By Shari Balouchi and Taylor Morris
2013 promises to be an enthralling year for astronomy. This semester, the phases of the moon will fall predictably on Feb. 26 (give or take a day). Additionally, there may be opportunities later in the spring to observe interesting planetary activity and meteor showers (with the new Meteor Camera at the Cordell-Lorenz observatory). Already this month, the close conjunction between the Moon and Jupiter’s was visible from Sewanee. However, the full moon puts a pause on detailed observing for at least a week. Though astronomical observation is heavily dependent on weather, over the course of the semester we will make an ongoing effort to update the community on optimum observing periods.
In addition to unusual phases of the moon, eclipses, and meteor showers, there is a unique opportunity to view what is predicted to be, perhaps, the most spectacular comet of the millennium. Comet ISON, also known by its scientific name C/2012 S1, was first sighted on Sep. 24, 2012. This comet has been compared to Comet Hale-Bopp, one of the most spectacular long-period comets, with a period around the Sun of around 5,000 years.
Comets are largely composed of ice and dust, and as they approach the Sun the ice melts, releasing gas. This gas reflects light from the Sun, which produces the glow we associate with comets. Initial predictions by The International Astronomical Union’s Minor Planet Center indicate that Comet ISON could get bright enough to remain visible to the naked eye from early November 2013 until the first few weeks of 2014. The comet may even come close enough to Mars in early October 2013 to be observable by cameras on the rover Curiosity. Some predictions also have it not only bright enough to be viewable during daylight hours, but brighter than the full moon.Comet ISON’s orbit bears strong resemblance to the first comet observed by Isaac Newton in 1680. If the comet’s perihelion is close enough to the Sun, it will become bright enough to be seen by the naked eye. Sky and Telescope magazine author Kelly Beatty says, “The comet is inbound from the Oort Cloud and will pass very close to the Sun — just 725,000 miles (1.2 million km) from its white-hot photosphere — on Nov. 28, 2013. Before then and thereafter (if it survives perihelion), Comet ISON could put on a spectacular show.”