Space

1. Space

2. Part One The Origin and Evolution of the Universe

3. What do we know about space? • What is it? • Where is it? • What’s in it? • Is everything important?

4. 1.1 What’s Important?

5. Gravity • An attractive force that pulls things together Why don’t people on the other side of the earth fall into space? • Because they are attracted towards the centre of the earth by gravity • Any two objects with mass experience a gravitational attraction towards each other

6. Top Five Complete the Top Five assignment with a partner! • Found on Mr. Birrell’s website http://mrbirrell.wikispaces.com

7. Planets • From Greek meaning “wandering star” • Smaller than stars and do not emit light • Two types: • Large, low-denisty gas giants • Smaller, rocky terrestials • First confirmed discovery of a planet outside of our solar system came in 1995

8. Planets in our solar system http://www.aerospaceweb.org/question/astronomy/solar-system/planets.jpg

9. Mars Surface Mar Sunset Video Nasa.gov

10. Stars • Start as huge clouds of dust and gas called “nebulas” • As the clumps swirl and bump into each other, they get larger, and their gravitational force gets stronger • Eventually the clumps are dense and hot enough for nuclear fission to start • Now called a star

11. Nasa.gov

12. Types to know: • Red Giant • The size of our sun or smaller • Red Supergiant • 10 times or more larger than our sun • White Dwarf • After a star is dying, it shrinks in size and becomes hotter

15. Other terms: • Supernova • An enormous explosion at the end of a star’s life • Star has used up its fuels to keep nuclear fission going • Core collapses to become either a neutron star or a black hole • Shock waves cause the outer layers to explode outward in a rapidly expanding nebula • Only one has been seen with the naked eye

18. Planetary Systems • A group of objects including at least one planet orbiting around a star • Our solar system is an example

19. Galaxies • Made up of billions of stars, planetary systems, gas and dust, held together by gravity. • The galaxy that our solar system is located is called the Milky Way Galaxy. If you could travel at the speed of light, you could travel from one side of the Milky Way Galaxy to the other side in 100,000 years.

20. Andromeda (our nearest neighbour)

22. Humans vs. Galaxies What is the greater number: the number of cells in your body or the number of stars in a galaxy? Typical galaxy: ~400 billion (400000000000) Cells in body: ~75 trillion (75000000000000) Largest galaxy known: ~100 trillion

23. Clusters of Galaxies • Groups of galaxies held together by their mutual gravitational force • Largest known gravitational bound objects • Typically contain 50 to 1000 galaxies • The Milky Way is in a cluster of about 40 galaxies

24. Galaxy Cluster ACO 3341

25. The Universe • Everything that exists, including matter and energy everywhere

26. 1.2 Space is Big How big is it? Really BIG Question: How long would you survive if you were ejected into outer space?

27. Powers of Ten Scales of very large things and very small things are tough to visualize. “Powers of Ten” by IBM helps.

28. Special Heliocentric Illustration Tissue Demonstration Quick, to the hallway!

29. Scientific Notation • Scientific notation is a method of writing numbers thatcan make large or smaller numbers easier to read. • Nobody wants to write 24000000000000000000 km over and over again. • This is the distance from Earth to the nearest nieghbour galaxy

30. Rules for Writing in Scientific Notation • Write down all the significant numbers • Put a decimal after the first number. (the number will now be between 1-10) • Write “x 10” • Write the power corresponding to the number of places the decimal was (would have) been moved. (Moving right is negative, moving left is positive) • Count the number of digits between where the decimal was before and where it is now

31. 25 000 000 000 000 • Write down all the significant numbers • Put a decimal after the first number. (the number will now be between 1-10) • Write “x 10” • Write the power corresponding to the number of places the decimal was (would have) been moved. (Moving right is negative, moving left is positive) 25 . x 10 13

32. Write 3.42 x 108 in standard notation. Work in reverse! As the exponent is positive, we move the decimal to the right as many times as the exponent says to. 3.42 x 108 = 342 000000

33. How long would it take… Formula to find how long it takes to get somewhere: Ex. How long to travel 550 km going 80 km/h? MAKE SURE YOUR UNITS AGREE!

34. 1.3 Where Did The Universe Come From? • We don’t really know, but have a theory. Flavour of the day: THE BIG BANG!

35. What is The Big Bang Theory?

36. You Tell Me!

37. The Big Bang • Observations of galaxies by Hubble and other astronomers in the 1920s show that the distant galaxies are all moving away from us at high speeds proportional to their distances. • According to the Doppler Effect, this means that the universe is expanding.

38. To be precise, it is space that is expanding, and carrying the galaxies along as it expands. • Therefore, the galaxies appear to be moving away from each other. • The galaxies themselves are not moving through space. • Think of the “balloon analogy”

39. If space is expanding, then it is larger now than it was. • What would the Universe look like as you go back in time? What would it look like at half its age? A quarter?

40. If the universe is constantly expanding, this leads to the conclusion that some time in the distant past, the universe was so small that it was just a point. • This is the beginning of the universe, termed the “Big Bang”. • Again, think of it not as an explosion, but a rapid expansion, such as blowing up a balloon.

41. Balloon Analogy Activity • The two dimensional surface of the balloon will be used as an analogy for the three dimensional volume of space. • Draw two dots about a thumb’s width on the surface of the balloon. Note the seperation. • Partially blow up the balloon and again note the seperation of the dots. • Watch the dots as your partner finishes blowing up the balloon.

42. Balloon Analogy Questions • What happened to the dots as you blew up the balloon? • The separation increased • What was moving: the dots, or the surface of the balloon? • The surface of the balloon expanded and carried the dots with it as it moved through expansion

43. Balloon Analogy Questions • What would an ant living on the surface of the balloon see? Would they see a center or an edge to their universe? • They would just see a surface with no center or edge

44. Observations are accumulating to show that the Big Bang happened about 13 billion year ago, therefore, this is also the age of the universe as we know it. • The Big Bang theory is the best theory of the origin of the universe we have at this time because several observations support it.

45. First, if this theory were true, we would expect that in the distant past the universe, being small and dense, would be very hot. As the universe (i.e., space itself) expands, it will cool. The signature of this cooling has been observed in detail by the COBE satellite in the early 1990s.

46. Second, astronomers know that the element Helium makes up about one quarter of the matter in the universe. Indeed, the Big Bang theory predicts that Helium is produced during the Big Bang, by exactly the right amount.

47. 1.4 Evolution of the Universe

48. Classification of Galaxies • Examine the following image. • How would you classify the galaxies pictures?

50. Hubble Classification of Galaxies • The best known and often used Hubble Classification was devised by Edwin Hubble. • It splits galaxies into ellipticals, spirals, and irregulars.