1. How did the universe form?

2. THE BIG BANG

4. The Big Bang!
15-20 billion years ago

5. The Big Bang Theory: Occurred ~ 15-20 billion years ago
Before the Big Bang, there was NOTHING!
All of time, space, energy and matter were compressed into something smaller than an atom

6. After the Big Bang, all of this energy and matter were released, forming the galaxies, stars, planets, and other celestial objects in the universe

7. The entire universe is ~ 25 billion light years in diameter and is still expanding!

8. 100,000 years after the Big Bang
Clouds of hydrogen and helium

9. The Fate of the Universe?
Some scientists think that the universe will continue to expand forever (red shift)

10. Others think that the force of gravity will eventually reverse the expansion and the universe will fall back together (blue shift)
This will be called the BIG CRUNCH!!!

11. The 2 possible fates of our Universe….

13. The collision between the Milky Way and the Andromeda Galaxy

14. Evidence?

15. Evidence for Big Bang: Background Radiation (echo) –
-crackling noises detected from space
-noise from the Big Bang

16. The
Doppler
Effect

17. wavelength
Moving Towards?
Moving Away?

18. Electromagnetic Spectrum
According to the ESRT, which has a longer wavelength –
blue or red?
RED!!!

19. The Doppler Effect
Doppler Effect – Stars from distant galaxies are emitting light in longer wavelengths (towards the red end of the spectrum)

20. This indicates that they are moving away from each other Red Shift = our universe is expanding

21. Blue shift = when a star or galaxy is moving towards you

22. The Doppler Effect

23. Standard
Closer = Blue Shift
Further away = Red Shift

24. A Red Shift A Blue Shift The Visible Spectrum The Absorption Spectrum
The Emission Spectrum
A Red Shift
A Blue Shift

26. The Birth of today’s Earth 4.5 bya
Water from volcanoes
The Birth of today’s Earth 4.5 bya
Water from meteors crashing into Earth.

27. 1st plants used the CO2 in the atmosphere for photosynthesis creating
Formation of Life 3.5 bya
Blue-green algae
1st plants used the CO2 in the atmosphere for photosynthesis creating
OXYGEN!

28. Early Models of the Universe
Ptolemy

31. Basic Geocentric View Celestial Sphere Saturn E Mercury Jupiter Moon
Mars
Venus
Sun

32. The Geocentric Universe
Ancient people (Aristotle) “knew” from observations that
The stars appear fixed on the sky relative to each other.
Planets, moon and sun change position with respect to the stars.
Mercury and Venus only seen near sun.
These observations led them to theorize that the Earth is at the center and all objects move around it.
Earth DOES NOT MOVE! After all, can you feel it moving?

33. Problem: Retrograde motion of Mars
Planets usually move from west-to-east in the sky with respect to the stars over long periods of time.
Sometimes planets go east-to-west in sky=retrograde motion.
Note: Retrograde motion was very hard to explain
Main challenge to ancient models of the solar system.

34. Retrograde Motion

35. Solution! Ptolemy – Created the idea of epicycles.
Predicted the position of the planets accurately with some problems.
Theory lasted 15 centuries.

36. Retrograde motion explained!
But what about those other planets whose position could not be accurately determined?

38. So what happened to this theory…
The model became so complicated that they had to come up with a new idea!
Too many epicycles!

39. Nicholas Copernicus (1473-1543)
Heliocentric (sun centered) model of the Solar System.
More simply predicted paths of planets

41. Basic Heliocentric ViewJ V M E
Celestial Sphere
Heliocentric Model = sun at center
All planets orbit the sun
Moon orbits the Earth.
Circular orbits

42. Retrograde motion in action!

43. How would the distance a planet is from the sun affect its period of revolution?
The closer a planet is to the sun the shorter it takes to go around the sun.
Closest planet Mercury only 88 days to make it’s trip around the sun.
The farther a planet is from the sun the longer it takes to go around the sun.
Neptune takes years to make it’s trip around the sun.