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More detailed info:

https://www.psi.edu/epo/moon/moon.html

All of you showing concern over this event should have a gander at orbit@home, a distributed computing approach to monitoring near-Earth asteroid activity.

Yes, it takes quite a while. There is more than one way to make a generally circular depression in the Earth's surface. The article mentions salt diapir structures ("salt domes"), but volcanic features, updoming or depression of rock layers due to tectonics, differential erosion of various rock types, rounded igneous intrusions, and all sorts of other things can produce circular features. Furthermore, many craters aren't depressions in the first place (they get filled in, and the larger craters have a central uplift). For this reason a circular structure is only a candidate crater and the odds are fairly low that an individual circular structure is an impact crater. It takes geological work on the ground to determine whether it really is a crater, such as finding impact melt, breccia, shatter cones, shocked quartz, and other signatures of an impact. Here is a pretty good site that describes the typical geological features of impacts. Given that many of these candidate features are in remote locations and only a few people do this kind of work it can take some time before someone investigates a particular feature.

The location you provided the link for (a bay in easternmost Russia) isn't a good candidate. The curved shape of the coastline on the west side of the bay is just an effect of a wave-swept coastline -- it tends to develop a broad curve away from the points of land on either side due to the refraction of the waves and transport of sediment laterally. here are some similar examples on Sakhalin Island, and here are some on the Kamchatka Peninsula. In the latter image you can see the shoreline-parallel beach ridges that define the coast. In the north end of the bay you mention, there are mountains that seemingly cut across the arc of the rim -- not what you would expect if the rest of the circular area is an excavated impact crater, although I suppose it is remotely possible they were uplifted subsequently.

It has large error bars, but it's the best we have until we can send radiometric dating to these areas. [Crater Counting]

If you'd like a somewhat more detailed explanation, try Dr. Hartmann and Herres six year old explanation at:

http://www.psi.edu/projects/mgs/cratering.html

Its probably a good time to remind people that the distributed computing project to search for dangerous NEOs is soon to get under way. Test workunits have already been sent out and the news is that they ran very well.

These articles rarely mention that there are two camps in the scientific community, one of which is largely American, and rejects any evidence for recent liquid water on Mars, and the other of which is more European, and accepts it.

The Mars cratering model indicates that a billion year old surface on Mars should have multiple 100 meter craters per square kilometer, and maybe ten 50 meter craters per square km . Basically, if you see a picture of the Martian surface, and there aren't lots of little craters on it, then that is not a billion year old surface, regard of what the press release says. It isn't hard to find such images. Here is another, and another.

Received its funding from NASA a little while back.

http://orbit.psi.edu/

You can already sign up!

Distributed computing search for NEOs is ramping up:
http://orbit.psi.edu/

The Giant Impact theory for the formation of the Moon was accepted by much of the community over the course of a single meeting, I've been told by a participant.

A quick search reveals that is the case:

Some work was done by Thompson and Stevenson in 1983 about the formation of moonlets in the disk of debris that formed around Earth after the impact. However, in general the theory languished until 1984 when an international meeting was organized in Kona, Hawaii, about the origin of the moon. At that meeting, the giant impact hypothesis emerged as the leading hypothesis and has remained in that role ever since. Dr. Michael Drake, director of the University of Arizona's Planetary Science Department, recently described that meeting as perhaps the most successful in the history of planetary science.

That's very cool.

My economics professor told us essentially the same thing about the Coase theorem. Allegedly, Coase presented it to a group of economists all of whom rejected the theory right off, but by the time they'd left, he'd convinced every last one of them. (I, however, think it needs a few qualifications.)

Changing an asteroid's path is just a technological achievement.

The purpose of changing an asteroid's path is a political decision.

The 'Save the Earth' Technology also becomes one hell of a weapons platform when put into the hands of the military. Cheaper than a nuke and more powerful too, with no radioactive residue.
Spaced based weapons scaling from city sized attacks up to planet killers. Ouch.

Problem overseas? Drop a big rock on the capital of a country, or its major industrial city, or its highest density population center.

Tunguska Destroyed Forest

Make it look like a 'natural event' and hide your countries true political motives...

To assume that technology could be used only for the good of the people is naive, at best.

But here's the thing. Earth's Moon was born in a catastrophic collision more than 4 billion years ago.

So is this established fact now? I thought the that was far from proven, and even a quite debated theory. But maybe the impact hypothesis has gained traction in the science community since I heard of this?

Then you probably haven't heard for twenty years or so. The Hartmann/Davis/Cameron/Ward theory is pretty much the only one that accounts for the known facts (composition, angular momentum, etc.) and has been the standard explanation for decades. It's never been really seriously questioned since it was proposed in the mid 1970's. Are you perhaps thinking of the pseudo-scientific collision-with-Venus nonsense instead?

See the Planetary Science Institute's writeup for more details, or just Google.

