1 / 48

480 likes | 647 Vues

Prof . Geoff Marcy. Jupiter and Europa. Saturn and Enceladus. Textbook and Homework : The Cosmic Perspective Special Issue Bennett et al. (2014) Buy book at bookstore with its attached “ MasteringAstronomy kit” 2. Homework is online: MasteringAstronomy :

Télécharger la présentation
## Prof . Geoff Marcy

**An Image/Link below is provided (as is) to download presentation**
Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.
Content is provided to you AS IS for your information and personal use only.
Download presentation by click this link.
While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

**Prof. Geoff Marcy**Jupiter and Europa Saturn and Enceladus**Textbook and Homework:**The Cosmic Perspective Special Issue Bennett et al. (2014) Buy book at bookstore with its attached “MasteringAstronomy kit” 2. Homework is online: MasteringAstronomy: www.pearsonmastering.com Register: Course ID: marcy49057**Reading this week:Chapters 1 and 2**“Our place in the Universe “ & “Discovering the Sky” Homework: Due every Friday at 6pm This week: Chapter 1 and Chapter 2 Assignments in MasteringAstronomy: Due Friday, Sept 6 at 6pm. -3% for each wrong try (but you can try again). +2% for not using a hint.**Instructor:Professor Geoff Marcy**Office Hours: Wed 1pm & Fri 11am Hearst Field Annex: Bldg B, Room 103 gmarcy@berkeley.edu Five GSIs: Sky Lovill– skylovill@berkeley.edu Beth McBride –bethmcbride@berkeley.edu Kyle Fricke – kwf@berkeley.edu Bill Mitchell – bill.mitchell@berkeley.edu Danny Goldstein – dgold@berkeley.edu 12 Discussion Sections 1 hr each (All start next week.) Review, Clarification, Homework Help. Observing Projects**Discussion Sections**• 1 hour: All startthis week. • Review, Clarification, Homework Help. • Go to any one: • 101 Wed 9-10A, 264 Evans Hall:Beth McBride • 102 Wed 1-2P, 264 Evans Hall: Danny Goldstein • 103 Wed 2-3P, 264 Evans Hall:Kyle Fricke • 104 Wed 3-4P, 122 Barrows Hall:Bill Mitchell • 105 Th 2-3P, 264 Evans Hall: Beth McBride • 106 Tu 2-3P, 264 Evans Hall: Beth McBride • 107 Th 11-12P, 264 Evans Hall:Bill Mitchell • 108 Tu 11-12P, 264 Evans Hall:Bill Mitchell • 109 Tu 12-1P, 264 Evans Hall: Sky Lovill • 110 Th 12-1P, 264 Evans Hall: Sky Lovill • 111 W 11-12P, 264 Evans Hall: Kyle Fricke • 112 Wed 12-1P, 264 Evans Hall: Danny Goldstein**Course material on bSpace:http://bspace.berkeley.edu**• Syllabus • Lecture slides • Assignments: reading, homework, observing projects • Course information**Last Time ::**The Solar System**The Solar System**Inner Solar System Outer Solar System**The Solar System:Sun and 8 Planets Moons, Rings,**Asteroids, Comets, and Dust**Milky Way Galaxy**200 Billion Stars Photo taken from Earth You Are Here**Our Milky Way Galaxy**Our Sun moves relative to the other stars in the local Solar neighborhood. Our Sun and the stars orbit around the center of the Milky Way Galaxy every 230 million years.**The ``Local Group”**of Galaxies 100,000 Light Years The Galactic Neighborhood**And outward…**10 Million Light Years**The Universe:**All matter and energy > 100 Billion Galaxies**B**Astronomical Numbers Best to use Exponential Notation 103 = 1000 Thousand 106 = 1,000,000 Million 109 = 1,000,000,000 Billion 1012 = 1,000,000,000,000 Trillion Also: 10–3 = 1/1000 = 0.001 Exponential notation is handy: 10N x 10M = 10(N+M) Example: 103x106 = 109 thousand million billion**Interactive Quiz**B How many stars in our visible Universe? 1012 (1 million million) 1018 (1 billion billion) 1022 infinite**Interactive Quiz**B How many stars in our visible Universe? 