Posted 1:24 am Tuesday, November 13, 2007
Exploding Comet Still Visible In Night Sky
BY DR. SCOTT M. LIEBERMAN
Special Contributor
Amateur and professional astronomers are witnessing a once-in-a-lifetime event, and so can viewers of the East Texas night sky.
A comet named 17p/Holmes, which has apparently exploded, is making an unexpected appearance in the evening northeastern sky.
The comet is giving off a ball of gas, which has so expanded in size that it has become larger then the planet Jupiter.
On Oct. 24, the comet, which had been a faint dot in the sky visible only with a telescope, suddenly became almost a million times brighter over a 24-hour period.
It rapidly became visible to the unaided eye and has been easily visible ever since, even in well-lit cities - but it is now starting to dim again.
Comets are thought by astronomers to be made of ice and rock and orbit the sun. Usually, they get brighter the closer they pass to the sun, melting and giving off gases - creating a "tail" seen in reflected sunlight.
Comet Holmes, which orbits between the orbits of Jupiter and Mars every 6.9 years, was most recently moving away from the sun and was not expected to brighten.
Astronomers are unsure if gas was vented from inside the comet or if it was struck by an asteroid, but they believe may have happened before.
When the comet was first discovered in 1892 by Edwin Holmes, an amateur astronomer in England, the comet behaved in a similar manner, brightening twice in several weeks.
The comet, about 155 million miles away from Earth, is moving away, and astronomers don't know how much longer it will be visible.
It can be seen in the constellation Perseus, and through binoculars appears as a large fuzzy ball of light with a bright center. A small tail is developing but not yet visible without a telescope. After sunset on a clear night, sky watchers should face north, find the "W" shape of the constellation Cassiopeia, then look down and to the right to spot the comet.
Special Contributor
Amateur and professional astronomers are witnessing a once-in-a-lifetime event, and so can viewers of the East Texas night sky.
A comet named 17p/Holmes, which has apparently exploded, is making an unexpected appearance in the evening northeastern sky.
The comet is giving off a ball of gas, which has so expanded in size that it has become larger then the planet Jupiter.
On Oct. 24, the comet, which had been a faint dot in the sky visible only with a telescope, suddenly became almost a million times brighter over a 24-hour period.
It rapidly became visible to the unaided eye and has been easily visible ever since, even in well-lit cities - but it is now starting to dim again.
Comets are thought by astronomers to be made of ice and rock and orbit the sun. Usually, they get brighter the closer they pass to the sun, melting and giving off gases - creating a "tail" seen in reflected sunlight.
Comet Holmes, which orbits between the orbits of Jupiter and Mars every 6.9 years, was most recently moving away from the sun and was not expected to brighten.
Astronomers are unsure if gas was vented from inside the comet or if it was struck by an asteroid, but they believe may have happened before.
When the comet was first discovered in 1892 by Edwin Holmes, an amateur astronomer in England, the comet behaved in a similar manner, brightening twice in several weeks.
The comet, about 155 million miles away from Earth, is moving away, and astronomers don't know how much longer it will be visible.
It can be seen in the constellation Perseus, and through binoculars appears as a large fuzzy ball of light with a bright center. A small tail is developing but not yet visible without a telescope. After sunset on a clear night, sky watchers should face north, find the "W" shape of the constellation Cassiopeia, then look down and to the right to spot the comet.
