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
; m: m9 I- f6 [: V  T' L2 Nplanets and moons in our solar system, including our own moon, are pock-marked with loads of craters. 5.39.217.77:8898  I+ Y8 j8 s" g
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
7 q& j/ L- G+ z& s# X- B2 G  {9 istructures 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. 5.39.217.77:8898* O( f; ^0 j$ Q' h$ K
One well-known example is our own Barringer crater, also known as Meteor Crater, in Arizona. The images here 2 G5 u4 I. c8 ?6 b" o
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
  @8 O% `! a! c5.39.217.77:8898in part to its location in the Sahara Desert in Chad. The 10 mile-wide crater is probably around 350 million 公仔箱論壇3 J/ d5 |! C% E
years old. The stripes are alternating rock ridges and sand layers, known as yardangs, caused by persistent
0 V' D4 @# A" D  r5.39.217.77:8898unidirectional wind. The image above was taken by astronauts in the International Space Station in July. tvb now,tvbnow,bttvb# [0 W* }; ]9 ~  z5 r
In the radar image below, taken from the space shuttle in 1994, reveals that Aorounga may be one of two or three craters.2 \; t4 ~: u/ M* G7 C6 m

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The Shoemaker crater in Western Australia, formerly known as the Teague crater, was renamed in honor of the planetary + n. x# a; Y1 G4 N9 ^1 ?
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。7 {$ j9 s6 N8 B- ?' J7 M
could be 1.7 billion years old, which makes it the oldest known impact in Australia. The brightly colored splotches are
seasonal salt-water lakes. This image was taken by the Landsat 7 satellite.

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# |/ K7 V4 `" \  p3 E4 ~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。5 Z$ a* s3 l+ k# {5 i' ~
around 210 million years ago at the end of the Triassic period and may have caused a mass extinction that killed around
& ?+ r+ T& N0 J60 percent of all species. Though the crater has mostly eroded, Lake Manicouagan outlines what is left of the 43-mile wide + V+ M- T% i; d! d3 C. q$ `
impact 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.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。+ Z* Q( @7 Q$ x- U2 q, N& L8 u
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( o: P. ?( ]7 j  q' a公仔箱論壇This crazy looking structure in Western Australia is called the Spider crater, for obvious reasons. Geologists determined it was 2 P  y! x# S- B9 s
an impact crater when they found shatter cones, telltale cone-shaped, grooved rocks found only around impacts. The crazy 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。; ]' r  {, }! Y2 \
looking legs surrounding the impact are mostly due to erosion of different rock layers. The harder sandstone ridges withstood tvb now,tvbnow,bttvb4 y9 D; D( |* R2 }  C5 E
the weathering of wind and water better than the softer intervening layers. The crater is somewhere between 600 million
3 E) h8 d  q$ @5.39.217.77:8898and 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 tvb now,tvbnow,bttvb" P% V0 Y! d+ R
NASA’s Terra. The true-color image below was captured by Taiwan’s Formost-2 satellitetvb now,tvbnow,bttvb2 E0 ?- A) U: G& ?+ B0 n/ Q
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The Gosses Bluff crater in Australia’s Northern Territory sits between two mountain ranges. The raised circular feature in the
: L9 a: D1 O; K& Q) N! S: Wcenter of the structure is around 2.8 miles across, but the original crater rim was probably at the edge of the surrounding
! p5 G; z0 h$ M0 Ttvb now,tvbnow,bttvbgrayish area. The crater was formed caused by an asteroid impact around 140 million years ago.
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6 a- Z7 B( D- F0 {tvb now,tvbnow,bttvbClearwater Lakes in Quebec, Canada were formed by a pair of asteroid impact craters. The impacts probably occurred ! D0 ]  a# K6 v% \( v. C- d1 [$ B! V- @
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
) Z% o' l4 m: j# y1.5 mile-wide rim stands out as a bright ring in the lower left of the image, which was taken by a radar instrument on board5.39.217.77:88986 j* R# i1 p: g$ W+ S9 ~: W; T
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
" ~5 B+ O% G( fejected during the impact, the red is limestone outcrop and the green areas are mostly vegetation. The impact occurred
around 5 million years ago.tvb now,tvbnow,bttvb/ y, |0 i1 f8 a5 y
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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.
Scientists determined the structure was caused by an asteroid through clues such as the presence of maskelynite, 2 M" S3 |/ @4 _2 n; q, i" z2 J
a glass that is only formed by extremely high-velocity impacts. The impact occurred around 50,000 years ago.
This image was captured by the Advanced Spaceborne Thermal Emission and Reflection Radiometer on NASA’s 公仔箱論壇! F( {/ r' u$ X
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。) u! P3 q/ S- V5 c
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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.公仔箱論壇- q: o) e. N) y. _0 z2 q

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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
a 300-mile wide asteroid would look impacting Earth. This event probably would have killed everything on the planet.
8 @2 K/ D  ]6 a1 h$ yFortunately, NASA says nothing this big is headed our way anytime soon.