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Asteroid Impact Craters on Earth as Seen From Space

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Asteroid impact craters are among the most interesting geological structures on any planet. Many other
9 s! m2 i; y$ ]9 zplanets and moons in our solar system, including our own moon, are pock-marked with loads of craters. 5.39.217.77:8898& c% C5 w# d1 A4 N6 \  s$ ?
But because Earth has a protective atmosphere and is geologically active — with plate tectonics and volcanic
8 g  H5 T; H( @& Z# j5.39.217.77:8898eruptions, mostly relatively young oceanic crust, and harsh weathering from wind and water — impact
+ u+ q3 y- U0 b* O+ U5.39.217.77:8898structures don’t last long and can be tough to come by.
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' @. X! d' u, Y9 A& OBut on a few old pieces of continent, especially in arid deserts, the marks of asteroids have been preserved. 5.39.217.77:8898/ ~+ s: J9 I5 j0 M( a! S
One well-known example is our own Barringer crater, also known as Meteor Crater, in Arizona. The images here ; n( D2 D2 g) X  L3 O
show some of the biggest, oldest and most interesting impact craters on the planet.TVBNOW 含有熱門話題,最新最快電視,軟體,遊戲,電影,動漫及日常生活及興趣交流等資訊。9 J- J. w& p/ z

: o0 R. k1 a4 _. n公仔箱論壇Aorounga crater, pictured above and below, is one of the best preserved impact craters on Earth, thanks
; h1 M- {: p( B9 M# H/ ~公仔箱論壇in part to its location in the Sahara Desert in Chad. The 10 mile-wide crater is probably around 350 million 9 ~# j& b- z' J+ r
years old. The stripes are alternating rock ridges and sand layers, known as yardangs, caused by persistent $ \1 t/ ~: ]  I2 e0 B
unidirectional wind. The image above was taken by astronauts in the International Space Station in July. * ?% t& c% J1 a% y+ t; Z4 ?
In the radar image below, taken from the space shuttle in 1994, reveals that Aorounga may be one of two or three craters.# O% H5 I& q7 `  _8 I2 f( j  A7 M
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The Shoemaker crater in Western Australia, formerly known as the Teague crater, was renamed in honor of the planetary 公仔箱論壇* v. {+ ~: u" w1 k3 z
geologist Eugene Shoemaker for whom the Comet Shoemaker-Levy 9 is also named. The age of the crater unclear, but it 5.39.217.77:88984 L) }5 r6 t4 }) N; D, n9 m7 q
could be 1.7 billion years old, which makes it the oldest known impact in Australia. The brightly colored splotches are tvb now,tvbnow,bttvb5 n4 _: u/ S* P7 E, J+ ^5 c
seasonal salt-water lakes. This image was taken by the Landsat 7 satellite.5 z$ E  Z) v  n) ]( d% f7 ^
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The Manicouagan Crater in northern Canada is one of the largest impact craters known on Earth. The impact occurred tvb now,tvbnow,bttvb' w) }, N1 e6 x
around 210 million years ago at the end of the Triassic period and may have caused a mass extinction that killed around TVBNOW 含有熱門話題,最新最快電視,軟體,遊戲,電影,動漫及日常生活及興趣交流等資訊。* H; @6 C( r2 o% r4 \; U& g
60 percent of all species. Though the crater has mostly eroded, Lake Manicouagan outlines what is left of the 43-mile wide TVBNOW 含有熱門話題,最新最快電視,軟體,遊戲,電影,動漫及日常生活及興趣交流等資訊。) P) a: g1 ?6 Y& h
impact structure. The asteroid that created the crater is thought to have been about three miles wide. Today the lake is a
! y! x+ r; g& h/ S1 y* m, T2 l3 Ireservoir and popular salmon fishing location.TVBNOW 含有熱門話題,最新最快電視,軟體,遊戲,電影,動漫及日常生活及興趣交流等資訊。! G* n: o. J9 [- D( q2 ^0 ~

