Time Travel for Skywatchers

Time travel is one of the best things about astronomy. Check out two websites that give skywatchers a more visceral sense of stellar distances and how constellations change shape across the sweep of time. Every time we look at the Sun we see it as it was 8.3 light-minutes ago. Bob King We all know the quickest way to travel back in time. Just look up at the stars. Wait. You don't even have to do that. Hold your hand 6 inches (15 cm) from your face and you see it as it was about a billionth of a second ago. We can't help but see into the past because light takes time to reach our eyes, even traveling at 300,000 kilometers a second. That beautiful full Moon we saw over the weekend is 1.3 light seconds away, the Sun 8.3 minutes and the nearest star, Proxima Centauri, 4.24 light years. You wonder if there is such a thing as the present, when there's...
Read More

Radio Experiment Launches With China’s Moon Orbiter

A Dutch radio astronomy experiment hitched a ride today with China's relay satellite for the upcoming Chang'e 4 mission. The lunar farside and Earth, as captured by the Chang'e 5 test mission that flew in 2014. Chinese National Space Administration / Xinhuanet A Long March-4C rocket roared to life last night, lighting up the night skies over China and opening up the next chapter of lunar exploration. Aboard the rocket: an innovative lunar relay orbiter and a ground-breaking radio astronomy experiment. The launch occurred at 21:28 UT from Xichang Space Center in Sichuan, China. This orbiter is part of China's ambitious first attempt to deploy a lander and rover on the farside of the Moon later this year. All lunar landings to date, including the Apollo missions and China's 2013 Yutu Jade Rabbit lander and rover, have been conducted on the Moon's near side, within sight of Earth and radio communications. Chang'e 4, however, will land and rove on the farside of the Moon, requiring...
Read More