Jennifer Blazejack Lecture 8/29/12

Discussed in Lecture:

            Black Holes

            Cosmic Origins

            Seeing the Universe

            Washington D.C. Voyage Model

            AU/ Ecliptic Plane

            Raisin Bread example

Black Holes

            We show a slide show on black holes and the slide show discussed how black holes are fairly new (black holes have only been discovered in the last century). No light can escape this “small volume” and once an object is sucked in there is no escape. Caleb Schraf states that black holes direct the evolution of the Universe. Stars move at the speed of light near a black hole and that there is a black hole in the center of the Milky Way.

Cosmic Origins

            The universe began because the Big Bang and over time the universe began to expand. Galaxies and galaxy clusters have formed, but they do not expand. Hydrogen and helium were the only two elements present in the universe until other elements made our stars and were recycled in the galaxy.

Seeing the Universe

            We can only see what galaxies were like the past because light needs time to travel.

Washington D.C. Voyage Model

            A model that gives people an idea of what the universe is like.  It shows how the universe isn’t crowded but instead has lots of space. To get a physical sense of the size of planets and the Sun- The Sun is the size of a grapefruit, Jupiter the size of a marble, and Earth the size of a ballpoint tip of a pen. There are currently 100 billion galaxies in the universe and the example they give is to count all the dry sand particles on every beach in the world to get a sense of all the stars in them.

AU/Ecliptic Plane

            An astronomical unit (AU) is 150 million kilometers. The ecliptic plane is very important because that is Earth’s orbital path.  There is no tilt in space and no up or down- someone in one hemisphere might say they are up and you are down.

Raisin Bread example

This example helps to give an idea of what multiple galaxies do in the universe. The raisins represent galaxies and the bread represents the universe. Before the bread is baked everything is close together (like the beginning of the Big Bang). As the bread bakes, over time, it begins to expand (which represents “space” because “matter” can not expand).