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LOS ANGELES - Scientists believe heat from radioactive decay inside a tiny, icy Saturn moon shortly after it formed billions of years ago may explain why geysers are erupting from the surface today. The Cassini spacecraft last year beamed back dazzling images of Yellowstone-like geysers spewing from a warm section on Enceladus, raising the possibility that the moon, which has an overall surface temperature of about minus-330 degrees, may have an internal environment suitable for primitive life.
A single, specific memory has been wiped from the brains of rats, leaving other recollections intact.
A simple formula can predict how people would want to be treated in dire medical situations as accurately as their loved ones can, say researchers.
The finding suggests that computers may one day help doctors and those acting as surrogate decision-makers to better estimate the wishes of people in a coma.
By signing what is known as an "advance directive", people can specify what types of medical care they would want if they lost the ability to make decisions. Many people, however, do not complete such a directive in advance of these critical situations and their relatives or others must then decide on their behalf.
The finding suggests that computers may one day help doctors and those acting as surrogate decision-makers to better estimate the wishes of people in a coma.
By signing what is known as an "advance directive", people can specify what types of medical care they would want if they lost the ability to make decisions. Many people, however, do not complete such a directive in advance of these critical situations and their relatives or others must then decide on their behalf.
By casting a wide net, astronomers have captured an image of more than a thousand supermassive black holes. These results give astronomers a snapshot of a crucial period when these monster black holes are growing, and provide insight into the environments in which they occur.
The new black hole panorama was made with data from NASA's Chandra X-ray Observatory, the Spitzer Space Telescope and ground-based optical telescopes. The black holes in the image are hundreds of millions to several billion times more massive than the sun and lie in the centers of galaxies.
The new black hole panorama was made with data from NASA's Chandra X-ray Observatory, the Spitzer Space Telescope and ground-based optical telescopes. The black holes in the image are hundreds of millions to several billion times more massive than the sun and lie in the centers of galaxies.
Modern humans were living in northern Africa far earlier than previously thought, according to scientists. A new analysis of a 160,000-year-old fossilised jawbone from Morocco shows that the homo sapiens in the area had started having long childhoods, one of the hallmarks of humans living today.
It is known that the species homo sapiens emerged in Africa 200,000 years ago, but the oldest fossils that resemble modern humans come from sites in Europe dated to around 20,000 to 30,000 years ago.
The latest find shows that the key time in the development of a complex human society came much earlier than previously thought. The longer people had to learn and develop their brains as children, the more sophisticated their society could become. The new study pushes the date that modern humans emerged back by more than 100,000 years.
It is known that the species homo sapiens emerged in Africa 200,000 years ago, but the oldest fossils that resemble modern humans come from sites in Europe dated to around 20,000 to 30,000 years ago.
The latest find shows that the key time in the development of a complex human society came much earlier than previously thought. The longer people had to learn and develop their brains as children, the more sophisticated their society could become. The new study pushes the date that modern humans emerged back by more than 100,000 years.
In 1926, Russian physicist Yakov Frenkel proposed a theory that put a limit on the amount of stress a perfect crystal can withstand before its structural planes begin to slip over one another. Now, however, physicists from Norway have made a theoretical model showing that before Frenkel's limit is ever reached, crystals will deform due to a process called "thermal runaway" -- whereby strain and heat amplify rapidly. This could shed light on the mechanisms underlying deep earthquakes, and could help engineers to determine material tolerances more accurately.
Frenkel's theory applies to perfect crystals, and has long been known to set the stress limit too high for most real materials. This is because real materials often contain defects that can move through the structure and make it easier for planes to slip. But this is not always true: some materials such as rocks in the Earth's interior and metallic glasses have structures that act to prevent defects from moving, and so can demonstrate unusually high shear strengths.
Frenkel's theory applies to perfect crystals, and has long been known to set the stress limit too high for most real materials. This is because real materials often contain defects that can move through the structure and make it easier for planes to slip. But this is not always true: some materials such as rocks in the Earth's interior and metallic glasses have structures that act to prevent defects from moving, and so can demonstrate unusually high shear strengths.
An unusual type of arms race involving nuclear bombs and supermassive spacecraft has been heating up this week in Washington, D.C.
