It looks like asteroid 2012 DA14 isn’t going to hit the Earth. Darn. I was looking forward to an entertaining weekend coming up.
But what would be the outcome if one like this, traveling at about the same speed, fell into, say, the Pacific Ocean? For the purpose of this exercise, let’s assume it plunges straight down, not at an angle, and as far from any land as possible, so the most likely damage would be from tsumanis or atmospheric reactions. Let’s also assume (if it’s reasonable to do so) that it would not break up substantially before water impact. How high would the tsunami be, and how far and fast would it travel? Would there be other distant effects I haven’t considered?
Having not had an event like that ever occur during the modern era of science, is there really a good way to predict what would happen outside computer modeling?
I think the answer is we would have an educated guess at best and that guess would spell doom for a lot of coastal areas at a bare minimum.
see above re: 10 megatons. If it hits close to shore, there might be a tsunami; if it’s out in the ocean, there wouldn’t be much of a ripple. Wouldn’t want to be near where it came down, though.
If it hits land, even though the Arizona crater was much heavier due to being made of iron, I’d assume it’d still put a pretty big dent in any city we’ve got. It’s not a dinosaur killer, but wherever it hits is gone.
You can simulate it at Purdue’s Impact:Earth site.
2012 DA14 is 45 meters diameter, 130 million kg, for a density of 2725 kg/m^3. You can play with the other parameters. I tried dropping it into 1 km of water at 16 km/s, 1000 km away from me. Among the results:
Kind of boring. I tried dropping it into land only 10 km away, but that wasn’t interesting either.
I ran it with the same numbers and it says that it doesn’t even make it to the ground, maybe a few fragments:
Even directly under it (I used 1 km since it doesn’t accept anything less than 1), the only thing of note is the air blast, up to 80 mph (60 mph at 10 km), enough to cause some damage but not worse than a severe thunderstorm.
Also, they have a list of several notable impacts which you can simulate (click on “calculate impact effects” and it will preload the values). The Meteor Crater was created by a similarly-sized asteroid but had very different effects due to its composition.
One thing to note is that this is likely a stony meteorite vs. the iron one that made Meteor Crater. So fragmenting in the atmosphere is much more likely which reduces the damage done on the ground.
A nasty blast for the inhabitants in the area. Almost everyone else wouldn’t notice much had happened. Not anywhere near an extinction event.
Wasn’t the [fragment of whatever] that created the Tunguska event estimated to be about 100 feet across? If that had hit/disintegrated over a populated area, it would have been a pretty miserable day for any inhabitants.
If that Impact:Earth site is accurate, it makes an asteroid hit, at least one of the size, composition and velocity of 2012 DA[sub]14[/sub] look puny compared to recent tsunamis. I would have thought the opposite. Bring it on!
Where it hits seems most important of all. The Pacific Ocean, not so much.
Well, that depends. For a smaller impact, an ocean strike does less damage just because there’s probably nobody there to get hurt. But I understand that with the big impacts an ocean strike is worse because it absorbs more of the impact energy; for example on land you end up with a molten crater that radiates heat back up through the atmosphere into space, while in the ocean the waters cover it back up and all the heat goes into the hydrosphere. Plus of course tsunami.