Recent analysis on more than 100,000 stars studied by the European Space Agency's Hipparcos satellite showed that about 20 percent of them within 1,000 light years are moving in unusual trajectories. Rather than circular paths around the galactic center, they're moving toward or away from the core. The cause: so-called 'density waves' that compress gas and have a hand in star formation; they also seem to be able to deflect normal stellar motions. But don't count on a stellar near miss to give us an easy way to go interstellar, at least not any time soon. The closest encounter with another star won't occur for another 1.4 million years, when Gliese 710 will pass within 1 light year of the Sun (some 70,000 AU, perhaps within the Oort Cloud of cometary debris). In any case, Gliese 710 does not appear to be one of the stars affected by galactic density waves; its motion around the galactic center seems relatively normal. Barnard's Star is approaching us as well, at a speed of 87 miles...

Very Long Baseline Interferometry combines data from multiple telescopes around the world. Once collated and compared, the data can be processed into images that exceed those available at any of the individual telescope sites. In fact, the resulting image has a resolution equal to that of a telescope as large as the maximum antenna separation. Now becoming available is the digital version -- call it e-VLBI -- where data from the various observatories are routed through the Internet and combined at a center in the Netherlands. The result: real-time long-baseline interferometry. No more waiting as data tapes are shipped around the world to be combined at a central processing facility, a wait that in the past has taken weeks or months. For more, see this Particle Physics and Astronomy Research Council page.

A team of Australian researchers has built an unmanned observatory high on an Antarctic plateau that may provide images nearly the equal of Hubble's. That's the word from Nature, where University of New South Wales associate professor Michael Ashley, co-author of the paper, described the capabilities of the new viewing site. The paper's lead author is Dr. Jon S. Lawrence, a postdoctoral fellow at the University of New South Wales. The location is known as Dome C, 3250 meters above sea level on the Antarctic Plateau, at latitude 75 degrees south. Among its favorable characteristics are low infrared sky emission, dry and extremely cold air, few clouds and low dust and aerosol content. The upshot: much less 'star jitter.' All of these factors make the site, which is 400 meters higher than the South Pole, far better for viewing than the location of instruments currently in place in Chile, Hawaii and the Canary Islands. Having established the superiority of Dome C, the team now argues for...

NGC 6543 is called the Cat's Eye Nebula; it was one of the first planetary nebulae to be discovered. This gorgeous view from Hubble shows that it is also one of the most complex nebulae ever studied. You're looking at a Sun-like star at the very end of its life, losing its outer gaseous layers to create concentric clouds in ways that are still mysterious. Each bright ring is actually the edge of a spherical bubble of gas. Hubble used its Advanced Camera for Surveys (ACS) to make this image.

It looks bright enough to be a foreground star, but this supernova, called SN 2004dj, is 11 million light years away in a galaxy known as NGC 2403. Not particularly germane to interstellar propulsion or finding candidates for robotic probes, but simply too remarkable a sight to ignore. You can read more about this Hubble photograph here. From the press release issued by the Space Telescope Science Institute: The heart of NGC 2403 is the glowing region at lower left. Sprinkled across the region are pink areas of star birth. The myriad of faint stars visible in the Hubble image belong to NGC 2403, but the handful of very bright stars in the image belong to our own Milky Way Galaxy and are only a few hundred to a few thousand light-years away. This image was taken on Aug. 17, two weeks after an amateur astronomer discovered the supernova. What we're seeing here is the creation of heavy chemical elements like calcium, iron and gold, all of which, on Earth and elsewhere, came from...