Each team of players hopes to be the one to design the U.S. government's weapon of choice for deflecting comets and asteroids that could be on a collision course with Earth.
A NASA task force today presented Congress with a report that includes recommendations for the best technologies for avoiding an impact with a so-called near-Earth object (NEO).
The debate has been raging among experts about which solution will be the safest, cheapest, and most reliable.
Ed Lu, a NASA astronaut and physicist, has been developing one of the leading contenders: a "gravitational tractor."
Each team of players hopes to be the one to design the U.S. government's weapon of choice for deflecting comets and asteroids that could be on a collision course with Earth.
A NASA task force today presented Congress with a report that includes recommendations for the best technologies for avoiding an impact with a so-called near-Earth object (NEO).
The debate has been raging among experts about which solution will be the safest, cheapest, and most reliable.
Ed Lu, a NASA astronaut and physicist, has been developing one of the leading contenders: a "gravitational tractor."
Worldwide, 100 billion cubic meters of natural gas is wasted every year. Now, the Denver-based company Swift LNG aims to turn that gas into a usable liquid fuel with a thermoacoustic natural gas liquefaction technology just licensed from Los Alamos National Laboratory.
The thermoacoustic natural gas liquefier converts heat into sound waves and then converts the hot sound wave energy to cold refrigeration using highly pressurized helium contained in a network of welded steel pipes. First, the system combusts a small fraction of the natural gas to heat one end of the steel pipe network. Then, the resulting acoustic energy refrigerates the opposite end of the network, which cools the rest of the natural gas. At minus 160 degrees Celsius the natural gas liquefies - rendered dense enough for economical transport. This technology requires no moving parts, contributing to its economy of operation.
The thermoacoustic natural gas liquefier converts heat into sound waves and then converts the hot sound wave energy to cold refrigeration using highly pressurized helium contained in a network of welded steel pipes. First, the system combusts a small fraction of the natural gas to heat one end of the steel pipe network. Then, the resulting acoustic energy refrigerates the opposite end of the network, which cools the rest of the natural gas. At minus 160 degrees Celsius the natural gas liquefies - rendered dense enough for economical transport. This technology requires no moving parts, contributing to its economy of operation.
The more massive a galaxy is, the faster its stars and gas will move. This relationship holds regardless of whether a galaxy looks like an ellipse, a cosmic pinwheel or some other odd shape, a new study finds.
This rule even applies to "train wrecks" left after galaxies collide and merge with one another, which is surprising, said study team member Susan Kassin, a postdoctoral researcher at the University of California, Santa Cruz (UCSC). "It indicates that there is a remarkable regularity to galaxies, irrespective of what they look like," Kassin said.
The new finding, to be detailed in an upcoming issue of Astrophysical Journal Letters, shows that the relation between a galaxy's mass and the orbital speed of its stars and gas is remarkably consistent over a wide range of galaxy shapes and over billions of years of galaxy evolution.
"We think this trend reflects a regularity in the process that led to the formation of galaxies," said study leader Sandra Faber, also of UCSC. "We are not sure where it comes from, but it is a major constituent on galaxy formation."
This rule even applies to "train wrecks" left after galaxies collide and merge with one another, which is surprising, said study team member Susan Kassin, a postdoctoral researcher at the University of California, Santa Cruz (UCSC). "It indicates that there is a remarkable regularity to galaxies, irrespective of what they look like," Kassin said.
The new finding, to be detailed in an upcoming issue of Astrophysical Journal Letters, shows that the relation between a galaxy's mass and the orbital speed of its stars and gas is remarkably consistent over a wide range of galaxy shapes and over billions of years of galaxy evolution.
"We think this trend reflects a regularity in the process that led to the formation of galaxies," said study leader Sandra Faber, also of UCSC. "We are not sure where it comes from, but it is a major constituent on galaxy formation."
The British military's Skynet 5 satellite has been launched into space from Kourou in French Guiana.
The spacecraft is part of a £3.2bn system that will deliver secure, high-bandwidth communications for UK and allied forces.
The spacecraft is part of a £3.2bn system that will deliver secure, high-bandwidth communications for UK and allied forces.
