Space News: Insight Safely Lands on Mars

Transcription

1 Space News: Insight Safely Lands on Mars Interior Exploration using Seismic Investigations, Geodesy and Heat Transport MarCO-A and -B (EVE and Wall-E) are also sending signals back!

2 Study Points What is a supercluster? How are galaxies distributed in the universe? What is Hubble Law? Can you apply it to stars? To galaxies in the Local Group? To more distant galaxies? How do astronomers calculate distances to galaxies? What does Hubble s Law tell us about the origin of the universe? When we see objects like stars or galaxies in pictures, are we seeing them as they look now or in the past? Why? Is the red shift caused by galaxies moving through space or by space-time expanding? Is the universe expanding, contracting or neither? How do we know? Is the universe cooling? Discuss the raisin bread model or balloon model to explain why we do not have to be at the center of the universe. What is the name of the theory of how the universe evolved? How old is our universe? How old is our solar system?

3 Review Hubble s Law Galaxies Collide Cluster of Galaxies The Local Group Superclusters Hubble s Law Red Shift of galaxies Big Bang model

4 Do galaxies collide? Galactic collision simulation od1evg&feature=related

5 NGC 2207 and IC 2163 colliding, 80 MLY away

6 Clusters of Galaxies Galaxy cluster mass ~160 trillion times the mass of the sun

7 The Local Group Group of galaxies including Milky Way

8 Virgo Supercluster Milky Way is part of the Virgo Supercluster Supercluster* Cluster of galaxy clusters

9 Neigboring Superclusters within 1 billion light years Every dot is a galaxy

10 Laniakea Supercluster Named & Discovered in 2014 Home to the Milky Way & 100,000 Galaxies

11 Laniakea Supercluster in yellow Superclusters: Virgo (MW) Hydra Centaurus Pavo-Indus More Info here: Picture:

12 Superclusters How are galaxies distributed? In great strings and voids* What does the distribution look like to you?

13 Superclusters How are galaxies distributed? In great strings and voids* What does the distribution look like to you? Edges of soap bubbles Holes of Swiss cheese

14 Superclusters Laniakea: Our home supercluster Watch Video by Nature, Sept. 3,

15 Doppler Effect What does the red shift or blue shift tell you?

16 Doppler Effect Red shift / blue shift tells you Direction of motion (away/toward) & speed Bigger shift means faster For all cases like galaxies, stars, cars For light and sound

17 FOR DISTANT GALAXIES ONLY (not stars or cars) we can use Hubble s Law Measure distance, D, to galaxies Recall: Type of star gives L, then B = kl/d 2 Measure red shift of those galaxies to get their speeds, v. Edwin Hubble 1929

18 Speed, v Distance, D Edwin Hubble, 1929 Graphed v vs. D

19 Hubble s Law V Straight Line!! speed * * * * * * * D Distance

20 Hubble s Law V speed Distant galaxies move faster.* * * * * * * * D Distance

21 V * * * Hubble s Law * * * v = HD * Distant galaxies move faster* D

22 Hubble s Law Implications? For distant galaxies, the speed gives you the distance!* V * * * * * * * v = H*D D H = Hubble s Constant (slope)

23 Hubble s Law *So, today, to measure distance to a galaxy Measure the Red Shift. That gives the speed. V * * * * * * * D Then use Hubble s Law ( v = H*D ) to get distance.* (Don t try this with stars or cars! Only for far-off galaxies.)*

24 Hubble s Law All galaxies (outside the Local Group) show a Red Shift.* Distant galaxies move faster* v = H*D V * * * * * * * D

25 Hubble s Law Implications? What does this mean? All galaxies Red Shifted* All galaxies moving away from us!* V * * * * * * * D Universe is expanding!* This expansion is from the expansion of spacetime.*

26 Hubble s Law But if universe is expanding, what was it like yesterday? Smaller!* V * * * * * * * D And billions of years ago?? Even smaller!

27 So at one point it must have been very small. Hence the name V * * * * * * * D BIG BANG

28 BIG BANG Bad Name (misnamed) Was not BIG Did not BANG V * * * * * * * More descriptive name Great Unfolding Or Big Stretch D

29 Big Bang Universe (space and time) springs into (tiny) existence about 14 billion years ago.

30 Big Bang Universe (space and time) springs into (tiny) existence about 14 billion years ago. Expanding ever since Science states that is the universe is expanding, and it is cooling as it expands. The universe started hot and has been cooling ever since. The expansion should be slowing down due to the force of gravity pulling everything inward.

31 Big Bang Universe (space and time) springs into (tiny) existence about 14 billion years ago. Expanding, cooling ever since Does this expansion ever run out of energy?

32 Big Bang Universe (space and time) springs into (tiny) existence about 14 billion years ago. Expanding, cooling ever since What is the rate of expansion now? Is the rate a) Slowing down b) Speeding up c) Not changing

33 Big Bang Universe (space and time) springs into (tiny) existence about 14 billion years ago. Expanding, cooling ever since What is the rate of expansion now? Is the rate a) Slowing down due to gravity Old Model b) Speeding up c) Not changing

34 Big Bang Universe (space and time) springs into (tiny) existence about 14 billion years ago. Expanding, cooling ever since What is the rate of expansion now? Is the rate a) Slowing down due to gravity Old Model b) Speeding up Current Model* c) Not changing

35 Big Bang Universe (space and time) springs into (tiny) existence about 14 billion years ago. Expanding, cooling ever since* (started hot) Expansion slowing due to gravity (first ~9 Byr) Expansion speeding up due to dark energy (last ~5 Byr & currently) Rate of expansion is speeding up!* The cause is named Dark Energy.* (more on dark energy in next lecture) Expansion Rate is about 14 (mi/sec)/million light years

36 Time (~14 billion Time years) (~14 billion years) Universe Expansion Acceleration Due to Dark Energy ~5 Byrs ~9 Byrs

37 After accounting for the universe expansion: Galaxies moving away from us are in red, those moving toward us in blue (Nature Video, based on Tully et al 2014)

38 Why do distant galaxies move faster? Remember that space-time itself is expanding! Galaxies are NOT moving much through space but space-time is expanding, dragging galaxies with it.

