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Lunar tandem successfully enters orbit around the Moon
...Ringing in the new year with back-to-back successes, a second NASA science satellite slipped into orbit around the moon Sunday, one day after an identical spacecraft braked into the same polar orbit for a $496 million mission to map the moon's interior by precisely measuring how its gravity affects the trajectories of the twin spacecraft...
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Astronomy Now's year in space
...Pluto’s new moon, salty water on Mars, interstellar travel and black trees on a world with two suns; look back over the year as we count down the most read news stories of 2011...
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First “mini-Earth” discovered around Sun-like star
...A rocky exoplanet smaller than Earth, and its neighbouring Earth-sized world with a thick water-vapour atmosphere, have been detected around a Sun-like star already known to host three larger planets....
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The water-generating Moon
DR EMILY BALDWIN
ASTRONOMY NOW
Posted: October 15, 2009


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Analysis of data from Chandrayaan-1's SARA instrument confirms how water is likely being generated on the Moon, with some surprising results.

Last month, data from Chandrayaan-1's Moon Mineralogy Mapper, Deep Impact, Cassini and LRO all provided evidence for water not only existing on the Moon, but also being created there. Now, further evidence from Chandrayaan-1's SARA (Sub-keV Atom Reflecting Analyzer) instrument confirms the solar wind as the key player in generating water.

Chandrayaan-1 SARA measurements of hydrogen flux recorded on the Moon on 6 February 2009. Images: Elsevier 2009 (Wieser et al.), ESA-ISRO SARA data.

The solar wind – a stream of charged particles – bombards the lunar surface, the top layer of which is a loose collection of grains, collectively known as the regolith. Incoming particles from the solar wind should be trapped in the spaces between the grains and absorbed. Protons landing on the lunar surface are expected to interact with the oxygen in the regolith to produce hydroxyl – one oxygen and one hydrogen atom – and water.

The signature for these molecules was recently found and the SARA results confirm that solar hydrogen nuclei are indeed being absorbed by the lunar regolith. But there is a curiosity in the results: roughly one in every five protons rebounds into space. In the process, the proton joins with an electron to become an atom of hydrogen.

“We didn’t expect to see this at all,” says Stas Barabash, Swedish Institute of Space Physics, and the European Principal Investigator for SARA.

Furthermore, the hydrogen is shooting off into space at speeds of around 200 kilometres per second, without being deflected by the Moon's weak gravity, or, since hydrogen is also electrically neutral, by magnetic fields in space. Since these atoms travel in straight lines it should be possible to trace them back to their points of origin to create a new type of surface map.

Whilst the Moon does not generate a global magnetic field, some lunar rocks are magnetized. Barabash and his team are currently making images, to look for such ‘magnetic anomalies’ in lunar rocks. These generate magnetic bubbles that deflect incoming protons away into surrounding regions making magnetic rocks appear dark in a hydrogen image.

Like the Moon, Mercury also suffers from the direct hits of solar wind particles, and the SARA team expects that a similar phenomenon may occur here too, but that the innermost planet is likely reflecting more hydrogen than the Moon because the solar wind is more concentrated closer to the Sun.

The Planets
From tiny Mercury to distant Neptune and Pluto, The Planets profiles each of the Solar System's members in depth, featuring the latest imagery from space missions. The tallest mountains, the deepest canyons, the strongest winds, raging atmospheric storms, terrain studded with craters and vast worlds of ice are just some of the sights you'll see on this 100-page tour of the planets.
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Hubble Reborn
Hubble Reborn takes the reader on a journey through the Universe with spectacular full-colour pictures of galaxies, nebulae, planets and stars as seen through Hubble's eyes, along the way telling the dramatic story of the space telescope, including interviews with key scientists and astronauts.
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3D Universe
Witness the most awesome sights of the Universe as they were meant to be seen in this 100-page extravaganza of planets, galaxies and star-scapes, all in 3D!
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Infinity Rising
This special publication features the photography of British astro-imager Nik Szymanek and covers a range of photographic methods from basic to advanced. Beautiful pictures of the night sky can be obtained with a simple camera and tripod before tackling more difficult projects, such as guided astrophotography through the telescope and CCD imaging.
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Starry Night
Explore the Universe with these new versions of the award-winning Starry Night Software. Available now from the Astronomy Now Store.
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Exploring Mars
Astronomy Now is pleased to announce the publication of Exploring Mars. The very best images of Mars taken by orbiting spacecraft and NASA's Spirit and Opportunity rovers fill up the 98 glossy pages of this special edition!
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Mars rover poster
This new poster features some of the best pictures from NASA's amazing Mars Exploration Rovers Spirit and Opportunity.
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