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Scientists using NASA's High Energy Solar Spectroscopic Imager satellite said they have observed a source of high-energy gamma rays that originate on Earth's upper atmosphere, not from outer space. They are very short blasts of gamma rays, lasting about one-thousandth of a second and emitted into space by electrons traveling at 99.99 percent of the speed of light. Originally discovered in 1994, the origin of terrestrial gamma-ray flashes (TGFs) has remained a mystery. The best guess at present is they are generated by the build-up of electrical charges at the tops of thunder clouds due to lightning discharges. TGFs have been correlated with lightning strikes, the scientists said.
There are 2 space missions currently observing Sun. They are Ulysses and SOHO. A joint NASA/ESA spacecraft, Ulysses, was launched in 1990 to take it to a unique solar orbit out of the ecliptic (the plane of rotation of the Earth around the Sun) so that it could observe the polar regions of the Sun. Its main mission is to study the huge bubble of solar wind blowing off the Sun - the heliosphere - from the equator to the poles. SOHO has been incredibly successful. As well as using helioseismology to probe the interior, it has been observing the corona and the solar wind with a range instruments in which UK teams have been heavily involved. Launched in 1995, it has been able to follow the rise of solar activity to its maximum in 2000-2001, monitoring and imaging solar flares as they happen and the huge clouds of material that are ejected into space.
A team of European scientists has announced a huge, frozen sea lies just below the surface of Mars. Their assessment is based on pictures taken by Mars Express spacecraft of the planet’s near-equatorial Elysium region that show plated and rutted features across an area 800 by 900 km.
Large reserves of water-ice are known to be held at the poles on Mars but if this discovery is confirmed by follow-up observations, it would be a first for a region at such a low latitude.
The water that formed the sea in the southern Elysium, five degree north of the equator, appears to have originated beneath the surface of Mars, erupting from a series of fractures known as the Cerberus Fossae.
Further data is now required to support the initial observations but already other scientists think the interpretation is reasonable.
NASA has set May 15 as space shuttl Discovery’s launch to be followed by a July 12 Atlantis launch.
Discovery’s crew of seven is to be led by Commander Eileen Collins.
Discovery and Atlantis will be so-called rescue shuttles for each other should something go wrong. NASA has been readying both shuttles side by side.
According to Readdy, engineers at the Kennedy Space Center have been working hard to upgrade the space shuttles, including hardening the vehicle and preparing them for returning to space, "The vehicles look like they are brand new cars," he said.
NASA has been developing repair techniques for the space shuttle’s thermal protection system for the past two years. Not all of the techniques have panned out and the Discovery crew will be testing only three potential fixes for tile instead of the five originally planned. There will be no tests on repair techniques for the reinforced carbon used on the shuttle’s wings, where the hole was created in Columbia.
Also, NASA has stated there will be no repair technique for a hole the size of the one that caused Columbia’s demise. Instead, the agency has focused on stopping foam from shedding from the external tank so no hole will be created in the first place.
Astronomers have been stunned by the amount of energy released in a star explosion on the far side of our galaxy, 50,000 light-years away. The blast occurred on the surface of an exotic kind of star - a super-magnetic neutron star called SGR 1806-20. The flash of radiation on 27 December 2004 was so powerful that it bounced off the Moon and lit up the Earth’s atmosphere. If the explosion had been just 10,000 light-years away, Earth could have suffered a mass extinction.
The event overwhelmed detectors on space-borne telescopes, such as the recently launched Swift observatory. This facility was put above the Earth to detect and analyse gamma-ray bursts - very intense but fleeting flashes of radiation.
This remarkable super-dense object is a neutron star - it is composed entirely of neutrons and is the remnant collapsed core of a once giant star. Now, though, this remnant is just 20km across and spins so fast it completes one revolution every 7.5 seconds. It has this super-strong magnetic field and this produces some kind of structure which has undergone a rearrangement - it’s an event that is sometimes characterised as a ‘star-quake’, a neutron star equivalent of an earthquake.
As NASA is preparing to fly Shuttle again, some critics contend that the agency is rushing back to the unforgiving environment of space with much of the job left undone.
The accident board which investigated Columbia tragedy recommended that NASA develop a "practicable capability" to inspect the shuttle while it is in orbit and repair damage to its thermal-protection system. NASA now says it will not be able to make any but the most minor repairs in space.
