warn-of-city-killer-asteroids.

“The oldest and strongest emotion of mankind is fear, and the oldest and strongest kind of fear is fear of the unknown.” –H. P. Lovecraft

When it comes to risk assessment, there’s one type that humans are notoriously bad at: the very low-frequency but high-consequence risks and rewards. It’s why so many of us are so eager to play the lottery, and simultaneously why we’re catastrophically afraid of ebola and plane crashes, when we’re far more likely to die from something mundane, like getting hit by a truck. One of the examples where science and this type of fear-based fallacy intersect is the science of asteroid strikes.

Images credit: Oleg Kargopolov / AFP / Getty Images (L), Chebarkul town head Andrey Orlov (R).

Just a couple of years ago, a meteor struck the environs of Chelyabinsk, Russia, near a city with over a million people, injuring over 1,000 and causing significant property damage. With all we know about asteroids today, what’s the actual risk to humanity?

Image credit: Howard Edin (Oklahoma City Astronomy Club), via http://apod.nasa.gov/apod/ap081011.html.

Come get the facts — and not the fear — and consider just how dangerous asteroids actually are.

Comments

#1 Ragtag Media
May 21, 2015

Kosmikophobia- Fear of cosmic phenomenon

Hmm, there really is a phobia for this stuff.

When I was in elementary school a boy had brought in an asteroid for show and tell. From what I recall, it was small perhaps half the size of a baseball or less and black looking and kind of molten flowing in a direction that made it seem it was what he said, an asteroid.
He said (if I recall properly) they found it on his roof, I believed him but over the years have wondered if that was possible to land on his roof and not crash through. He was young so maybe he misspoke and meant it bounced off his roof.
#2 Omega Centauri
May 21, 2015

Given the fact that maybe ninety percent of the humans that ever lived lived before we had good event documentation, and the general amount of meteorites with sizes over a few centimeters that fall, I consider it highly likely that at least one human has been killed by a falling meteorite. These are of course from the small background that even a really good threat detection system wouldn’t be able to deal with.

I do think that within a decade or two, we will probably have early warning of most citykiller sized impacts.
#3 Wow
May 21, 2015

We have records of several people killed by meteorites. Google it up.

There are more spoon related fatalities than there are meteorite related ones, however.

So worry about the Spoon.
#4 Denier
May 21, 2015

I’m not sure even an asteroid the size of the one that killed off the dinosaurs would wipe humans out. There have been many extinction events in Earth’s history. With the possible exception of the Theia impact, life has adapted. The DNA mechanism for producing adaptation is remarkably good at its job but is paced by the time between generations. Small animals have quicker generations than large animals and thereby adapt faster. You can rate how bad an extinction event was by the size of the largest animal that survived it.

Humans, with their intellect, now adapt faster than even the genetic adaptations of the smallest forms of life and every day the rate by which we can adapt increases. I’m not saying a dinosaur-type impact wouldn’t suck, but I think we’d shrug it off.

If you want to find the thing that could end us, worry about Artificial Intelligence. In 30 years your smartphone will be a smarter person than any single human that ever lived. In 31 years your smartphone will be smarter than EVERY human person who ever lived combined.

While we might adapt faster than the Necrolestes, the mammal that survived the dinosaur extinction and adapted to fill every niche, we aren’t capable of out-adapting Artificial Intelligence. Right now we’ve got bigger fish to fry. Worrying about rocks falling from the sky is downright silly.
#5 Wow
May 21, 2015

“I’m not sure even an asteroid the size of the one that killed off the dinosaurs would wipe humans out. ”

i know that was a stupid statement. For any reasonable definition of “sure” about an event that hasn’t taken place yet, yes, we can be sure that it would wipe us out.

Eskimos learn cost accountancy (not too useful after an apocalypse) but nobody is teaching accountants how to survive in a polar winter (such as would happen in the aftermath of such an asteroid strike).
#6 Wow
May 21, 2015

“Humans, with their intellect, now adapt faster than even the genetic adaptations of the smallest forms of life and every day the rate by which we can adapt increases.”

No we don’t.

We find ways not to have to adapt. And the rate at which we bugger things up without the complex mechanisations we’ve got to avoid the consequences is increasing just as fast as our ability to “adapt” (a misuse of the term: we’re learn, we don’t adapt). And meaning that every bit that depends on the step before working becomes another thing that will kill us before we learn how to survive without it.
#7 Denier
United States
May 22, 2015

@Wow #5

“Eskimos learn cost accountancy (not too useful after an apocalypse) but nobody is teaching accountants how to survive in a polar winter (such as would happen in the aftermath of such an asteroid strike).”

I watched a documentary the other day on what it was like to live in Antarctica. In one section of the film they showed the head of base operations marry the accountant. It was a fun event where the groom borrowed the only formal suit jacket in all of McMurdo Station.

Even in conditions where it can reach -120F, its pitch black for 4 solid months, and they have at least one Category 1 storm hit every winter, life goes on. That even includes life for accountants in polar winters.
#8 Craig Thomas
May 22, 2015

My favourite meteorite – Bronze age, landed in a populated area:
http://www.gi.ee/geoturism/MetCraters_ENG_062011_100dpiS.pdf
Recorded in local runic inscriptions and even Herodotus recorded folklore he had heard about it.
#9 Wow
May 22, 2015

“That even includes life for accountants in polar winters.”

As long as heat, shelter, protection and food are supplied to them…
#10 Wow
May 22, 2015

You DO know there aren’t any Eskimos in the Antarctic, right?
#11 dean
May 22, 2015

Even in conditions where it can reach -120F, its pitch black for 4 solid months, and they have at least one Category 1 storm hit every winter, life goes on. That even includes life for accountants in polar winters.

