May 2007

Helium: Speed Brake for the Solar Wind?

May 21, 2007

Someday fleets of interplanetary craft powered by the solar wind may cross the Solar System, using huge magnetic fields as their ‘sails.’ The concept is increasingly well understood, and I notice that researchers like Robert Winglee (University of Washington) have been extending it to include beamed propulsion methods as well (Winglee’s concept is called MagBeam), [...]

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A Galactic Collision, and the Sun’s Future

May 19, 2007

I remember a startling painting from an astronomy book I once had when I was a kid. It showed two spiral galaxies much like the Milky Way in the process of collision, and I recall the caption saying that the stars in galaxies were so widely spaced that even in an event like this, few [...]

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Amateur Bags GJ 436 b Transit

May 18, 2007

One of the most exciting aspects of the exoplanet hunt is that it is not confined to huge telescopes and professional astronomers. Timothy Ferris described the remarkable advances in amateur equipment and observing techniques in Seeing In the Dark (Simon & Schuster, 2002), but he’ll need a whole new chapter to cover what’s happening not [...]

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Plumes on Enceladus: A Tidal Squeeze

May 17, 2007

An object in an elliptical, egg-shaped orbit experiences interesting gravitational stresses. Enough so that the changing forces it endures may be the cause of the plumes of water vapor that Cassini found on Saturn’s moon Enceladus in 2005. In essence, the tiny moon is being alternately squeezed and stretched as it makes its way around [...]

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Transiting ‘Hot Neptune’ Found

May 16, 2007

Whether or not Gliese 581 c, that intriguing world that may or may not offer temperatures conducive to life, will make a transit of its star is not yet known. But the principle that radial-velocity searches can identify a planet that is subsequently studied via transit received further validation today with the detected transit of [...]

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A Ring of Dark Matter

May 15, 2007

Dark matter has to be made up of some sort of elementary particle, but we know astoundingly little about it. Its existence can be inferred from its necessary effects — something we can ‘t see seems to be holding galaxy clusters together, because the gravity from the stars we do observe in them isn’t sufficient [...]

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Looking Hard at Gliese 581

May 14, 2007

We’d all like to know more about Gliese 581 c, the most talked about exoplanet of them all because of the possibility — however controversial — that it may be habitable. One way to learn more would be to observe a transit, which is what the Canadian space telescope called MOST is now attempting to [...]

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The Search for Vulcan

May 12, 2007

40 Eridani is a triple-star system some 16 light years from Earth. If it rings a faint bell, that’s probably because of its association with Star Trek. In the universe of the show, 40 Eridani is home to Vulcan, birthplace of the inscrutable Mr. Spock (Gene Roddenberry himself signed off on the idea). Not so [...]

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In Search of Ancient Stars

May 11, 2007

We’ve seen recently how difficult it can be to pin down the age of a star. Even the Alpha Centauri system is problematic, with age ranges for Centauri A and B varying from slightly less than four billion years to as many as eleven (depending on which star we’re talking about, and which of several [...]

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Titan’s Tholins: Precursors of Life?

May 10, 2007

Tholins are interesting molecules, large and complex. They’re organic aerosols — particles small enough to remain suspended in the atmosphere for some time — formed from methane and nitrogen. Their presence on Titan is intriguing because they’re thought to contain some of the chemical precursors of life. That makes studying how they form there a [...]

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