Planetary Science
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Planetary Science
What whacked the inner solar system?
Planetary scientists have determined that the cavalcade of space debris that hammered the inner solar system for the first 700 million years of its existence were main-belt asteroids, not comets.
By Ron Cowen -
Planetary Science
Sun grazers: A thousand comets and counting
An amateur astronomer analyzing images from the Solar and Heliospheric Observatory has found the 999th and 1,000th comets detected by the craft.
By Ron Cowen -
Planetary Science
Fresh Mars: Craft views new gullies, craters, and landslides
A comparison of images taken just a few years apart by a Mars orbiting spacecraft reveals recent landslides, freshly carved gullies, and a 20-meter-wide crater gouged in the planet's surface no earlier than 25 years ago.
By Ron Cowen -
Planetary Science
Icy world found inside asteroid
New observations of Ceres, the largest known asteroid, hint that frozen water may account for as much as 25 percent of its interior.
By Ron Cowen -
Planetary Science
Top of the Martian hill
After a 14-month climb up a Martian hill, NASA's rover Spirit took a panoramic image of the view from the top.
By Ron Cowen -
Planetary Science
Satellites could detect quakes on Venus
Strong seismic activity on Venus could cause brief but detectable temperature increases high in that planet's atmosphere.
By Sid Perkins -
Planetary Science
Radar for rovers on future Mars trips?
Scientists are developing ground-penetrating radar equipment that could serve as geologists' helpers on future Mars-roving vehicles.
By Sid Perkins -
Planetary Science
Enceladus: Small but feisty
Close-up observations of Saturn's tiny moon Enceladus reveal that its south pole is hotter than its equator and that the icy satellite continues to undergo eruptions.
By Ron Cowen -
Planetary Science
Bigger than Pluto: Tenth planet or icy leftover?
Astronomers have found a body larger and more distant than Pluto, the biggest object found in the solar system since Neptune and its moon Triton were discovered in 1846.
By Ron Cowen -
Planetary Science
Cassini eyes youthful-looking Saturnian moon
On July 14, the Cassini spacecraft came within 175 kilometers of the south polar region of Saturn's bright, tiny moon Enceladus, revealing a tortured terrain of faults, folds, and ridges.
By Ron Cowen -
Planetary Science
A Grand Slam
A 372-kilogram copper projectile released from NASA's Deep Impact spacecraft successfully slammed into Comet Tempel 1 on July 4, producing some heavenly fireworks.
By Ron Cowen -
Planetary Science
Pebbles from Heaven: Tracking planets in the making
Recording radio waves from the region around a young star, astronomers have for the first time documented the making pebbles, a key step in the rocky road to planethood.
By Ron Cowen