The black hole at the core of the Milky Way flares up in a series of images captured by NuSTAR.   Image credit: NASA/JPL-Caltech   On 13 July, NASA launched the Nuclear Spectroscopic Telescope Array (NuSTAR), an orbital X-ray telescope that can produce detailed images in high-energy.  Now, NuSTAR has directly observed the supermassive black hole at the centre of the Milky Way galaxy (known as Sagittarius A*, or just Sgr A*) flaring up as material falls in. Unlike some other … Continue reading →

As we put more robots on or around Mars, we get more data suggesting that Mars was once a wet world.  The most convincing data yet comes from the Curiosity rover (an SUV sized plutonium powered robotic explorer, formally known as the Mars Science Laboratory) which has just driven through what is almost certainly an ancient dry river bed.  The evidence is purely geological:  smooth pebbles, cemented into a layer of conglomerate rock, prove convincingly that water used to flow … Continue reading →