An activity to explore your place in the universe. Galactic Address An activity to explore your place in the universe.

Our Universe Everything that exists anywhere; includes planets, stars, galaxies, and black holes Age- between 10 and 15 billion years old In open space, away from stars, the temperature is -454 degrees F, that is 3 degrees away from absolute zero.

Origin of the Universe Most widely accepted scientific explanation is The Big Bang Theory, which continues to be tested with each new discovery about the universe. The whole universe was originally packed into a dense sphere of hydrogen, not much larger than the sun is today. About 15 billion years ago the sphere exploded, forming an expanding cloud that moved outward, all of the elements of the Periodic Table were formed at this time.

Origin of the Universe… continued Areas of the cloud eventually condensed to form billions of galaxies. In 1929, Edwin Hubble found evidence showing that the universe is still expanding. In 1978, Penzias and Wilson found leftover energy from The Big Bang and won the Nobel Prize in physics.

Galaxies A galaxy is a large scale group of stars, gas, dust, and planets bound together by gravitational attraction. Galaxies contain millions to billions of stars and there are billions of galaxies in the universe, millions of light-years apart. With a telescope, a galaxy is a fuzzy light source, while a star is a pinpoint of light

Three main types of galaxies: Galaxies…continued Three main types of galaxies: Spiral galaxies (75 %)-central lens-shaped nucleus with spiral arms (containing gas and dust) that come out from opposite sides of the nucleus and trail behind as the galaxy rotates. Ex. Milky Way, Andromeda Galaxy Elliptical galaxies (20%)-nearly spherical to lens-shaped, with most of the stars close to the center. Irregular galaxies (5%)-smaller, fainter, and less common than the other two types. Ex. Magellanic Clouds

Your Galactic Address It is now time to take a quick tour before you work to find your place in the universe, your galactic address…due at the end of class period tomorrow. Examine the Milky Way Galaxy at different scales.