⚫ What is the major difference between a planet and a dwarf planet? Study Points ⚫ Name a dwarf planet. ⚫ Where are the dwarf planets in our solar system? ⚫ Distinguish between a meteor, a meteorite, and a meteoroid. ⚫ What is a "shooting star"? Why do we see it? On average, how big is one? ⚫ Why do we study meteorites? ⚫ What is a comet? ⚫ Describe a comet including the nucleus, head and tail. Why do we see a comet? ⚫ Roughly, how big are comets? ⚫ What is the Asteroid Belt? the Oort Cloud? the Kuiper Belt? Where is each located? ⚫ Why study comets? ⚫ What is a meteor shower? What is the comet connection to a meteor shower? What’s in our solar system? Sun Planets Terrestrial Jovian Dwarf Small Solar System Bodies Meteoroids Comets Dust Sun (future lecture after Test 2 all about the Sun) a. Most of mass (>99%) of solar system b. Star – produces own energy by fusion c. Hot http://sohowww.nascom.nasa.gov/gallery/images/large/eit001_prev.jpg What’s in our solar system? Sun Planets Terrestrial Jovian http://www.techastronomy.com/UserFiles/2007/7/22/solar_system4(1).jpg From**KNOW Last THIS**Lecture: Terrestrial* Jovian* “Earth-like” “Jupiter-like” • Small, less massive • Large, massive • Close to Sun (warm) • Far from Sun (cold) • Rings • Big storms, turbulent atmosphere, belt rotation • Heavy elements • Hydrogen rich (light elements) • High density • Low density • Solid Surfaces • Gas and Liquid • Cratered • Few moons • Many moons • Thin atmospheres • Thick atmospheres • Weak magnetic fields • Large magnetic fields (some tilted) • Slow rotation • Fast rotation • Fast revolution (Kepler) • Slower revolution Terrestrial Jovian Writing Assignment – Part of Test 2: • Planet Highlights – 1 Terrestrial & 1 Jovian • See class website calendar for details • 20 points on next test • 5 Highlights for each planet • Print and bring to Test 2 What’s in our solar system? Sun Planets Terrestrial Jovian Dwarf What objects are planets and dwarf planets?* Question Planet Dwarf Planet Orbits Sun? X X Round? X X Not a moon? X X Cleared orbit? X Not cleared orbit? X International Astronomical Union 2006 http://www.iau.org/news/pressreleases/detail/iau0603/ Dwarf Planets* ⚫ Ceres (Asteroid Belt) ⚫ Pluto ⚫ Eris Plutoids ⚫ Makemake ⚫ Haumea Haumea ⚫ Telescopes discovered: DWARF PLANET HAUMEA HAS A RING (10/11/2017) ⚫ https://www.universetoday.com/137444/dwarf-planet-haumea-ring/ Pluto Location Pluto Orbit https://spaceplace.nasa.gov/ice-dwarf/en/ Pluto- Hard to classify Pluto and its largest moon, Charon (top left) https://www.nasa.gov/feature/pluto-s-big-moon-charon-reveals-a-colorful-and-violent-history Pluto Moons Keberus Styx http://apod.nasa.gov/apod/ap120716.html Watch Motion Video of Pluto’s 5 Moons https://spaceplace.nasa.gov/ice-dwarf/en/ https://www.nasa.gov/audience/forstudents/k-4/stories/nasa-knows/what-is-pluto-k4.html Pluto: Planet or ? • Round • Moons • Orbit tilted to plane of solar system • Orbit more elliptical than other planets • Sometimes Pluto is closer to sun than Neptune • Denser than Jovians, less dense than Terrestrials • One of many objects orbiting sun beyond Neptune • It is a Dwarf Planet What are the names of the 2 areas in our solar system with asteroids or meteoroids?