…it’s just the latest one:
On 8 October an asteroid detonated high in the atmosphere above South Sulawesi, Indonesia, releasing about as much energy as 50,000 tons of TNT, according to a NASA estimate released on Friday. That’s about three times more powerful than the atomic bomb that levelled Hiroshima, making it one of the largest asteroid explosions ever observed.
However, the blast caused no damage on the ground because of the high altitude, 15 to 20 kilometres above Earth’s surface, says astronomer Peter Brown of the University of Western Ontario (UWO), Canada.
Brown and Elizabeth Silber, also of UWO, estimated the explosion energy from infrasound waves that rippled halfway around the world and were recorded by an international network of instruments that listens for nuclear explosions.
Emphasis mine. We get hit a lot more often than people realize. And we’ve been very lucky so far that none of them have hit populated areas.
Fortunately, the asteroids continue to have lousy aim. But eventually they’ll get one on the mark.
Does anyone really know how extraordinary our luck has been? Can a probability be worked out for each of the last five or ten known major impacts what fraction of the Earth’s surface, had it been struck, would have led to a humanitarian disaster? Also, what fraction of the Earth’s surface could have been struck without anyone even being aware of the impact (thereby helping us better estimate the true annual rate of major impacts)?
Forget asteroids. The big dangers (for the CONUS) are 1) the Big One that puts LA into the Pacific Ocean, 2) the Big one that dumps Seattle into Puget Sound, 3) the Big One that slides Memphis into the Mississippi (I keep telling my wife I want to put latches on our kitchen cabinets here in Madison, WI to keep the dishes off the floor), 4) the Tsunami that takes out the East Coast of Florida, and 5) the Yellowstone Volcano that buries the whole Eastern half of the United States.
Yeah, but none of those would start a nuclear war. A 50-kT blast at low altitude in the Middle East, SW Asia, or the Indian subcontinent very well could.
Interesting–Last night I was just looking up some things in Morison about the Battle of the Java Sea which happened near this blast location. (Exeter, Houston, Perth, Ford, Pope, Alden, Electra, Jupiter, Encounter were some of the ABDA ships).
Gets me thinking that if this thing had impacted back then in 1942 and actually been big enough (or of the right composition) to actually hit the ground, all of man’s struggles, so serious and deadly then, would have been rendered immediately moot and irrelevant by this broadside of a cosmic sort.
And so it ever is. Today’s crisis issue that must must must be solved is tomorrow’s extravagant and unwarranted luxury.
Well, and then there’s my own monster-under-the-bed: a solar mass ejection like the one in 1859, which generates and EMP that instantaneously fries all transistorized electronics in the world, and blows all our electrical power grids, thereby ending the current technological civilization. And probably also extinguishes any human colonies on the Moon or elsewhere in the solar system…
Once teh zombies etz are branz it won’t matter.
Seriously, we as a species are in serious need of some fault tolerance in the form of another basket in which to place our collective eggs.
Maybe we deserve to die out on this little rock if we can’t see what is truly important.
Mr. Milenkovic – The most likely Big One is the one that vapourises Manhattan Island. It’s also the only one that humanity can currently do anything about.
“if dinosaurs had a space program .. ” they would have sat around endlessly wringing hands about the destination it needs to go to, whether you need heavy lift or can you send brontosaurus up in pieces, and the purpose of it all.
Until the hit came.
“Maybe we deserve to die out on this little rock if we can’t see what is truly important.”
Fortunately, we don’t all have to see it (or nothing might ever get done), merely enough of the right people…
The big variable is how often they come. Given recent revelations about Tunguska being smaller than thought (http://impact.arc.nasa.gov/news_detail.cfm?ID=179), our understanding of the frequency has increased.
The rest of the calculations deal with actually how small an area on the planet we humans inhabit. Such a large percentage of us are concentrated into cities, with the rest of the planet being oceans or undeveloped it’s actually kind of hard to hit a large concentration of people.
Three items counter the ‘low concentration’ argument (the preview is showing a format change for the first two entries…not my intentional doing):
1. Large enough impactor effecting the climate – They’re rare
2. Infrastructure in an industrialized nation (think impact in a field in the US that takes out a cross-country gas line and/or a high-voltage electrical line) – Don’t know the odds of this sort of thing
3. Ocean impact causing tsunamis – This was a big worry of mine until a friend pointed out that an impactor would be a ‘prompt’ event compared to some sort of undersea landslide which moves much more water. The examples he cited were the Crossroads Able and Baker (I’d link, but Rand’s new rules only allow one so you’ll have to Google them yourselves. You’ll recognize some of the video) tests in the 40s which didn’t create much of a wave on the nearby islands. I haven’t done much research to counter this argument. If someone has such info, I’d love to see it.
“if dinosaurs had a space program .. ”
… they would also have had the ability to survive the K/T asteroid impact (as a species) without a space program. Food stockpiles and seed banks are cheap.
You know, maybe the dinosaurs did have a space program, and that’s why they’re no longer here.