Untangling a knot of galaxy clusters. Astronomers have observed a dramatic, continuing collision involving at least three galaxy clusters. Astronomers are using data from the Chandra X-ray Observatory of NASA, the XMM-Newton of the European Space Agency, and three radio telescopes to understand this chaotic spectacle. These collisions and mergers are …

The beaming face of a cute-looking teddy bear appears to have been carved into the surface of our nearest planetary neighbor, waiting for a passing satellite to discover it. And when the Mars Reconnaissance Orbiter passed over last month, carrying aboard the most powerful camera ever to venture into the Solar System, that’s …

A CoTweet is a co-authored tweet that was posted to both writers’ timelines and the timelines of their followers at the same time. Twitter has announced that it has shut down its collaborative posting feature ‘CoTweets’, which the micro-blogging platform had been testing for the “last several months”. “For the …