* ⚫ 1. ⚫ 2. ⚫ And where is each located?* ⚫ 3. location of 1. = ⚫ 4. location of 2. = Other Problem Objects Large meteoroids (asteroids) Asteroid Belt between Mars and Jupiter Ceres (largest object in asteroid belt) Orbits sun Round Part of neighborhood of other objects =Dwarf Planet ~600 mi → Pictures and video from DAWN http://solarsystem.nasa.gov/planets/ceres Planet Terrestrial (small, dense…) Jovian (large, gaseous…) Dwarf Current definition of Dwarf Planet* a. *Orbits a star b. *Round by own gravity c. *Has not cleared its neighborhood Dwarf Planets 1. Pluto 2. Eris 3. Haumea 4. Makemake 5. Ceres Dwarf Planets Dwarf Planet Candidates Dwarf Planet Locations* Asteroid Belt Kuiper Belt What’s in our solar system? Sun Planets Terrestrial Jovian Dwarf Small Solar System Bodies Meteoroids Comets Dust http://www.techastronomy.com/UserFiles/2007/7/22/solar_system4(1).jpg Small Solar System Bodies Meteoroids ▪ Definition: rocky matter in space* ▪ Small, rocky, oblong ▪ Mostly between Mars and Jupiter (Asteroid Belt) ▪ Asteroid – larger meteoroid Comets ▪ Definition: Icy object orbiting Sun* ▪ Some from beyond Neptune = Kuiper Belt Objects (40 AU) ▪ Some from farther out (1/4 way to next star) = Oort Cloud (1LY=63000AU) http://herschel.jpl.nasa.gov/solarSystem.shtml Kuiper Belt – Asteroid Belt – Many icy, rock Cluster of objects beyond meteoroids Neptune between Mars and Jupiter Oort Cloud – Icy matter, including many comets way out here http://upload.wikimedia.org/wikipedia/commons/thumb/d/dc/Eris_ Orbit.svg/644px-Eris_Orbit.svg.png Planet 9? • Part of Kuiper Belt and influences other orbits • Video here with more info if interested: • http://www.universetoday.com/133555/pl anet-9-cant-run-forever-two-asteroids- give-clues/ http://www.universetoday.com/wp- content/uploads/2016/03/Planet_Nine _animation.gif The Goblin – Potential Dwarf Planet http://earthsky.org/space/new-dwarf-planet-the-goblin-planet-x Meteoroids/Asteroids ⚫ *Orbit the sun ⚫ *Mostly between Mars and Jupiter (Some Gaspra throughout the solar system) ⚫ *Rocky, sometimes icy ⚫ Most are oblong ⚫ *Larger ones often called asteroids Meteoroids Small (grain/rice size) is most common* Largest is up to Minnesota size ⚫ Dwarf Planet (Largest in asteroid belt), Ceres, at ~600 mi. is a dwarf planet ⚫ 2nd largest asteroid, Vesta, at ~300 mi. but not as round or massive, so it remains an asteroid Vesta 2nd Largest Object in Asteroid Belt Planet or Dwarf planet or Asteroid? Vesta http://apod.nasa.gov/apod/ap120919.html Lutetia from Rosetta/ESA ~120 km diameter (~70 mi) http://www.esa.int/esa-mmg/mmg.pl?b=b&type=I&mission=Rosetta&single=y&start=4 Mathilde Gaspra Ida ~12mi X 7 mi Gaspra (asterioid) Phobos (Mars’ moon) Deimos (Mars’ moon) Ida and Dactyl 36mi X 14 mi http://antwrp.gsfc.nasa.gov/apod/ap990807.html Eros 21 mi NEAR Shoemaker Asteroid Itokawa Japan’s Hayabusa 2005-10 http://www.isas.jaxa.jp/e/snews/2005/1102.shtml Japan’s Hayabusa2 - 2018 ⚫ Watch https://www.nbcnews.com/mach/science/watch-japan-s- hayabusa-2-spacecraft-touch-down-asteroid-ncna979756 Landed on asteroid Feb. 2019 ⚫ 2 Bouncing rovers ⚫ Sample return mission to Earth in 2020 ⚫ Picture: ⚫ Itokawa and Ryugu