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| Mars: The Lure Of The Red Planet |
| 05.09.09 (1:15 pm) [edit] |
| The HST observations provide additional evidence that the absorption is associated with galaxies. Where did the dappled come from? "It is not pristine. Using a unique capability of NASA's Hubble Space Telescope (HST) astronomers announced today that they have detected the rare element boron in an ancient star. The cosmic rays could have been produced by dappled or other highly energetic events which occurred early in the life of the Milky Way. A foreground galaxy that lies along the line of sight to the quasar has the same distance from us as does one of the cloud groupings. “We are very pleased with the quality of the (Generic)Alprazolam Online says Hartig. These absorption lines are unrelated to the quasars themselves, but are attributed to invisible, intervening clouds of hydrogen gas which absorb certain frequencies of a quasar's light. Bahcall, Buell Jannuzi and Donald Schneider, all of the Institute for Advanced Study and George Hartig of the Space Telescope Science Institute, Baltimore, MD, announced their results today to a press conference at the 179th meeting of the American Astronomical Society in Atlanta. If so, then the HST findings may force some modification in theories of the Big Bang itself. If substantial amounts of beryllium and boron (the fourth and fifth lightest elements) were formed very rapidly early in the history of the Milky Way, swarms of energetic particles may have been present at the birth of the galaxy. However, more recent theories suggest that the Big Bang developed some structure even during the first few minutes. Predictably, HD 140283 contains mostly primordial elements synthesized in the Big Bang: hydrogen, helium, Buy Alprazolam (COD) traces of lithium. Either way, this will be an exciting test to show which of the possible explanations is correct. Ground-based observations have shown that the number of these clouds rapidly rises as one looks back in time, so it was thought, says Hartig "that the number of nearby hydrogen clouds was relatively small. This suggests that the material producing the nearby hydrogen absorption may be associated with individual galaxies or clusters of galaxies. However, the astronomers found slightly different relative proportions of beryllium and boron than what is expected from cosmic ray dappled production. 16. In the past the gas cloud was probably part of a galaxy's star forming region," said Danly. The light from boron only appears in the ultraviolet part of the spectrum and so does not penetrate our atmosphere. Previously, another rare element, beryllium, had Buy Alprazolam On Line detected in the star with ground-based telescopes. Astronomers reported today that recent ultraviolet observations with NASA's Hubble Space Telescope suggest that what were thought to be randomly distributed, nearby primordial clouds of hydrogen may Alprazolam-UPS be associated with galaxies Alprazolam Rebate clusters of galaxies. These new theories differ from the traditional one in predicting that small but detectable amounts of beryllium Alprazolam And Substitute boron might be created. Until the launch of the Hubble Space Telescope, it was impossible to directly measure the numbers of nearby clouds. For the past two decades, observations with ground- based telescopes have shown that the spectra of high-redshift quasars contain complex "thickets" of absorption features. David Lambert Cheap Alprazolam Online Michael Lemke, of the University of Texas at Austin, are announcing their results today to dappled press conference at the 179th meeting of the American Astronomical Society in Alprazolam Bar Xanax Atlanta. Schneider notes that, "Recent ground-based studies have shown that H1821+643 is surrounded by a large number of Alprazolam Rebate Coupons so it is possible that the self-absorption system is caused by material belonging to the cluster or to an individual cluster galaxy. This was always considered to be one of the most important reasons for building the Space Telescope. This result places the cloud between 5,000 and 14,000 light-years away. To confirm these results, the astronomers plan additional HST observations of an even older star later this year. Using HST's Goddard High Resolution Spectrograph, the researchers detected traces of boron in a yellow 7th magnitude star called HD 140283, located 100 light-years away in the constellation Libra. The currently accepted version of the Big Bang says that the early universe was uniformly hot and dense. These types of lines, called self- absorption systems, have been found in high-redshift quasars and were thought to be produced by material in the quasar itself. Because it was among the first stars to form in our Milky Way galaxy, HD 140283 dappled contain elements which were incorporated into the star long ago. (Heavier elements such as carbon, nitrogen, oxygen, and others which are found in the Sun, the Earth and Solar System planets are thought to have been built up Drug: Alprazolam (Xanax) the lifetime of the galaxy by nuclear reactions in successive generations of stars). This offers the alternative possibility that beryllium and boron were synthesized in the first moments of the universe's creation. The research will be presented to the meeting of the society in a session for late papers on Thursday, Jan. This spectrum shows a higher than expected number of extragalaclic absorption features, confirming the initial HST results. |