--MarkusQ

but only after they crash into you

In Soviet Russia the comet shoots YOU.
(http://www.psi.edu/projects/siberia/siberia .html)

And at Stanford University in California an experiment might be done later this year to create mice with human brains.

the odds of an asteroid hitting earth: 1/1,000,000,000,000 or soemthng like that.

No. The odds of a city-busting size rock hitting Earth are so close to 100% we're talking a miracle if it never happens again. Last one fortunately hit an uninhabited area of Sibera.

The question is when and where, not if.

The reply to your comment is right.
Lets say the 7.7 miles/sec for the asteroid hits earth along its orbit(I don't know the validity of this, but giving the benefit of the doubt). Earth is traveling at around 18.2 miles/sec. That makes the distance between them shrink at about 27 miles per second. So it is more like 2 seconds to break the atmosphere and hit earth, but it is more likely not to actually make contact. It would probably just burn the earth for miles.
This is assuming that it is morning at ground zero of the impact site, a maximum
Interesting Link

100 feet makes it significantly smaller than Tunguska, which was theorized to be 50 to 80 meters. So, it is a city killer, not a planet killer.

Umm. Says who? Let me quote from this webpage:

The Earth's atmosphere protects us from most NEOs smaller than a modest office building (50 m diameter, or impact energy of about 5 megatons). From this size up to about 1 km diameter, an impacting NEO can do tremendous damage on a local scale. Above an energy of a million megatons (diameter about 2 km), an impact will produce severe environmental damage on a global scale. The probable consequence would be an "impact winter" with loss of crops worldwide and subsequent starvation and disease. Still larger impacts can cause mass extinctions, like the one that ended the age of the dinosaurs 65 million years ago (15 km diameter and about 100 million megatons).

A 2 kilometer wide "big rock" as you call it would cause life-ending destruction on a worldwide scale. True we'd probably survive as a race and eventually recover but billions would die. I'd call that a "life-ending level of destruction on a worldwide scale".

Now obviously would it be better to let that 2km rock hit the Earth or break it into smaller pieces? These smaller pieces that survived the atomosphere would still hit with the impact of thermonuclear bombs (read up on the Tunguska event sometime) and destroy everything for miles around ground zero. Obviously if one of these fragments impacted in or near a large city the death toll could be in the millions -- but I'll take that any day over a nuclear winter and billions of people straving to death.

With all the messages referring to Microsoft being involved in an incident that occured before Microsoft really existed as such, I wonder if they are also to blame for the 1908 Siberian blast.

More importantly, is Microsoft still operating under the directive of an old memo that said "send self-destructing OS to USSR" in which someone accidentally left the last two letters of USSR off? That could explain a lot.

Apparently they failed

It's the media that adds the "this killed the dinosaurs" hype to it. They merely find evidence of collisions, but it's near impossible to accurately date them.

I am not sure about the impossibility story. Reworking of the surrounding and subsequently formed rock structures certainly makes it difficult. For example, if one can put date on rocks that were obviously disturbed by the impact, this puts a "floor" on the oldest time of the impact. Difficult, but not impossible.

Many of the craters probably predate all life on earth. Maybe one of em is the one that split off the big chunk of rock that we call the Moon now.

Comets crash in Siberia!

I suppose the previous post would have been more impactful with a link

Please take a few minutes staring at the Moon and reconsider. The many huge craters on it hint at the number of impacts which hit planets...and remember the lava-covered flat 'marias' used to have visible craters too. Also consider the Moon itself as evidence of the power of impacts. The Moon was blasted loose from the Earth by an impact.

You're probably underestimating the number of collisions, the violence of the collisions, and the effect of the low Mars gravity. Also, any rocks leaving Mars would be in an orbit similar to Mars -- near the ecliptic (the plane of all the planets). Rocks with a velocity slower than Mars (whether due to the impact or repeated close encounters with Mars) would head toward the Sun, crossing Earth's orbit. Space is very empty, but having the objects in similar planes and orbits greatly increases the chances of encounter.

There also are indications here on Earth of energetic impacts. If you look at the meteorite impact site maps, you'll see there have been many dozen of these impacts (most of Earth has not been mapped for impacts). These are impacts which were so violent that they changed the magnetic pattern in rocks "at some depth".

Here's a link to some information about one of the most famous and asteroid/meteor explosions in history. It landed in Tunguska, Siberia.

All you need to do is nudge a small space rock.
This could be done with non-nuclear rockets...

An ion engine with a couple thousand pounds of fuel comes to mind. Storable, Efficent, Hard to Detect...

Remember they estimate size of the rock that caused the 1908 siberian explosion is 50 meters (1/2 a foot ball field).
Link here

Doesn't take much to change the orbit of a rock that small.

TastesLikeHerringFlavoredChicken

Well, the current status of the theory is that it still seems the best one. You might be thinking of the early 1997 research which is mentioned near the bottom.

--- Brian