By Mike Lynch
The morning skies are definitely worth waking up for as we get to enjoy the annual Geminid meteor shower that reaches its peak this week.
The Geminids are one of the best meteor showers of the year. Meteor showers are best seen from midnight to morning twilight, especially about two to three hours before morning twilight when our part of the Earth has rotated into the direction of the debris trail.
What makes the Geminids especially good this year is that the moon will be setting before the predawn hours, leaving the skies extra dark — especially if you take in the show in the dark skies of the countryside.
Meteor showers occur when the Earth runs into a debris trail of dust and small pebbles as it orbits around the sun. For most meteor showers the debris is left behind by a passing comet that’s partially or maybe even totally melted.
The Geminids are unusual because the debris trail was left behind by a messy asteroid dubbed by astronomers as 3200 Phaethon.
This asteroid was discovered in 1983 and is thought to have a diameter of about 3 miles. It has a highly elliptical orbit that swings it by our part of the solar system every year and a half.
Each time it passes it refreshes the debris trail.
By the way, 3200 Phaethon could be a potential killer asteroid and wipe out most life on Earth if it hit us at just the correct angle.
It’s not expected to do that in the foreseeable future, but in 2093 it’s going miss the Earth by less than 2 million miles.
In the boonies you may see well over 50 meteors an hour and maybe even 100 by the end of the week in the premorning twilight sky.
Even if you’re challenged with suburban light pollution you’ll see enough of them to make losing a little sleep worth it.
Some of these meteors are slamming into our atmosphere at over 40 miles a second. These bits of dust and pebbles get incinerated and vaporized anywhere from 40 to 60 miles above our heads.
There’s no way you would be able to see the actual combustion of tiny debris that high up. The light you see is the result of the tiny column of air the debris is slamming through getting temporarily destabilized and excited.
Electrons from the atoms get bounced away their orbits around the nuclei and then quickly return to their stable orbit. Many times these streaks can stay visible for a second or two after the meteor passes.
Meteors can and do sport different colors depending on what kind of gases they run into, how large they are and how fast they’re moving.
In general, the reddish tinged meteors tend to be slower meteors and faster meteors are more bluish.
This shower is called the Geminid meteor shower because all of the meteors from our vantage on Earth appear to be coming from the general direction of the constellation Gemini the Twins, which is in the western half of the sky in the early morning.
By no means should you restrict your viewing to that part of the sky, however, because the meteors will be all over the heavens.
The best thing to do is to be well layered in coats and blankets and lay back on a fully reclining lawn chair, rolling your eyes all around and keeping count of how many meteors you see.
Meteor shower watching is especially fun with a group of people, because the more sets of eyes you have patrolling the sky the more meteors you’ll see.
Dress warm and enjoy the show.
Mike Lynch is an astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis and is author of “Stars, a Month by Month Tour of the Constellations.” Check his website, www.lynchandthestars.com.
The Everett Astronomical Society: www.everettastro.org/.