Looking all the world like sperm cells whipping their tails to propel themselves toward an egg, comets Encke and Ison are seen in this animation of spacecraft images swimming through the solar wind toward the sun.
This is actually the first view of Comet Ison from one of NASA’s two STEREO spacecraft. The dark, cloud-like features coming in from the right are actually denser concentrations of the particles streaming outward from the sun that comprise the solar wind. This is what’s causing Encke’s tail to ripple and whip back and forth.
As you’ve probably heard, Ison will be rounding the sun on Nov. 28, 2013, passing within a mere 700,000 miles of it. Considering that the sun is about 870,000 miles across, this will be a very close encounter — and Ison may not survive it intact.
Encke orbits the sun every 3.3 years. But for Comet Ison, this is its first trip around the sun. And that’s really significant, according to NASA, because it means that:
. . . it is still made of pristine matter from the earliest days of the solar system’s formation, its top layers never having been lost by a trip near the sun. Scientists will point as many ground-based observatories as they can and at least 15 space-based assets towards the comet along the way, in order to learn more about this time capsule from when the solar system first formed.
Comet Ison is now visible to the naked eye — in the east before sunrise. Over the next few days it should get brighter, but probably increasingly difficult to spot because of the light from the sun. To help you find it, use this chart from Discover’s sister publication, Astronomy Magazine.
Stay tuned! More images of Ison to come…