7#连接
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http://bbs.taisha.org/viewthread.php?tid=1007576&page=1#pid11030662
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BLACK HOLE0 n+ w- p" p% P* }) j O; c5 b
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8 a, X( i; V. p8 p& ?9 _（还记得关于黑洞的考题吧.特意做了这篇阅读.希望涵盖的内容够全面吧）
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This photo released by NASA shows a montage assembled by combining a visible-light image of the Abell 901/902 supercluster taken with the MPG/ESO 2.2-meter telescope in La Silla, Chile, with a dark matter map derived from observations with NASA's Hubble Space Telescope. The magenta-tinted clumps represent a map of the dark matter in the cluster, which is an invisible form of matter that accounts for most of the universe's mass. The image shows that the supercluster galaxies lie within the clumps of dark matter. (AP Photo/NASA) Hubble cannot see the dark matter directly. Astronomers inferred its location by analyzing the effect of so-called weak gravitational lensing, where light from more than 60,000 galaxies behind Abell 901/902 is distorted by intervening matter within the cluster. Researchers used the observed, subtle distortion of the galaxies' shapes to reconstruct the dark matter distribution in the supercluster.
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Scientists in California have uncovered the best evidence yet that cosmic dust in the early universe mostly came from the explosions of giant stars.
5 H% F3 ]2 f4 u# t& GThe Spitzer Space Telescope recently detected large amounts of space dust, 10,000 Earth masses worth, in the supernova remnant Cassiopeia A located 11,000 light-years away.
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The discovery comes two months after Spitzer found freshly made dust in the wind bursting out of super-massive black holes.
E; z5 v# [ _8 m7 b3 g @3 ZAstronomers believe both supernovae and quasars are responsible for the dust that helped seed early stars. Dust is essential in the cooling process to make stars, which are predominantly gas.
6 v( ?6 L u2 _8 OResearchers at NASA's Spitzer Science Center at the California Institute of Technology used a telescope instrument to analyze infrared light from the supernova and construct maps of the dust to determine the quantity and composition.
, O7 c& N4 Z* fResults will be published in the Jan. 20 issue of the Astrophysical Journal.
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This composite photo provided by NASA shows A powerful jet from a supermassive black hole is blasting a nearby galaxy in the system known as 3C321, according to new results from NASA. This galactic violence, never seen before, could have a profound effect on any planets in the path of the jet and trigger a burst of star formation in the wake of its destruction.
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+ B9 A3 M. |1 `) x/ U! nNASA Resurrects Black Hole Mission
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% n2 p# ~. Z+ i$ W/ y' H) g jNASA on Friday resurrected a telescope mission that will use high-energy X-rays to conduct a census of black holes in the universe.
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The Nuclear Spectroscopic Telescope Array, or Nustar, was canceled last year because of budget constraints.
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5 O V; x% K+ QNustar, now scheduled for launch in 2011, will fly two years prior to the launch of the James Webb Space Telescope, the successor to the aging Hubble Space Telescope.
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# S, ? D3 A2 W4 D"I thought the program was dead," said principal investigator Fiona Harrison of the California Institute of Technology. "It's a great opportunity to find black holes that are hidden to optical telescopes."
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% n5 H4 t2 X. k% e6 `: c& VDust in black hole winds helped form early stars
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Planets and much on them, including humans, come from dust — mostly from dying stars. But where did the dust that helped form those early stars come from?
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! n. {1 |2 l! M2 _6 O7 TA NASA telescope may have spotted one of the answers. It's in the wind bursting out of super-massive black holes.
! N a1 [1 Y) H A/ ?& Q7 j1 aThe Spitzer Space Telescope identified large quantities of freshly made space dust in a quasar about 8 billion light years from here.
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8 S5 q+ f# m7 f) z" IAstronomers used the telescope to break down the wavelengths of light in the quasar to figure out what was in the space dust. They found signs of glass, sand, crystal, marble, rubies and sapphires, said Ciska Markwick-Kemper of the University of Manchester in England. She is the lead author of a study that will be published later this month in Astrophysical Journal Letters.
, B) b9 U$ I) F) U# FDust is important in the cooling process to make stars, which are predominantly gas. The leftover dust tends to clump together to make planets, comets and asteroids, said astronomer Sarah Gallagher, a study co-author at the University of California Los Angeles.
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{7 b! Y- |. j8 `% h4 k"In the end, everything comes from space dust," Markwick-Kemper said. "It's putting all the pieces of the puzzle together to figure out where we came from."
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Astronomers figure that the planets that formed in the past several billion years — and those away from quasars — came from dust that was belched from dying stars. That's what happened with Earth.
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, x* i0 i: n9 h! X7 Z4 u0 B% tThat still leaves a question about where the dust from the first couple billion years of the universe came from, which helped form early generations of star systems.
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3 _3 v: ^, W! v+ t"It's formed in the wind," of the black holes, Markwick-Kemper said. Gas molecules collide in the searing heat of the quasar, which is thousands of degrees Fahrenheit, and form clusters.
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"These clusters grow bigger and bigger until you can call them dust grains," she said.Scientists who weren't part of the study hailed the work.
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本帖最后由 miao555 于 2008-3-19 10:14 编辑 ]
