The Universe – What’s Out There?

Friday, December 14, 2011

What do you see?

What is the universe?

= THE TOTALITY OF EVERYTHING THAT EXISTS!

What is astronomy?= the scientific study of the universe

What are the main structures in the universe?

1. Stars2. Planetary Systems3. Galaxies

What are the main structures in the universe?

1. Stars: A star is a huge sphere of very hot, glowing gas held together by gravity

What are the main structures in the universe?

What is the name of the star that is closest to us?

THE SUN!The Sun appears to bright because

it is so close!

The Sun is about 1 million times

larger than Earth.

What are the main structures in the universe?

2. Planetary Systems: a star and all of the objects that orbit the star• The Solar System (the Sun and its planets) is

the name of our planetary system

What are the main structures in the universe?

Many of the stars that we see in the sky are part of their own planetary system.

What are the main structures in the universe?

3. Galaxies: a collection of planetary systems bound together by gravity• galaxies are the major building blocks of

the universe• the galaxy that we live in is called the Milky

Way Galaxy

What are the main structures in the universe?

The Milky Way

What are the main structures in the universe?

• it is expected that there are > 170 billion galaxies in the universe, and each galaxies has millions to trillions of stars

Now what do you see?