Featured
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News |
Perseid meteors promise shower of science
Astronomers worldwide prepare for a night of meteoroid studies.
- Lucas Laursen
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Review Article |
The four hundred years of planetary science since Galileo and Kepler
For 350 years after Galileo's discoveries, ground-based telescopes and theoretical modelling furnished everything known about the Sun's planetary retinue. Over the past five decades, data from spacecraft sent to all the planets and some of their satellites have shown the diversity of Solar System bodies. Many planets and satellites have changed substantially since their birth, and violent events punctuate their histories.
- Joseph A. Burns
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News |
Space capsule probed for asteroid dust
Hayabusa holds lessons for future sample-return missions.
- David Cyranoski
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News |
Comet strike could explain Neptune's air
Carbon monoxide in planet's atmosphere points to icy impact.
- Eric Hand
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News |
Asteroid ice hints at rocky start to life on Earth
Cool discovery suggests asteroids brought water and organic material.
- Zeeya Merali
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News & Views |
A frosty finding
The asteroid belt is classically considered the domain of rocky bodies, being too close to the Sun for ice to survive. Or so we thought — not only is ice present, but at least one asteroid is covered in it.
- Henry H. Hsieh
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Letter |
Detection of ice and organics on an asteroidal surface
Recent evidence has blurred the line between comets and asteroids, although until now neither ice nor organic material had been detected on the surface of an asteroid. Here, the spectroscopic detection of water ice and organic material on the asteroid 24 Themis is reported. Water ice thus seems to be more common on asteroids than previously thought, and may be widespread in asteroidal interiors at smaller heliocentric distances than expected.
- Andrew S. Rivkin
- & Joshua P. Emery
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Letter |
Water ice and organics on the surface of the asteroid 24 Themis
It has been suggested that Earth's current supply of water was delivered by asteroids. The presence of water on the surface of some asteroids has been inferred from the comet-like activity of several small asteroids, including two members of the Themis dynamical family, but hitherto has not been measured. Here, infrared spectra of the asteroid 24 Themis are reported; the results show that ice and organic compounds are not only present, but also prevalent, on its surface.
- Humberto Campins
- , Kelsey Hargrove
- & Julie Ziffer
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News |
Comet crash creates potential for life
Shock waves could force amino-acid forming chemistry.
- Katharine Sanderson
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Letter |
Earth encounters as the origin of fresh surfaces on near-Earth asteroids
Telescopic measurements of asteroids' colours rarely match laboratory reflectance spectra of meteorites owing to a 'space weathering' process that rapidly reddens asteroid surfaces. 'Unweathered' asteroids, however, with spectra matching ordinary chondrite meteorites, are seen only among small bodies with orbits that cross inside the orbits of Mars and Earth. Such unweathered asteroids are now shown to have experienced orbital intersections closer than the Earth–Moon distance within the past half-million years.
- Richard P. Binzel
- , Alessandro Morbidelli
- & Alan T. Tokunaga
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News & Views |
Stripped on passing by Earth
Asteroids are weakly bound piles of rubble, and if one comes close to Earth, tides can cause the object to undergo landslides and structural rearrangement. The outcome of this encounter is a body with meteorite-like colours.
- Clark R. Chapman