Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Objectives • Give a brief overview of how scientists think stars and planets formed. • List and describe evidence from our solar system that supports that overview. • List and describe evidence from outside our solar system that supports that overview. • What is a nebula? • What is a protostar? • Name an excellent example of a star birth region. • Why are the Terrestrial planets dense but the Jovian planets are not? • Name and describe the two most common ways to find exoplanets (1. Doppler Shift a.k.a. radial velocity, 2. Transit). How Stars and Planets are Born Birth of Stars Nebular Hypothesis Solar Nebula Theory Nasa-Jpl-CalTech Star/Planet Birth Nebula = large gas and dust cloud Star/Planet Birth • Piece of nebula contracts due to gravity and shock waves • Often other stars forming at same time from other parts of gas cloud Star/Planet Birth That piece of contracting gas cloud • Flattens • Rotates faster Orion Nebula (video clip) - Great example of a Star Birth Region http://www.spitzer.caltech.edu/video-audio/381hiddenuniverse026-Orion-Nebula-GalleryExplorer- Star/Planet Birth • Center: Most matter Protostar Star Protostar = o Large object o From contraction/collapse of part of a large gas cloud o Will become a star Star/Planet Birth • Disk: Smaller objects stick and collide to form larger objects Star/Planet Birth • Disk: Warmer near protostar Light elements blown away Cooler further out Light elements like H stay around Water freezes Big, less dense planets form from H Star/Planet Birth • Happens within cocoon of gas and dust • Often bi-polar jets Star/Planet Birth Star Birth • Protostar turns on: Fusion Protostar Star • Strong stellar winds Star/Planet Birth • Nebula cleared: – Heavy stuff by Collisions and close encounters • Planet Birth – Light stuff by Strong stellar winds Nasa/JPL - Caltech Star/Planet Birth Summary • • • • • • 1. 2. 3. 4. 5. 6. Star/Planet Birth Summary 1. 2. 3. 4. Nebula Contracts, Flattens, Rotates Disk with Protostar Contracts to form Cocoon around Protostar 5. Solar wind blows Cocoon away and left with Star 6. Disk forms Planets Star/Planet Birth Star Birth Simulation http://www.youtube.com/watch?v=YbdwTw B8jtc&playnext=1&list=PLFC84C8CBA3C1 B6D6&feature=results_video Evidence for Star & Planet Birth a. From our solar system b. From outside our solar system Evidence from our Solar System Model • • • • • Today’s Solar System Sun at center (most of mass) Sun and planets – not much else Flat/planar for most part Preferred direction of rotation and revolution Composition (Mostly H, He like stars and gas clouds) Evidence from our Solar System Model • Smaller objects form larger objects Today’s Solar System Evidence from our Solar System Model • Smaller objects form larger objects • Meteoroids and comets • Craters Today’s Solar System • Craters Gaspra http://www2.jpl.nasa.gov/galileo/images/gaspra.gif 12 mi X 7 mi Miranda (moon of Uranus) Craterers • Comets • Meteoroids Comet Tempel 1 Size ~ 1/2 Manhattan (14kmX4km) http://apod.nasa.gov/apod/ap110216.html Size: ~1/3 Manhattan ~8kmX5km Impacted on July 4, 2005 by part of the NASA Deep Impact probe Evidence from our Solar System Model • Asteroid belt • Kuiper Belt • Oort Cloud Today’s Solar System Distant leftovers – Asteroid belt Kuiper Belt Oort Cloud • Credit: NASA/JPL-Caltech/T. Pyle (SSC) Evidence from our Solar System Model • • • • • Today’s Solar System Smaller objects form larger objects Meteoroids and comets Craters Asteroid Belt, Kuiper Belt, Oort Cloud Mini “systems” like Saturn and Jupiter Evidence from our Solar System Model Today’s Solar System • Terrestrial vs. Jovian planets Outer solar system is cooler Big, less dense planets form from H Rotation and Revolution • How does rotation and revolution happen? Everything is in motion. Random motion causes pockets of rotation/revolution. • Why so fast? Angular momentum demo • Collisions, close encounters and solar wind clear nebula • Demo – Crooke’s radiometer • Video explanation • https://www.youtub e.com/watch?v=llx qNcipTwA Evidence from our Solar System Model • • • • • • • Today’s Solar System Smaller objects form larger objects Meteoroids and comets Craters Asteroid Belt, Kuiper Belt, Oort Cloud Mini “systems” like Saturn and Jupiter Terrestrial vs. Jovian planets Rotation and revolution Evidence for Star/Planet Birth a. From our solar system b. From outside our solar system Evidence from beyond our solar system • Gas clouds in Milky Way (H, He) http://apod.nasa.gov/apod/ap990224.html • Pipe Nebula Pipe Nebula – dark area in lower left http://apod.nasa.gov/apod/ap970621.html http://apod.nasa.gov/apod/ap990511.html