When I was in graduate school we had a visiting professor who, in his younger days, had worked for a couple years at a research station in the Antarctic. (ROTC guy, chose to go there: “fascinating work, no place to blow your pay”)
He said he didn’t regret it, but also said that they all knew that if anything went wrong at the station, and they were cut off from relief when it happened, prospects were dim. “Nobody, nobody, would want to live there if they weren’t doing what we did.”

The only amusing story: he had a picture of a group of about 10 men, all completely naked, not even socks, standing outside by a flag pole. They had all run, naked, from the indoor sauna to stand next the pole for a picture, in order to gain entry to some informal ‘club’. When we pointed out that it seemed like a stupid thing to do, his comment was “Well, remember, there isn’t much else to do down there.”
#12 Ethan Waldo
May 22, 2015

The danger of using statistics to explain the likelihood of a humankind impacting event is the statistician has no way of knowing where we are at in the time line of an event in that probability set. Using the statistic as a prediction median is also flawed as you cannot know how far off from the median the last event was compared to the upcoming event in the next event series.

Now that we are (slumberingly) awakened to the fact of our non-human controllable single-point of failure, particularly one whose solution will also possibly solve other even less probabilistic points of failure, I would much rather see humanity survive due to a misguided sense of what is probable than to see humanity perish out of principal and realism.
#13 Graham Shaw
England
May 22, 2015

Slight error in the maths: the Tsar Bomba had an actual yield of 50Mt or thereabouts, so if the Tunguska event was 10Mt then that would make it about 20% of the energy, not 40%.
#14 Charles Roth
Ann Arbor
May 22, 2015

For all the talk of “quantitative reasoning” in the article, the science behind it is actually pretty poor. Seriously — do the math.

You simply can’t make a reasoned argument about the long-term likelihood of city-killer events, based on the very brief history of the human record. That’s like saying a die will never come up 6 because you measured it twice, and it came up 1 and 2.

Take instead the best knowledge from the geological record for likely city-killer impacts, and now you’ve got at least the beginnings of a mathematical model. Measured on that scale, the risk is still extremely low, of course. But it’s non-zero.

And of course, the fundamental flaw in the article’s argument is using expected-value mathematics to calculate the best level of concern. You simply can’t do that. If one of the outcomes is “everyone dies”, you can’t simply factor that in as the probability that everyone dies times the number of humans on earth. Sure, you can do the multiplication, but it no longer *means* anything. It’s akin to “9 women can make one baby in one month”.

Besides… if all goes well, in a hundred years, our descendants will wonder how we could be so stupid as to *not* know where every piece of space junk is. It might turn out to be because they’re valuable, or they’re in the way of whatever space travel we have, or something beyond my imagination. But it will be as absurd then as the idea that we once drove w/o seatbelts is now.
#15 Dave Hirsch
Washington, USA
May 22, 2015

The author ignores the elephant in the room: you cannot compare the risk of an individual, or millions of individuals dying, to the risk that our species might perish. The effort we should be willing to expend for the latter is not simply the effort we might expend on one person’s survival, scaled up by the size of the population. The author is wrong to say that other risks (war, disease) pose the same kinds of species-killing risks. They do not. Some would survive war or disease, but no humans would survive the Cretaceous-Tertiary event.
A big bolide is the only real risk to our species, and we should rightly work to avoid it happening, no matter how small the risk.
#16 Dank Maymays
Vancouver
May 22, 2015

I usually enjoy the articles on this site, but this one shockingly misses the point. The problem of asteroids is not danger to the individual; I’ve never met a single person who was afraid of being killed by an asteroid. The issue is the risk to the survival of humanity. This lends itself to a very simple cost-benefit analysis (sum of the products of probabilities of events and their corresponding cost/benefit). A planet killer asteroid that wipes out humanity has a cost/benefit value of negative infinity. Thus, this term in a cost-benefit analysis dominates as long as the probability of the event occurring is above zero — which we know it is. The article completely ignored the obvious in order to, I presume, rant about the perceived (and non-existent) problem of people fearing being killed by an asteroid. Disappointing.
#17 eric
May 22, 2015

A big bolide is the only real risk to our species, and we should rightly work to avoid it happening, no matter how small the risk.

Supernova within a few LY. Gamma ray burst pointed at us (coincidentally, I’m not implying aliens). I don’t know but maybe a several-century burst of high solar activity could do it too. A genetically modified disease (think Australia’s mousepox: in 9 days, the entire exposed population was dead). Full nuclear exchange. Loss of habitat. Loss of food supply. Another glacial period might do it, though I expect we’d survive as long as we didn’t kill each other in competition over the non-glacial equatorial regions. And so on, and so on, and so on.
#18 Wow
May 22, 2015

Or our own greed and idiocy causing us to continue causing yet more climate change and thereby collapsing our civilisation, never to be able to start it again, becoming a minor hairless ape that’s only really food for better designed animals, never again to have a civilisation before they go extinct.
#19 PJ
Perth, west Oz
May 22, 2015

@ # 15
A bolide is an asteroid which has exploded, generally, in the upper atmosphere. The energy is mostly expended at that stage, leaving fragments to fall over an expansive area. Risk decreased compared to an asteroid coming in whole.
@ # 16
An asteroid of that magnitude is likely to be spotted long before it strikes. In the advent of a sneaky one, you would not have time to think about the cost / benefit. No-one would be around to evaluate the damage. That’s life; ” the asteroid giveth, and the asteroid taketh away”.
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May 26, 2015

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