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Explore the wonders of the Solar System in this informative course covering Uranus, Neptune, Pluto and more. Study the unique characteristics, moons, and history of these fascinating celestial bodies.
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Astronomy 101The Solar SystemTuesday, ThursdayTom Burbinetomburbine@astro.umass.edu
Course • 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 = 4/3r3
HW • Homeworks #21, #22, #23, and #24
Uranus • Discovered by William Herschel in 1781 • In 1977, the first nine rings of Uranus were discovered
Atmosphere • 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 collision
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 Uranus’ Satellites
Instead of being named after people from classical mythology, Uranus' moons take their names from the writings of William Shakespeare and Alexander Pope.
Neptune • 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 atmosphere
Great Dark Spot • Thought to be a hole Scooter Small dark spot
Triton • Largest moon of Neptune • Has retrograde orbit (orbits the planet in the opposite direction as the planet is rotating) • May be captured Kuiper Belt Object
Pluto • 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 1930
Pluto • Venetia Burney (born 1919) was the first person to suggest the name Pluto for the 9th planet
However • 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 orbits
Density • 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.
Kuiper 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 known
Eris • It has a moon - Dysnomia • Larger than Pluto
Mission • 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 life