What Causes Triton’s Geysers?
One of many surprising discoveries made by Voyager 2, the only spacecraft to visit Neptune, was that its largest moon, Triton, had huge geysers erupting from the surface in its south polar region. They reached heights of 8 km (5 mi), 140 times the height of Old Faithful! Voyager’s instruments were not able to determine what they were made of, but scientists have two hypotheses. They could be like the plumes seen on Saturn’s moon, Enceladus, consisting of water ice spraying from a subsurface liquid ocean through cracks in the surface. Or they could be outbursts of nitrogen gas and ice from sunlight heating the nitrogen snow on the surface. It was southern summer when Voyager passed by, and the warmth from sunlight, 900 times weaker than here on Earth, would keep this nitrogen aloft in a thin atmosphere. In winter, though, it would snow back onto the ground. Seasons on Triton last 41 years, but it’s only been 34 years since Voyager 2’s flyby. Read More
Latest News About Neptune
Immiscible ice layers may explain why Uranus and Neptune lack magnetic poles
December 17, 2024
Their disorganized magnetic fields may arise from the icy fluids that make up their interiors Read more
Neptune and Uranus have a magnetic mystery — but the case may finally be cracked
November 25, 2024
They have missing "dipole magnetic fields." Here's why that's really weird Read more
Asteroid grains shed light on the outer solar system’s origins
November 6, 2024
A weak magnetic field likely pulled matter inward to form the outer planetary bodies, from Jupiter to Neptune Read more
Fascinating Facts About Neptune
- 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 softball.
- From Neptune’s surface, the Sun appears about three-hundredths as large as it does from Earth and sunlight appears about 900 times dimmer.
- 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.
- At times during the course of Neptune's orbit, dwarf planet Pluto is closer to the sun than Neptune is. This is due to the unusual elliptical (egg) shape of Pluto's orbit.
- Neptune is the windiest world in the solar system; winds have been measured up to speeds of 2000 kilometers per hour.
- Neptune emits about 2.6 times the energy it receives from the Sun. This energy is thought to come from the continued cooling of the planet after its gravitational collapse during the formation of the solar system. Because of this, the weather on the planet is internally driven: it depends on the energy emitted by the planet itself. On the other hand, the weather on Earth is externally driven, by the sun!
- Neptune has the second largest gravitational force of any planet in the solar system after Jupiter.
- Neptune is a sister ice giant to Uranus. 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.
Missions
Voyager 2 (1977)
Mission to study the outer solar system