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Asteroid Impact Craters on Earth as Seen From Space


. K" h  T' O* V$ J: D6 H/ h; T8 stvb now,tvbnow,bttvb
+ i& B' v2 q$ i' w- C/ ?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。Asteroid impact craters are among the most interesting geological structures on any planet. Many other
& h& y. y' G! t& G( C: y- S  t公仔箱論壇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  o$ j/ y& [% @6 m  X7 `
But because Earth has a protective atmosphere and is geologically active — with plate tectonics and volcanic tvb now,tvbnow,bttvb6 g. Q6 J* W  \' @
eruptions, mostly relatively young oceanic crust, and harsh weathering from wind and water — impact
/ O8 f# I+ o6 L3 F- [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。structures don’t last long and can be tough to come by." }; P" H1 V* k# S: q

& p. N9 E/ P; A$ n  D5.39.217.77:8898But on a few old pieces of continent, especially in arid deserts, the marks of asteroids have been preserved.
1 N* _( {1 t5 v4 z2 X' BOne well-known example is our own Barringer crater, also known as Meteor Crater, in Arizona. The images here
- e5 j3 c6 C; d8 A# {4 L4 Jshow some of the biggest, oldest and most interesting impact craters on the planet.
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* X8 R) [, O0 Q0 j* R/ [公仔箱論壇Aorounga crater, pictured above and below, is one of the best preserved impact craters on Earth, thanks tvb now,tvbnow,bttvb. q/ G( M5 H0 M7 `. ]
in part to its location in the Sahara Desert in Chad. The 10 mile-wide crater is probably around 350 million
% G: J$ n9 O0 c! k  G- Q9 D6 kyears old. The stripes are alternating rock ridges and sand layers, known as yardangs, caused by persistent 公仔箱論壇% I% r; r, g; L6 h- a( C
unidirectional wind. The image above was taken by astronauts in the International Space Station in July.
- ~1 \) x/ W1 H7 M9 a1 u3 P' NIn 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* ^* b# g; g: q: t

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; N1 ^: [- A2 K公仔箱論壇The Shoemaker crater in Western Australia, formerly known as the Teague crater, was renamed in honor of the planetary
' ?: @1 Y# Y3 F5.39.217.77:8898geologist Eugene Shoemaker for whom the Comet Shoemaker-Levy 9 is also named. The age of the crater unclear, but it 2 S' F2 f. @9 F/ b4 o8 A
could be 1.7 billion years old, which makes it the oldest known impact in Australia. The brightly colored splotches are
9 ~  B  q/ y9 L* n) D4 @5.39.217.77:8898seasonal salt-water lakes. This image was taken by the Landsat 7 satellite.tvb now,tvbnow,bttvb& V0 `* `& F8 g' U$ i9 R; _

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The Manicouagan Crater in northern Canada is one of the largest impact craters known on Earth. The impact occurred
% G. W$ u6 ?* X) \around 210 million years ago at the end of the Triassic period and may have caused a mass extinction that killed around
8 d& g  B: I3 _  M# h5 {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。60 percent of all species. Though the crater has mostly eroded, Lake Manicouagan outlines what is left of the 43-mile wide
6 O8 v& E- U# J# E7 @3 pTVBNOW 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。impact structure. The asteroid that created the crater is thought to have been about three miles wide. Today the lake is a
  Z( I/ I' `& `* E! {* b公仔箱論壇reservoir and popular salmon fishing location.tvb now,tvbnow,bttvb7 R* A6 _, \/ l+ O! P3 P, p
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This crazy looking structure in Western Australia is called the Spider crater, for obvious reasons. Geologists determined it was
7 N) {; i6 G; B2 O公仔箱論壇an impact crater when they found shatter cones, telltale cone-shaped, grooved rocks found only around impacts. The crazy
5 N7 z# h# t' }3 z, M6 ttvb now,tvbnow,bttvblooking legs surrounding the impact are mostly due to erosion of different rock layers. The harder sandstone ridges withstood
1 n+ h4 u4 J  p; Ctvb now,tvbnow,bttvbthe weathering of wind and water better than the softer intervening layers. The crater is somewhere between 600 million " g* i: M% b# u
and 900 million years old and the raised area at its center is around 1,600 feet wide.0 z8 c0 Y) k" G# F4 ~
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The image above is a false-color image taken by the Advanced Spaceborne Thermal Emission and Reflection Radiometer on 公仔箱論壇1 q) Y8 }$ x7 f5 [
NASA’s Terra. The true-color image below was captured by Taiwan’s Formost-2 satellite5.39.217.77:88985 b+ ?* l; E' I4 @! Y
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9 K: @& ]  K6 f1 j5.39.217.77:8898The Gosses Bluff crater in Australia’s Northern Territory sits between two mountain ranges. The raised circular feature in the
& y) |4 p% ]' N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 5.39.217.77:8898# _- D4 ^/ j  b9 A+ i& X. r
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
% v, _0 m+ T, ]/ |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。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
$ S+ R. w$ m! B. p8 A* l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 boardTVBNOW 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。1 J2 r- ?, t% \& s4 o  @9 ~3 L
the space shuttle. Irregular surfaces show up brightly and smooth areas are dark. The white splotch at the bottom of 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。* G8 h: H8 Q2 V( Y9 k4 f
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
# `% d, t0 y$ T0 W公仔箱論壇ejected during the impact, the red is limestone outcrop and the green areas are mostly vegetation. The impact occurred
. u1 p- r. D0 n3 X. kTVBNOW 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。around 5 million years ago.7 y% d8 F" R( p( X$ z  V3 n" y

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# S. ~! m% o4 c' S% y5.39.217.77:8898The Lonar crater in Maharashta, India is around 6,000 feet wide and 500 feet deep and contains a saltwater lake.
1 f2 ]# d) |2 Q' ^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。Scientists determined the structure was caused by an asteroid through clues such as the presence of maskelynite, 公仔箱論壇" c# h! O7 b1 k& L8 @3 G
a glass that is only formed by extremely high-velocity impacts. The impact occurred around 50,000 years ago. 8 J6 y% v- ?9 ?% i  Z# _8 j* @
This image was captured by the Advanced Spaceborne Thermal Emission and Reflection Radiometer on NASA’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。& c8 f7 j9 {$ [
Terra satellite. It is a simulated true-color image公仔箱論壇' i% d" q8 s! N5 ~9 \( {# a
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The Vredefort Dome in South Africa is possibly the oldest and largest clearly visible asteroid impact on Earth.
4 x* r5 z6 P) O! H3 _! ]公仔箱論壇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   Y/ p3 w6 O9 d) R6 N% ]4 F- m+ h
a 300-mile wide asteroid would look impacting Earth. This event probably would have killed everything on the planet. 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。- Y9 p& H2 b; ]7 r2 `" ?
Fortunately, NASA says nothing this big is headed our way anytime soon.

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  • k23bb

真係厲害好少見
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