I got an email from Prague this morning:
Good morning and Happy Halloween. I live 13 miles ENE of Prague. This morning at 0500 I went out to let the horses out of the paddock, into the pasture as usual. I looked up and saw a rather large falling “Star/Meteor/Comet”. It was going from West to East. The reason I say Meteor or Comet is because it was so much larger than anything I’d seen before. Do you know what it might have been?
I do not know much about comets or meteors, but I have heard that there is a comet that is currently visibly in the sky, and this is what might have been seen this morning in Prague.
I was able to find out more by searching the web:
What had been a modest comet seen only with binoculars or telescopes flared up last week to become visible to the naked eye.
Comet SWAN, as it is called, is in the western sky after sunset from the Northern Hemisphere. It remains faint, likely not easy to find under bright city lights but pretty simple to spot from the countryside.
The comet, also catalogued as C/2006 M4, is about halfway up in the sky in the direction of the constellation Corona Borealis.
As with most comets, this one looks like a fuzzy star. It has an interesting green tint, however, indicating it has a lot of the poisonous gas cyanogen and diatomic carbon, astronomers say.
Comets, the stuff of legend and myth, are frozen leftovers of the solar system’s formation. Most orbit the Sun out beyond Neptune, but a few wander through the inner solar system now and then. As a comet gets closer to the Sun, solar radiation boils the frozen gases, along with dust, off the comet’s surface. Sunlight reflects off this material, creating a head, or coma. Some comets never get very bright. Others brighten dramatically. Some even come unglued as they round the Sun.
Some comets, like SWAN, also sport a tail or two. Such detail is best seen with binoculars or a small telescope.
Comet SWAN was discovered last year. It is named for the Solar Wind ANisotropies instrument aboard the SOHO spacecraft, whose images revealed the icy wanderer.
It made its closest approach to Earth last Thursday. Eventually it will return to the distant reaches of the solar system. Nobody knows how long the comet will grace the night sky.