Astronomy_lem

A Summary of Astronomy

The Birth of the Universe: An Introduction to the Big Bang The universe was created in an episode of mass explosion called the Big Bang. In this span of about a second the universe developed from nothing and expanded rapidly. During this time matter, antimatter and radiation (light) were being formed. This matter forms protons and neutrons, which bonded to make nuclei. As the universe cools atoms are created when the nuclei attract electrons. These atoms were first Helium and then Hydrogen was formed. The Big Bang was incredibly short, only about 3 seconds long, but it affected the universe forever.

Clusters of Stars; the Formation of Galaxies After the Big Bang occurred galaxies were formed. The universe collapsed because of gravity and this allowed galaxies to form. A galaxy is a cloud of swirling gas that orbits a central point. It is suspected that the central point of our galaxy is a huge black hole. Galaxies are classified as elliptical, spiral or irregular according to their shapes. In the early universe collisions and merges of galaxies were common. These collisions created the arms on galaxies. Someday, our galaxy may merge with the Andromeda galaxy.

What do Candy Bars Have to do with Astronomy?; the Milky Way Galaxy The Milky Way Galaxy is a spiral galaxy that houses our solar system and our planet. There are two main parts of our galaxy. The central bulge is located in the middle of the galaxy and is most likely, as a stated before, a huge black hole surrounded by a cloud of gas. The second part is the disk. This disk is a flat layer of stars that extends in both directions away from the central bulge. In fact the entire galaxy is made up of stars that form clusters called halos. Our sun is one of the stars in the disk. The Milky Way is a huge galaxy, so huge that we will probably never be sure of the real structure of it. But like most everything in astronomy, we have a pretty good guess that this is how it appear. Though the milky way galaxy may not be as delicious as the candy bar, it is the place we call home and should be cherished.

The Planets The planets were created in the swirl of matter circling the sun. They were formed from planatisimals crashing together and sticking. In the outer solar system there was gas because the sun was radiating energy and pushing the lighter gas back. That's why the outer planets, Jupiter, Uranus, Saturn and Neptune, are made of gasses. The four inner planets, Mars, Venus, Mercury and Earth, are all closer to the sun and therefore were created at warmer temperature. When these planets were made, the molten metals on the surface sunk to the center of the planet, while the lighter rock became the new surface. The planets cooled a bit more and hardened in this fashion. Earth is the only planet we know of that supports life, but other planets may be just a hospitable. That is the purpose of this mission.

The Rotation of the Galaxy The Galaxy rotates not as a whole but each individual star in its own orbit. The stars orbit around the nucleus of the galaxy in the spiral arms. It takes the average star 250 million years to get around the whole galaxy if they were traveling at 250 light-years per second. The way that our galaxy rotates it tells us that it could be 5 times bigger than it appears to us now. The rotation of the stars around the central bulge keep them from being pulled into it because of its gravity. The rotation is essential to the stability of the galaxy.

 Moons, and Comets, Oh My!  Moons, rings and comets are all very similar to planets because they are all simply clumps of matter. Rings are formed when small bits of matter are pulled into the gravity of the planet. These rings are usually around pla   nets with more mass because therefore they have more gravity and more capability to attract matter. This is also the reason for the number of moons a planet has. A moon is simply a larger clump of matter that was pulled into the gravity of the planet. Most moons are very small compared to their host planets, that is why the formation of our moon is so puzzling. Our moon is much closer in size to Earth than usual. Comets are created when icy planatesimals hit the warmth of the sun. They form "tails" that are their matter being released. Moons, rings and comets are made of about the same material as planets but it is their gravity that separates them.

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