WEEK 3 LECTURE NOTES
WEEK 3 LECTURE NOTES ASTR 121
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This 4 page Class Notes was uploaded by Anisa sudra on Friday April 17, 2015. The Class Notes belongs to ASTR 121 at University of Oregon taught by Scott Fisher in Spring 2015. Since its upload, it has received 155 views. For similar materials see ASTR 121 The Solar System in Astronomy at University of Oregon.
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Date Created: 04/17/15
MONDAY 41315 Photo of the day Comet with the Pleiades m45 a relatively small and icy object that orbits a star The ice allows the comet to form the tail of the comet A comet s nucleus is about the size of a mountain 0 The tail is MUCH larger than that most are millions of miles long 0 The tail forms as ice and gas boils away as the comet nears the sun 0 Stuff in the comet tail dust water coZ methane ethane etc also all stuff that the comet is made off of 0 These materials come off of the nucleus and form the tail it is made primarily of ice water and coZ dry ice comets are thought to be the main source of the water on Earth In earth s early formation cometary impacts brought the water 0 Raises the where did all the water on the planet come from Rosetta mission a spacecraft in orbit around a comet RIGHT NOW 0 Spacecraft will follow the comet around the sun 0 It released a lander named Philae that landed on the comet 0 Then it bounced and landed on the side of a cliff but it worked 0 on earth Philae weighed about 5kg but on the comet it weighed the amount of a paperclip a star and all the material that orbits it including its planets and moons The name of the sun is also sol gt ours is the solar system The Pluto situation Kuiper belt object an object with an orbit that extends beyond Neptune and into the Kuiper belt 0 There is not jus tone Pluto there are thousands o Pluto is kinda big and kinda near this is why it was discovered in 1930 o Pluto wasn t Demoted but PROmoted is id the first of a new class of object o Pluto was discovered when telescopes weren t as advanced as they are today the telescopes we have today allow us to see many other objects similar to Pluto o Pluto will be revisited soon by the new horizonsquot mission It will get to Pluto in 3 months from now But plutos gravity is not strong enough to hold down the mission so it will just fly by o LARGEST KNOWN KUIPER BELT OBJECTS Xena pluto 2005 fy9 2003 el61 sedan quaoar a great island of stars in space all held together by gravity and orbiting a common center 0 They are the largest single objects in all the universe 0 A galaxy like the milky way contains around 100 billion stars and probably at least that many planets 0 We cannot take a photo of the milky way bc we cannot get a camera that will capture the whole frame of stars 0 Andromeda galaxy m31 0 Types of galaxies 0 Spiral Younger galaxies o Elliptical As galaxies evolve and age they start out as spirals but then progress into elliptical galaxies the sum total of all matter and energy that is everything within and between all galaxies 0 Watch the known universe by amnh WEDNESDAY 41515 Photo of the day new horizon s first color pic of Pluto Andromeda is an analog of the milky way when will we be able to see what the Andromeda galaxy looks like now roughly 25 million years in the future back it will take the light that long to get from Andromeda to earth THE ULTIMATE SPEED LIMIT C 0 Light travels at a finite speed NOTHING can travel faster than this 0 186000 milessec N 7 times around the earth in 1 second 0 because of the fact that is takes light time to move we see objects as they were in the past The farther away we look in the distance the further back we look in time Hundred thousand light years across o All galaxies outside our local group are moving away from us 0 The more distant the galaxy the faster its racing away 0 Conclusion we live in an expanding universe 0 Galaxies that are farter away are moving away from us farther Liner relationship on hubble s law plot a galaxy 2 times farther away is moving away 2 times as fast 0 insert photo of plot o All galaxies outside the local group in all directions are moving away from us 0 Beginning of thought experiment Yesterdaythey were closer than todaylast year they were closer than this yearetc running the clock backwardsquot universe getting smaller and smaller In Which means implications bc the universe had a beginning In Which means we have measured the universethe universe is 1384 billion years old 0 We did this by measuring how fast the galaxy is moving 0 And by a spacecraft mapping the entire sky with temperature I THE BIG BANG what the beginning event is caHed n Observable universe what we can seewe can only see 1384 billion light years away FRIDAY 41715 0 The big bang 0 Only hydrogen and helium and a little bit of lithium were created in this event 0 80 of you is carbon nitrogen oxygen 0 we are made of starstuff sagan how did we come to be 0 Galactic recycling Stars like the sun give out energy this energy warms us is a byproduct of fusion 0 Stars slowly convert to H and He into heavier elements 0 Elements are distributed throughout the galaxy by supernovae stellar winds 0 Clouds of gas and dust the ISM form into a new generation of stars Meaning for life We are the universe contemplating itself 0 You are not in the universe the universe is in you