Russian Meteor Largest In a Century

gbrumfiel writes "A meteor that exploded over Russia's Chelyabinsk region this morning was the largest recorded object to strike the earth in more than a century, Nature reports. Infrasound data collected by a network designed to watch for nuclear weapons testing suggests that today's blast released hundreds of kilotons of energy. That would make it far more powerful than the nuclear weapon tested by North Korea just days ago, and the largest rock to strike the earth since a meteor broke up over Siberia's Tunguska river in 1908. Despite its incredible power, the rock evaded detection by astronomers. Estimates show it was likely only 15 meters across — too small to be seen by networks searching for near earth asteroids." Today's meteor event came a day after California scientists proposed a system to vaporize asteroids that threaten Earth. Of course, the process needs to be started when the asteroid is still tens of millions of kilometers away; there's no chance to shoot down something that's already arrived.

Rain of Iron and Ice

[MetricT]

My favorite book on impacts. Scarier than any Stephen King novel you'll ever read, because it's real.

http://www.amazon.com/Rain-Iron-And-Ice-Bombardment/dp/0201154943/ref=sr_1_1?ie=UTF8&qid=1360966611&sr=8-1&keywords=rain+of+iron+and+ice [amazon.com]

Nature is wrong

[K. S. Kyosuke]

"A meteor that exploded over Russia's Chelyabinsk region this morning was the largest recorded object to strike the earth in more than a century, Nature reports."

Meteors don't hit earth, meteorites do.

Russian Meteors

[Exquisite Clothes]

Watch the drive-by movie made by russian citizens passing by here (You can also hear the bang) : https://www.youtube.com/watch?v=wJO9Io4Suog [youtube.com]

Does Russia have a bullseye painted on it?

[erice]

This one, Tunguska,and one in 1947 called Sikhote-Alin [wikipedia.org] that some are claiming is bigger than yesterday's rock (though still smaller than Tunguska).

Granted, Russia is the largest country in the world by land area but do *all* the big rocks have to land there?

Re:Nature is wrong

[Ol Biscuitbarrel]

"Meteorite: A meteor that survives its passage through the earth's atmosphere such that part of it strikes the ground."

Re:kiloTONs of ENERGY?

[Anonymous Coward]

The ENERGY released by Nuclear bombs is often measured in kilotons which is an equivalent weight of tnt. Therefore, kilotons makes sense, but it is a weird unit.

Re:kiloTONs of ENERGY?

[Kozar_The_Malignant]

The kiloton unit came into use to describe the explosive energy of the early nuclear bombs. A one kiloton nuclear explosion released the same energy as a 1000 ton (kiloton) TNT explosion. For people in the 1950's who were used to reading about 500 lb. and 1000 lb bombs used in WWII, it provided a useful mental scale.

Re:kiloTONs of ENERGY?

[Deadstick]

Energy is measured in joules fools.

Yes it is, professor, and a kiloton is 4.18*10^12 of them.

Re:Kiloton? Kessel Run?

[tp1024]

By convention, it is the energy released by spontaneous decomposition of 1000t of trinitrotoluol - or 4.2 TJ of energy.

Re:Still overdue

[icebike]

They say to expect a Tunguska sized one once a century and this one wasn't that big. They mostly ocean explode or strike so there's few signs of them but an ocean strike can be worse than a land one given the water they displace. They've got to wake up and start properly funding the near Earth program. It still won't protect against rouges but at least they can map ones that cross our orbit.

Really?

Just detecting these things can cost billions. Doing anything about them can cost trillions.

And most of these are air-burst, like yesterday's, (and like Tunguska). Since statistically, 3/4 of all are likely to hit ocean, the return on investment is going to be un-measurably small.

Air bursts over water are not likely to generate any significant amount of water displacement, and therefore no ocean wave damage.
In fact, if you take the Tunguska event, you learn from wiki "To the explorers' surprise, no crater was to be found. There was instead around ground zero a vast zone (8 kilometres [5.0 mi] across) of trees scorched and devoid of branches, but standing upright.". A similar event over water might generate some local surface waves, but nothing of significance because there would be nothing offering any resistance to the blast wave.

Take something the size of the object that created Meteor Crater (50 meters in diameter), about 3 1/2 times as big as yesterday's object, didn't air-burst, but a substantial portion of it burned up on entry. The crater (3/4 miles in diameter) could have killed at most several million people if it hit down town London or New York city. But the biggest cities on earth are a tiny target.

But its likely it would have never been spotted, not by any technology today, and not by any technology proposed. I suspect the cost of developing the technology and maintaining it year in and year out, upgrading it every so often, shutting it down in periods of austerity, firing it back up when fears are rekindled are simply not worth the effort, especially when you consider the chance of success is minuscule at best. Its most beneficial effect would be as a jobs program, for people who believe the government should be the source of all jobs.

Re:Nature is wrong

[osu-neko]

Well, what "meteor" actually means (from Greek) is "suspended in the air". So no, technically, the moment it touches ground, it's no longer a meteor. Arguably, meteors and meteorites are meteoroids. That term is usually only used while it's still in space, but technically any such rock in the solar system is a meteoroid, and it's still in the solar system while it's burning through the atmosphere, or sitting on the ground on Earth. A meteorite ceases to be a meteor when it hits ground, but they're both really still meteoroids.

Re:Still overdue

[Jarik C-Bol]

Radio Telescopes function by 'listening' to the noise generated by stars and other celestial objects. radar works by sending out a signal, and 'listening' it being reflected back, and uses the distortions in that reflection to calculate the location of an object. (more or less, thats a simplified version obviously). Now, imagine trying to detect something, that is moving so fast, that by the time the radio reflection gets back to you, it has moved entirely out of the area of sky you where scanning. the result would simply be a brief 'pip' on the screen, and the next scan pass would show nothing. Now imagine that there are hundreds, if not thousands of those objects out there, at various ranges and speeds, PLUS all the artificial satellites between us and those objects. The result on your screen would be something like the 'snow' on a TV tuned to an empty over the air broadcast channel. And that is just looking at a more or less postage stamp sized swatch of the sky. Beyond that, the interference caused by flooding the sky with radar signals would likely cause problems for terrestrial vehicles that use radar for navigation. Yes, it would be good if we could detect and track the (probably billions) of near earth objects, down to the smallest grain of interstellar gravel, but in the practical sense, we have neither the time, money, computing power, or sensing technology to achieve such a goal.