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Domain: exosci.com
Stories and comments across the archive that link to exosci.com.
Stories · 21
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White Dwarfs Could be Dark Matter
Porfiry writes "An international team of astronomers has detected what could be a significant portion of the galactic dark matter that has eluded astronomers for nearly 70 years. Scanning digitized images of the southern sky, the team found 38 previously unseen cool white dwarfs within about 450 light years of Earth. If the density of these newly discovered white dwarfs is indicative of the rest of the galaxy's halo, these dead stars would comprise at least three percent of the dark matter of the halo, and perhaps as much as 35 percent." -
Universe Teeming With Black Holes
Porfiry writes "For the first time, astronomers believe they have proof black holes of all sizes once ruled the universe. NASA's Chandra X-ray Observatory provided the deepest X-ray images ever recorded (a million-second exposure), and those pictures deliver a novel look at the past 12 billion years of black holes. Combining infrared and X-ray observations, the Penn State team found veils of dust and gas are common around young black holes. 'The discovery of this object, some 12 billion light years away, is key to understanding how dense clouds of gas form galaxies, with massive black holes at their centers,' said Colin Norman of Johns Hopkins University." -
Wet Venus?
Porfiry writes "Researchers at Washington University in St. Louis, studying hydrous mineral decomposition rates at extreme temperatures, have concluded that hot and dry Venus may have been a wet planet in the past, like Earth and ancient Mars. The new evidence suggesting a wetter Venusian history comes from a series of experiments documenting the chemical stability of tremolite, a mineral that forms in the presence of water." This is a little bit similar to the Venus article we just posted, but still interesting. -
Wet Venus?
Porfiry writes "Researchers at Washington University in St. Louis, studying hydrous mineral decomposition rates at extreme temperatures, have concluded that hot and dry Venus may have been a wet planet in the past, like Earth and ancient Mars. The new evidence suggesting a wetter Venusian history comes from a series of experiments documenting the chemical stability of tremolite, a mineral that forms in the presence of water." This is a little bit similar to the Venus article we just posted, but still interesting. -
Death Spiral First Evidence Of Black Hole
Porfiry writes "NASA's Hubble Space Telescope may have, for the first time, provided direct evidence for the existence of black holes by observing the disappearance of matter as it falls beyond the "event horizon." An event horizon is the mysterious region surrounding a black hole that forever traps light and matter straying nearby. By definition, no astronomical object other than a black hole can possess an event horizon. The discovery comes from a detailed statistical analysis of a 1992 observation of one of the first black holes ever discovered, Cygnus XR-1, which lies 6,000 light-years from Earth in the summer constellation Cygnus the Swan."And Tackhead sends in this related information: "The folks at the Chandra X-Ray Observatory appear to have detected event horizons by comparing the X-ray luminosity of the accretion discs surrounding black-hole-based X-ray novae versus neutron-star-based X-ray novae during their phases of dormancy. X-ray novae are caused by ignition of fusion in the accretion discs of hot gas drawn from companion stars near black holes or neutron stars. While the novae were dormant, the discs surrounding black hole companions were observed and found to be 100 to 1000 times fainter than those surrounding neutron star companions. The conclusion: 'something' must be consuming the energy that would otherwise be expected from the disc; the most likely candidate being an event horizon."
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Death Spiral First Evidence Of Black Hole
Porfiry writes "NASA's Hubble Space Telescope may have, for the first time, provided direct evidence for the existence of black holes by observing the disappearance of matter as it falls beyond the "event horizon." An event horizon is the mysterious region surrounding a black hole that forever traps light and matter straying nearby. By definition, no astronomical object other than a black hole can possess an event horizon. The discovery comes from a detailed statistical analysis of a 1992 observation of one of the first black holes ever discovered, Cygnus XR-1, which lies 6,000 light-years from Earth in the summer constellation Cygnus the Swan."And Tackhead sends in this related information: "The folks at the Chandra X-Ray Observatory appear to have detected event horizons by comparing the X-ray luminosity of the accretion discs surrounding black-hole-based X-ray novae versus neutron-star-based X-ray novae during their phases of dormancy. X-ray novae are caused by ignition of fusion in the accretion discs of hot gas drawn from companion stars near black holes or neutron stars. While the novae were dormant, the discs surrounding black hole companions were observed and found to be 100 to 1000 times fainter than those surrounding neutron star companions. The conclusion: 'something' must be consuming the energy that would otherwise be expected from the disc; the most likely candidate being an event horizon."
