Astronomy 101 The Solar System Tuesday, Thursday Tom Burbine [email protected] 7Slide 8AtmosphereUnusualProbablyUranus’ SatellitesSlide 13NeptuneSlide 15GalileoSlide 17Great Dark SpotGreat Dark Spot has disappearedNeptune’s RingsTritonPlutoSlide 23Slide 24Slide 25Slide 26HoweverSlide 28Slide 29DensitySlide 31SatellitesSlide 33Slide 34Slide 35Slide 36Slide 37Slide 38Slide 39Slide 40Slide 41Kuiper BeltSlide 43Slide 44ErisSlide 46New HorizonsSlide 48MissionEarthSETIIntelligent LifeEuropaSlide 54Slide 55Slide 56The only star we know that has Earth-Like Planets is the SunGalactic Habitable ZoneHabitable ZonesHabCatWhat do else do you need?For simple lifeSlide 63Slide 64Drake EquationNumber of habitable planetsFraction of Planets that have life in the GalaxyFraction of the Life-Bearing Planets in the Galaxy upon which a Civilization capable of interstellar communication has at some time arisenSlide 69RadioFraction of all civilizations that have existed in the galaxy that exist nowSlide 72Fermi’s ParadoxSlide 74Reason for questionExplanationSlide 77Slide 78Slide 79Slide 80Fermi’s paradoxAny Questions?Slide 83Astronomy 101The Solar SystemTuesday, ThursdayTom [email protected]•Course Website:–http://blogs.umass.edu/astron101-tburbine/•Textbook:–Pathways to Astronomy (2nd Edition) by Stephen Schneider and Thomas Arny.•You also will need a calculator.Final•May 7th •Friday•4 pm•Totman Gym•Cumulative•Review Session–Hasbrouck 20, 6:15 pm, Wednesday (May 5th)Formulas•p2 = a3•F = GMm/r2•F = ma•T (K) = T (oC) + 273.15•c = f*•E = h*f•KE = 1/2mv2•E = mc2•Density = mass/volume•Volume = 4/3r3HW•Homeworks #21, #22, #23, and #24UranusUranus•Discovered by William Herschel in 1781•In 1977, the first nine rings of Uranus were discoveredAtmosphere•The atmosphere of Uranus is composed of 83% hydrogen, 15% helium, 2% methane and small amounts of acetylene and other hydrocarbons. •Methane in the upper atmosphere absorbs red light, giving Uranus its blue-green color.Unusual•Tipped on its side•Why?Probably•Due to a collisionUranus’ Satellites•Cordelia •Ophelia •Bianca •Cressida •Desdemona •Juliet •Portia •Rosalind •2003U2 •Belinda •1986U10 •Puck•2003U1•Miranda •Ariel •Umbriel •Titania •Oberon •2001U3 •Caliban•Stephano •Trinculo •Sycorax •2003U3 •Prospero•Setebos •2002U2•Instead of being named after people from classical mythology, Uranus' moons take their names from the writings of William Shakespeare and Alexander Pope.NeptuneNeptune•After the discovery of Uranus, it was noticed that its orbit was not as it should be in accordance with Newton's laws.•It was therefore predicted that another more distant planet must be perturbing Uranus' orbit.•Neptune was first observed by Johan Galle and Heinrich d'Arrest on 1846 Sept 23 very near to the locations predicted from theoretical calculations based on the observed positions of Jupiter, Saturn, and Uranus.Galileo•Galileo's astronomical drawings show that he had first observed Neptune on December 27, 1612, and again on January 27, 1613; •On both occasions Galileo had mistaken Neptune for a fixed star•Neptune's blue color is largely the result of absorption of red light by methane in the atmosphereGreat Dark Spot•Thought to be a holeScooterSmall dark spotGreat Dark Spot has disappearedNeptune’s RingsTriton•Largest moon of Neptune•Has retrograde orbit (orbits the planet in the opposite direction as the planet is rotating)•May be captured Kuiper Belt ObjectPluto•Pluto is a Dwarf Planet•Smallest planet•Diameter = 2306 ± 20 km (18% of Earth)•Mass = (1.305±0.007)×1022 kg (0.0021 Earths)•In the late 19th century, astronomers started speculating that Neptune's orbit was being disturbed by another planet.•Pluto was discovered after an extensive search by Clyde Tombaugh at the Lowell Observatory in Arizona in 1930Pluto•Venetia Burney (born 1919) was the first person to suggest the name Pluto for the 9th planetHowever•Pluto is far too small to have the effect on Neptune's orbit that initiated the search. •The discrepancies in Neptune's orbit observed by 19th century astronomers were due instead to an inaccurate estimate of Neptune's mass.•Pluto’s orbit is exceptional among the planets–high inclination (>17 °) and eccentricity (~0.25). –Only Mercury's orbit shows a significant inclination (~7°) and eccentricity (~0.2)•Other planets follow quasi-circular, near–ecliptic orbitsDensity•2.03 g/cm3 •What does this mean?Satellites•Charon–discovered in 1978 by astronomer James Christy•Two smaller, provisionally designated ones–Nix–Hydra•Barycenter (center of mass) lies above the planet's surface.•Charon is large relative to Pluto–Diameter is half of Pluto •Some astronomers label it a double planet system•Pluto's icy surface is 98% nitrogen (N2). •Methane (CH4) and traces of carbon monoxide (CO) are also present. •The solid methane indicates that Pluto is colder than 70 Kelvin.PlutoPlutoKuiper Belt•Pluto is thought to be one of the largest Kuiper Belt Objects (KBOs)•Kuiper Belt is a region of the Solar System beyond the planets extending from the orbit of Neptune (at 30 AU) to approximately 55 AU from the Sun•Over 1,000 Kuiper Belt Objects (1,130) are knownEris•It has a moon - Dysnomia•Larger than PlutoErisNew HorizonsMission•Will characterize the global geology and morphology of Pluto and its moon Charon•Map their surface composition and characterize Pluto's neutral atmosphere and its escape rate•Will also photograph the surfaces of Pluto and Charon.Earth•Is the only planet known to have lifeSETI•Search for Extra-Terrestrial Intelligence•SETI programs tend to survey the sky to detect the existence of transmissions from a civilization on a faraway planetIntelligent Life•You have to be able to build a radio telescope•Of electromagnetic radiation, only radio and gamma can cross the Milky Way Galaxy•It takes far less energy to produce radio waves than gamma raysEuropa•Moon of Jupiter•Has an outer layer of icehttp://en.wikipedia.org/wiki/Image:Europa-moon.jpgEuropa•Is thought to have a liquid ocean beneath an icy surface•Energy source provided by tidal heating (keeps ocean from
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