Friday, 21 November 2008

Visiting and finding planets

It has been a good month for one of the great scientific endeavours: the study of the other worlds in our solar system.

Last week in Sydney there was a presentation by Alan Stern, the chief investigator on the New Horizons mission to Pluto, which we've never yet visited, and beyond. After the encounter with Pluto (shown here with its oversized moon Charon, plus baby moons Nix and Hydra), NH will visit a few additional, probably small, objects in the Kuiper Belt, the part of the solar system you didn't learn about in school. Think of the asteroid belt, but put it out beyond Neptune, and put it on steroids: crawling with dwarf planets and dirty snowballs of all sizes.

New Horizons, launched in 2006, flew by Jupiter in early 2007 for a gravity assist and is now a ways beyond the orbit of Saturn. It will make its closest approach to distant Pluto on Bastille Day, 2015.

Meanwhile ARGO is all the talk as a proposal for the fourth “New Frontiers” mission. (NH is the first spacecraft launched within the New Frontiers scheme: the concept is medium-class, investigator-driven projects awarded on tender, like a grant). Flybys of Jupiter and Saturn, then a close encounter with Neptune and its huge retrograde moon Triton, which will then sling it on outwards to a big Kuiper Belt object of the investigators' choice. Triton itself is believed to be a dwarf planet from the KB captured by Neptune, so this mission would effectively visit two such worlds in succession. This is the most exciting uncharted-territory mission I know that's in prospect.

The astronomers have also been busy, with the first visual observation of planets orbiting other stars.

In cyberspace, the new blog is threatening to feed my infatuation with planetary science missions beyond all reason ...

... and closer to home, NASA has released a digitally remastered version of the splendid 1966 photograph of a full-crescent Earth, with a swathe of the Moon's surface in the foreground.

[The image of the Pluto-Charon system is from the Hubble Space Telescope and is discussed here]

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