Here’s our first good look at Comet (C/2012 S1) ISON. The Hubble Space Telescope captured this shot on April 10, when the comet was slightly closer than Jupiter’s orbit at a distance of 634 million kilometers (394 million miles) from Earth. Later this year, this comet could become a brilliant object in the sky, perhaps 10 times brighter than Venus. Astronomers say preliminary measurements from the Hubble images suggest that the nucleus of ISON is no larger than 4-6 km (3-4 miles) across. The astronomers said this is remarkably small considering the high level of activity observed in the comet...