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Astronomers aided by the Hubble Telescope have spied two more rings encircling Uranus, the first additions to the planet’s ring system in nearly two decades
The faint, dusty rings orbit outside of Uranus’ previously known rings, but within the orbits of its large moons. The discovery, announced Thursday, means scientists now believe the seventh planet from the sun possesses 13 rings.
In 1986, Voyager 2 became the first spacecraft to zip past Uranus and beam back thousands of images of its dazzling rings and numerous moons. It found two new rings in addition to the nine previously discovered from Earth.
The newly discovered rings are made up of short-lived, faint bands of dust grains that are constantly being replenished by erosion of larger space bodies. Scientist think the dust in the outermost ring is being supplied by the moon Mab, discovered in 2003.
NASA plans to change the space shuttle’s external fuel tank again, this time removing a troublesome section of protective foam that broke off during the launch of Discovery last July.
The removal of more foam from the tank and further testing to find the root cause of cracks in the foam could lead to a longer delay until the next shuttle flight, tentatively set for May.
A distant object has been spotted circling the sun far beyond Neptune in a strange tilted orbit. Officially called 2004 XR 190 but code-named Buffy, the object is now about 58 times as far from the sun as Earth, and twice as far from the sun as Neptune. Buffy is a considered a Kuiper Belt object. The Kuiper Belt is a ring of space objects that may be remnants from the early solar system. Most of these objects orbit the sun between 30 and 50 times the distance that Earth orbits. The distance from Earth to the sun — 93 million miles — is known as one astronomical unit. Most Kuiper Belt objects are contained in this thick swath of space, and most have elliptical orbits, which means they get much closer to Neptune during parts of their orbits. They generally orbit in the same plane as most of the planets and other solar system objects.
But Buffy’s circular track means it stays beyond the 50 astronomical unit range for its entire orbit, never getting much closer than 52 astronomical units, or AU, and sometimes swinging out to 62 AU.
The only other known object that never gets within the 50 AU boundary is Sedna, which flings out to 900 AU and swoops in to 76 AU. But Sedna’s orbit is typically elliptical, while Buffy goes around in a near-perfect circle.
And Buffy’s orbit is tilted at a 47 degree angle from the rest of the solar system.
The highly eccentric orbits of the other Kuiper Belt objects are thought to be the result of being flung outward in a slingshot effect by Neptune’s gravity. But Buffy’s orbit does not follow that pattern.
The return of the Hayabusa probe will be delayed until 2010 because of a thruster problem. It was originally was expected to return to Earth in June 2007
While the prospects for re-establishing contact with the probe and halting the spin are high, the agency decided to postpone its return because it was unclear how long those procedures would take.
A team of astronomers has taken an important step toward mapping the Milky Way by accurately measuring the distance to the star-forming region W3OH in the Perseus spiral arm, the nearest arm to us. This long strand of stars streaks out of the Milky Way’s disk in the same manner as others seen in galaxies across the universe.
The new results are from a telescope nearly the size of Earth. The astronomers used the Very Long Baseline Array, taking observations from several telescopes stretching from Hawaii to the Virgin Islands, to create the resolution of a telescope nearly 5,000 miles (8,000 kilometers) in diameter.
Scientists have established that the radio telescope, the Very Long Baseline Array, can measure distances with unprecedented accuracy — nearly a factor of 100 times better than previously accomplished.
In doing so, they determined that W3OH is 1.95 ± 0.04 kiloparsecs away. That’s about 36,000,000,000,000,000 miles.
Although the VLBA has extremely high resolution, the source objects need to be very bright and compact. Spiral arms are just that — bright clouds of star-forming gas. In particular, this team focused in on a cloud of methyl alcohol surrounding a newly formed star.
This technique, also known as parallax, comes straight out of a high-school geometry textbook. In this case, the researchers used the changing vantage point from Earth as it orbits the sun to form one leg of the triangle. Then, they calculated the star’s distance by measuring the change in its position as Earth orbits the sun.
The astronomers found that this young star is actually moving around the Milky Way in an orbit that is about 10 percent off from being circular. It appears to rotate slower than other stars in circular orbits and is falling toward the center of the Milky Way.
Although scientists don’t really understand the details of spiral arm formation, these observations support the "spiral density-wave theory." This theory suggests that a combination of gravitational instabilities and shear forces — a result of the outer edge of the galaxy moving slower than the inner — causes material to cluster and eventually shoot off in an arm.
The researchers are now shifting the VLBA’s gaze toward three other spiral arms, where they will look at about a dozen star-forming areas similar to W3OH.
Earth’s north magnetic pole is drifting away from North America and toward Siberia at such a clip that Alaska might lose its spectacular Northern Lights in the next 50 years, scientists said Thursday. The shift could mean Alaska may no longer see the sky lights known as auroras, which might then be more visible in more southerly areas of Siberia and Europe.
The magnetic poles are part of the magnetic field generated by liquid iron in Earth’s core and are different from the geographic poles, the surface points marking the axis of the planet’s rotation.
Scientists have long known that magnetic poles migrate and in rare cases, swap places. Exactly why this happens is a mystery.
