A Leonid meteor shower
I have always been fascinated by the night sky. Maybe it is the vastness, the oneness or just the sheer beauty of wondering what is out there.
Ever since I was in junior high school and we had a class assignment to find and chart all the constellations, I have been hooked. At the time I wasn’t so thrilled since it was in the middle of January’s freezing cold. Naturally, you have to wait until it is completely dark and there is no cold like a Michigan night when all is clear. However, once I was out there and saw all the beauty that the night sky has to offer, let’s just say that every season finds me looking up after dark.
Although I love seeing comets, meteors and the planets, finding the constellations still gives me the biggest thrill. They are groups of stars that form an imaginary outline or pattern on a celestial sphere. They represent animals, mythological persons or creatures and inanimate objects. They are totally imaginary things that people, poets, farmers and astrologers made up over 6,000 years ago that help people orient themselves using the night sky.
Small patterns of stars within a constellation are called asterisms. The Big and Little Dippers are asterisms within the constellations Ursa Major and Ursa Minor.
All told, there are 88 official constellations. Some are only visible in the northern hemisphere and some in the southern. Of those that can be seen in both hemispheres, some may appear upside down, depending on your location. Some can be viewed all year long but most are seasonal and only appear at certain times.
Distant galaxies and nebulae, which are clouds of gas and dust in outer space, also form part of constellations. Our sun is the only known star in our galaxy which is not part of one.
To identify the constellations, you will need a star chart which is a map of what the night sky will look like at a certain time and location. These can seem confusing because east and west seem to be switched until the map is held over your head which is the way it is supposed to be read. The outer edge of the map represents the horizon, so the further the stars on the map are from the edge, the higher in the sky they will be.
The center of the star chart represents stars and constellations that are directly overhead. To get your bearings, first locate Polaris or the North Star. This is easy to do. Find the Big Dipper which is visible all year in the northern hemisphere and is part of Ursa Major. Draw an imaginary line between the outer two stars in the “bowl” of the dipper. Look up five lengths of this line and you will see the North Star which is the brightest star and the first star in the handle of the Little Dipper in the constellation of Ursa Minor.
The constellation of Ursa Major
In the southern hemisphere, find the constellation Southern Cross which always points south. This time draw a line between Alpha and Beta Centauri and you will find the South Star. Wherever you are, knowing your stars will always help you find your direction. The North Star and South Star is a place in the sky where the Earth’s north and south poles point. Thus, it will not always be the same stars that have this designation.
Stars do not stay fixed in the night sky. As Earth rotates, they change position so the night sky will look differently at midnight than it did a few hours before or after. Most constellations are also seasonal, so ones that are visible in winter may not be in summer and vice versa.
Planets are different from the stars as their position in the sky changes slightly from one night to the next. Thus, they are so named because the word planet means “wondering star.” Stars are so far away that they appear to twinkle because of turbulence in the earth’s atmosphere. So-called the naked eye planets because they can be seen without a telescope, Mercury, Venus, Mars, Jupiter and Saturn are close enough to earth to form a sizable disk in the night sky. When well above the horizon, these planets shine with a steadier light than stars.
Mercury, Venus and Mars are often visible at dawn and dusk, earning them the nicknames of morning and evening stars. In addition to helping locate the constellations, star charts will also aid in finding the eight planets. Whoa, you must be thinking I made an error since there are nine planets. Not any more since astronomers decided in 2006 to move Pluto’s status to dwarf planet. I am not sure how this is going to work out since I learned to keep the planets in order from the sun by reciting, “My very educated mother just served us nine pickles.” It doesn’t make much sense since we have lost our pickle!
Finding the constellations is satisfaction in itself, however nights that offer a meteor shower have a special attraction. Technically, meteors are bits of interplanetary debris that slam into earth’s upper atmosphere. Even the tiniest specks can produce huge streaks of light. During certain meteor showers, upwards of 50 per hour may be seen and most of them are 50 to 75 miles above the ground.
Meteor showers are best viewed on moonless nights from midnight until the first glimmer of dawn. They flash across the sky at unexpected times. Fireballs are meteors that are brighter than any of the stars or planets. These “falling or shooting stars” have always had a little magic attached to them since wishes made while one was “falling” were said to come true. Who knows??
Comets are another phenomenon of the night sky. They are small celestial bodies that orbit the sun. Their bodies are made mostly of ices mixed with smaller amounts of dust and rock. When a comet’s orbit brings it close to the sun, it heats up and spews dust and gases from a giant head that is larger than most planets. The tail that we see is millions of miles long. Material streams from comets and populates their orbits. If Earth or other planets happen to move through that stream, those particles fall to Earth as meteor showers. This is how the occurrence of meteor showers can be predicted.
I was reminded just how spectacular the night sky can be this summer on our trip to Utah. When suburbs sprawl into the country, they bring their light pollution with them. The earth is seeing less and less of truly dark skies. In Utah, far from any cities, we sat outside at night and watched the show, the “night show” from which so many parts of the world are deprived. The best part about the shows that the night skies offer is that they are free for the taking.
Photos courtesy of Getty Images