The Discovery of UranusDiscovered in 1781 by William Herschel; firstplanet to be discovered in more than 2000yearsFirst planet discovered by a telescope
The Discovery of NeptuneNeptune was discovered in 1846, by Urbain Le Verrier.Analysis of Uranus’s orbit indicated Neptune’spresence.First planet discovered by mathematics.Confirmed Newton’s Laws of gravitation I think there’s another planet out there!
Little detail can be seen from Earth; arrows point to three of Uranus’s moons:Details of Neptune cannot bemade out from Earth either;arrows again point tomoons:
Physical Properties of Uranus and NeptuneUranus and Neptune are very similar:
Physical Properties of Uranus and NeptunePeculiarity of Uranus: axis of rotation liesalmost in the plane of its orbit. Seasonalvariations are extreme.
The Atmospheres of Uranus and NeptuneOuter atmospheres of Uranus and Neptune aresimilar to those of Jupiter and SaturnUranus and Neptune are coldenough that ammoniafreezes; methane dominatesand gives the characteristicblue color
The Atmospheres of Uranus and NeptuneUranus is very cold; clouds only in lower,warmer layers.Few features arevisible:
The Atmospheres of Uranus and NeptuneBand structure of Neptune is more visible, andNeptune has internal heat source of unknownorigin:
The Atmospheres of Uranus and NeptuneNeptune has storm systems similar to those onJupiter, but fewer:
Magnetospheres and Internal Structure Uranus and Neptune both have substantial magnetic fields, but at a large angle to their rotation axes.The rectanglewithin eachplanet shows abar magnet thatwould produce asimilar field. Notethat bothUranus’s andNeptune’s aresignificantly offcenter.
Magnetospheres and Internal StructureMagnetic fields of Uranus and Neptune must notbe produced by dynamos, as the other planets’fields are.Interior structure of Uranus and Neptune,compared to that of Jupiter and Saturn:
The Moon System of UranusUranus has 27 moons, five of which are major:Miranda, Ariel, Umbriel, Titania, and OberonVery similar to Saturn’s medium-sized moons,except that all are much less reflective.Umbriel is the darkest:
The Moon Systems of UranusMiranda is the most unusual; origin of thecracks and grooves is unknown:
The Moon System of NeptuneNeptune has 13 moons, but only two can beseen from Earth: Triton and NereidTriton is in a retrograde orbit; Nereid’s is highlyeccentricTriton’s surface hasfew craters,indicating an activesurface
The Moon System NeptuneNitrogen geysershave been observedon Triton,contributing to thesurface features:
The Moon System NeptuneAlso, there appear to beice volcanoes:
The Rings of the Outermost PlanetsUranus and Neptune have faint ring systems,recently detected.Uranus’s ringsare narrow:
The Rings of the Outermost PlanetsTwo shepherd moonskeep the epsilon ringfrom diffusing:
The Rings of the Outermost Jovian PlanetsNeptune has five rings, three narrow and twowide:
Summary• Uranus, Neptune were discovered in the last350 years• Uranus and Neptune are similar: gaseousand cold• Uranus’s spin axis is almost in the plane ofits orbit• Surface features are hard to discern onUranus, but more obvious on Neptune• Uranus has no excess heat emission, butNeptune does
Summary• Uranus’s midsized moons are similar tothose of Saturn• Neptune’s moon Triton has a retrograde orbit• Uranus and Neptune both have faint ringsystems