Meteors and Comets
Meteors and Comets
Perhaps every one of us has seen a falling star,shooting star or meteor and been amazed and wondered what was going on. Fewer perhaps have seen a comet and wondered about it’s quite different appearance. These are my subjects this time.
Meteors are normally a short streak in the sky at night. Usually a quarter of the sky or less is it’s track and sometimes they leave a bit of a trail. Most are a small, quick and brief momentary experience. Not necessarily too impressive but strangely pleasurable. For me I have the feeling of delight, like a stolen moment probably no one else saw. A kind of gift to just me from the great cosmos. These meteors are about the size of a grain of sand, the smallest even less. Amazing how such tiny a thing can give such a show. It’s about speed and the density of our atmosphere and the heat formed from these playing together. The atmosphere creates the friction that increases the heat to burning and disappearance. Now this celestial debris can sometimes be bigger than a grain of sand. A pebble, rock or planet effecting giant, like in the movies and in our past history, that can actually change the world in a stroke. My most amazing meteor experience was in Joshua Tree National Monument in Southern California. J. Tree, we used to call it, is the high desert and has magnificent night skies. This night my buddy Del and I sat high on a rock listening to coyote’s voices in the shadows when from over our shoulders came the huge fireball of a meteor. It broke in half right before us splitting into two fragments one of which broke again into two as the other faded. Then the final two fragments faded out near the horizon line midst our Ahhhs and whoops and hollers. We were blow away!These meteors do come from outer space and there is always a back ground of specks of various sizes floating out there. They usually form about 50 to 75 miles up. Space is not that empty. There is actually such a thing as dark matter but that’s another story.Now Comets are quite different. They come in visually slowly and move from the outer reaches of our solar system in towards the sun which they circling in an orbit much like our earth’s around the sun except much larger and more elliptical. Comets are actually a part of our solar system, our distant bother and sister heavenly bodies, orbiting the sun like us. Sometimes they spend decades, centuries or maybe even more traveling in their orbit till they make the swing around our sun where we are close enough to see them. Also the sun’s gravity effects them and “turns them on” usually lengthening their tails and brightening them. And their tails always point away from the sun no matter the direction of travel they have. Now isn’t that strange? Comets, you’ve probably heard, are made up of ice and dirt, a dirty snowball, and it’s the coldness of outer space that keeps them in tact and the heat of the sun which makes that tail which is the comet loosing gaseous material in a spectacular way as it gets close to the sun.When we see photo’s or drawing of comets they look like they are quickly moving in the direction of their tails. This is not is not so. They move visually slowly taking days or weeks or months to move through our visual field. First they are seen by deep sky telescopes then binoculars can pick them up and finally a few of them become so big and so close as to be seen by the naked eye. Some, if you remember a number of years ago, become iconic in scale and beauty, like Hyutake. It was definitely my most spectacular personal comet: early that memorable morning, at it’s closest to us at 4 AM I just had to wake up friends and we sat and stood looking up speechless at the hugeness above us and the stangeness of a sight never seen before, perhaps never again. It was a wonderfully beautiful life time image. Now here’s where comets and meteors converge: When we hear of predictable, even yearly meteor showers it is because from experience scientists have learned that Comets leave a trail in space of dust and specks of dirt as they go through their travels around the sun. As our earth goes around the sun we occasionally and predictably go through these orbits: trails left in space, roads upon which that particular comet travels. In it are the road dust of that comet and as we get there we plow through the debris. Sometimes these are the most regular of showers, like the Perseids [from comet Swift-Tuttle] we experience every year like clockwork on August 12th. They can rain down many meteors a minute, even hundreds in rare cases. Perseids were first recorded in China in 36 AD. We never quite know how many or exactly when to look. But for the intrepid hunter with much patience, the rewards can be amazing. Now the showers aren’t named for the Comet, they are named for the constellation in the sky where you can expect the meteors to radiate from. Like Perseid showers on the August 11th-12th, they happen each year, on the same night, and are our most dependable and plentiful [normally] meteor shower for the time being. Comet’s orbits can increase in meteors with consecutive passings of the comet and decrease with age and fizzle out. Comets are usually named for the people who first saw them and brought them to our attention.If you hear about an upcoming meteor shower from me or elsewhere viewing it is easy. The early morning hours are best because our planet it steaming towards them then rather than seeing them as we move away from them before midnight. The moon and lights minimize the effect. Get comfortable and warm under a dark sky and have fun. Of Note:Meteors: The Leonids meteor showere Peak on November 18th with perhaps 15 per hour but can be seen less spectacularly from 14th – 29th.The Geminids are active from December 7th – the 17th and peak on December 14th with 6 – 10 an hour. Please notice that the Milky Way, our galaxy, is spread out beautifully east to west in November. Remember it was much more north to south earlier this summer. This observation gives you a sense of the movement of the sky overhead over time. It’s not a simple east/west but a swinging turning over head, east to south to west sort of. Strange and beautiful. November and December’s full moons are called the Frosty or Beaver Moon and the Moon before Yule or the Long Night Moon respectively.On December 22 is the Winter Solstice the day with the earliest nightfall and considered the longest day of the year.