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中国語 スペイン語 日々のべんきょうの記録

daxiongmao.exblog.jp
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2007年 04月 23日

Boltysh crater  ボルティシュ クレータ Silverpit crater  シルバーピット・クレーター


複数の隕石 小惑星が ほぼ同時に飛来した可能性がある。

Boltysh Ukraine N 48° 45' E 32° 10' 24
crater.
Boltysh crater  ボルティシュ クレータ Silverpit crater  シルバーピット・クレーター_d0034507_10413148.jpg

The Boltysh Crater is an impact crater in Ukraine (Kirovohrad Oblast). It is 24 km in diameter and its age is estimated to be 65.17±0.64 million years.
6517万年±64万年

This age is almost exactly the same as that of the Chicxulub Crater in Mexico, and the KT boundary.

The Chicxulub impact is believed to have caused the mass extinction at the end of the Cretaceous era, which included the extinction of the dinosaurs.

As well as Boltysh, the United Kingdom's Silverpit crater and several other craters around the world have estimated ages of about 65 million years, leading to the suggestion that the Earth was struck by multiple impactors at that time.

The collision of Comet Shoemaker-Levy 9 with Jupiter in 1994 showed that such multiple impacts over a few days are possible.

http://en.wikipedia.org/wiki/Boltysh_crater


Silverpit crater
シルバーピット・クレーター
Silverpit crater is a buried sub-sea structure under the North Sea off the coast of the United Kingdom. The crater-like form, named after the Silver Pit — a nearby sea-floor valley recognized by generations of fishermen, was discovered during the routine analysis of seismic data collected during exploration for oil, and first reported in 2002 as a possible impact crater.[1] If correct, it would be the first impact crater identified in or near the United Kingdom, however, the interpretation is controversial and alternative origins have been proposed.[2] The age of the feature is constrained between 74 – 45 million years (Late Cretaceous – Eocene).[3]

http://en.wikipedia.org/wiki/Silverpit_crater

シルバーピット・クレーター

クレーターは隕石あるいは彗星の衝突によるものだとする見方が支配的であるが、一方で宇宙からの飛来物と無関係にできたとする見方もある。実際にクレーターを確認し、調査を行うことは不可能であるため、決定的な証拠を得ることは非常に困難である。
http://ja.wikipedia.org/wiki/%E3%82%B7%E3%83%AB%E3%83%90%E3%83%BC%E3%83%94%E3%83%83%E3%83%88%E3%83%BB%E3%82%AF%E3%83%AC%E3%83%BC%E3%82%BF%E3%83%BC

Likelihood of multiple impact
複数の小惑星が同時に飛来した可能性は

Although the ages derived for Chicxulub and Boltysh are the same to within the statistical errors, it does not necessarily follow that they formed at exactly the same time. At the estimated rate of impacts on the Earth, it would not be extremely unusual for a Boltysh-sized crater to be formed within half a million years of Chicxulub.

However, the subsequent discovery of the Silverpit crater and its dating to approximately the same epoch gives greater weight to the theory that the Earth was struck by multiple impactors at this time.
epoch  時代, 時期

The dating of these impact craters is not yet accurate enough to establish whether the multiple impactors arrived over several thousand years, as part of a generally elevated rate of impacts at that time, or were almost simultaneous, like the impacts of the fragments of Comet Shoemaker-Levy 9 on Jupiter in 1994.

Another crater to form at the same time was the Shiva

by pandaxiongmao | 2007-04-23 22:30 | 英語


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