Asteroid Impact Craters on Earth as Seen From Space

5 Y. p* l3 F: u+ O. d5 N7 ^7 Y, WAsteroid impact craters are among the most interesting geological structures on any planet. Many other
planets and moons in our solar system, including our own moon, are pock-marked with loads of craters.
' l+ g8 C$ U1 I) [tvboxnow.comBut 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 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 B- u$ S! }7 m- q! z
structures don’t last long and can be tough to come by.

- ?  U5 t) W) H1 `/ B公仔箱論壇But on a few old pieces of continent, especially in arid deserts, the marks of asteroids have been preserved.
One well-known example is our own Barringer crater, also known as Meteor Crater, in Arizona. The images here 5 ?; w  h$ H: \7 F' Z+ T
show some of the biggest, oldest and most interesting impact craters on the planet.
5 G) W, L, \$ X6 a# c3 a: fTVBNOW 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。" v1 q( \$ `: u0 l; \, O" x& M
Aorounga crater, pictured above and below, is one of the best preserved impact craters on Earth, thanks + E( h9 A# Q* x5 v. N3 B8 B1 h: @: y
in 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0 z' O( [8 P+ J! x
years old. The stripes are alternating rock ridges and sand layers, known as yardangs, caused by persistent - R9 Y1 g5 J( a) B: a7 T" M, A
unidirectional wind. The image above was taken by astronauts in the International Space Station in July. tvb now,tvbnow,bttvb0 \* H2 I& y2 U! P0 e( A( c
In the radar image below, taken from the space shuttle in 1994, reveals that Aorounga may be one of two or three craters.
$ D! |/ O* c7 d3 f/ [) C2 q* }' y' n# o  M+ L: R$ E5 k) M

6 M6 E5 @, y, W3 xtvb now,tvbnow,bttvb
* s5 ?1 j! M3 ~4 T" n  mtvboxnow.com8 Y* @! P5 o2 l/ v6 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。% U5 e0 t- ^! m7 b
The Shoemaker crater in Western Australia, formerly known as the Teague crater, was renamed in honor of the planetary
- E# n$ n- b" U5 b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 tvboxnow.com. L! [+ L' y; E# _( P- ]! i$ t
could be 1.7 billion years old, which makes it the oldest known impact in Australia. The brightly colored splotches are tvboxnow.com  H* f& w( o4 l8 q. b* F+ B
seasonal salt-water lakes. This image was taken by the Landsat 7 satellite.. ~0 u6 ?5 ?7 ^, a

# D1 T9 t6 K2 E" ~+ q  m; }公仔箱論壇& G% B0 k5 H" \9 }# \* q, S

The Manicouagan Crater in northern Canada is one of the largest impact craters known on Earth. The impact occurred ! q' i1 N0 [/ C) h' A$ b
around 210 million years ago at the end of the Triassic period and may have caused a mass extinction that killed around tvb now,tvbnow,bttvb" y7 \( M, x6 H2 m2 }
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 & o* w/ x1 t( @/ l* R% s; }  D
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。# L. \, z5 y5 o5 L9 ]
tvb now,tvbnow,bttvb! N* L8 `6 [7 ?1 {  O

; R/ J! z! z: W7 Ztvboxnow.com
) R4 x, p' R7 _; K
tvboxnow.com) @+ i0 J' D, Q: g. z! `
This crazy looking structure in Western Australia is called the Spider crater, for obvious reasons. Geologists determined it was
# d* {8 F, N- Y6 U5 v- B( {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 3 Q$ h' [" f* l# t$ F8 V
the weathering of wind and water better than the softer intervening layers. The crater is somewhere between 600 million / x$ _4 J$ c7 @0 `' @7 O- g7 ]
and 900 million years old and the raised area at its center is around 1,600 feet wide.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 B. W6 @+ o) U# a/ U
tvboxnow.com" t$ q8 B- C7 h3 B3 c8 R
The image above is a false-color image taken by the Advanced Spaceborne Thermal Emission and Reflection Radiometer on
7 b% F! `3 S& x, |9 }% `NASA’s Terra. The true-color image below was captured by Taiwan’s Formost-2 satellitetvb now,tvbnow,bttvb1 ~- t# v) l; @4 s/ _
/ X! ^& I  [- q/ h$ |
2 _1 }1 A9 R  A! I% q

# H! i/ M4 g" Z* Z! g! O! e" \

0 }9 j, f& [( R7 g5 u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 tvb now,tvbnow,bttvb+ s8 h4 l' v3 {  R7 I
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。% k2 u' R+ ^6 r* ]) s
grayish area. The crater was formed caused by an asteroid impact around 140 million years ago.
( o; P! V* u* Ntvb now,tvbnow,bttvb& `# ^9 r, K) a

- W: u, W1 x5 Z" \tvboxnow.com
" j5 S7 L' w* a3 ~Clearwater Lakes in Quebec, Canada were formed by a pair of asteroid impact craters. The impacts probably occurred tvboxnow.com" _* b" h4 x) _6 K& G. N) P) Q
simultaneously around 290 million years ago. The larger crater measures 22 miles across.1 z! }# o; \# c3 @
% X+ _8 T) W$ \/ d6 Q

7 T% B* E" s, M( mtvboxnow.com
$ P3 F# `4 f( k+ d' w% s8 ktvboxnow.comThe Roter Kamm crater in Namibia is hard to see in visible light, but shows up more clearly with imaging radar. The crater’s tvboxnow.com4 D6 S: S2 m9 |4 ?
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 x& A* F2 X% @- a8 c) f公仔箱論壇 the space shuttle. Irregular surfaces show up brightly and smooth areas are dark. The white splotch at the bottom of the " x# \0 @' v' A; r
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 # S  \+ U2 r2 k8 g8 X8 {
ejected during the impact, the red is limestone outcrop and the green areas are mostly vegetation. The impact occurred
around 5 million years ago." H0 {3 o. w( L! Y. m3 p, z3 l

tvb now,tvbnow,bttvb+ |& W3 Z: k+ n, {+ w  Y' w# s" S
公仔箱論壇3 W+ H, \8 W- J2 O
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。1 S+ Q* H! n! a4 C$ I
Scientists determined the structure was caused by an asteroid through clues such as the presence of maskelynite,
a glass that is only formed by extremely high-velocity impacts. The impact occurred around 50,000 years ago. tvboxnow.com) M7 m, ]% t% H$ V" U5 B; j
This image was captured by the Advanced Spaceborne Thermal Emission and Reflection Radiometer on NASA’s
! W0 ]" ^5 U" ]7 ^* T/ _+ itvboxnow.comTerra satellite. It is a simulated true-color imagetvboxnow.com# q2 u" n( o- K5 c+ p, }% h

% O3 h$ T; M5 F. T
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.- ^6 y) ~+ ]9 }& y' ?$ U1 S5 m

. z( ?/ v: S& o5 Q) b: A: d! Y1 s" H* z5 I. c

/ i# N( t4 m' Z5 Y) B
$ s# i; d4 P% @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
a 300-mile wide asteroid would look impacting Earth. This event probably would have killed everything on the planet. ' e9 E5 G/ t5 u- P4 m
Fortunately, NASA says nothing this big is headed our way anytime soon.