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 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。8 T' P% ], G* T
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 5 U3 C. d' w3 I$ k. o2 a+ y* l) z
eruptions, mostly relatively young oceanic crust, and harsh weathering from wind and water — impact 公仔箱論壇1 r$ [' Z. c; |1 v9 i( [( Y
structures don’t last long and can be tough to come by.tvboxnow.com# F( Y) j# a% u  I
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But on a few old pieces of continent, especially in arid deserts, the marks of asteroids have been preserved. tvboxnow.com7 ?9 ?: s8 d* i- r$ v  a4 j
One well-known example is our own Barringer crater, also known as Meteor Crater, in Arizona. The images here
1 O6 x- H( t' S: L: v0 w( Jshow some of the biggest, oldest and most interesting impact craters on the planet./ r* ?3 l$ l  P# v' M) T# [/ O

( S. A8 E. s6 ?0 h6 G, d, AAorounga crater, pictured above and below, is one of the best preserved impact craters on Earth, thanks 公仔箱論壇! S5 M2 `) n, @9 N1 g3 H
in 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。5 G9 k  D$ f" U$ l2 v0 Z
years old. The stripes are alternating rock ridges and sand layers, known as yardangs, caused by persistent tvb now,tvbnow,bttvb; D, j: Z  G' A$ M) f3 E2 @& H9 y
unidirectional wind. The image above was taken by astronauts in the International Space Station in July. tvb now,tvbnow,bttvb8 R$ d: v/ {0 m' {: {. d  R
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
! Q, R" R6 m# x4 ktvboxnow.comgeologist Eugene Shoemaker for whom the Comet Shoemaker-Levy 9 is also named. The age of the crater unclear, but it
could be 1.7 billion years old, which makes it the oldest known impact in Australia. The brightly colored splotches are
4 k) F+ {# j! Ttvboxnow.comseasonal 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 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 Y' A3 @0 x* a+ D1 Z/ q" b
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。3 |$ }2 u; H" K$ ?# l6 n* d
60 percent of all species. Though the crater has mostly eroded, Lake Manicouagan outlines what is left of the 43-mile wide
impact structure. The asteroid that created the crater is thought to have been about three miles wide. Today the lake is a + ]) D1 y% P# Z6 s& q1 Z# D- w
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 . F: o3 r2 V8 u$ w7 [
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 tvb now,tvbnow,bttvb, L$ q, L9 G3 s  h/ \
the weathering of wind and water better than the softer intervening layers. The crater is somewhere between 600 million
- Q: l$ t+ i1 l) r  D$ _tvboxnow.comand 900 million years old and the raised area at its center is around 1,600 feet wide.

The image above is a false-color image taken by the Advanced Spaceborne Thermal Emission and Reflection Radiometer on
- e0 D, y; O( x. }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 $ Z4 @+ D; p4 h0 Y. V7 I# j
center of the structure is around 2.8 miles across, but the original crater rim was probably at the edge of the surrounding : R' \+ T6 U/ P2 u  J4 U0 S
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。/ H/ j1 E  u9 j/ [

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  P  x( l( y; n9 I2 g, N4 F0 ?! IClearwater Lakes in Quebec, Canada were formed by a pair of asteroid impact craters. The impacts probably occurred
) ^/ R9 i. L; E  U8 Rsimultaneously 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 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。- c0 w5 t, O6 S) o: E5 t% M  \
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
the space shuttle. Irregular surfaces show up brightly and smooth areas are dark. The white splotch at the bottom of the
" w8 {/ E; }# U4 ~% Dphoto is a rocky hill, the darkest areas are wind-blown sand dunes, the blue around the crater’s rim may be material that was . B- o# p/ T9 q/ O) V3 N2 w, V- b
ejected during the impact, the red is limestone outcrop and the green areas are mostly vegetation. The impact occurred tvb now,tvbnow,bttvb- t6 Z' Z' ?4 A2 x
around 5 million years ago.

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: i' W6 x) R# ^+ A& y2 P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. 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 J1 C4 i% I5 n1 F0 W
Scientists determined the structure was caused by an asteroid through clues such as the presence of maskelynite, . B( c; N" \% f  v! E  I
a glass that is only formed by extremely high-velocity impacts. The impact occurred around 50,000 years ago.
8 H  v$ i9 N& Q$ w0 wtvboxnow.comThis image was captured by the Advanced Spaceborne Thermal Emission and Reflection Radiometer on NASA’s
Terra satellite. It is a simulated true-color imagetvboxnow.com0 h$ t1 W/ [# E$ I% N& ]
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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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9 _/ c$ c- ^' q4 z6 z+ Ttvboxnow.comArtist’s rendering of a space object or phenomenon, so we couldn’t resist this beauty. This is one man’s idea of what
. G3 b. x" k/ M- xtvb now,tvbnow,bttvba 300-mile wide asteroid would look impacting Earth. This event probably would have killed everything on the planet. + h& d9 c' u/ n6 e
Fortunately, NASA says nothing this big is headed our way anytime soon.