As you may know, a meteor hit Russia and it was a kind of dangerous meteor.
Why did nobody realize the meteor? If they had realized, why did no one do anything about it? Why didn’t they try to prevent it from being dangerous?
Because on a cosmic scale, it was microscopic (about 50 feet in diameter). There is no tool in use that would detect such a small object, coming in on a random vector from any direction of the sphere, except by accident.
Even if they did see it, what measures could anyone have done to prevent it from being dangerous?
They could evacuate the area.
It was too small to have been seen before. Current estimates put it at about 15 metres diameter, only about a quarter of the diameter of the asteroid 2012 DA14 which passed by much later that day. There must be significant numbers of smaller objects which pass the Earth without hitting it all the time and we don’t see them; I can only urge that a program is put into place that could detect the smaller ones too.
Actual question: Is it even possible to plot the impact point of such an object with any reasonable degree of precision and far enough in advance to make evacuation possible?
This foundation is trying to do just that.
From their web page:
The B612 Foundation is a nonprofit 501(c) 3 organization dedicated to opening up the frontier of space exploration and protecting humanity from asteroid impacts. On June 28, 2012, the Foundation announced its plans to build and operate the first privately funded, launched, and operated interplanetary mission – an infrared space telescope to be placed in orbit around the Sun to discover, map, and track asteroids whose orbits approach Earth and threaten humanity.
Arthur C. Clarke suggested such around 1973. We do have a system that will detect most larger (100m) objects, but tracking smaller ones that are still capable of doing damage is an orders-of-magnitude problem
Even if you could, I don’t think it would be useful — it’s my understanding that most of the injuries were from the shockwave that resulted from the explosion of the meteor in the sky, before fragments impacted the Earth. While given a path and velocity I’m sure you could calculate an impact point, I don’t know that you can reliably predict when and where a meteor will lose enough integrity to explode in the sky.
In other words, if a meteor is traveling west to east over the U.S. and its trajectory indicates that New York City is going to have a bad day, it’s not much use to evacuate Manhattan if it explodes over Chicago and injures millions who expected a nice light show.
This asteroid was much smaller - only 2-5 meters, or 1/7 to 1/3 of the diameter and 9-56 times less cross-sectional area, yet was detected with two days’ lead time:
Presumably, this one was discovered because they were doing a sky survey in the general direction it came from, suggesting that the Russian meteor wasn’t detected simply because nobody was looking there, not because we don’t have the capability to see such small objects.
(My bold)
That can’t be the right word. “Fiery decomposition all at once?”
I don’t know what the mechanism is. If I had to make a WAG, I’d say the rock heats and at some point fragments into two or more pieces, providing more surface area for more heat to be generated. These pieces may be less structurally stable than the whole meteor was, and thus they fragment, and so on. After the first fracture, the rest could happen in seconds. It would increase the surface area available for heating pretty significantly and I’m guessing the big boom comes from the shockwave from the rapid expansion of air.
So there may be a more precise word, but “explosion” surely seems to be fairly widely accepted.
Demonstrated in these examples:
[QUOTE=Leo Bloom]
Yet why did the Russians not freak out that they were under attack?
[/QUOTE]
Oh, you just have to give those crazy Russkis time to get in front of a microphone:
Meteor strike result of secret US weapons test: Russian MP
[QUOTE=Liberal Democratic Party leader Vladimir Zhirinovsky]
A member of Russian parliament says the recent meteor strike in the Ural Mountains was in reality the result of secret testing of new weapons by the US.
“Those were not meteorites; it was Americans testing their new weapons," said Russia’s controversial Liberal leader Vladimir Zhirinovsky.
"[US Secretary of State] John Kerry wanted to warn [Russia’s Foreign Minister] Lavrov on Monday, he was looking for Lavrov, and Lavrov was on a trip. He meant to warn Lavrov about a provocation against Russia,” Zhirinovsky added.
[/QUOTE]
Haven’t paid close attention (so I won’t be surprised if I am wrong), but I thought the shockwave was from a collosal sonic boom.
aka an explosion.
Looks like it came from the general direction of the sun which might have something to do with it not having been detected earlier.
But remember that Clarke’s SPACEGUARD had a few things going for it:
[ul]
[li]it was the result of a cataclysmic disaster[/li][li]it was backed by a planetwide government[/li][li]it was a necessary plot device.[/li][/ul]
Not really.
Why should anyone have? Space is big. Really big. Really really big; the meteorite was very small and very fast.
In principle, we could detect an object like that and predict its impact point years in advance. In practice, though, that would require us to be extremely lucky, since it would involve coincidentally pointing a bunch of powerful telescopes at just the right spot in the sky before we could even discover it.