Greg Redfern, wtop.com WASHINGTON - This week, the western sky
will have a visitor from the depths of the outer solar system:
the Comet PanSTARRS. March 12 through 18 is the prime time to
view the comet, since it will start to fade after this week.
Officially known as Comet C/2011 L4 in order to distinguish it
from the other comets discovered by the automated sky survey
observatory Pan- STARRS in Hawaii, the comet will finally be
visible to observers in the Northern Hemisphere. Comets are
named after their discoverers, so Pan-STARRS gets the credit for
finding this icy interloper from the outer solar system in June
2011. Comets are best described as dirty snowballs. They are
frozen leftovers from the formation of our solar system 4.6
billion years ago. They are thought to have a rocky or rubble
pile center known as the nucleus a couple of kilometers in
diameter that is covered with frozen water and gases. Over a
trillion comets are thought to form the Oort Cloud, a vast
spherical reservoir of comets very dist