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The Webfooted Astronomer - November 1999
Minutes: The Magnificent Universe
by Leslie Irizarry
Joanne Green received an Astronomy League Lunar Club certificate for observing 100 features on the moon, using naked eye, binocular, and telescope. Bruce Kelly announced that there are calendars and observers' handbooks available.
Bellevue Community College is looking for an Astronomy 101 instructor: the candidate should have a degree in astronomy or related field. Peter Hirtle announced that Telescope Makerís SIG will meet at 6:30 p.m. Saturday. Keith Allred announced that the Astrophotography SIG will meet the second Sunday in November at 2 p.m. at his house. At Rattlesnake Lake there is a sign that says, "Closed and Locked at 1 p.m." Beware: If you're not near your car, you may get locked in. A repeat vote for the Awards Banquet dinner was held. The club voted for top sirloin and salmon by a narrow margin of 1.
What is needed in the universe to make life possible on Earth? If you throw out everything, you should at least keep the Earth and the sun. You may think, "Thatís all we need." However, the moon may have caused life to emerge from the ocean. Jupiter and Saturn's gravity protect us from millions of asteroids. So, we at least need the Earth, the sun, the moon, and the gas giants Jupiter and Saturn. What about galaxies? Without giant galaxies, life on Earth would not exist. The Earth would not exist!
There are three types of galaxies: elliptical, spiral, and irregular. M87 is an elliptical galaxy in the Virgo cluster. It is uniform in color with predominantly yellow-orange stars. Yellow-orange stars donít give birth to new stars. Blue and white stars donít last very long. In the 1950s, there was a major astronomical debate: what is now known as The Big Bang theory in which there was a beginning to the universe vs. the Steady State theory, in which the universe was eternal, without a beginning. The uniform colors convinced them that the steady state theory was incorrect. The Big Bang theory can explain why this is the case.
Our galaxy is a spiral galaxy. Spirals still give birth to new stars. M33 is an example of a spiral galaxy. Young stars are blue. Spiral galaxies appear blue due to the large number of young stars. They also rotate, whereas elliptical galaxies do not. The sunís path around the galaxy varies from a circle by 10%. It has a 230- million-year orbit. In giant ellipticals, stars dive into the center and out. Some traumatic event had disordered their orbits.
Elliptical galaxies form when two spiral galaxies collide. Galaxies generally donít escape collision. To illustrate the comparative distances of stars vs. galaxies, if stars were the size of a quarter, the next star would be 400 miles away. If galaxies were the size of a quarter, the next galaxy would be 1 foot away! When spiral galaxies collide, because of gas and dust, new stars are formed. The Ring galaxy is a half of a billion light years away. It is exotic. The Cartwheel galaxy used to be like the Milky Way, but an intruding galaxy caused a compression wave.
Hydrogen and helium and a small amount of lithium were created in the Big Bang. Life, however, needs heavier elements. Stars create heavy elements. Stars arise in gas clouds. The red glow is ionized hydrogen. Rigel is not hot enough to ionize hydrogen. There is a star-forming region in the spiral arm of The Eagle Nebula. The pillars are regions of star formation. There is a transformation through "alchemy" the forming of one element into another. Our carbon and other heavier elements were formed in this way.
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