This week will include the peak evenings for the annual Perseid meteor shower. Although sky watchers have already seen a few exciting fireballs already, August 12 and 13 are expected to be the primary nights for viewing.

And this year, there will be an exciting pre-showing of planetary alignment in the west with Mars, Venus, and Saturn formed in a close triumvirate, and the crescent moon and Mercury a few clicks away (view a sky map). Once this special arrangement has set around 10 pm--which includes the Moon this year, so dark viewing should be optimal!--then the main attraction for the evening soon begins and will last until the Sun returns for the day.

The Perseids are pieces in the wide debris field left over from the 133-year cycle of Comet Swift-Tuttle. And, this comet is a big one, with a nucleus around 16.8 miles wide. The comet's path follows particularly close to the Earth and Moon, and it was not long ago in 1992 that its calculated orbit was quite off from the latest observation. So far off that it was predicted that the next passage in 2126 could strike the Earth. Additional research was compiled to discover records of more ancient observations, and along with new direct observations puts the calculated orbit in safe distances for at least the next two thousand years.

On September 15 in the year 4479, humanity's safety (or whomever or whatever is still hanging around the planet) might be more of a concern, however, as Comet Swift-Tuttle is predicted to come as close as 2.8 million miles. Certainly this moment is a way off, so hopefully we'll have enough time to develop useful deflection technologies for such massive bodies. In the mean time, just sit back and enjoy the annual showing of Comet Swift-Tuttle bits burning up in our atmosphere.

You can track the calculated orbit of Comet Swift-Tuttle through the year 2201 with the JPL Small-Body Database Browser (launch the database of 109P/Swift-Tuttle).

"Planets Align for the Perseid Meteor Shower" :: NASA Science News :: August 5, 2010 :: [ READ MORE]

Image credit: Looking northeast around midnight on August 12th-13th; from NASA Science News