By Andrew Hartsel and Evelyne Ridinger
Time Line of Uranus 1781- Discovered 1783- Orbit Predicted 1784- Prediction fails- discover Neptune 1787- First two moons discovered- Titania and Oberon 1821- Bouvard to solve Uranus orbit- fails. 1977- Rings discovered.
Discovering Uranus Discovered March 13, 1781- First planet discovered in modern time. Discovered by William Hershel while systematically searching the sky with a telescope in Britain. It had been seen many times before, but everyone else thought it was just a star. Originally named The Georgium Sidus (The Georgian Planet) in honor of King George III- his patron. Name Uranus was first proposed by Bode so it would go with the classical mythology theme of other planets. Name did not become official until 1850.
Physical Properties and Features Gas Giant 15% hydrogen. Little Helium. Composed mainly of rock and various ices. No solid surface.
Atmosphere and Weather Composed mainly of Hydrogen and Helium- Like that of Neptune. 83% hydrogen, 15% Helium, 2% Methane. Inner regions consists of oceans of ammonia, water, and methane. Bands of clouds that blow around rapidly. Appears blue because it absorbs red light by methane in upper atmosphere.
Uranus Has Rings! Composed of different sized particles ranging from 10m diameter to dust. 11 different rings total. Distances of rings range from 38,000 to 51,140 km. Widths range from 1 km to 100 km. Very faint and dark. First rings to be discovered after Saturn's. Rings are perpendicular to orbit.
Woot! Moons! Has 20 moons. Most moons named after Shakespeare and Alexander Pope characters. 3 classes of moon: 11 small very dark inner ones discovered by voyager 2. 5 large ones- newly discovered, distant. Orbits nearly circular around Uranus s equator. Outer 4 are more ecliptic.
More Moons! Oberon and Titania 1 st to be discovered, by Herschel. Ariel and Umbriel 2 nd to be discovered, by William Tassel (first man to see moon orbiting Neptune). Voyager 2 found 10 of the moons. Appear to be roughly ½ ice ½ rock.
Major Moons. Miranda- inner most and smallest of the 5 major satellites. Has fault canyons 12x deeper than the Grand Canyon s. Different age-looking layers. Ariel is the brightest- believed to be the youngest of the few large moons. Few small craters. Interesting valleys. Unbriel- oldest and darkest of 5 large moons. Lots of craters. Bright ring on one side. With so many of the satellites as close as they are, astronomers don t understand how they have not colided. Many believe there s still more moons to be discovered around the inner rings.
All of the Moons Cordelia, Aphelia, Bianca, Cressida, Desdemand, Juliet, Portia, Rosaline, Belinda, Puck. All discovered by the Voyager 2 in 1986. Miranda by G. Kuiper in 1948. Ariel and Umbriel by W. Tassell in 1851. Titania and Okeren by W. Herschel in 1787. Caliban and Stephano by Gladman in 1997 and 1999. Sycorax by Nichcolson in 1997 Prospero by Holman in 1999. Setebos by Kevelarse in 1999.
Planetary Data- Orbit Axis almost parallel to the ecliptic- most perpendicular South Pole points directly at the sun (time of voyager 2 visit). Even though the planet receives more energy at it s polar regions, it s still hotter at the equator. Cause unknown. Orbit- 2 870 990 000 (19.218 AU) from sun. Orbital Inclination- 0.772* Eccentricity- 0.0457 Axis tilt- 82*
Planetary Data- Facts Aphelion- 3 e 9. Perihelion- 2.74 e 9. Minimum distance from Earth- 2.57 e 9. Rotation period (day)- 0.7179 earth days (17.23 hours). Orbital period (year)- 84.01 earth years (30 685.7 days) 43, 000 days in its year. Mass- 8.6832 e 25 Radius- 25 744 Density- 1 270 kg/m 3
Planetary Data Con t Seasons last for over 20 years on Earth. Temperature doesn t differ much from summer to winter because its so far from the sun. Average Temperature- -216*C / -375*F Even though Uranus mass is 14 times that of Earth, since it s a big ball of gas, it has a weaker gravitational pull, about 91% of that of Earth s. Gravity- 8.69 m/s
Life?!? Life as we know it could not exist on Uranus for multiple reasons. It s too cold for life. There is no food supply. There s no real atmosphere. No oxygen. But who s to say there isn t a type of life that could withstand those conditions?