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
' V% U. l/ C/ f% e1 @8 N  Gplanets and moons in our solar system, including our own moon, are pock-marked with loads of craters. 5.39.217.77:8898  y5 m2 d9 Z6 r
But because Earth has a protective atmosphere and is geologically active — with plate tectonics and volcanic
( l- b1 R, L: Z( m5 L" X公仔箱論壇eruptions, mostly relatively young oceanic crust, and harsh weathering from wind and water — impact
structures don’t last long and can be tough to come by.7 u) N- E( W/ M8 f

# T- e3 R. b& P5 j% E公仔箱論壇But on a few old pieces of continent, especially in arid deserts, the marks of asteroids have been preserved. 5.39.217.77:8898% k5 e. \4 w2 X+ ]7 h
One well-known example is our own Barringer crater, also known as Meteor Crater, in Arizona. The images here 5.39.217.77:8898$ H3 F, Q9 L) T$ q% U
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,bttvb( B& g9 @0 O7 q- U+ L
in part to its location in the Sahara Desert in Chad. The 10 mile-wide crater is probably around 350 million
: F2 }2 H% h+ N1 `9 L0 h公仔箱論壇years old. The stripes are alternating rock ridges and sand layers, known as yardangs, caused by persistent
6 p- D9 }6 W% w( P公仔箱論壇unidirectional wind. The image above was taken by astronauts in the International Space Station in July.
( K; }7 ]: s! w$ EIn the radar image below, taken from the space shuttle in 1994, reveals that Aorounga may be one of two or three craters.tvb now,tvbnow,bttvb, i! H2 C  ?2 ^, A! {( `9 H

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The Shoemaker crater in Western Australia, formerly known as the Teague crater, was renamed in honor of the planetary
7 C) r- z: _/ W" h5 u公仔箱論壇geologist Eugene Shoemaker for whom the Comet Shoemaker-Levy 9 is also named. The age of the crater unclear, but it
0 L+ s/ G. t' M. E( }' U1 qcould be 1.7 billion years old, which makes it the oldest known impact in Australia. The brightly colored splotches are
- F" P' V& Q" W2 W3 q公仔箱論壇seasonal salt-water lakes. This image was taken by the Landsat 7 satellite.
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The Manicouagan Crater in northern Canada is one of the largest impact craters known on Earth. The impact occurred 公仔箱論壇! t; m( [1 {- M8 w
around 210 million years ago at the end of the Triassic period and may have caused a mass extinction that killed around 5.39.217.77:88988 o- l7 H" x4 d! B4 l! H7 S
60 percent of all species. Though the crater has mostly eroded, Lake Manicouagan outlines what is left of the 43-mile wide
7 o" r1 O! |" b1 ~! `$ Ximpact 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。2 O* P& u( A# e8 a1 `. h
reservoir and popular salmon fishing location.公仔箱論壇9 Q4 n' c" ^& |8 V4 X

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This crazy looking structure in Western Australia is called the Spider crater, for obvious reasons. Geologists determined it was 公仔箱論壇) @$ K4 F+ r$ n9 q
an impact crater when they found shatter cones, telltale cone-shaped, grooved rocks found only around impacts. The crazy
looking legs surrounding the impact are mostly due to erosion of different rock layers. The harder sandstone ridges withstood 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。( ~- u+ p% C4 O' [. z) L( F1 R
the weathering of wind and water better than the softer intervening layers. The crater is somewhere between 600 million
( N! r* G7 c' \+ L' ~公仔箱論壇and 900 million years old and the raised area at its center is around 1,600 feet wide.tvb now,tvbnow,bttvb8 ]. @/ U* Z2 V' h. ]$ J$ W
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The image above is a false-color image taken by the Advanced Spaceborne Thermal Emission and Reflection Radiometer on
; I8 G' M7 T6 f% WNASA’s Terra. The true-color image below was captured by Taiwan’s Formost-2 satellite. j6 O: ]- A. O, f3 e& N

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The Gosses Bluff crater in Australia’s Northern Territory sits between two mountain ranges. The raised circular feature in the 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 |0 U2 e5 K8 e' V  h1 k
center of the structure is around 2.8 miles across, but the original crater rim was probably at the edge of the surrounding
, S6 r' L, g* A( w  M6 Tgrayish area. The crater was formed caused by an asteroid impact around 140 million years ago.公仔箱論壇; }/ P( j- G6 d' w) f8 H2 [" E

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5 h! [- o3 d! A8 l公仔箱論壇Clearwater Lakes in Quebec, Canada were formed by a pair of asteroid impact craters. The impacts probably occurred
( `5 g! G: Y3 C: J8 ?simultaneously around 290 million years ago. The larger crater measures 22 miles across.公仔箱論壇; e1 Q" t" {' h0 |
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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 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。$ C. p3 _/ _/ |
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
7 |- C; k+ ^) w' b6 T6 Q3 K; u the space shuttle. Irregular surfaces show up brightly and smooth areas are dark. The white splotch at the bottom of the   d* g3 v  z, w: A% n$ C9 j
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& f  E) K7 u4 T0 r
ejected during the impact, the red is limestone outcrop and the green areas are mostly vegetation. The impact occurred tvb now,tvbnow,bttvb5 a' q5 |: R2 l7 x9 x
around 5 million years ago.公仔箱論壇% ?) h& Z. i) T: T. U! R. G* O

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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.
4 o5 o% \: g! f+ O5 fScientists determined the structure was caused by an asteroid through clues such as the presence of maskelynite,
2 v* H9 x. \/ V5.39.217.77:8898a glass that is only formed by extremely high-velocity impacts. The impact occurred around 50,000 years ago.
2 h. ?2 j" y# X$ p! s1 y5 b4 T, yThis image was captured by the Advanced Spaceborne Thermal Emission and Reflection Radiometer on NASA’s . P( \4 z" S( \- I
Terra satellite. It is a simulated true-color image
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The Vredefort Dome in South Africa is possibly the oldest and largest clearly visible asteroid impact on Earth.
The 155-mile crater is approximately 60 miles southwest of Johannesburg and was formed around 2 billion years ago.
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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 tvb now,tvbnow,bttvb4 X) V6 x4 C! G  s
a 300-mile wide asteroid would look impacting Earth. This event probably would have killed everything on the planet. 公仔箱論壇7 i) r% A8 f* i, A2 D
Fortunately, NASA says nothing this big is headed our way anytime soon.