2. Our Universe
What it is like, how it started, how it evolved to its current state, and how it will end

3. First, let’s look at some of the objects we might find if we explored our Universe

4. Where do we live?

5. Where is the Earth?

6. The Solar System

7. Q: What is a STAR?

9. Our Sun is a star!

10. Stellar Facts A star is a big ball of burning gas
Our Sun is a very average star
When we look out into the night sky, many of the stars we see are very similar to our own sun
In fact some of these stars also have planets, just like our own Solar System

11. What is this?

12. What is it made of?

14. MANY STARS

15. MANY STARS
SOME SUN-LIKE

16. Galactic Facts Stars tend to group together to form galaxies
Galaxies contain hundreds of thousands of stars
At the centre of most galaxies is a massive black hole!
Our sun is part of a galaxy

17. You are here!

19. Our Galaxy from the Earth

20. We live on the Earth
The Earth is a planet in the Solar System, orbiting our star which we call the Sun
The Sun is part of a galaxy
When we look out into the sky at night, all of the stars we see are in our galaxy
But our galaxy is just one of many…..

21. Galaxies: Hubble Space telescope image

22. ‘Zoom out’ - galaxies form filaments and voids

23. It is hard to comprehend the size of the Universe!
We will now all help make a scale model of the solar system to get an idea of the distances we are talking about

24. IN THE BEGINNING…….

25. EVERYTHING!

26. EVERYTHING!

27. STARTS EXPANDING…..
EVERYTHING!
ENERGY INCREASING, BECOMING LIKE A BOMB…….

28. Tick tick tick……

29. BOOM!

30. The Big Bang Not really an ‘explosion’
Universe expanded rapidly as a whole
(Universe is still expanding today as a result of the Big Bang)
Matter was created in the form of tiny particles (protons, neutrons, electrons)
Too hot for normal ‘stuff’ to form (eg atoms, molecules)

32. COSMIC ‘SOUP’

33. COSMIC ‘SOUP’
PROTON
NEUTRON
ELECTRON

34. 300,000 Years Later….. Universe much cooler, atoms start to form…..
Hydrogen, Helium, normal ‘stuff’

36. Universe is now a GAS

37. Universe is now a GAS
HELIUM
HYDROGEN

39. GRAVITY!

40. Gravitational Collapse
We started with a uniform gas
Small regions became more dense
The denser regions had larger gravity and started to pull other particles towards them
The gaseous Universe began to look ‘clumpy’

41. Formation of Structure!
The Universe began very hot & dense following the Big Bang.
As it expanded and cooled, large clouds of gas could be compressed by gravity, forming stars and galaxies..

42. Gravitational Collapse
Regions with more particles (higher density) become gas clouds
Gas clouds become stars and galaxies
Galaxies congregate together in filaments, groups and clusters

43. But we are inside one of these galaxies, so all we see are the
nearby stars. We can see other galaxies if we use a telescope

44. Cosmic Microwave Background Radiation!
Shows that the universe is nearly the same temperature in every direction.
Indicates a massive explosion-like event occurred in the universe about 13.7 Billion years ago!

45. The BIG BANG! Evidence: The universe is expanding.
The amount of gas in the universe matches with what should have been created by a big bang.
We see dim microwave radiation coming from every direction… an afterglow!

46. The Gemini Telescope

49. Working Timeline since BB

50. Future? The Universe is still expanding All galaxies are moving apart
The ‘explosion’ of the big bang is still happening!
It may contine expanding forever
Or is may stop expanding, and fall inwards in a big CRUNCH!

51. What have we learned? The Universe started with a BIG BANG
Gradually the particles were drawn together under GRAVITY to form STARS and GALAXIES
Many stars have planets around them
The fate of the Universe is uncertain…

52. THE END