July 2005

The Real Planet X

July 30, 2005

A day after the news about 2003 EL61, a Kuiper Belt object originally thought to be larger than Pluto, we now have another world that appears significantly larger still. 2003 UB313 was discovered with the Samuel Oschin Telescope at the Palomar Observatory by astronomers Mike Brown (Caltech), Chad Trujillo (Gemini Observatory), and David Rabinowitz (Yale […]

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A New Planet Larger Than Pluto?

July 29, 2005

A bright, slowly moving object in the outer Solar System may be a world larger than Pluto. A team of astronomers led by Jose-Luis Ortiz at the Sierra Nevada Observatory in Baja, California found the object, called 2003 EL61, using observations made in 2003. It is some 51 AU from the Sun (one AU, or […]

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Tantalizing Evidence for Cosmic Strings

July 28, 2005

An object called CSL-1 may have a lot to say about the nature of the universe. The odd thing about this double source — evidently a pair of galaxies — is that both galaxies appear identical. They share a common redshift, a similar shape, and their luminosity profiles match that of two giant elliptical galaxies. […]

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Enceladus Flyby Reveals Bizarre Geology

July 27, 2005

No body in the solar system is as reflective as Saturn’s moon Enceladus. Its terrain also appears relatively young, with the early Cassini flybys revealing regions that are only lightly cratered. It seems that Enceladus has undergone a number of episodes of geologic convulsion, with the southernmost latitudes seeing the most recent activity, producing a […]

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The Hunt for ‘Hot Earths’

July 26, 2005

By now we all know what a ‘hot Jupiter’ is — a gas giant orbiting breathtakingly close to its parent star. The radial velocity searches for extrasolar planets that have found so many new worlds are particularly sensitive to high-mass planets in close orbits, so it makes sense that the early list of discoveries would […]

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Lighting Up the Solar Wind

July 25, 2005

Tracking down the history of a star is no easy matter, but a supernova called SN 1979C is providing unexpected assistance. Just as researchers can study ancient climates by examining the concentric rings inside a tree, astronomers using the European Space Agency’s XMM-Newton space observatory have found a way to study the rings around a […]

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To the Stars via Radioactive Decay

July 22, 2005

If you wanted to reach Alpha Centauri in 40 years, one way to do it would be to boost a spacecraft up to 10 percent of lightspeed as quickly as possible and then let it coast to destination. Or you could do something entirely different: push your payload at constant acceleration halfway to Centauri, turn […]

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Terrestrial Worlds in the Making?

July 21, 2005

So many of the planets discovered in the last ten years have been gas giants, circling their parent stars in extremely tight orbits. We assume there are rocky, terrestrial worlds out there in abundance, but until more advanced detection techniques are in place, how can we be sure? An important answer may be offered by […]

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Rare Occultation Promises New Look at Charon

July 20, 2005

With excitement building over what everyone hopes will be a January launch of the New Horizons mission to Pluto and Charon, astronomers have found yet another tool for studying the distant worlds. They’re taking advantage of a rare alignment in which Charon, Pluto’s moon, passes in front of a star. Such an event has been […]

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Puzzling Disk Raises Questions About Planetary Formation

July 19, 2005

How unlikely would it be to find a 200-year old person? That’s the comparison astronomer Lee Hartmann (Harvard-Smithsonian Center for Astrophysics) is using in talking about a dust disk around a pair of red dwarf stars. The disk looks conventional enough — as examined by the Spitzer Space Telescope, its inner edge is about 65 […]

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