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Star Facts:
Interesting Facts About Stars
Astronomers have studied stars for centuries but only recently have begun to understand them. Stars, constellations, galaxies and nebulae are all related as you will see.
For most of recorded history the Earth was thought to be the center of the universe and never moved. The constellations were named and stories were told about them as they appeared through the seasons. Without a telescope or other aid the stars seem to be just points of light that move across the sky at night.
How Far Away Are The Stars?
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The luminous band stretching across the sky is called the Milky Way. We and the rest of our solar system live in that galaxy. It is comprised of 100 billion stars (including our own sun). Despite the appearances, the stars in the galaxy are not closely crowded together.
Let’s take a look at how big it really is. The Milky Way Galaxy looks like a rather loose spiral and is rotating round its center (much like the planets in our solar system circle the sun).
About Shooting Stars
A meteor is a small particle (that could be the size of a grain of sand) which enters the earth’s atmosphere at a velocity of up to 45 miles per second (162,000 m.p.h.). Friction causes the particle to become superheated; destroying itself in the streak of luminosity known as a shooting star. Very few of these particles penetrate below a height of 50 miles above the ground.
About Constellations
A constellation is a pattern of stars. When you look in the night sky you see really bright stars and some around them that are not as bright.
Many cultures told stories about hunters, warriors, queens and kings, birds, bears, horses, and other figures they saw in the sky. They used these myths to teach their history and how they saw their place in the universe.
The reason we can't see some constellations all the time is that they are up in our sky during the day. As the Earth orbits the sun different constellations become visible.
About Galaxies
A galaxy is like an island in space made up of gas, dust and millions of stars. Our own galaxy, the Milky Way, includes about a trillion (a thousand billion) stars in a disk shape. Recent research indicates that there may be millions of galaxies in our universe.
We are about two-thirds of the way out on one of the arms of our galaxy. We are in a group of galaxies called the Local Cluster.
A few years ago the Hubble Space Telescope took an image called the Hubble Deep Field. It was a spot of sky near the Big Dipper about the width of a dime 75 feet away. Scientists counted over 1500 galaxies in that small section! Take that number times the volume of space in every direction and you would calculate that there are millions of billions of galaxies with billions of stars in each galaxy.
Even More Star Facts…
- Alpha Centauri, the nearest star to us, is 4 1/3 light years away. That’s pretty close compared to the rest, Polaris, the North Star, is 1,000 light years away.
- The closest galaxy to ours is called the Andromeda Galaxy, It is 2,200,000 light years away.
- The Palomar 200-inch reflector telescope has found 100 million galaxies within photographic range. That’s up to 5,000 billion light years away!
- The Hubble space telescope has found over a million galaxies!
- The farthest known galaxy, named 4c41.17, photographed recently by an infrared camera at the W. M. Keck Observatory in Hawaii, is about 12 billion light years from Earth. That’s 72 trillion billion miles.
- Now that you have digested all of that; let’s take a look at the big picture. The galaxies seem to be moving away from us and from each other, so that the entire universe seems to be in a state of expansion!
- And still another fun fact for your expanding mind: A spacecraft would have to reach a speed of 93,000 miles per hour just to pull away from the sun’s gravity. And it would take 80,000 years to reach Alpha Centauri… if it could maintain that speed.
- Stars come in different sizes. Super Giant stars range from 100 to 1000 times the diameter of the sun and giants range from 10 to 100 times the diameter of the sun. Dwarf stars can be 1000 times smaller than the sun. Stars also vary in color.
- Double Stars are two stars that look like one to the naked eye but separate in a telescope view. They may not be orbiting each other as in a true Binary Star but appear to line up that way.
- In an Eclipsing Binary, stars orbit in such a way as to eclipse each other as seen from Earth.
- Variable Stars are stars that vary in brightness for various reasons.
- Novas and Supernovas are exploding stars that are blowing off their outer shells.
- Stars can be packed so close as to be seen as Star Clouds, grouped like a ball as in Globular Clusters or rather loosely assembled in Open Clusters.
- Patterns are called Constellations and parts of these like the Big Dipper in Ursa Major are called Asterisms.
- A light year is the distance that light travels in one year. How much is that?
- If you multiply the speed of light: 186,000 miles per second
- By the amount of seconds in a year: 31,500,000
You’ll find the distance of a light year…6,000,000,000,000 miles!
- The sun is 25,000 light years away from the center of the galaxy and takes about 225 million years to complete one 360˚ circuit.
- The diameter of the galaxy is 100,000 light years (that’s 6,000,000,000,000,000,000 miles; 6 quintillion miles across.)
- Alpha Centauri then is 26 trillion miles away and remember, besides our sun, it’s the closest star to us.
- There are 100,000,000,000 (100 billion) other stars in our Milky Way Galaxy.
- Galaxies are classified using Edwin Hubble’s scheme describing spiral, barred spiral, elliptical, peculiar and irregular shapes.
- Gas, dust and debris from star explosions and around star forming regions are called nebulae. A nebula can reflect light (Reflection Nebulae) or absorb light (Dark or Absorption Nebulae) while Emission Nebulae emit light on their own.
- The remnants of a star explosion are called Planetary Nebulae because they looked like planets to early astronomers with small telescopes. Some are named because of their recognizable shapes like the Ring Nebula in the constellation Lyra.
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