Not entirely new, but an organization called the B612 Foundation has been getting significant press in the past few days based on a visualization it has made of asteroid hits on earth, gleaned from nuclear test monitoring data since 2000. The visualization can be run from the linked page.
From data first published last year, it seems that between 2000 and 2013, 26 asteroids with energy equivalent to 1000 tons of TNT or greater struck Earth, with the largest estimated at 600 kilotons. This turns out to be a much higher frequency than previously estimated. Worse yet, all of these strikes were by objects of sizes that seem to be below the threshold of detection by current systems.
The main reason we haven’t noticed this rocky hail before seems to be a) most exploded many miles up in the atmosphere (thanks, thin layer of air!) and most also arrived over open ocean or relatively uninhabited areas (Chelyabinsk, Russia being a notable exception).
B612 (apparently named after the home of Saint-Exupery’s Little Prince) is promoting the idea of a detection system that would be more successful at detecting these smaller objects. With odds that imply a potential city-buster arriving every six months, on average, they may have a point. Meanwhile, I’m going to do the manly thing: go home and cower in bed with the covers over my head.
Well, suppose that one that hit Russia a couple of years back had occurred during the most recent Ukraine fiasco? It would probably benefit us all if some space scientists were able to shout “duck” a few hours in advance, even if all it means is that no one presses the big red button in a panic.
Well, looking at it that way, the story is: “Approximately 26 giant asteroids were harmlessly disintegrated in Earth’s upper atmosphere. OK, a few made it to the surface. Most hit the ocean, 'cause it’s 70% of said surface. The chances of anything landing in a populated area are extremely remote.”
Dinky ones like that aren’t worth the trouble- think about the surface area of the earth covered by cities, houses, etc… relative to the total amount. It’s vanishingly small, and the likelihood of a city being hit by one is minuscule.
And… even at that, a 1 kiloton asteroid hitting a city wouldn’t be THAT destructive- it would wreck shit in a circle between roughly half a mile and 3/4 of a mile wide. Bad, but only bad like a tornado, not bad like a nuclear weapon.
And far less likely than tornadoes are in places prone to them.
The cynic in me wonders how many of those asteroid strikes were actual clandestine nuclear tests…
The Chelyabinsk meteor inflicted nearly 1,500 injuries (mostly due to broken glass and flash blindness) and caused approx. $33 million in damages – I wouldn’t call that “minor”. And while it was indeed a rarity, keep in mind that the Earth’s far more densely populated than at any time in history – heck, there could’ve been a devastating asteroid strike in a Native American village back in the 1700’s, but we have no way of knowing about it.
So yeah, maybe we should be paying more attention to rocks that fall from outer space…
1500 injuries but 0 deaths isn’t minor but it’s not major either.
Nevertheless, they should keep an eye on them if only to keep itchy trigger fingers from pressing red buttons. Can you imagine if a 600 kiloton-force meteor struck in the Korean peninsula without warning? Even if it plunged into the water off the coast it could cause a war if nobody knew what it was.
There’s plenty of other regions where an unlucky meteor strike or burst could lead to mayhem: Pakistan/India, Venezuela/Colombia, Iran, Israel, Eastern Europe, etc…
I accept that the actual odds of a city-busting strike remain fairly low, but I’ve gotta dispute the above. Tornadoes don’t impact, without warning, at 20-40,000 miles per hour. IMO a ground impact would indeed be much more like a small nuke going off than a tornado, and the loss of life would almost certainly be far higher than for any given tornado.
I’m very happy indeed that the atmosphere absorbs most of the energy of these things, but remain fascinated by the knowledge that objects of maybe 50-100 meters apparently are bursting over our heads a couple times a year, and yet going more or less completely unnoticed.
Well, no, that is the wrong conclusion to draw. What it really means is that the estimate of the quantity of of meteors which impact the Earth, which is largely based upon extrapolation of recorded impacts, has just increased. And because small celestial bodies pretty closely follow a power law distribution, we can infer that the number of larger bodies which could cause regional or global catastrophe will also increase, and the mean intervals between impacts will decrease, which substantially increases the probability of such a large impact (the so-called “meteor flux”) in human lifespan.
We tend to assume that because such a catastrophic impact has not–as far as we are aware–occurred within the historical record, it will not occur, but such reasoning is statistically flawed; although these kind of large impacts fall into the outlying tails of a normal (or more properly log-normal) distribution, we don’t have enough data to really define the shape of these tails, and our estimates of the frequency of occurrence may easily be wrong by orders of magnitude. A single large bolide impact of even 500 meters diameter could do sufficient damage to essentially wipe out a good chunk of Europe or the entire US Eastern Seaboard.
As for what can be done about the problem? The first step is to get a handle on just how many threats there are. To do that we need a better survey ability than is available from ground telescopes. A small constellation (3-6) solar orbiting observatories at ~0.9 AU would increase our ability to detect potentially hazardous objects by several orders of magnitude to the point that we should be able to catalogue every object of threatening size which is in a short period orbit. The cost for this? Oh, probably 2-3 billion US dollars–about half the cost of a single new ballistic missile submarine. The second is a method to intercept and deflect hazardous objects. Many proposals have been advanced, but my personal suggestion is to use a series of radiation-generated plasma “slugs” to push the hazardous object(s) into a non-intercept orbit. Cost to develop such a system? 10-20 billion US dollars (depending on capability), and a few billion a year to deploy and maintain it, i.e. about 5% of the cost of upgrading and fielding the fleet of ~450 Minuteman III ICBMs. (Most of the hardware to do this is literally off-the-shelf; the major development effort would be validation of the system capability.)
So, for a fraction of what it costs us to defend against terrestrial threats based upon political squabbles, we could significantly mitigate the possibility of the deaths of tens or hundreds of millions of people and the potential destruction of trillions of dollars of real estate and industrial capability. Chew on that.
I went out to HYDESim, a nuclear weapon simulator page, and simulated a 1 kiloton surface burst.
Since it would be pretty much blast only, without serious heat (relative to a nuke), and no radiation, the radius of a 1 kiloton nuke’s 3-5 psi overpressure curve is about half a mile to 3/4 of a mile. That’s about where regular wood frame homes would be seriously damaged.
That’s something like half a square mile of destruction. By contrast, the Moore, OK tornadoes last year were something like 30 square miles of destruction of the same degree.
You’ve heard of Tunguska, right? Had that happened a few hours later, it might have hit St Petersburg or Oslo. Getting people to shelter would save many lives.
I didn’t spot 1000 x ton (of dynamite) either. I was vaguely familiar with the news, and I just thought, Oh, is there someone with this last name (perhaps pronounced Kil -AHH- t’n) leading the research? :o
