1. The Big Bang Theory

2. Steady State Theory Steady State Theory: 1917
The universe is not expanding or contracting

3. Expanding Universe Theory
The universe is continually moving outward

4. The Big Bang Theory The Big Bang Theory: 1927
13.8 billion years ago all the matter in the universe was very hot and dense. Since then, it has expanded and is still expanding

5. Evidence for the big bang

6. Evidence for the Big Bang
The abundance of light elements
The ratio of hydrogen to helium we see in the universe tells us how long ago the Big Bang happened
Background Microwave Radiation
There is microwave radiation left over from the energy released during the Big Bang

7. Evidence for the Big Bang
3. The evolution of stars
Scientists calculate the age of the universe by observing the life cycle of stars
4. Hubble’s Red Shift of data
Distant galaxies are showing a red shift in light because they are moving away from each other

8. Theories about the Future of the Universe
The Big Rip Theory
The universe is expanding so fast that someday it will be going so fast that matter will tear itself apart

9. Theories about the Future of the Universe
The Big Crunch Theory
Someday the universe will reach its maximum and matter will collapse back in on itself

10. Smallest to Largest Solar system Planet Comet Asteroid Meteor Universe
Put in order from the smallest to the largest
Solar system
Planet
Comet
Asteroid
Meteor
Universe
Galaxy
Star
Moon

11. Smallest to Largest Meteor Asteroid Moon Comet Planet Star
Solar system
Galaxy
Universe

12. How big, how far, how fast

13. Measuring the Solar System
Astronomical Unit (AU):The distance from the Earth to the Sun
How far is 1 AU?
149.6 million km (93 million miles)

15. Measuring the Universe
Parsec: a measurement used to describe the distance to stars
1 parsec = 8 trillion miles (8,000,000,000) or 206,265 AUs

16. Speed of Light Speed of light
186,282 miles per second or 670,615,200 mph
Light Year: (LY)the distance light can travel in one year
1 LY = 5.9 trillion miles

17. Nearest Star The nearest star: Proxima Centauri
How far away is the nearest star? 4.2 light years away
24.78 trillion miles
The Voyager 1 spacecraft is on an interstellar mission. It is traveling away from the Sun at a rate of 17.3 km/s. If Voyager were to travel to Proxima Centauri, at this rate, it would take over 73,000 years to arrive. If we could travel at the speed of light it would still take 4.22 years to arrive!

18. Nearest Star
How big, how far, how fast?
How long would it take our fastest space probe to get there?
79,000 years
How long would it take us to get there if we could travel at the speed of light?
4.2 years

19. Age of the Earth, Solar System and Universe
Universe: 13.8 billion years
Solar System: 4.6 billion years old
Earth: 4.5 billion years old

20. Evidence for the age of the universe
Stellar evolution
Background microwave radiation

21. Radioactive Decay
Radioactive Decay: The decay of radioactive elements into other elements
Mass and energy get released in the form of radiation

22. Radiometric Dating
Radiometric Dating: Uses the rate of decay of elements to date objects

23. Evidence for the age of the Earth
Date earth rocks
Date meteorites
Date moon/lunar rocks