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Physical Science

Mercury’s Magnetic Field: Another Attempt to Save Theory from Data
February 13, 2004
Nature Feb. 121 restates a puzzle about Mercury known since the Mariner 10 encounters (1974-5): …why, against expectations, does Mercury have a global magnetic field? The planet’s diminutive size means that it should have cooled quickly after it formed.  Any molten core would have become solid, or almost completely so.  A magnetic-field-generating dynamo in an […]
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Dumb Ideas

Comets as Cosmic Storks
February 10, 2004
Chandra Wickramasinghe and colleagues at Cardiff University have raised the bar on tale-telling ability.  They believe that comets splatting on earth can carry away germs of life that gradually spread farther and farther out, eventually escaping the sun’s pull.  Over time, they might spread life to other worlds.  They estimate that since the origin of […]
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Solar System

Accretion: The Missing Link in Planetary Evolution
February 3, 2004
Every school child has seen artwork of planets evolving from a disk of dust and gas around a star like our sun, but there’s a missing link in the story. How did the dust particles stick together?
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Solar System

Mars Rover Lands
January 3, 2004
From the scene of news at Jet Propulsion Laboratory At 8:35 p.m. Pacific Time Saturday, January 3, signal was lost as a large set of air bags bounced on the surface of Mars.  After several nail-biting minutes, signal was reacquired by two Earth stations, indicating that the Mars Exploration Rover “Spirit” had survived the heat […]
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Solar System

Stardust Mission Successfully Flies Through Comet Cloud
January 2, 2004
In the first of what is hoped will be a series of spectacular space missions in 2004, the Jet Propulsion Laboratory flew the Stardust spacecraft today on a wild ride right into the dusty coma of comet Wild-2 (pronounced Vilt-2).  Though the dust storm would have killed an astronaut at that range, the craft emerged […]
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Solar System

Keeping Planetary Rings Going for Eons
December 8, 2003
It’s common knowledge that planetary rings, like those at Saturn, don’t last forever (see 02/12/2002 headline), so scientists either have to find a way to keep them going, or admit that we live in a special period in the lifetime of the solar system to see them now.  That latter option is “philosophically unappealing” to […]
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Solar System

Vega Has a Neptune?
December 1, 2003
The BBC News and EurekAlert are pretty excited about a discovery at Vega, the sapphire-blue star that hangs overhead in summertime (from the Northern Hemisphere; Aussies see it at the horizon).  Astronomers think they see a clump of material that might be at the distance from the star similar to Neptune’s distance from the sun.  […]
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Solar System

Ring Around the Moons
October 20, 2002
51; Saturn is known for its rings, and some small moons have been found inside its rings.  But wouldn’t it be strange if some of its moons had rings of their own?  Such a thing had not been widely considered before 2007, when there was a tentative detection of a ring around Rhea (see 03/10/2008).  […]
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Solar System

Planets and Moons Suddenly Got Much Younger
October 20, 2002
A planet or moon covered with craters just looks old, doesn’t it?  Planetary geologists have long relied on crater counts to estimate the absolute ages of surfaces, such as on the moon, Mars, Europa, and every other solid body.  Lots of craters meant old.  Few craters meant young.  Presumably, impacting bodies came in like clockwork […]
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Cosmology

Questioning Earth’s Privileges
September 20, 2002
51; Two articles this week downplayed considerations that would make the Earth seem like a special place in the universe.  Both have ties to NASA.     Are life-friendly stars limited to a narrow band in the galaxy called the Galactic Habitable Zone (GHZ)?  NASA-supported Astrobiology Magazine cast doubt on the idea.  Citing a study […]
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Solar System

A “Completely Different Slant” on Solar System Formation
July 20, 2002
51; “Did great balls of fire form the planets?” New Scientist asks.  A new theory “challenges the notion that the solar system started out as a placid sea of dust motes which simply clumped together to form planets.” If accepted, it “puts a completely different slant on what happened in the early solar system in […]
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Solar System

Hiding Comets Out of Bounds
June 20, 2002
51; There’s a new theory floating around about where most of the comets came from: other stars.  For many years, astronomers hid them in an unobservable region called the Oort cloud that was assumed to be partly a remnant of the sun’s primordial disk, and material that was ejected outward.  Now, according to the BBC […]
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