1. Scale of Earth’s Systems
Journey tot eh Edge of the Universe

2. http://htwins.net/scale2/ The Universe- the largest SYSTEM
What is the Universe?
How large is the universe?
How many galaxies are in the universe?
Section 28.4 on page 631

3. Powers of Ten Cosmic Zoom activity
Cosmic Zoom activity

4. Scientific Notation
Convenient way to write extremely large or extremely small numbers
Has 2 parts: base and exponent
Base exponent
Examples: 103 = 10x10x10 = 1000
10-2 = 1/10x1/10 = 0.01

5. Units to Measure the Universe
Astronomical Unit = AU
Unit of Length
Average distance between Earth and Sun
Ave. 93,000,000 miles
Light Year = LY
The DISTANCE light travels in one year
Distance = speed of light x 1 year

6. Light years is a DISTANCE
Speed of light: 300,000 km/sec.
(186,000 miles/sec)
Times 86,400 seconds in a day
Times 365 days in a year
10 trillion kilometers!
10,000,000,000,000 km
1013 km
Or about 6 trillion miles!!!

7. Lag Time Because the sun is 93,000,000 miles away from earth,
It takes time for the sunlight to travel that distance (even at a speed of 186,000 mi/s)
It takes 8 minutes for the sunlight to reach earth.
So…. The light we see from a star that is 1500 ly away, left that star 1500 years ago!

8. Orion Nebula Nebula of gas, and stars. In the constellation Orion.
1500 light years away.
1344 ly x 6 trillion miles = ??

9. Horsehead