Previous studies have shown that the strength of the Earth’s magnetic shield has decreased 10 percent over the past 150 years. During the same period, the north magnetic pole wandered about 685 miles out into the Arctic, according to a new analysis by Stoner.
The rate of the magnetic pole’s movement has increased in the last century compared to fairly steady movement in the previous four centuries, the Oregon researchers said.
The north magnetic pole was first discovered in 1831 and when it was revisited in 1904, explorers found that the pole had moved 31 miles.
For centuries, navigators using compasses had to learn to deal with the difference between magnetic and geographic north. A compass needle points to the north magnetic pole, not the geographic North Pole. For example, a compass reading of north in Oregon is about 17 degrees east of geographic north.
The satellites inventory, developed by the Union of Concerned Scientists and released Wednesday, indicates the United States has 413 active satellites in space. That’s more than the 382 the rest of the world has spinning above the Earth
The group’s inventory lists 21 different details on satellites with missions ranging from weather forecasting to transmitting music and news for companies like Sirius Satellite Radio. Perhaps most controversially, the repository includes what’s known about top-secret spy satellites run by the U.S. and other governments.
The Russians, who follow the U.S. in total number, have 87. The Chinese have 34. The numbers are approximations that may vary depending on how joint ventures are counted.
While it did not provide precise orbits that would enable someone to find a satellite at any moment, the union’s database does give other closely held information.
The inventory also provides details about a highly classified $1 billion satellite, known as Misty-2, including its expected life span of more than 5 years and May 22, 1999, launch date.
Japanese probe Hayabusa may not have collected a surface sample, an official said Wednesday.
Data from the Hayabusa probe did not indicate that the vessel had fired a metal projectile onto the asteroid’s surface during its landing as previously thought.
JAXA had announced on Nov. 26 that the Hayabusa appeared to have briefly touched down on Itokawa, fired a metal projectile and collected the dust that was kicked up, then lifted off again to transmit data to mission controllers.
Spirit and Opportunity, the two robots roving the red planet, have lasted more than 22 months, far longer than anyone anticipated and signs of fatigue are beginning to show. Around 10 days ago, the mechanical arm on Opportunity stopped moving. If it has failed, it will be a significant hit. It is the contact arm of the mission. One of the steering actuators has also blown on Opportunity, but it can still be driven.
Spirit, which has roamed Mars for 684 days, is faring better. The only complication right now is with the rock abrasion tool. It has worn out. Made to only take three samples, Spirit has conducted 15 rock scrapings. The mission was supposed to last only 90 days, and most of the components were stress-tested for a lifetime of 270 days. With temperatures that can swing 100 degrees Celsius in a day, Mars is a tough environment for electrical components.
The two vehicles have brought a wealth of information about the planet back to Earth. A climb up the Columbia Hills on Mars, for instance, has revealed an astounding variety of rocks in a small area.
So far, Spirit has traveled 5.5 kilometers, while Opportunity has gone 6.5 kilometers. Together they’ve captured 130,000 images.
Scientists asserted that the clay in Martian soil and other geological and seismic evidence points to the existence, at least sporadically, of water on Mars. Mars likely had large bodies of water on its surface 3.5 billion years ago, but climatic changes dried up the vast majority of it. Mars lost most of its atmosphere and, with it, its water. Since then, water has been limited to certain periods of time and it was local.
Around 2.6 billion years ago, for instance, a volcanic explosion created a lava flow. It caused part of a glacier to melt, thereby freeing up water. The glacier, however, eventually won that contest and formed a structure called the Enigmatic Ridge, a long, straight line across the Martian surface. It was so called because scientists in the early 1970s studying the structure couldn’t figure out how it got formed.
However, Mars still likely has pockets of water.
The International Space Station provides an essential platform to support manned missions to the Moon and Mars but NASA currently lacks a complete or convincing plan for finishing and making use of the orbiting outpost, according to a report issued by the US National Research Council.
Key problems identified in the NRC report include the space shuttle’s limited availability to reach the station, the current reduction in the station’s crew, and restricted research – all of which can be traced back to funding issues.
The space shuttle is needed to deliver large components required to complete construction of the ISS and ferry up crew supplies and other equipment. But NASA hopes to cut costs by flying fewer shuttle missions to the station than the 18 or 19 currently planned.
If the station has not been completed by the time the shuttle is retired – at the end of 2010 – there is no back-up plan for hauling up any remaining heavy pieces. The NRC panel says that NASA needs to plan how to finish the station and also how to support it in the post-shuttle era.
Another problem is crew size. In the absence of shuttle deliveries, the station personnel is limited to a skeleton crew of two people, who spend so much time maintaining the station that they have very little time for research.
Previous NRC reports have suggested that a full six-person crew is needed to conduct useful research, but NASA timetables do not envision reaching that level until somewhere between 2009 and 2015. The new report recommends the crew be expanded to six as soon as possible, preferably by 2008.
IThe NRC report further criticises NASA for failing to figure out how best to fulfil the station’s potential. The panel found "no evidence of an integrated resource-utilisation plan" for station support of future exploration programmes. It also found no assurance that high-priority projects would be flown carried out and do not interfere with each other’s schedules or put an unnecessary strain on resources.
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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