We have recently learned that the probability of an asteroid striking the earth in 2032 is 3.1%. That’s a substantial increase from past estimates.
3.1% is HUGE. That’s not the issue. But that’s the probability that it will hit somewhere.
What will it most likely hit? Water and not a lake or a river, but, rather, an ocean. The reason is that oceans cover 71% of the earth.
Still, that leaves 29%. But think about what we know about that 29%. Most of it has no one living on it, or, if it has people living on it, the population density is probably less than 50 people per square mile. An AI-assisted Google search says that over 90% of the Earth’s land has a population density of under 50 people per square mile. That leaves 10% (or a little less) of the earth’s surface with more than 50 people square mile.
Now we’re ready to do some calculations.
The probability of the asteroid hitting an area with more than 50 people per square mile = 0.031 * 0.29 * 0.1 = 0.000899.
That’s a 1 in 1,112 chance.
That’s still large. But it’s not huge.
What about the idea that even if the asteroid hits an ocean or a piece of land on which almost no one lives, it will destroy the earth?
The article I read says that that’s not true. It states:
To assess the danger of asteroids, scientists use the Torino Scale, which ranges from 0 to 10. A score of 0 means no risk, while a 10 indicates a global catastrophe. Asteroid 2024 YR4 currently holds a rating of 3, meaning it has a chance of localized destruction. This rating is rare and is only [sic] given to objects with an impact probability greater than 1%.
At its current size estimate of 131 to 295 feet, YR4 falls into the “city killer” category. Bruce Betts, chief scientist for the nonprofit Planetary Society, explained, “If you put it over Paris or London or New York, you basically wipe out the whole city and some of the environs.”
This kind of impact could devastate cities like Mumbai, Bogota, or Lagos, which lie within its projected trajectory, endangering about 110 million people.
However, the asteroid is not large enough to cause a global catastrophe like the one that wiped out the dinosaurs. “This is not the dinosaur killer. This is not the planet killer. This is at most dangerous for a city,” reassured Moissl.
Does that mean we should do nothing about it? No. I hope Elon Musk gets on it, as he probably will.
READER COMMENTS
Alan Goldhammer
Feb 21 2025 at 3:12pm
You are neglecting the possibility that ETs have already targeted the location of the asteroid. If Ross Douthat and Tyler Cowen can believe in UFOs, I guess I can as well. My understanding is the coordinates for the crash have already been dertermined and are:
26°40′37″N 80°2′13″W Just a word to all who are around in 2032 to stay at least 300 miles away so you are not exposed to any collateral damage. It could be worse than the Tungasuka event in Russia that happened in 1908.
Craig
Feb 21 2025 at 7:39pm
“26°40′37″N 80°2′13″W”
Gave me a good chuckle but I do live in Palm Beach County.
Craig
Feb 21 2025 at 4:53pm
Reminds me about reading about the Tunguska event but wondering how much warning there will be regarding a specific impact point if it should be bearing down on Earth?
Kevin Dick
Feb 21 2025 at 4:57pm
NASA seems to have updated the base probability of impact to a much lower number:
https://x.com/nasa/status/1892636852584165484
“New data gathered last night (Feb. 19-20) dropped the December 2032 impact odds of asteroid 2024 YR4 to 0.28%. Monitoring continues. http://go.nasa.gov/3I0ZA7K“
David Henderson
Feb 21 2025 at 7:34pm
Thanks, Kevin.
Andrew_FL
Feb 21 2025 at 4:58pm
The Earth has probably been hit at least once in the last 120 years by a “city destroyer small to large nuke” asteroid, that we know of. The Tunguska Event, in 1908, when such an asteroid exploded over a forest in Siberia. Fortunately this was indeed in the middle of nowhere, so it’s thought that maybe as many as three people might have been killed. We have no definitive historical record of other such events (of this magnitude) in human history, which would be odd if they occur about once every 150 years or so, unless of course most of them occur over the ocean and most of the ones that do occur over land occur in sparsely inhabited places-like Siberia.
On the other hand, there is probably marginally more risk to human populations than at any prior point in history, because more places have become more developed and more heavily inhabited. A colonial report from 1908 suggests that Lagos had a population of around 58,215 at the time of Tunguska. Today, estimates vary and are controversial, but probably somewhere between 10 and 20 million. The disappearance of a city of 50 thousand people, even in pre colonial times, probably would not have escaped the historical record, so such events must still be infrequent enough that they’ve never hit a substantially populated area before. But that’s a potentially many orders of magnitude worse disaster.
Overall I would say your assessment of the risk is correct-it is actually quite low. But in the long term, it’s definitely worth developing the capacity to deflect asteroids like this, to say nothing of dinosaur extinction level asteroids.
David Henderson
Feb 21 2025 at 7:36pm
I agree with everything you said.
I would just add that I would rather leave it to people like Elon Musk and Nathan Myrhvold than to the feds.
Mark Barbieri
Feb 22 2025 at 12:36pm
I’m not sure what the size of the impact area is expected to be. If we assume that a “city killer” destroys a typical sized city, I’m going to guess something like 100 sq miles. Earth is home to about 8 billion people and has a surface area of roughly 197 million square miles. So the expected death total would be 0.031 * 8,000,000,000 / 197,000,000 * 100. That’s 1,259. That’s a much lower expected annual death toll than deaths from earthquakes (about 37,000/year) or hurricanes (15,000/year).
David Henderson
Feb 22 2025 at 1:27pm
Well done, Mark.
john hare
Feb 22 2025 at 5:41pm
Even assuming a confirmed impact, there are several strategies for deflection that don’t involve nukes. A couple of the more outlandish ones in the links. The second one partially tested with the double asteroid deflection test a couple of years back.
https://selenianboondocks.com/2009/09/moving-asteroids/
https://selenianboondocks.com/2013/03/dinokiller-eight-ball/
Monte
Feb 23 2025 at 9:16am
The global catastrophic risk of digital totalitarianism is much higher (40-60%) than the threat of this asteroid colliding with earth. I agree with Bryan Caplan that an eternity of that would be much worse than extinction.
Michael Stack
Feb 23 2025 at 4:33pm
I’ve seen arguments of this type but I’m not convinced, and here is why.
Yes, where it eventually hits is unlikely to do a lot of damage, but the concern I have is the damage done in the days leading up to the impact.
My guess is that there will be a fairly large margin of error when determining the impact site. There will be a lot of people in that area desperate to be anywhere but right there. It could lead to chaos as people panic to evacuate. That’s the biggest risk I see.
I also think there could be tsunami concerns if the meteor hits the ocean. In fact, it might be safer if it doesn’t hit an ocean, but I don’t know enough to be sure.
David Seltzer
Feb 24 2025 at 11:36am
Michael: Good points. I suspect NASA is using the Buffon’s Needle hypothesis to determine the asteroid’s probability of landing in any specific area.
Mark Z
Feb 25 2025 at 6:59pm
Perhaps counterintuitively it may be more dangerous if it hits an ocean. If it’s close enough to land, the resultant tsunami could be quite catastrophic, and coastal regions are much more densely populated than terrestrial land in general. (By ‘more dangerous’ I mean the expected cost given it hits water may actually be higher than the expected cost given that it hits land).
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