The board called for sharp reductions in the amount of foam that might fall off of the external tank and strike the tiles and panels protecting the craft, but internal agency documents suggest that NASA’s efforts to limit the size of pieces are still fraught with uncertainty.
NASA appointed a task force to monitor its progress in complying with the recommendations of the accident board. That task force, led by two former astronauts, Richard Covey and Thomas Stafford, is expected to make its final determination of NASA’s progress next month, but it already appears to be willing to allow NASA some slack.
NASA officials say that no shuttle mission can be risk-free and that the agency has generally raised safety levels enough to justify returning to flight.
A lonely young star has been discovered fleeing from the Milky Way galaxy at the most fantastic speeds ever seen. In another 80 million years, it could be entirely clear of the Milky Way and hurtling out into the vast and endless reaches of intergalactic space.
Runaway stars are not uncommon in our galaxy but this one is moving at more than 1.5 million mph.
How did the single star achieve such astonishing velocity? The stellar outcast had a companion once. The two — together known as a binary star — were rotating around each other, linked together like a couple twirling in a high-speed waltz. The two stars, in turn, were speeding together around the massive black hole at the center of the Milky Way galaxy in an orbit about 1.5 billion miles out.
The black hole’s immensely powerful gravity drew one of the stars closer, while the speed of the other star — both around its companion and around the black hole — flung it away, like a rock from a slingshot. As the outcast sped off, the black hole gripped the other star ever tighter and forced it into a closer orbit.
As for the outcast star’s companion that was left behind, it was probably now flying in a closer and closer orbit around the black hole at the Milky Way’s center. Eventually, the black hole’s immense gravity probably will tear that orphan star apart "and swallow it."
A weak El Nino and human-made greenhouse gases could make 2005 the warmest year since records started being kept in the late 1800s, NASA scientists said this week.
Due to carbon dioxide, the most common greenhouse gas, Earth’s surface now absorbs more of the sun’s energy than gets reflected back to space.
That extra energy, together with a weak El Nino, is expected to make 2005 warmer than 2003 and 2004 and perhaps even warmer than 1998, which had stood out as far hotter than any year in the preceding century, NASA said in a statement.
The warmest year on record was 1998, with 2002 and 2003 coming in second and third, respectively. Last year was the the fourth-warmest recorded, with a global mean temperature of 57 degrees Fahrenheit (14 Celsius), which was about 1.5 degrees warmer than the middle of the century, NASA scientist Drew Shindell said in an interview.
An asteroid expected to fly past Earth in 2029 will be visible to the naked eye from Europe, Africa and western Asia.
The 2029 event will be the closest brush by a good-sized asteroid known to occur. The rock will pass Earth inside the orbits of some satellites.
1,000 feet (320 meters) wide asteroid, catalogued as 2004 MN4, was discovered last June.
On April 13, 2029, it will be about 22,600 miles (36,350 kilometers) from Earth’s center.
Were an asteroid the size of 2004 MN4 to hit Earth, it would cause local devastation and regional damage. It would not be expected to cause any sort of global disruption.
Astronomers using a giant telescope atop Mauna Kea have discovered a hot spot at the tip of Saturn’s south pole. The infrared images suggest a warm polar vortex — a large-scale weather pattern likened to a jet stream on Earth that occurs in the upper atmosphere. It’s the first such hot vortex ever discovered in the solar system. Sunlight has bathed Saturn’s southern hemisphere for the past 15 years without a break, so it’s no surprise that the environs are slightly warm. But researchers at NASA’s Jet Propulsion Laboratory were startled to see just how hot the south pole is, with a stratospheric temperature of 151 kelvins.
Polar vortices are found on Earth, Jupiter, Mars and Venus, and are colder than their surroundings. The new images from the Keck Observatory show the first evidence of a polar vortex at much warmer temperatures. On Earth, the Arctic Polar Vortex is typically located over eastern North America in Canada and plunges cold arctic air to the northern Plains in the United States.
What is causing Saturn’s hot spot remains unclear, though particulates that absorb sunlight and are trapped in the planet’s upper atmosphere could be to blame. Scientists may learn more from the data coming from the infrared spectrometer on the Cassini spacecraft currently orbiting Saturn.
Mo'nonymous on New companion of Nep...
Mo'nonymous on New companion of Nep...
Mo'nonymous on New companion of Nep...
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