The year's brightest comet this week will fly across the night sky.
However, predicting a comet's brightness is much more hard than forecasting the weather. For the average person, the comet will be visible with the naked eye and will provide a rare sky-watching event.
The comet, named after astronomer Carl Wirtanen, will make its closest approach on Sunday Dec. 16, coming within 7.2 million miles of earth. "Nevertheless, if you're under a clear night sky away from city lights, you should be able to spot 46P/Wirtanen throughout December if you know where to look", the museum added. With a width of 0.7 miles, 46P/Wirtanen orbits the Sun fairly quickly for a comet - once every 5.4 years - making it a short-period comet - (long-period comets, on the other hand, have orbital periods greater than 200 years).
For nonscientists, this lasting memorial to a Wisconsin comet hunter will simply be a fresh opportunity to look up - if the winter skies cooperate.
"This will be the closest 46P/Wirtanen has come to Earth for centuries and the closest it will come to Earth for centuries", said Dr. Paul Chodas, manager of the Center for Near-Earth Object Studies at NASA's Jet Propulsion Laboratory.
An observation campaign is underway to take advantage of the close approach for detailed scientific study of the properties of this "hyperactive" comet, which emits more water than expected, given its relatively small nucleus. It should be just as visible for a week or two because its appearance will change gradually.
The comet reaches its closest point to the sun on Dec. 13 and will be at its brightest on Dec. 16, the evening before it makes its closest approach to Earth Dec. 16.
Don't expect to see the comet's tail. Looking at the radio-range wavelengths of light the comet releases, astronomers can examine the distinctive gases that come off of the visitor.
So why does the comet look fuzzy or ghostly? The comet appears to be a close twin to comet Hartley 2, the second target of the Deep Impact mission.
"NASA-sponsored ground, air and space-based observatories getting in on the action include NASA's Goldstone Solar System Radar in California; the NASA Infrared Telescope Facility on Maunakea, Hawaii; the Hubble, Chandra, Swift and Spitzer space telescopes; and an airborne observatory known as the Stratospheric Observatory for Infrared Astronomy (SOFIA)", NASA officials wrote in a statement".
You can follow the project, called the Comet Wirtanen Observing Campaign, at its website here: http://wirtanen.astro.umd.edu.
Farnham oversees an online clearinghouse of information about the comet that educates the public and encourages collaboration among astronomers who gather data about it. But the atmosphere around the comet, or coma, is bigger than Jupiter.