1012 (1 million million) 1018 (1 billion billion) 1022 infinite Number of Stars in a galaxy: ~100 billion = 1011 Number of galaxies in Universe: 100 billion = 1011**B**U.S. Debt vs. Time There are 1011 stars in the galaxy. That used to be a huge number. But it's only a hundred billion. It's less than the national debt. We used to call them astronomical numbers. We should call them economical numbers. Richard Feynman**In 2013, the National Debt is**$17 Trillion = $17 x 1012 U.S. Population = 315 x106 people Your Personal Debt: $17 x 1012 / 3.15 x 108= $5.4 x104 = 17/3.15 x 1012-8 = $54,000 per person**Distance, time and number :**Radius of our Galaxy: 6,000,000,000,000,000,000 m = Radius of a Hydrogen atom: 0.00000000005 m= Time for one vibration of an oxygen molecule, O2: 0.00000000000001s = Age of the Universe: 430,000,000,000,000,000s = Scientific notation: 6 x 1018 m 0.5 x 10–10 m 1 x 10–14 s 4.3 x 1017s = 13.6 billion years**SI (Systeme International) Units**Base units: 1 meter (m) length ~ 3.3 ft 1 kilogram (kg) mass ~ 2.2 lb 1 second (s) time**SI (Systeme International) Units**• Base units: 1 meter (m) length • 1 kilogram (kg) mass • 1 second (s) time • MKS System of units and measure Sometimes easier to derive other units from these: km, g, ms, µs, … km = 103 m kilo g = 10-3 kg kilo ms = 10-3 s milli µs = 10-6 s micro**$Billion error**UNITS ARE IMPORTANT!!! Mars Climate Orbiter: Launch: 11 Dec. 1998 Orbit insertion: 23 Sep. 1999 Followed by: Loss of Communication WHY? Failed to convert from English units (inches, feet, pounds) to Metric units (MKS)**B**Speed of Light and Light-travel time: C = 3 x 108m/sec = 3 x 105 km/sec = 300,000 km/sec = 0.3 m/ns (1 ns = 10-9s) Light Year = 9 trillion km = 6 trillion miles Light Hour Light Minutes are unit of Distance: How far Light Travels in that interval of time 1 light second = 3 x 105 km 1 light ns = 30 cm ≈ 1 foot**How long does it take the sun’s light to reach the Earth?**Distanced = 1 AU = 1.5x1011m Speed of lightc= 3x108m/s Time**B**Driving Curiosity Rover on Mars • How long does it take to communicate withCuriosity ?**Interactive Quiz**B How long does it take for radio waves (light) to reach Mars? • Less than 1 second • 1 minute • 10 minutes • 1 hour**Interactive Quiz**How long does it take for radio waves (light) to reach Mars? • Less than 1 second • 1 minute • 10 minutes • 1 hour Earth-Mars distance: between 55 and 400 million km. tmin = dmin/v = 5.5×107 km / (3×105 km/s ) =1.8×102s= 3 minutes tmax = dmax/v = 4.0×108 km / (3×105 km/s ) =1.3×103s= 22 minutes**A Scaled Model of the Solar System**10 Billion x Smaller Sun’s diameter: 14 x 1010 cm Reduce by 1010: 14 cm Earth diameter: 13000 km 0.13 cm Jupiter’s diameter: 150,000 km 1.5 cm Earth’s distance from Sun: 1 “Astronomical Unit” = 1 “AU” = 1.5 x 108 km 1010 Scaled Down “Sun” 14cm 1 AU ?? cm 1.5 cm 15 cm 150 cm 1500 cm Ans: 1500 cm = 15 meters**G**How large is the Solar System? • Let’s view it to scale • Say the Sun is the size of a large grapefruit, 14 cm (6 inches) - then:**Planet Dist (AU) Scaled Dist (m) Where?**Mercury 0.4 6 6 rows back Venus 0.7 10 10 rows Earth 1.0 15 15 rows Mars 1.5 22 22 rows Jupiter 5 75 3/4 football field away Saturn 10 150 1.5 football field away Uranus 20 300 Sproul Plaza Neptune 30 450 Bancroft Ave Pluto 50 750 Durant Ave Oort Cloud 50,000 5 x 105 Oakland**G**You Are Here: Earth’s Orbit Saturn o Jupiter o Uranus o . . 