NASA's Hubble space telescope has caught a glimpse of a fast moving comet, one of the brightest examples in decades, as it prepares to skim the surface of the sun later this year. Comet (C/2012 S1) ISON was first identified in September last year, with later observations leading astronomers to predict that the hurtling chunk of rock and ice could be the brightest sighted in fifty years. Now, a new photograph shows the comet already active.
When the photo was captured, on April 10, ISON was still 386m miles from the sun (and slightly further away than that from Earth). However, the comet was already active, NASA's scientists say, with the top layer of frozen volatiles warming up and releasing strong, jet-blasting dust particles.
With some false color added - NASA has put in the blue hue artificially, though the photo was captured using visible light - the effect is already clear. That has scientists impressed, too, since the core nucleus of the comet is believed to be relatively small for the amount of activity it's showing, around 3-4 miles in diameter. However, the dusty coma - the smudge at the head - is already around 3,1000 miles across.
Both dwindle in comparison to the dust tail left behind, however. NASA says that extends in excess of 57,000 miles, and is in fact so long that Hubble's frame of view can't encompass it all. ISON is expected to skim an astronomically-tiny 700,000 miles above the sun's surface on November 28 2013, though scientists are still crunching data from observations like these to figure out what the effect will be.
Whatever's left will then continue on, coming within 39.9m miles of Earth before the year is out.