By Chris Fellows, Serenity Mobile Observatory
Let’s watch a meteor shower
One of the most thrilling events in the night sky is spotting a shooting star or meteor entering the Earth’s atmosphere and burning up in a fiery display. In this article we will explore what a meteor is and when is your best chance to see one.
Meteors are generally small leftover chunks of debris from the formation of our solar system. Most are the size of large grains of sand up to something the size of a pea or larger. These hit the top of the atmosphere at around 50 to 75 miles up at speeds around 20 to 45 miles per second! Rarely a larger chunk encounters our atmosphere and will break up into several pieces as it decelerates, creating a spectacular multi-part fireball called a bolide. These are rare but I have seen a few in my years of looking up. In any case, the friction caused by the little bit of stone colliding with the air molecules heats the air into a plasma that glows very brightly for a second or two. These types of meteors happen every day. If you go out under a dark sky and lie back in a lounge chair for an hour you will most likely see one or more of these rogue visitors. More spectacular are the dates that the earth passes through a comet’s path – on these days you can expect quite a show.
When a comet falls in towards the sun it gets heated up by the sun’s energy and ice and other volatiles start to sublimate off its surface. This happens with quite a bit of energy and displaces material from the comet’s surface. These bits of rock and dust that have been locked up in the freezer for billions of years are liberated and fall into an orbit similar to the comet but are strung out far behind the parent object. This bread crumb trail of detritus continues to orbit the sun until it encounters something else, like the earth. The earth passes through several of these dusty trails every year as we circle the mother star and on those nights we can get quite a show. The great thing about this mechanical process is that it is predictable. We know where the dust trails are and we know when the earth will encounter them. We call these night meteor showers and there are no less than 10 strong showers per year.
Meteor showers are named for the constellation that they seem to radiate from. As the earth orbits the sun it has a particular direction and depending on the time of year there is a stellar constellation in that direction. When the earth passes through the river of dust left behind by the comet, the meteors will seem to radiate from that constellation so we call the shower by the name of the constellation. The table below gives the shower’s name, the constellation it radiates from, the best day of the year to see the most meteors, the estimated meteors per hour rate, and the parent comet name. The Geminids in December seem to be the most energetic this year.
To watch one of these showers you need nothing more than your eyeballs and a bit of patience. In my opinion, the best way to watch these is to throw a barbecue the afternoon of the shower and invite several friends over. After sundown, arrange your lounge chairs in a circle with everyone facing outward but with all your heads together. Make sure you have a good supply of your favorite beverage at hand, lie back and call out the meteors as you see them. It’s a lot of fun and you will hear many oohs and aahs as your friends and family spot meteors. Let me know if you have a shooting star party and how it went. Better yet, if I am in your area invite me over – I would love to watch one of these with you.
Till next time …
Chris Fellows, Serenity Mobile Observatory
Find Chris on Facebook (or, if you’re lucky, at your campground). (Editor: Check out his amazing photos on his Facebook page!)