1. How many Stars are there?

2. How many Stars are there?
You can see 3000 stars on the clearest night with your eyes.
How do we see more?
Hubble Space Telescope looked at a spot just above the big dipper the size of a grain of sand held at arms length for 10 days.

4. How many Stars are there?
Count how many objects you see in one part of the camera. Find the average number of objects per square for your group.
How many objects did Hubble see?
113 X 16 = about 1800 objects
What are these objects?
Most of the 1800 objects are galaxies

5. Galaxies
Collection of millions or billions of stars, gasses, and matter
Milky Way- our own spiral galaxy
Andromeda- the nearest galaxy to the Milky Way
Colliding Galaxies

6. How many Stars are there?
How many grains of sand would it take to cover the sky?
3 X 107
1800 X 3 X 107 = 50 billion galaxies.
Each galaxy has 100 billion stars.
The number of stars is
100 X 109 X 50 X 109
5000 X 1018
5 X 1021 Stars (5 sextillion)
5,000,000,000,000,000,000,000