* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Discovery Uranus visible with naked eye(faint) discovered in 1781
Survey
Document related concepts
Heliosphere wikipedia , lookup
History of Solar System formation and evolution hypotheses wikipedia , lookup
Late Heavy Bombardment wikipedia , lookup
New Horizons wikipedia , lookup
Jumping-Jupiter scenario wikipedia , lookup
Planet Nine wikipedia , lookup
Naming of moons wikipedia , lookup
Formation and evolution of the Solar System wikipedia , lookup
Planets in astrology wikipedia , lookup
Dwarf planet wikipedia , lookup
Eris (dwarf planet) wikipedia , lookup
Definition of planet wikipedia , lookup
Kuiper belt wikipedia , lookup
Transcript
Chapter 13: The Outer Solar System Uranus Visuals uranus3.jpg Neptune Visuals neptune.jpg Neptune_Full.jpg vital statistics Orbital distance (AU) Orbital period (Yrs) Rotation period Axial tilt Known Satellites Mass (xMEarth) Radius (xREarth) Density Surface Gravity Global Temp Escape Velocity (km/s) (earth’s 11.2 km/s) Uranus 19.2 84.0 17.2 hrs 98º 15 14.5 Neptune 30.1 164.8 16.1 hrs 30º 8 17.1 4.0 3.9 1.3 .91 g 60 K 21 1.6 1.19 g 60 K 23 1 [See also tables 13.1, 2] Discovery Uranus visible with naked eye(faint) discovered in 1781 by William Hershel during a study of visible stars. (“accidental”) Neptune existence deduced from perturbations in Uranus’s orbit calculation (+ luck/assumptions) → predicted positions by Couch and Leverrier ~1846 → observed location by Galle ~1846 2 Uranus [figure 13.2,4] and Neptune [figure 13.6-8] Gas giants with ring systems Neptune: small axial tilt Uranus: severe axial tilt (~ 98º) [figure 13.1,13_2.mov] Atmospheres [figure 13.5] methane gives blue coloring Uranus: featureless Hydrogen and Helium: Solar Mix no atmospheric convection Neptune clouds and storms Great Dark Spot belts and zones from convection 3 Uranus and Neptune (cont’d) Interiors: [Figure 13.9] Rocky cores Water, molten rock Gas exterior (mostly hydrogen, helium) Internal Energy Uranus: essentially no excess heat radiated “insulated” by suppressed convection? Neptune: ~60% radiated energy (“self-luminous”) from internal heat Magnetospheres [Figure 13.10] no large metallic hydrogen core fields not aligned with axis of rotation center of fields not at center of planet probably generated in icy fluid region outside of rocky core 4 Uranus and Neptune (cont’d) Rings: Uranus [figure 13.12, 14 ] discovered during stellar occultation [figure 13.11] narrow rings of large particles (w/ shepherd moons) [fig 13.15] + dust in regions between rings Neptune [figure 13.16-18 ] 2 thin rings + broad inner ring, all made of microscopic particles 5 Trans-Neptunian Objects (TNO's) Pluto (and Charon) [figure 13.23, Plutoids.jpg] Pluto's discovery: additional perturbations of Uranus’s orbit → prediction by Lowell ~ 1905 Pluto found much smaller than predicted, via photographs ~ 1930 [discovering_pluto.jpg] reclassified 2006 as dwarf planet orbit “crosses” Neptune’s orbit [Figure 13.19] orbital resonance makes + geometry makes collision impossible mass (of Pluto + Charon) ~ 1/6 Earth’s moon eclipses + intensity variation to map surface [Fig 13.20,21] determine sizes Pluto’s radius ~ 2300 km, Charon ~ 1200 km => density ~ 2 x water => not just icy materials thin atmosphere icy surface (highly reflective) 6 Other TNOs No large planets discovered beyond Neptune Over 1200 TNOs discovered [TheTransneptunians_73AU.svg.png] possibly over one million TNOs with diameters larger than tens of kilometers Large TNOs [EightTNOs.png] Eris: larger than Pluto! Kuiper Belt Objects (KBOs) Icy bodies Circular orbits near plane of solar system Resonant KBOs trapped in resonance with Neptune Scattered Disk Objects (includes Eris) Larger, more eccentric and more inclined orbits Centaur objects: already “encountered” Neptune, closer orbits, “doomed” Possible history of the solar system [figure 13.24] 7 Redefining Pluto Planet: orbits the sun, massive enough to have spherical shape, dominates neighborhood (clearing of other objects) Dwarf Planet: orbits the sun, massive enough to have spherical shape TNO's Pluto, Eris, Haumea and Makemake plus non-TNO Ceres 2000px-Solar_System_size_to_scale.svg.png 8