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 公仔箱論壇) s! |% i5 p( }" X% D
planets and moons in our solar system, including our own moon, are pock-marked with loads of craters. 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。  V# G5 @' W4 x: l3 C- @: Y! o
But because Earth has a protective atmosphere and is geologically active — with plate tectonics and volcanic " U' x9 T9 {) G% D0 m
eruptions, mostly relatively young oceanic crust, and harsh weathering from wind and water — impact
/ J$ Q$ Y3 A2 ftvb now,tvbnow,bttvbstructures don’t last long and can be tough to come by.

But on a few old pieces of continent, especially in arid deserts, the marks of asteroids have been preserved. 5.39.217.76, f; H& B: Y* f2 s) o
One well-known example is our own Barringer crater, also known as Meteor Crater, in Arizona. The images here
5 h& c) x, V. B6 D( k+ W1 I5.39.217.76show some of the biggest, oldest and most interesting impact craters on the planet.tvb now,tvbnow,bttvb. z, V3 Z( d- {/ p2 ^

9 v( ~$ {# f4 c3 M5 ^5.39.217.76Aorounga crater, pictured above and below, is one of the best preserved impact craters on Earth, thanks
/ x  \& ]3 C+ n- Q, U3 l3 b- l. S7 Lin part to its location in the Sahara Desert in Chad. The 10 mile-wide crater is probably around 350 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。0 h8 S' K. [) n$ m
years old. The stripes are alternating rock ridges and sand layers, known as yardangs, caused by persistent
2 E. q5 F3 ^# X; l$ `8 r公仔箱論壇unidirectional wind. The image above was taken by astronauts in the International Space Station in July.
9 N3 G& ?. e4 W9 }- t公仔箱論壇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
7 H# \3 c* V% e5 a" x. `geologist Eugene Shoemaker for whom the Comet Shoemaker-Levy 9 is also named. The age of the crater unclear, but it ) |1 ~) d# N3 G/ k+ T2 n2 L
could be 1.7 billion years old, which makes it the oldest known impact in Australia. The brightly colored splotches are # B# C5 [$ h" q2 s, j" K
seasonal salt-water lakes. This image was taken by the Landsat 7 satellite.公仔箱論壇; ]( m7 x9 y* R, L

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The Manicouagan Crater in northern Canada is one of the largest impact craters known on Earth. 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。) S  y0 V8 O- o  n! J" q
around 210 million years ago at the end of the Triassic period and may have caused a mass extinction that killed around
60 percent of all species. Though the crater has mostly eroded, Lake Manicouagan outlines what is left of the 43-mile wide
9 r: H3 r0 b, n# L; gimpact structure. The asteroid that created the crater is thought to have been about three miles wide. Today the lake is a
reservoir and popular salmon fishing location.5.39.217.76) N4 x9 N' U% O; p2 |
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This crazy looking structure in Western Australia is called the Spider crater, for obvious reasons. Geologists determined it was
$ z, {; s* _. Q. Ztvb now,tvbnow,bttvban impact crater when they found shatter cones, telltale cone-shaped, grooved rocks found only around impacts. The crazy
% x( j* `1 F* Ttvb now,tvbnow,bttvblooking legs surrounding the impact are mostly due to erosion of different rock layers. The harder sandstone ridges withstood
$ o, \" P$ v$ i/ t% V6 X. Mthe 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。/ S  W2 H9 F1 f- O
and 900 million years old and the raised area at its center is around 1,600 feet wide.5.39.217.76  ^& S) K. \5 C7 j: s' k; |

The image above is a false-color image taken by the Advanced Spaceborne Thermal Emission and Reflection Radiometer on
NASA’s Terra. The true-color image below was captured by Taiwan’s Formost-2 satellite

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6 V( o1 V9 A4 X5 p公仔箱論壇The Gosses Bluff crater in Australia’s Northern Territory sits between two mountain ranges. The raised circular feature in the
8 }$ S( @9 W7 R) F公仔箱論壇center of the structure is around 2.8 miles across, but the original crater rim was probably at the edge of the surrounding 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。% o! H& |/ a/ a1 f. `2 {
grayish area. The crater was formed caused by an asteroid impact around 140 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。7 t& c/ v. {4 v; @
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; n: U  {4 [; E# B5.39.217.76Clearwater 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.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。+ |: ~$ N& C- q# v
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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
: j; B) _0 X! I% _' m& Y* x& N. n1.5 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
the space shuttle. Irregular surfaces show up brightly and smooth areas are dark. The white splotch at the bottom of the ) _$ H; C0 \! ]. Z2 C3 ^
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
, e+ h' b. ~- `6 s$ i公仔箱論壇ejected during the impact, the red is limestone outcrop and the green areas are mostly vegetation. The impact occurred 1 i7 J% e7 O2 b, E0 `" F5 n
around 5 million years ago.5.39.217.76& o6 e# X- P# |8 x7 k4 F. |* d

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# s" P9 L% v$ v4 K; u/ j公仔箱論壇The Lonar crater in Maharashta, India is around 6,000 feet wide and 500 feet deep and contains a saltwater lake. . [: @0 @3 [! `0 S) S. G
Scientists determined the structure was caused by an asteroid through clues such as the presence of maskelynite, 公仔箱論壇1 \. b1 f4 K: M1 T2 @4 O/ R& I
a glass that is only formed by extremely high-velocity impacts. The impact occurred around 50,000 years ago. tvb now,tvbnow,bttvb/ @. n6 _+ A2 z  b  M
This image was captured by the Advanced Spaceborne Thermal Emission and Reflection Radiometer on NASA’s 5.39.217.763 U/ _5 K7 c; P
Terra satellite. It is a simulated true-color imageTVBNOW 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。* O/ z8 _0 T  ^0 o9 U1 o  I6 r

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The Vredefort Dome in South Africa is possibly the oldest and largest clearly visible asteroid impact on Earth.
0 m- `0 ?: Q. y% t5 [5.39.217.76The 155-mile crater is approximately 60 miles southwest of Johannesburg and was formed around 2 billion years ago.; c- i& P7 n6 `& r( d
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/ R8 h, B, v8 a; [tvb now,tvbnow,bttvbArtist’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,bttvb+ c. l) a! t. F# c3 W6 Z
a 300-mile wide asteroid would look impacting Earth. This event probably would have killed everything on the planet.
" X6 ^% j8 n: \# u* l' n. J, |: JFortunately, NASA says nothing this big is headed our way anytime soon.