+Neptune

Neptune

10 Need-to-Know Things About Neptune:

1. If the sun were as tall as a typical front door, the Earth would be the size of a nickel and Neptune would be about as big as a baseball.

   Vertical relief in Neptune's bright cloud streaks.

2. Neptune orbits our sun, a star. Neptune is the eighth planet from the sun at a distance of about 4.5 billion km (2.8 billion miles) or 30.07 AU.
3. One day on Neptune takes about 16 hours (the time it takes for Neptune to rotate or spin once). Neptune makes a complete orbit around the sun (a year in Neptunian time) in about 165 Earth years (60,190 Earth days).
4. Like the other gas giants, Neptune does not have a solid surface. Neptune is mostly made of a very thick, very hot combination of water (H₂O), ammonia (NH₃), and methane (CH₄) over a possible heavier, approximately Earth-sized, solid core.
5. Neptune's atmosphere is made up mostly of hydrogen (H₂), helium (He) and methane (CH₄).
6. Neptune has 13 confirmed moons (and 1 more awaiting official confirmation of discovery). Neptune's moons are named after various sea gods and nymphs in Greek mythology.
7. Neptune has six rings.
8. Voyager 2 is the only spacecraft to have visited Neptune.
9. Neptune cannot support life as we know it.
10. At times during the course of Neptune's orbit, dwarf planet Pluto is actually closer to the sun, and us, than Neptune. This is due to the unusual elliptical (egg) shape of Pluto's orbit.

Uranus

Uranus

Uranus' moon Ariel (white dot) and its shadow (black dot) were caught crossing the face of Uranus in this Hubble Space Telescope image.

10 Need-to-Know Things About Uranus:

1. If the sun were as tall as a typical front door, Earth would be the size of a nickel and Uranus would be about as big as a baseball.

   Uranus: The Sideways Planet

2. Uranus orbits our sun, a star. Uranus is the seventh planet from the sun at a distance of about 2.9 billion km (1.8 billion miles) or 19.19 AU.
3. One day on Uranus takes about 17 hours (the time it takes for Uranus to rotate or spin once). Uranus makes a complete orbit around the sun (a year in Uranian time) in about 84 Earth years.
4. Uranus is a gas giant and therefore does not have a solid surface. The bulk (80 percent or more) of the mass of Uranus is made up of a hot dense fluid of "icy" materials (water (H₂O), methane (CH₄). and ammonia (NH₃)), above a small rocky core.
5. Uranus has an atmosphere which is mostly made up of hydrogen (H₂) and helium (He), with a small amount of methane (CH₄).
6. Uranus has 27 moons. Uranus' moons are named after characters from the works of William Shakespeare and Alexander Pope.
7. Uranus has faint rings. The inner rings are narrow and dark and the outer rings are brightly colored.
8. Voyager 2 is the only spacecraft to have visited Uranus.
9. Uranus cannot support life as we know it.
10. Like Venus, Uranus has a retrograde rotation (east to west). Unlike any of the other planets, Uranus rotates on its side, which means it spins horizontally.

About Saturn

10 Need-to-Know Things About Saturn

In this rare image taken on 19 July 2013, the wide-angle camera on NASA's Cassini spacecraft has captured Saturn's rings and our planet Earth and its moon in the same frame.

10 Need-to-Know Things About Saturn:

1. If the sun were as tall as a typical front door, the Earth would be the size of a nickel and Saturn would be about as big as a basketball.

   Cassini: Long-lived Saturn Explorer

2. Saturn orbits our sun, a star. Saturn is the sixth planet from the sun at a distance of about 1.4 billion km (886 million miles) or 9.5 AU.
3. One day on Saturn takes 10.7 hours (the time it takes for Saturn to rotate or spin once). Saturn makes a complete orbit around the sun (a year in Saturnian time) in 29 Earth years.
4. Saturn is a gas-giant planet and does not have a solid surface.
5. Saturn's atmosphere is made up mostly of hydrogen (H₂) and helium (He).
6. Saturn has 53 known moons with an additional 9 moons awaiting confirmation of their discovery.
7. Saturn has the most spectacular ring system of all our solar system's planets. It is made up of seven rings with several gaps and divisions between them.
8. Five missions have been sent to Saturn. Since 2004, Cassini has been exploring Saturn, its moons and rings.
9. Saturn cannot support life as we know it. However, some of Saturn's moons have conditions that might support life.
10. When Galileo Galilei looked at Saturn through a telescope in the 1600s, he noticed strange objects on each side of the planet and drew in his notes a triple-bodied planet system and then later a planet with arms or handles. Thehandles turned out to be the rings of Saturn.

Facts & Figures

	Discovered By Known by the Ancients Date of Discovery Unknown Orbit Size Around Sun (semi-major axis) Metric: 1,426,666,422 km English: 886,489,415 miles Scientific Notation: 1.4266664 x 109 km (9.53667594 A.U.) By Comparison: 9.537 x Earth Perihelion (closest) Metric: 1,349,823,615 km English: 838,741,509 miles Scientific Notation: 1.34982 x 109 km (9.023 A.U.) By Comparison: 9.176 x Earth Aphelion (farthest) Metric: 1,503,509,229 km English: 934,237,322 miles Scientific Notation: 1.50351 x 109 km (1.005 x 101 A.U.) By Comparison: 9.885 x Earth Orbit Circumference Metric: 8,957,504,604 km English: 5,565,935,315 miles Scientific Notation: 8.958 x 109 km By Comparison: 9.530 x Earth Average Orbit Velocity Metric: 34,701 km/h English: 21,562 mph Scientific Notation: 9.6391 x 103 m/s By Comparison: 0.324 x Earth Orbit Eccentricity 0.05386179 By Comparison: 3.223 x Earth Orbit Inclination 2.49 degrees Equatorial Inclination to Orbit 26.7 degrees Mean Radius Metric: 58,232 km English: 36,183.7 miles Scientific Notation: 5.8232 x 104 km By Comparison: 9.1402 x Earth Equatorial Circumference Metric: 365,882.4 km English: 227,348.8 miles Scientific Notation: 3.65882 x 105 km By Comparison: 9.1402 x Earth Volume Metric: 827,129,915,150,897 km3 English: 198,439,019,647,006 mi3 Scientific Notation: 8.2713 x 1014 km3 By Comparison: 763.594 x Earth Mass Metric: 568,319,000,000,000,000,000,000,000 kg Scientific Notation: 5.6832 x 1026 kg By Comparison: 95.161 x Earth Density Metric: 0.687 g/cm3 By Comparison: 0.125 x Earth Surface Area Metric: 42,612,133,285 km2 English: 16,452,636,641 square miles Scientific Notation: 4.2612 x 1010 km2 By Comparison: 83.543 x Earth Surface Gravity Metric: 10.4* m/s2 English: 34.3 ft/s2 By Comparison: If you weigh 100 pounds on Earth, you would weigh about 107 pounds on Saturn (at the equator). *Derived from a 1 bar radius of 60,268 km. Escape Velocity Metric: 129,924 km/h English: 80,731 mph Scientific Notation: 3.609 x 104 m/s By Comparison: Escape velocity of Earth is 25,030 mph. Sidereal Rotation Period (Length of Day) 0.444 Earth days 10.656 hours By Comparison: 0.445 x Earth Effective Temperature Metric: -178 °C English: -288 °F Scientific Notation: 95 K Atmospheric Constituents Hydrogen, Helium Scientific Notation: H2, He By Comparison: Earth's atmosphere consists mostly of N2 and O2.