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
planets and moons in our solar system, including our own moon, are pock-marked with loads of craters.
But because Earth has a protective atmosphere and is geologically active — with plate tectonics and volcanic
eruptions, mostly relatively young oceanic crust, and harsh weathering from wind and water — impact
- P2 x( U. n5 Z- v  M9 ustructures don’t last long and can be tough to come by.
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But on a few old pieces of continent, especially in arid deserts, the marks of asteroids have been preserved.
- |) g* c' M0 d* I3 I7 pOne well-known example is our own Barringer crater, also known as Meteor Crater, in Arizona. The images here www2.tvboxnow.com* y: Z2 V- L5 b1 }# Q1 D, q
show some of the biggest, oldest and most interesting impact craters on the planet.
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Aorounga crater, pictured above and below, is one of the best preserved impact craters on Earth, thanks tvb now,tvbnow,bttvb9 l" v0 U) L* E$ @& w
in part to its location in the Sahara Desert in Chad. The 10 mile-wide crater is probably around 350 million ) P4 f/ h3 w* F
years old. The stripes are alternating rock ridges and sand layers, known as yardangs, caused by persistent tvb now,tvbnow,bttvb+ e$ g, o$ B% A) b4 `2 H# n2 A1 ^0 D2 o. v
unidirectional wind. The image above was taken by astronauts in the International Space Station in July. 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。. s8 _% p8 B7 D! ?' g5 T6 ~
In the radar image below, taken from the space shuttle in 1994, reveals that Aorounga may be one of two or three craters.
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The Shoemaker crater in Western Australia, formerly known as the Teague crater, was renamed in honor of the planetary
geologist Eugene Shoemaker for whom the Comet Shoemaker-Levy 9 is also named. The age of the crater unclear, but it 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。& |  K+ P; t, n
could be 1.7 billion years old, which makes it the oldest known impact in Australia. The brightly colored splotches are 2 }% K; w5 i. M$ I& N3 ~* }: }' p6 b
seasonal salt-water lakes. This image was taken by the Landsat 7 satellite.tvb now,tvbnow,bttvb! N: h' s9 W: ?6 O8 O; S
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The Manicouagan Crater in northern Canada is one of the largest impact craters known on Earth. The impact occurred
4 T) L4 R" \% I$ Utvb now,tvbnow,bttvbaround 210 million years ago at the end of the Triassic period and may have caused a mass extinction that killed around www2.tvboxnow.com% T3 C, w- n3 a0 m+ E; _4 ^+ `
60 percent of all species. Though the crater has mostly eroded, Lake Manicouagan outlines what is left of the 43-mile wide
3 p! Y, l9 q4 ktvb now,tvbnow,bttvbimpact structure. The asteroid that created the crater is thought to have been about three miles wide. Today the lake is a 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。6 @  t! U" }- {  C5 a" W/ c/ |( i
reservoir and popular salmon fishing location.
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This crazy looking structure in Western Australia is called the Spider crater, for obvious reasons. Geologists determined it was
an impact crater when they found shatter cones, telltale cone-shaped, grooved rocks found only around impacts. The crazy 0 Y( d7 \, k# e- ^' k
looking legs surrounding the impact are mostly due to erosion of different rock layers. The harder sandstone ridges withstood - R$ [. W) K4 c& j& p# d, a
the weathering of wind and water better than the softer intervening layers. The crater is somewhere between 600 million 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。% Y$ q1 ^8 ^( s/ G/ }6 a- o
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
% N0 g, X0 w' t4 qwww2.tvboxnow.comNASA’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
$ Y! ^5 c3 }  V7 ~0 Xcenter of the structure is around 2.8 miles across, but the original crater rim was probably at the edge of the surrounding 公仔箱論壇6 A' U2 @1 V' O+ Y
grayish area. The crater was formed caused by an asteroid impact around 140 million years ago.
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Clearwater Lakes in Quebec, Canada were formed by a pair of asteroid impact craters. The impacts probably occurred
simultaneously around 290 million years ago. The larger crater measures 22 miles across.
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The Roter Kamm crater in Namibia is hard to see in visible light, but shows up more clearly with imaging radar. The crater’s
0 O, `3 a* G9 p2 b公仔箱論壇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 board
% E3 O  z/ f5 [www2.tvboxnow.com the space shuttle. Irregular surfaces show up brightly and smooth areas are dark. The white splotch at the bottom of the
photo is a rocky hill, the darkest areas are wind-blown sand dunes, the blue around the crater’s rim may be material that was tvb now,tvbnow,bttvb" w" T7 a( M; B. A4 i
ejected during the impact, the red is limestone outcrop and the green areas are mostly vegetation. The impact occurred 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。4 X: _& E1 C4 m  g  {6 P+ k
around 5 million years ago.& B: n2 v$ }7 y* y$ `2 }
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The Lonar crater in Maharashta, India is around 6,000 feet wide and 500 feet deep and contains a saltwater lake. 6 m3 c- l' g* v
Scientists determined the structure was caused by an asteroid through clues such as the presence of maskelynite,
a glass that is only formed by extremely high-velocity impacts. The impact occurred around 50,000 years ago. www2.tvboxnow.com4 s- S' E! G! ~* w- P8 X2 m9 G+ h
This image was captured by the Advanced Spaceborne Thermal Emission and Reflection Radiometer on NASA’s   p' u7 x( i/ k! N% E% ~
Terra satellite. It is a simulated true-color imagetvb now,tvbnow,bttvb: e, M& o* a" |6 @2 i# W* H3 `

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The Vredefort Dome in South Africa is possibly the oldest and largest clearly visible asteroid impact on Earth. tvb now,tvbnow,bttvb( w  I$ m, X4 n* F0 q# i6 A) H
The 155-mile crater is approximately 60 miles southwest of Johannesburg and was formed around 2 billion years ago.tvb now,tvbnow,bttvb0 V, `# _* @4 y+ p

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Artist’s rendering of a space object or phenomenon, so we couldn’t resist this beauty. This is one man’s idea of what 3 S) R* x7 q- u  z- A
a 300-mile wide asteroid would look impacting Earth. This event probably would have killed everything on the planet. www2.tvboxnow.com: b* ?6 W8 i, }9 v, F; q% S% W& G
Fortunately, NASA says nothing this big is headed our way anytime soon.