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Saturday, November 9, 2013

Comet Ison Passes Earth and Nobody Notices-- from Catholic Online

Comet ISON passes Earth, nobody notices

Comet isn't getting much attention as it falls below predictions.

Comet ISON is now closer to the Sun than Earth, having crossed Earth's orbit on Wednesday. The comet is behaving a bit strangely as it aims for its first-and last high-speed pass across the surface of the Sun.
Comet ISON as imaged last month.
Comet ISON as imaged last month.

LOS ANGELES, CA (Catholic Online) - Around Oct. 19, amateur observations of Comet ISON revealed the once-lauded "Comet of the Century" was brightening quickly. Now in the past several days, as it sweeps past Earth, observers have gone so far as to report the object dimming slightly. What gives?

Comet ISON, it appears, is behaving more like a solid body than a traditional comet. While it is very much a comet, it isn't emitting as much dust as comets normally do. It is still emitting gas and will continue to do both as it approaches the Sun and continues to warm.

Perhaps because of its lackluster performance, not many people have made mention of it recently. Certainly the media has been relatively quiet about this icy visitor from deep space.

On Nov. 28, Thanksgiving day in the U.S., ISON will pass just three-quarters of a million miles above the surface of the Sun.  Tidal forces could rip the comet apart. Alternatively, the comet could survive, having been heated enough to cause it to spew more dust and gas than ever before. That outgassing is expected to make the comet bright enough to see with the naked eye.

ISON should appear as a naked eye object in late November, being visible to casual observers in the first week of December.

The composition of the comet has much to do with how it performs. It is possible that the comet is more rocky than is typical, a fact that could make the object dimmer because it might not cast off as much dust and gas.

For anyone wishing to view the comet now, a telescope is your best bet. Binoculars may make out ISON, if you know what you're looking for. In most observations, it will appear as a small, fuzzy patch. The bright tail and other famous features of comets will not develop until December. Often those features require long-exposure images to reveal the fine and impressive detail.

Most of us will experience ISON for the first time in a little less than a month now, as it rises into the eastern sky after dark.

How bright it will eventually become, and if it will survive its close encounter with the sun is a mystery we are all anxious to see resolved. However, one thing is clear. Comet ISON probably isn't going to be the Comet of the Century. That distinction will belong to another freezing visitor from deep space that is already well on its way towards the Sun, but remains distant and undiscovered for now.

This chart shows the path of Comet ISON in the sky through December. This chart shows the path of Comet ISON in the sky through December.

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