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The Oldest Known Life Keeps Getting Older
Porfiry writes: "Remnants of organic matter in ancient soil more than 2.6 billion years old may be the earliest known evidence for terrestrial life, according to a team of Penn State astrobiologists. 'Our work shows that the organic matter in this soil very probably represents remnants of microbial mats that developed on the soil surface between 2.6 and 2.7 billion years ago,' says Dr. Hiroshi Ohmoto, professor of geochemistry and director of The Penn State Astrobiology Center. 'This places the development of terrestrial biomass more than 1.4 billion years earlier than previously reported.'" -
The Oldest Known Life Keeps Getting Older
Porfiry writes: "Remnants of organic matter in ancient soil more than 2.6 billion years old may be the earliest known evidence for terrestrial life, according to a team of Penn State astrobiologists. 'Our work shows that the organic matter in this soil very probably represents remnants of microbial mats that developed on the soil surface between 2.6 and 2.7 billion years ago,' says Dr. Hiroshi Ohmoto, professor of geochemistry and director of The Penn State Astrobiology Center. 'This places the development of terrestrial biomass more than 1.4 billion years earlier than previously reported.'" -
101 Giant Galaxy Clusters Discovered
Porfiry says: "Astronomers behind the Massive Cluster Survey (MACS) have uncovered 101 giant galaxy clusters, many of them so distant and thus forming so early in the history of time that they challenge our current understanding of how quickly the Universe evolved into its current hierarchical structure of stars, galaxies and clusters. Galaxy clusters are the largest gravitationally bound structures in the Universe, typically containing a few hundred to thousands of galaxies, each of which in turn contains many billions of stars." -
101 Giant Galaxy Clusters Discovered
Porfiry says: "Astronomers behind the Massive Cluster Survey (MACS) have uncovered 101 giant galaxy clusters, many of them so distant and thus forming so early in the history of time that they challenge our current understanding of how quickly the Universe evolved into its current hierarchical structure of stars, galaxies and clusters. Galaxy clusters are the largest gravitationally bound structures in the Universe, typically containing a few hundred to thousands of galaxies, each of which in turn contains many billions of stars." -
Organic Matter Can Survive Atmospheric Entry
Porfiry writes: "Astrobiologists have come to a number of interesting conclusions after observing the 1999 Leonids. "Last year's Leonid meteor storm yielded rich research results for NASA astrobiologists," said Dr. Peter Jenniskens. "Findings to date indicate that the chemical precursors to life -- found in comet dust -- may well have survived a plunge into early Earth's atmosphere. We discovered that most of the visible light of meteors comes from a warm wake just behind the meteor, not from the hot meteoroid's head," said Jenniskens. This warm wake has just the right temperature for the creation of life's chemical precursors." Note that this year's Leonids will be brightest on November 16 and 17. -
Organic Matter Can Survive Atmospheric Entry
Porfiry writes: "Astrobiologists have come to a number of interesting conclusions after observing the 1999 Leonids. "Last year's Leonid meteor storm yielded rich research results for NASA astrobiologists," said Dr. Peter Jenniskens. "Findings to date indicate that the chemical precursors to life -- found in comet dust -- may well have survived a plunge into early Earth's atmosphere. We discovered that most of the visible light of meteors comes from a warm wake just behind the meteor, not from the hot meteoroid's head," said Jenniskens. This warm wake has just the right temperature for the creation of life's chemical precursors." Note that this year's Leonids will be brightest on November 16 and 17. -
Black Holes May Promote Stellar Birth
Porfiry writes: "The unusually high rates of star births seen in some galaxies may be linked to voracious black holes at the center of those galaxies, according to a new analysis of astronomical data by researchers at Johns Hopkins University. The new results suggest that galaxies with rapid rates of star formation and galaxies with active black holes, long considered separate phenomena, are actually links in a single set of evolutionary processes that shape the development of galaxies." -
