I have a few questions about the Tunguska event of 1908.

I have been told that it was it was a small chunk of a comet that broke off, but I have also heard it was an asteroid. So what was it part of a comet or an asteroid.

Second question is could it happen again, but this time it a major populated area. Like the North East, California, Western Europe, China, ect. Could it happen again, and without warning.

Also if it could happen again what are the odds of it happening in the next 25 years.

No clue on the odds, but yeah, we're actually about due for one.

Current thought is that it was a Stony Meteorite, that Air-Burst.

As for what it would to city?

Think Megaton Explosion, if not more.

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"The whole problem with the world is that fools and fanatics are always so certain of themselves, but wiser people so full of doubts."
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If I remember correctly, the evidence behind a comet was the fact that the event happened during the annual Bootid meteor shower (which is caused by a comet). It is possible that the body that caused the event was just a big part of the comet that got separated from the parent body.
And it could certainly happen again. A few hours later and the event would have happened over Moscow or London, which is incredibly small in astronomical terms.

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It is a sobering thought that the Tunguska event (~60 degrees north) is a similar latitude to the major European population centres of Stockholm, Oslo, Helsinki... if the impact had occurred some 6 or 7 hours later, we would have little problems getting funding for NEO surveys today!

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Whether it was a small comet or a small stony asteroid is really irrelevent. Something exploded in the atmosphere and blew down hundreds of square kilometers of Siberian forest. If it had happened over a population center, it would have blown down several hundred square kilometers of city. The toll would have been in the hundreds of thousands or more. And yes, it could happen any time.

FWIW - A stony asteroid exploded over Chicago last year. Fortunately it was smaller than the Tungusta event. The blast did not do any damage, but fragments were found (and are still being found) over a large area.

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We lucked out with that one! The harsh truth is that I doubt we will luck out forever.

Check out this nice site from the UK...has some good maps: http://www.arm.ac.uk/impact-hazard/

Also, another great source of information about NEOs can be found here: http://www.permanent.com/a-impact.htm

I wonder why the "woo woos" of the world latch onto all sorts of stuff that doesn't exist when here you have something that should actually be ringing our alarms bells...loudly!

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The short answer, if it happened over a population center it would be bad. Very bad. Worse than crossing the beams.

I'm not sure we know enough or have enough statistics on NEOs (near-Earth objects) to make decent predictions, but I think it is going happen, and maybe soon, in the geological sense (meaning between tomorrow and 10,000 years from now).

And interesting but fictional prespective is the introductory chapter to Arthur C. Clarke's book Rendezvous with Rama.

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One Earth, One Sky - IYA 2009

As pointed out it would be very bad indeed. It could be even worse if it happens in a country with nuclear weapons. If it was not seen coming it could be easyly mixed up with a nuclear air blast and the country involved might retaliate on the suspected country. In the case of western countries the retaliation is not so likely as they would have more than one suspect so they should spend time investigating the origin before launching. However if it happend in countries that have an ongoing state of war with another country then this might not be the case.

If it was India or Pakistan they might instantly assume it was the other and fire. If it was North Korea they might assume it was the states and fire, also at S. Korea.

This is why it is most important that more reserch is done to track any space body that could impact and give a confusing message.

Edited for spelling

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http://boinc.mundayweb.com/one/stats...630/prj:6/.png

Which has the event occuring at 9:46 in the morning on September 11th destroying two cities.

I remember reading that in fact U.S. Air Force satellites have picked up meteors entering the atmosphere and have declassified some of that information (yeah, I could go goggle it, but I'll leave that for someone else). They are able to distinguish between meteors and weapons, probably by the details of their infrared signature. But I don't know the details myself.

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At night the stars put on a show for free (Carole King)

One Earth, One Sky - IYA 2009

I was wondering about the U.S and if they had the tech to tell the difference. The problem is not all countries will have this ability. Can you imagine a burst over N.Korea and the US trying to reasure them that it was an exploding comet?

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http://boinc.mundayweb.com/one/stats...630/prj:6/.png

http://www.space.com/scienceastronom...or_010524.html

http://www.space-frontier.org/Projec...ytracking.html
http://dsc.discovery.com/news/briefs...16/meteor.html
Ok, I googled. Here's a couple of links. Just briefly went through them, sounds like it is possible to tell the difference, but not quick or easy.

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At night the stars put on a show for free (Carole King)

One Earth, One Sky - IYA 2009

Well, that's great that there's technology available to tell bombs from meteors....we sure don't need any "Oops, we thought you guys were attacking us!" scenerios.

However, I've yet to read about any good options for diverting a NEO that was large enough to do us great harm. In fact the final paragraph of the "The Watch" article was certainly "cheerful".

"The disclosure of such intruders is seen as bolstering the idea that the earth is periodically subjected to strikes by even larger objects, including doomsday rocks a few miles wide. Objects this size are predicted to hit once every 10 million years or so, causing mayhem and death on a planetary scale."

Hmm...So, where are we on that "10 million years or so" timetable?

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It is not a timetable, but a statistical relationship. If you roll two dice, "snake-eyes" should come up once every 36 rolls. If you roll "snake-eyes", it does not mean that you will have to roll the dice 36 more time before it comes up again. It could happen on the very next roll.

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Any day you wake up on "the right side of the dirt" is a good day.

T. Anderson

Oh, that's just great! I knew it was bad...just not this bad.

However, the odds must be fairly large (we don't see huge things hitting us very often). Are there any statistics available on exactly what the risk is for something of significant size hitting us? I haven't been able to find out anything specific about this.

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An open mind is like an open window...without a good screen you'll get all sorts of weird bugs!

About 42,000 Americans get hit and killed by big cars, trucks, and SUVs every year. If you live in a place where swarms of these metallic things tend to congregate and move around at high speeds, your life is in danger on a daily basis.

But I wouldn’t worry about getting by a comet or asteroid anytime soon. The last big one that fell out here where I live missed my place by about 200 miles, and that was about 50,000 years ago. But those smaller metallic things are knocking people off every day out here.

The problem is that if something of sufficient size clobbers us then it would be a disaster of epic proportions. Large numbers of individuals can die in automobile accidents and it doesn't have the global consequences that a large impact would have....that's what alarms me.

I hope that something large doesn't find it's way here but as far as I can tell that still remains a possibility.

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An open mind is like an open window...without a good screen you'll get all sorts of weird bugs!

No one knows for certain what it was.

Yes it could happen again, it has been suggested that this kind of impact (where the impactor explodes above ground) may happen more often than we think.

Unknown Odds. It could happen today, it could happen ten years from now. It could happen a million years from now. No one knows for certain.

Az

There was once a theory that the Tunguska object may have been a chunk of the comet Encke. Something about the orbital characteristics closely matched the orbit of Encke, and the comet was fairly close to Earth at the time. But I'm not sure if that theory has been proved or discounted.

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