http://wordlesstech.com/wp-content/uploads/2010/12/orion-over-snowy-ireland3.jpg http://apod.nasa.gov/apod/ap131231.html Orion Nebula – star birth! http://www.telescopes.cc/m42.htm http://antwrp.gsfc.nasa.gov/apod/ap060816.html http://apod.nasa.gov/apod/ap121101.html with Rigel Stars form in groups from the same gas cloud http://antwrp.gsfc.nasa.gov/apod/ap060403.html Stars form in groups from the same gas cloud M33 Strong stellar winds sculpt the nebulae Recall Crooke’s Radiometer Demo Rosette Nebula 50 ly across 4,500 ly away, Monoceros Nebula Trifid Nebula - http://antwrp.gsfc.nasa.gov/apod/ap971208.html Part of Trifid Evidence from beyond our solar system • Gas clouds in Milky Way (H, He) • Stars form in cocoons • With bipolar jets • Stars form in cocoons • With bipolar jets • Stars form in cocoons • With bipolar jets http://hubblesite.org/newscenter/archive/releases/2010/13/image/a/ http://www.spitzer.caltech.edu/images/3513-ssc2011-03b-NorthAmerica-Nebula-Disappears http://www.spitzer.caltech.edu/images/3511-ssc2011-03c-Babies-in-the-North-America-Nebula Evidence from beyond our solar system • Gas clouds in Milky Way (H, He) • Stars form in cocoons • With bipolar jets • Disks of material around stars • Disks of material around stars • Disks of material around stars • Disks of material around stars Evidence from beyond our solar system • Gas clouds in Milky Way (H, He) • Stars form in cocoons • With bipolar jets • Disks of material around stars • Strong stellar winds sculpt birthing gas clouds • Strong stellar winds sculpt birthing gas clouds http://antwrp.gsfc.nasa.gov/apod/ap030630.html Evidence for Star/Planet Birth from Beyond Our Solar System • Gas clouds in Milky Way (H, He) • Stars form in cocoons • With bipolar jets • Disks of material around stars • Strong stellar winds sculpt birthing gas clouds • Exoplanets Exoplanets NASA Exoplanet Archive 11/1/2016 3,402 Confirmed Planets 575 Multi-Planets Systems 4,696 Kepler Candidates Kepler Spacecraft 2009 to look for Earth-like planets in the Milky Way Galaxy http://exoplanetarchive.ipac.caltech.edu/ http://exoplanetarchive.ipac.caltech.edu/ How to Find Planets • Transit (most common) • Doppler Shift (aka Radial Velocity) • Others: http://planetquest.jpl.nasa.gov/page/methods – Direct Imaging, taking pictures – Gravitational microlensing – Astrometry, miniscule movements Finding a planet – Transit • Planets can block a little light from their parent star causing a slight dip in the light http://kepler.nasa.gov/Mission/faq/ Finding a planet – Doppler Shift • Planets tug on their parent stars causing a slight wobble in the star http://planetquest.jpl.nasa.gov/page/methods First visible light picture of an exo-planet (from Hubble)! - 2008 http://antwrp.gsfc.nasa.gov/apod/ap081114.html Exoplanet Missions • • • • • • Kepler – transit method Spitzer – infrared Hubble – visible CoRoT – ESA decommissioned - transit Ground Based Telescopes Future: TESS (2017) and JWST (2018) Earth Exoplanets Outside Our Solar System • Many other planets are being found • HUGE NEWS, SEVEN EARTH-SIZED WORLDS ORBITING A RED DWARF, THREE IN THE HABITABLE ZONE • http://www.universetoday.com/133556/huge-news-seven-earth-sizedworlds-orbiting-red-dwarf-three-habitable-zone/ TRAPPIST-1 planetary system, about 40 LY away with a cooler, red dwarf star (12x less massive than our sun) Sunset Part 2 • • • • 10 Observation Points Started Tuesday, Mar. 28 Due: Apr. 25 Read details on class website about what to turn in for full credit. Homework & Updates • Watch this BBC clip about exoplanets: http://www.bbc.co.uk/programmes/p009gxf2 • Observations: Star Gazing, Telescopes & Moon Craters (60 pt.) • March 30, tonight, Eisenhower Community Center, Hopkins, MN • Need reservation and ask a worker to show you some constellations in the sky • April 1, Saturday, Baylor Park, Eagle Lake Observatory, Norwood-Young America, MN • Raquel will be there about 8-9pm. Find her with the lit-up clipboard. If you miss me, have a volunteer at a telescope sign your paper. • April 4 & 6, Tuesday & Thursday, Jackson Middle School, Champlin, MN • April 7, Friday, Bell Museum, University of MN, Minneapolis, MN • Times and directions on class website • Observation Option: Univ. of MN Public Lectures – Only Do 1! • Tues, Apr 4, 7pm, Bell Museum, Exploring the Mysteries of the Sun: Explosions on our Closest Star (find Raquel for 10 points) • Thur, Apr 20, 7pm, Ted Mann Concert Hall, A Deeper Understanding of the Universe from 1.2 miles Underground (find Raquel for 10 points) Test 2 Results • Test questions posted at front and on office doorway • Check for Scantron mistakes Test 2 Grades Number of Students • Multiple Choice curved by 2 points • Average: 78% 30 17 14 9 A B C Letter Grade D