Black Holes May Promote Stellar Birth
Porfiry writes: "The unusually high rates of star births seen in some galaxies may be linked to voracious black holes at the center of those galaxies, according to a new analysis of astronomical data by researchers at Johns Hopkins University. The new results suggest that galaxies with rapid rates of star formation and galaxies with active black holes, long considered separate phenomena, are actually links in a single set of evolutionary processes that shape the development of galaxies." -
Further Advances In Quantum Computing
Porfiry writes: "Scientists at the U.S. Department of Energy's Los Alamos National Laboratory have taken another step forward in the quest for a quantum-based computer by demonstrating the existence of a physical state immune to certain types of information-corrupting "noise," which could otherwise disrupt computations based on quantum states. The essential phenomenon that the Los Alamos team demonstrated is a state in what is called a "decoherence-free subspace." The researchers showed this state's existence using entangled photons, paired particles of light whose conditions are intimately linked." -
Further Advances In Quantum Computing
Porfiry writes: "Scientists at the U.S. Department of Energy's Los Alamos National Laboratory have taken another step forward in the quest for a quantum-based computer by demonstrating the existence of a physical state immune to certain types of information-corrupting "noise," which could otherwise disrupt computations based on quantum states. The essential phenomenon that the Los Alamos team demonstrated is a state in what is called a "decoherence-free subspace." The researchers showed this state's existence using entangled photons, paired particles of light whose conditions are intimately linked." -
Can Bacteria Survive Space Vacuum, UV?
Porfiry of ExoScience writes: "The theory that microbial life once came to Earth on a meteorite from another planet will be tested on July 26 when a NASA rocket carries into space special microorganisms from research at the University of Maryland Biotechnology Institute (UMBI). The tiny space pioneers will be riding an apogee, or suborbital, flight path similar to the historic 1961 flight of astronaut Alan Shepard. The passengers this time will be four dime-size cultures, each holding about 100 million cells of the microbes that will be exposed to space vacuum and solar radiation for 10 minutes." -
Can Bacteria Survive Space Vacuum, UV?
Porfiry of ExoScience writes: "The theory that microbial life once came to Earth on a meteorite from another planet will be tested on July 26 when a NASA rocket carries into space special microorganisms from research at the University of Maryland Biotechnology Institute (UMBI). The tiny space pioneers will be riding an apogee, or suborbital, flight path similar to the historic 1961 flight of astronaut Alan Shepard. The passengers this time will be four dime-size cultures, each holding about 100 million cells of the microbes that will be exposed to space vacuum and solar radiation for 10 minutes." -
Can Bacteria Survive Space Vacuum, UV?
Porfiry of ExoScience writes: "The theory that microbial life once came to Earth on a meteorite from another planet will be tested on July 26 when a NASA rocket carries into space special microorganisms from research at the University of Maryland Biotechnology Institute (UMBI). The tiny space pioneers will be riding an apogee, or suborbital, flight path similar to the historic 1961 flight of astronaut Alan Shepard. The passengers this time will be four dime-size cultures, each holding about 100 million cells of the microbes that will be exposed to space vacuum and solar radiation for 10 minutes." -
Can Time Flow Backwards?
PD writes "Exoscience has a story about the possibility that in some regions of space, time can actually flow backwards. Eggs would unbreak, supernovae would unexplode into stars, and living things would grow younger. I wonder if it makes hair grow back." -
Can Time Flow Backwards?
PD writes "Exoscience has a story about the possibility that in some regions of space, time can actually flow backwards. Eggs would unbreak, supernovae would unexplode into stars, and living things would grow younger. I wonder if it makes hair grow back."
