Comet PANSTARRS rings our bell this weekend
By this weekend, we may have an opportunity to see one of two bright comets likely to pass through our planetary neighborhood this year. The first one, comet PANSTARRS, starts its Northern Hemisphere arrival March 8-10, continuing through mid-March. This will be the ONLY time anyone on Earth will see PANSTARRS (or, less-affectionately, C/2011 L4); as it is a non-periodic comet, it may never return again.
Comet PANSTARRS was discovered in June, 2011 and named after the telescope used for its discovery, Pan-STARRS (an acronym for Panoramic Survey Telescope and Rapid Response System), located near the summit of Haleakala in Maui, Hawaii.
Until now, PANSTARRS has been gracing the skies of the Southern Hemisphere, but will be coming our way in mid-March with a small viewing window about 15 minutes after twilight over the Western Horizon. Its closest approach to Earth will be on March 10, when it travels at a distance of roughly 28 million miles from the Sun, and it will be visible to the unaided eye by March 12. It will slowly fade as March, well, marches on.
This has been quite the year so far for celestial visitors; on February 15, asteroid DA14 made a close pass to Earth, preceded by a surprisingly unrelated meteor impact over Russia earlier in the day (blog posts, A cosmic double feature comes to Earth today! and Meteorite Impact!! Chelyabinsk, Russia and Farmville, NC). Such visits from rocky bodies — ”left-overs” from solar system formation roughly 4.6 billion years ago — may remind us of our fragility in this great cosmic landscape; recall, asteroid impacts are responsible for the demise of many species of plants and animals throughout Earth’s history, including the dinosaurs ~ 65 million years ago.
This time, we are visited by a comet, a less-common, icy cosmic visitor originating from much farther out in our solar system than asteroids and meteors — rocky neighbors from the Asteroid Belt, between the planets Mars and Jupiter. Some comets, like Halley’s comet and other so-called short-period comets, reside in the Kuiper Belt, a ring of small icy bodies extending from the orbit of Neptune (~ 30 AU) to roughly 50 AU (1 AU, the distance from the Earth to the Sun, is about 93 million miles).
Comet PANSTARRS, however, is a non-periodic comet, and will not return to the vicinity of the Sun for hundreds or thousands of years, if ever. Comets like these come from even farther out in the solar system — the Oort Cloud, a hypothesized cloud of billions of icy bodies at an estimated 50,000 AU (that’s about 4.6 trillion miles!! Or, 4,600,000,000,000 miles… very, very far away…).
Comets are elusive objects — the coy visitors from space — which have fascinated astronomers since ancient times, and may even have helped seed our oceans billions of years ago. Like its cosmic brethren, PANSTARRS traveled millions of years to reach Earth, and will not likely return again. And, even if it does return, whomever is here to see it pass overhead will have likely evolved beyond our species, and occupy a very different world.
So, is it worth a look? I’d say, yes indeed. We are, after all, born of the same material that made everything in our Universe, comets included. Seeing a rare cosmic visitor with our own eyes renders that connection perhaps a little clearer in our minds. Perhaps you may even contemplate what this Earth will be like should it ever come this way again.
** STAY TUNED FOR SPECIAL EVENTS SURROUNDING THE HOPEFUL ARRIVAL OF SUPER-BRIGHT COMET ISON, NOVEMBER/DECEMBER, 2013! **
Program Note: Thursday, March 14 at 7:40 there will be a special rooftop viewing of Comet PANSTARRS (weather permitting) at the Museum, hosted by Raleigh Astronomy Club.