What are NASA’s asteroid plans? ⚫ NASA asteroid mission ⚫ NASA asteroid spacecraft Asteroids Visited by Spacecraft NASA OSIRIS – Rex Asteroid Sample Return Mission NASA & ESA DART Mission to redirect an asteroid Meteoroid* Meteor* Meteorite* Rocky (icy) Matter glowing Meteor on matter orbiting in Earth’s Earth the Sun atmosphere Asteroid – Larger Meteoroid* Meteor (Shooting star, falling star)* ⚫ Small (grain to pea size)* ⚫ Fast (~50 mi/s) ⚫ Nearby (40 to 80 miles) ⚫ Collide with Earth’s atmosphere, glow ⚫ Most do not reach ground in tact ⚫ Add thousands of tons to Earth each year Fireball ⚫ Larger (marble size+) ⚫ Basketball size+ can reach ground Chelyabinsk Meteor ⚫ Feb. 15, 2013, speed of about 40 mi/s or 19 km/s ⚫ 1500 people injured, 13,000 tons, 20 m diameter ⚫ https://www.youtube.com/watch?v=dpmXyJrs7iU Why study meteorites? ⚫ Composition and origin of Moon, Mars, and asteroids* Why study meteorites? ⚫ Estimate origin and age of our solar system* ⚫ 4.6 billion yrs* Why study meteorites? ⚫ Origin of life* Murchison meteorite (1969) Why study meteorites? ⚫ Possible catastrophes for us* Why study meteorites? Summary*: ⚫ Composition of Moon, Mars, & asteroids ⚫ Estimate origin and age of solar system ⚫ Origin of life ⚫ Possible catastrophes for us Barringer Crater in Winslow, AZ Meteor Crater in Winslow, AZ ⚫ Barringer Crater ⚫ Crater: 4/5 mile across, ~500 feet deep ⚫ Occurred ~50,000 years ago ⚫ Energy ~ 20 Megatons of TNT ⚫ Original meteor ~ house size (45m), 300,000 tons ⚫ Speed 40,000 mi/h Types of Meteorites Iron-Nickel Stony-Iron Stony Samples Comets* (cosmic snowball) * frozen gas, rock and dust *icy, fuzzy appearance, tails Bayeux Tapestry Comets Hang in sky for days/weeks* Comet McNaught http://antwrp.gsfc.nasa.gov/apod/ap070212.html Credit & Copyright: Minoru Yoneto Comet – orbit • Most have very elliptical orbits* • Some in plane of solar system but some not* Comet – why do we see them?* 1. Nears Sun & melts* 2. Debris reflects sunlight* 3. Sunlight blows debris away creating tail* Interactive comet orbit at http://www.windows.ucar.edu/tour/link=/comets/comet_model_interactive.html Comet Parts* Nucleus = Dense center Tail = gas/ice/dust blown back by sun Head = Nucleus + surrounding gas/ice/dust (Head and tail look dense but are not) Comet Nucleus– Original Description Frozen, dirty iceberg Comet Borrelly http://photojournal.jpl.nasa.gov/target/Other?subselect=Target:Borrelly Comet Nucleus– Additional Description ⚫ Many are frozen, dirty icebergs* ⚫ Others are loose collections of ice, gas, dust (Shoemaker- Levy 9 - 1993)* APOD – Wild 2 Comet Tempel 1 Size: ~1/3 Manhattan ~8kmX5km Average Comet Size (nucleus): few miles AverageSize ~ Comet1/2 Manhattan Tail: (14kmX4km)millions of miles Comet Parts Tail: Ions, gas, dust blown away by sun Two tails*: ⚫ Gas tail – Ions and gas, blown straight back from Sun (white) ⚫ Dust tail – Lags behind so looks curved (blue) Dust tail (blue) Gas tail (white) Period of Comet Long Period comets* Short Period comets* In plane of solar system Out of plane Halley (76 yr), Hale-Bopp (~4000 yr) Tempel-Tuttle (33 yr) http://www.eso.org/outreach/info-events/hale- bopp/comet-hale-bopp-summary-apr07-97-rw.html