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This crazy looking structure in Western Australia is called the Spider crater, for obvious reasons. Geologists determined it was
5 o$ h' z& R* m( o: _4 r公仔箱論壇an impact crater when they found shatter cones, telltale cone-shaped, grooved rocks found only around impacts. The crazy
0 K. }5 J7 d: K9 C5.39.217.77:8898looking legs surrounding the impact are mostly due to erosion of different rock layers. The harder sandstone ridges withstood
- \) \5 [4 A; }7 L& c  ethe weathering of wind and water better than the softer intervening layers. The crater is somewhere between 600 million 5 Z* j$ J4 ^+ S( {0 y. k* B- D, t$ q# A
and 900 million years old and the raised area at its center is around 1,600 feet wide.
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The image above is a false-color image taken by the Advanced Spaceborne Thermal Emission and Reflection Radiometer on TVBNOW 含有熱門話題,最新最快電視,軟體,遊戲,電影,動漫及日常生活及興趣交流等資訊。5 v( s6 O; `+ o& a. y1 b
NASA’s Terra. The true-color image below was captured by Taiwan’s Formost-2 satellite
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The Gosses Bluff crater in Australia’s Northern Territory sits between two mountain ranges. The raised circular feature in the
9 f- ~/ [2 l+ a  l9 xTVBNOW 含有熱門話題,最新最快電視,軟體,遊戲,電影,動漫及日常生活及興趣交流等資訊。center of the structure is around 2.8 miles across, but the original crater rim was probably at the edge of the surrounding 5.39.217.77:8898. q5 I: `7 k0 x, W. z! P$ X& v
grayish area. The crater was formed caused by an asteroid impact around 140 million years ago.
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. p) r% _2 U' C* iClearwater Lakes in Quebec, Canada were formed by a pair of asteroid impact craters. The impacts probably occurred
  J( J5 C7 F$ Xsimultaneously around 290 million years ago. The larger crater measures 22 miles across.
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- g) G& s# Z4 y/ q1 H/ {$ P* s* u  MThe Roter Kamm crater in Namibia is hard to see in visible light, but shows up more clearly with imaging radar. The crater’s TVBNOW 含有熱門話題,最新最快電視,軟體,遊戲,電影,動漫及日常生活及興趣交流等資訊。2 b  Z0 ^. I) e) F8 v! f3 U$ J
1.5 mile-wide rim stands out as a bright ring in the lower left of the image, which was taken by a radar instrument on boardtvb now,tvbnow,bttvb- p) ]% p6 o: \5 K5 {
the space shuttle. Irregular surfaces show up brightly and smooth areas are dark. The white splotch at the bottom of the
7 b1 C) E( t2 C* ?/ z4 @; Dtvb now,tvbnow,bttvbphoto is a rocky hill, the darkest areas are wind-blown sand dunes, the blue around the crater’s rim may be material that was
- f7 s4 ~. q( [6 }/ Z+ Y5.39.217.77:8898ejected during the impact, the red is limestone outcrop and the green areas are mostly vegetation. The impact occurred tvb now,tvbnow,bttvb2 W9 q2 M, \( j3 j$ c' H+ A6 A# R
around 5 million years ago.TVBNOW 含有熱門話題,最新最快電視,軟體,遊戲,電影,動漫及日常生活及興趣交流等資訊。* p5 C7 K# G9 z# R6 {/ o" s4 k

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. J$ I7 i2 q9 K7 P( ^/ z2 ^9 bThe Lonar crater in Maharashta, India is around 6,000 feet wide and 500 feet deep and contains a saltwater lake. TVBNOW 含有熱門話題,最新最快電視,軟體,遊戲,電影,動漫及日常生活及興趣交流等資訊。, Q6 \0 j- ?: X2 h* U$ @
Scientists determined the structure was caused by an asteroid through clues such as the presence of maskelynite, tvb now,tvbnow,bttvb3 N: S+ D& o& @  a/ i- H
a glass that is only formed by extremely high-velocity impacts. The impact occurred around 50,000 years ago. 公仔箱論壇3 }0 c/ M$ Q* ?- J# z1 _2 h
This image was captured by the Advanced Spaceborne Thermal Emission and Reflection Radiometer on NASA’s TVBNOW 含有熱門話題,最新最快電視,軟體,遊戲,電影,動漫及日常生活及興趣交流等資訊。) ~7 C) t% E& D
Terra satellite. It is a simulated true-color image
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1 K' Z) z2 S( k3 Y/ ]4 ]5 V; q5.39.217.77:8898The Vredefort Dome in South Africa is possibly the oldest and largest clearly visible asteroid impact on Earth.
/ W+ M5 e0 F- M, ~5.39.217.77:8898The 155-mile crater is approximately 60 miles southwest of Johannesburg and was formed around 2 billion years ago.
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% r0 {" T* d5 qArtist’s rendering of a space object or phenomenon, so we couldn’t resist this beauty. This is one man’s idea of what
7 h% I4 r( L: B: D! fTVBNOW 含有熱門話題,最新最快電視,軟體,遊戲,電影,動漫及日常生活及興趣交流等資訊。a 300-mile wide asteroid would look impacting Earth. This event probably would have killed everything on the planet.
/ o; m7 ~& q( ~. w4 k公仔箱論壇Fortunately, NASA says nothing this big is headed our way anytime soon.

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  • k23bb

真係厲害好少見
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