39 Why do distant galaxies move faster? Think of a rubber map and stretch it.

40 Why do distant galaxies move faster? Think of a rubber map and stretch it. Example: Triple size (3X) in one hour. A city 10 miles away will then be 30 miles away moved 20 mi/h A city 100 miles away will then be 300 miles away. moved 200 mi/h When the map stretches, more distant city moves faster. Similarly, as space-time expands, more distant galaxies move faster.

41 Universe Expansion Distant objects move faster Universe

42 Doesn t seeing a Red Shift of ALL galaxies imply that we are at the center of the universe? (all moving away?) NO! But why?

43 Raisin Bread Model Everything can appear to move away from you, no matter where you are located.*

44 Balloon Expanding Demo One piece of balloon sees all other pieces moving away That piece does not need to be at the center You can read more here about why we can t find the center of the universe.

45 Doesn t seeing a Red Shift of ALL galaxies imply that we are at the center of the universe? (all moving away?) NO! Expansion You see all other parts moving away You are not at center

46 I see a galaxy 10 BLY away

47 as it was 10 Byrs ago

48 when the universe was smaller

49 so I m looking back toward the center.

50 Yes and so are we looking out toward the center. so I m looking out toward the center.

51 We re all looking out toward the center

52 Center is here Center is here Center is here Center is here Center is here Center is here Center is here Center is here Center is here

53 An ant on a balloon has no way to know where the center is.* We can t find the center of the universe! And we don t think a center exists!* 09/07/31/the-size-of-the-universe-a-har/ CH27/CHAP27AT.HTM

54 Big Bang and the Evolution of the Universe

55 Big Bang and Evolution of the Universe* In the beginning??? What happened? How the universe evolved and changed after it started.* Rough timeline of events Evidence (next lecture)

56 Very Rough Cosmic Timeline Big Bang t > 0 Stuff Happens Now 14 billion years later H, He Milky Way First galaxies First stars Galaxies collide and grow Solar system and Earth First human s

57 Cosmic Calendar (From The Dragons of Eden 1977 & Cosmos TV Series - Carl Sagan) Jan Big Bang H and He, First stars, First galaxies Apr Feb Milky Way Galaxy May Milky Way Galaxy Mar Jun Jul Aug Sep Solar system, Earth Life on Earth Oct Oldest fossils Nov Dec First cells with nuclei

58 1 December O 2 Mars channels Worms Plankton 19 Fish Insects 22 Amphibians 23 Trees 24 Dinosaurs Mammals 27 Birds 28 Flowers 29 Primates 30 Hominids 31 Humans

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61 December 31 11:59:37 p.m. Agriculture 11:59:45 p.m. The Wheel 11:59:56 p.m. Ptolemy astronomy 11:59:58 p.m. Mayan civilization; Byzantine empire 11:59:59 p.m. Renaissance; experimental method in science; the telescope Now Watch Video. Cosmos: a Space-Time Odyssey with Neil degrasse Tyson, Episode 1

62 About how old is our universe?*

63 About how old is our universe?* 14 billion years*

64 About how old is our Milky Way Galaxy?

65 About how old is our Milky Way Galaxy? 13 billion years

66 About how old is our solar system?*

67 About how old is our solar system?* 5 billion years* (same age as our Sun)*

68 Observations Remaining Sunset Part 2 Due Dec. 6 (10 points) Take 2 nd picture of sunset in same location (about 4pm) Astrophysics Lecture Dec. 18 (10 points) Report option remains Planetarium (Plan) Due Dec. 18 (10 points) Go to a planetarium show Star Gazing (SG) Due Dec. 18 (25 points) Expert/volunteer shows student stars & more OR Student writes a report Telescope (Tel) Due Dec. 18 (25 points) Look through a telescope Moon Craters (MC) Due Dec. 18 (10 points) (Moon has to be visible) Look at moon craters through a telescope or binoculars Binoculars are available to borrow

69 Next Tuesday, 11/27: Lab Test 1 for Tuesday class Thursday, 11/29: Big Bang part 1 & Lab Test 1 for Thurs class Tuesday, 12/4: Life in the Universe & pick up lab notebooks Thursday, 12/6: Test 3 (60 multiple choice questions) Based on last 8 lectures & 5 D2L quizzes 9-13 Some questions from D2L quizzes Bring pencil, no calculator needed Tuesday, 12/11: Review for Final Test & handback Test 3 optional Lab Test 2! Thursday, 12/13: No lecture & optional Lab Test 2 Tuesday, 12/18: Final Test (60 multiple choice questions) Based on all 22 lectures & 13 D2L quizzes (the whole semester) Many questions from D2L quizzes Bring pencil, & calculator if you have one (some in classroom for you) Remember lowest of 4 tests is dropped (Test 1, 2, 3, & Final). If you took 3 previous tests and are happy with your grade, then you don t have to take the Final Test. If you missed a previous test, you must take the Final Test. If you are trying to increase your grade, take the final to hopefully drop a different test. No Astronomy on 12/20.

70 Class Feedback One side: What did you like about astronomy class? Topic Method of teaching/class structure Turn over, Other side: What would you change or improve about astronomy class? Any other thoughts? Name is optional When finished, place in big envelope