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Odd Impact Crater found in the North Sea
An anonymous reader writes "Just noticed this on MSNBC. It seems they discovered an impact crater in the North Sea that doesn't look like anything else seen on Earth. Supposedly it looks like something usually seen on moons of Jupiter."
Earth and what's seen on Jupiter...did I miss something in the article?
Its the concentric circles around the crater that set this one apart from other eathly craters. They still aren't convinced that an asteroid impact could create a crater like that but may rather have been caused by "an up-from-below phenomenon known as salt diapirism."
the article says that they're 99 percent sure that it was an impact crater, though.
Here's another story about it Nandotimes.com . I think that this is pretty neat. I'm glad to see how technology is able to detect stuff like this even deep under the sea.
...to catch space rocks. If you let them hit the water, they splash all over everything and heat up the air. Better to catch them _before_ they enter the atmosphere.
See, if the dinosaurs had been smarter, they wouldn't be extinct. Q.E.D.
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... the fact that many terrestrial impacts have only one ring, not many. It's an interesting question as to how the "extra" rings come about.
For an example of the difference here, try dropping a decent-sized rock on a beach. The crater it creates has only the one ridge (if any). So, how do you set up those multiple rings... especially since it appears that they have approximately the same amplitudes.
I could be wrong, but that seems to be the biggest difference... and my semi-uneducated guess is that it is most likely due to how close the impacted material is to a fluid (i.e. compare solid rock and sand), since fluids let deformation waves like these to propogate easier than solids. But, that's just a guess.
you will have to excuse my ignorance of geology and vulcanology, but could something like this happen if a volcano were to collapse in on itself? Like if all the magma came out and left a cavity in the center, then it collapses. Is that at all possible?
A good example of a caldera is Crater Lake National Park in Oregon.
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Could the extra rings be caused by multiple impacts?
Finding another impact from a metorite 65million years ago could hint at the possibility of a large solestial catastrophe that caused the end of the dinosaur era.
Large asteroid belt collision with comet / two very very large asteroids?
Many possible situations could lead to this... just interesting to me I guess...
Stewart said that if Silverpit was created 60 million years ago, there wouldn't be any cause to link the two impacts. "On the other hand, if it came out at 65 million years ago, we would have the possibility that Silverpit was in fact a fragment of Chicxulub [...]"
IANAG(eologist). It seems to me, though, that if Silverpit was a fragment of Chicxulub, it would have to have hit the surface of the earth within a matter of hours as the part that hit near the Yucatan. They speak in the article of pinning the time frame down to 65 million years ago, and I'm assuming give or take half a million. With the information I have at hand, Chicxulub and Silverpit could have been up to a million years apart. Do you know what a million years is, in hours? About 8.76 billion. That's a pretty big margin of error! I don't think we should get our hopes up about the multi-dinosaur-killing-meteorites thing despite all its appeal, unless there is some other more substantial reason to believe these two meteorites had anything to do with one another. After all, a lot of meteorites hit the earth every million years.
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I think this is a great article and all, and it raises some neat issues (maybe the catastrophe that killed the dinosaurs was a meteor storm, not just one meteor, or something), but no where in the article did it say WHY it looked like something from one of Jupiter's moons. Does anyone know why this is?
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obviously this crater was created when a giant black monolith plumitted to earth. hopefully the researchers will not club each other to death while studying this phenomenon.
Concentric circles would be more common on worlds with little atmosphere to slow the object. Since we know that Earth at that time had a (relatively) thick atmosphere, it just makes the puzzle all the more interesting. What would be interesting to find out is the metal composition at the center of the impact site -- that could tell us a great deal about what hit. Probably iron, but it *could* be something as heavy as uranium.
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I remember seeing a study on this on Discovery or TLC. The fired rifle bullets into sand at high velocities and at many different angles, and the resulting crater was almost always circular. A quick google search turns up this link, a section from some lecture notes at University College Worcester.
Craters are not always circular as they may have been created from impacts which hit the surface at oblique angles forming elliptical craters however as impact craters are formed by very high velocity impacts which act essentially like an explosion rather than a distortion of the surface so unless the impact is very shallow and ploughs along the surface the craters will tend to be circular.
Here is another interesting quote from the same page that may explain the concentric rings:
If the crater is larger and the same order of magnitude as the thickness of the lithosphere then shock waves will penetrate the more plastic athenosphere resulting in the formation of multiringed basins.
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See a map of the crater accompanying the National Geographic story.
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Here is a link to New Scientist's coverage of the crater. They suggest that, in order to form this kind of multi-ringed crater, you need a brittle layer over a watery layer before it hits the bedrock, and that seabed sludge might have provided this structure.
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