Some further thoughts on OGLE-2005-BLG-390Lb, the planet whose discovery portends numerous microlensing breakthroughs to come. Note the distance between the Sun and the red dwarf in question, which is variously reported as between 20,000 and 28,000 light years. The red dwarf is in the constellation Sagittarius and lined up between us and the center of the galaxy, a location that is a natural consequence of the microlensing method used to find the new world. For microlensing relies upon a closer star passing in front of one farther away, thus causing the gravitational effects used to pinpoint OGLE-2005-BLG-390Lb. To maximize the chances of seeing such an event, you need to point toward the largest possible field of stars, which is exactly what the OGLE project does. OGLE stands for Optical Gravitational Lensing Experiment, a study whose telescopes scan the central Milky Way each night. The scans are fruitful, for more than 500 microlensing events are discovered every year. Bear in...

The most Earth-like planet yet found has been discovered by a team of astronomers in a collaborative effort that involved 73 scientists in 12 countries. When astronomers use the term 'Earth-like' in this context, they're referring to planets whose mass is closer to Earth's than previous discoveries. They're also talking about surface conditions, for OGLE-2005-BLG-390Lb seems to have a rocky surface, and is only five times as massive as Earth. And what a fascinating find from the standpoint of technique. This is no relatively nearby gas giant found through observing the radial velocity changes it caused in its star's path through space. Instead, the new world, some 20,000 light years away, was found through microlensing, where the gravity of an intervening star magnifies the light of a more distant star. Close study of the brightening phenomenon can reveal defects that are the telltale sign of a companion object. In this case, as the star and its planet passed in front of the...

Busy times. Centauri Dreams has three new Acta Astronautica papers waiting for review, but Stardust is about to return with cometary dust (and, we hope, interstellar materials), and, of course, New Horizons is just four days from liftoff. Add to that the usual flurry of news from the just concluded American Astronomical Society meeting and it's clear I'm going to be behind the curve for a week or so just trying to catch up. Bear with me, though, because fascinating stuff keeps rolling in, such as the singular exoplanet detection below. What's interesting is not just the new planet but the detection method. Normally, Doppler radial velocity measurements rely on spectographs mounted on large telescopes. A new instrument called the Exoplanet Tracker (ET) uses an interferometer instead, a device capable of more precise measurements because it can capture more light. Image: An artist's rendition shows a planet orbiting a very young, active star pocked with dark star spots and speckled...