NASA's Messenger probe made its second pass by Venus on Tuesday afternoon, the maneuver will help guide the spacecraft on its circuitous journey to Mercury and give scientists a close-up look at Earth's cloud-shrouded neighbor.The fly-by gave researchers the rare opportunity to pair with a European spacecraft studying Venus."This is the first time that we are able to take observations from two different vantage points."Messenger is the seventh in NASA's Discovery program of lower-cost, scientifically focused space missions.If successful, Messenger, launched in August 2004, would be

Astronomers have long thought of constructing a telescope out of mercury. The reason is that such telescopes would be able to point straight up, and it is best direction to look, because line of sight passes through the least amount of atmosphere. The author reports the progress his group has made constructing a 6-meter liquid-mirror telescope, and he discusses plans for other instruments of this kind to be built at more suitable sites—perhaps even on the Moon.