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Comet ISON on ejection trajectory, will never be seen again

By Marshall Connolly, Catholic Online (NEWS CONSORTIUM)
July 24th, 2013
Catholic Online (www.catholic.org)

Astronomers have spotted Comet ISON spewing gas  and dust in new images Using a space telescope, astronomers estimate that ISON is already spewing millions of pounds of dust and gas every day. The comet is also on an ejection trajectory.

LOS ANGELES, CA (Catholic Online) - Reporting from nearby Pasadena, astronomers using NASA's Spitzer Space telescope say they have observed Comet ISON spewing carbon dioxide gas and dust as it approaches the sun.

Astronomers estimate ISON is losing 2.2 million pounds of gas and 120 million pounds of dust per day.

ISON is beginning to thaw as it approaches the orbit of Mars. The comet will eventually pass less than a million miles from the surface of the Sun, a close approach that could conceivably destroy the comet.

Astronomers believe this is Comet ISON's first visit to the inner Solar System, given the trajectory the comet is on. Typically, comets will have less steep trajectories the more times they pass the sun.

Comet ISON originated in the Oort Cloud, a spherical halo comprised of billions of comets left over from the formation of the Solar System. Although the Oort Cloud itself isn't visible from Earth, the theoretical region, that extends from a tenth of a light year to a full light-year away from the Sun, is widely believed to exist.

First time visitors to the inner Solar System are uniquely valuable because they retain their pristine composition. As such a comet approaches the Sun it warms, melting vapor and shedding dust that accumulated at the time of its formation, billions of years ago. Studying what the comet gives off at this time can help scientists learn more about the formation of the early Solar System.

Comet ISON is now approaching the water-ice line that astronomers say is just beyond the orbit of Mars. Within that boundary, solar energy is intense enough to melt ice of different compositions, turning the frozen gasses that form the comet into vapor.

Water is by far the most abundant frozen gas, but methane, ammonia, and carbon dioxide are also prevalent. All of these are believed to be basic building blocks of the Solar System and played a role in the formation of the Solar System.

Comet ISON is expected to pass the orbit of Mars in August. After that, it will continue to warm until it rounds the sun. As it warms, the amount of dust and gas it gives off will increase, causing it to brighten.

If the comet survives its close approach to the sun, it should be visible to the naked eye in late November and early December. Some estimates suggest the comet could be so bright that it will shine at least as brightly as the full moon, for at least a few days.

By the New Year's Eve, the comet will be long-departed. Current estimates suggest that Comet ISON is on an ejection trajectory, meaning that given its mass and velocity, it will actually exit the Solar System, never to return.

If ISON survives its close approach to the Sun, we may be treated to one of the most spectacular astronomical sights of the century. Or, we may be in for an astronomical disappointment. For now it's all speculation, as astronomers watch and wait.

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