100 m Neptune o**G**How Far is the Nearest Star? Alpha Centauri d = 4 light years = 4 x1016 m Scales to: 4 x 106 m (~ 3000 mi) Grapefruit-sized Sun in Berkeley Nearest Grapefruit: In Washington D.C. “Sun” in S.F. “Alpha Centauri” In Washington D.C.**G**Powers of Ten“Cosmic Voyage”The Movie**G**How to deal with very large & small numbers • Develop a useful arithmetic • Exponential notation; convert between units • Visualize using a sequence of images (movie) • Use different sequences • Visualize by way of a scale model • Try different models**G**A Universe in motion • Contrary to our perception, we are not “sitting still.” • We are moving with the Earth. • and not just in one direction The Earth rotates around it’s axis once every day.**G**The Earth orbits around the Sun once every year. The Earth’s axis is tilted by 23.5º !**B**Looking back in time • Light, although fast, travels at a finite speed. • It takes: • 8 minutes to reach us from the Sun • 8 years to reach us from Sirius (8 light-years away) • 1,500 years to reach us from the Orion Nebula • The farther out we look into the Universe, the farther back in time we see!**B**The Origin of the Universe (1) The two simplest atoms, H and He, were created during the Big Bang. • (2) More complex atoms were created in stars. • (3) When the star dies, chemical elements are expelled into space, to form new stars and planets! Most of the atoms in our bodies were created in the core of a star.**Galaxies appear to be moving away from us.**• The farther away they are, the faster they are moving. • Space itself is expanding pace itself expands.**B**How old is the Universe? • The Cosmic Calendar • if the entire age of the Universe were one calendar year • one month would be approximately 1 billion real years**B**The Universe in a Day Look at the entire history of the Universe as though it took place in a single day. The present is at the stroke of midnight at the end of that day. Since it is about 13.5 billion years old, each hour will be ~0.5 billion years. A million years takes only a little over 7 seconds. The Big Bang (a dense, hot explosion) and the formation of H and He all take place in the first nanosecond. The Universe becomes transparent in about 2 seconds. The first stars and galaxies appear after about 2am. Our Galaxy forms at 4am. Generations of stars are born and die.**B**The Universe in a Day The Solar System does not form until 3pm. The first life (bacterial) appears on the Earth by 4pm. Our atmosphere begins to have free oxygen at 7 or 8 pm, and this promotes the development of creatures which can move more aggressively and eat each other. Life does not begin to take on complex forms (multicellular) until 10:45pm. It moves onto land at 11:10. The dinosaurs appear at about 11:40, and become extinct at 11:52. Pre-human primates appear at around 14 seconds before midnight, and all of recorded history occurs in the last 70 milliseconds. Looking to the future, we can expect the Universe of stars to go on for at least another millennium (using the same time compression factor). After that, there are other ages of the Universe (not dominated by stars), which grow colder and more bizarre, and take place on astronomical timescales…**What is the Earth’s velocity about the Sun?**B Radius of Orbit (1 AU): 150 x 106 km Circumference: 2 π x radius Distance around the Sun that the Earth travels: 2 π x (1.5 x 108 km) = 9 x 1011 m Earth orbits the Sun once a year: 1 yr = 3 x 107 s Velocity = Distance/Time = 9 x 1011 m / 3 x 107 s = 3 x 104 m/s = 30 km/s 110,000 km/hr or 75,000 miles/hr!

More Related