Planet Compare – NASA Solar System Exploration
Oct 21, 2025 · NASA’s real-time science encyclopedia of deep space exploration. Our scientists and far-ranging robots explore the wild frontiers of our solar system.
Neptune 3D Model – NASA Solar System Exploration
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In Depth | Neptune Moons – NASA Solar System Exploration
Dutch-American astronomer Gerard Kuiper (for whom the Kuiper Belt was named) found Neptune's third-largest moon, Nereid, in 1949. He missed Proteus, the second-largest because it's too dark and …
In Depth | Kuiper Belt – NASA Solar System Exploration
As Uranus and Neptune drifted farther outward, they passed through the dense disk of small, icy bodies left over after the giant planets formed. Neptune's orbit was the farthest out, and its gravity bent the …
In Depth | Triton – NASA Solar System Exploration
Scientists think Triton is a Kuiper Belt Object captured by Neptune's gravity millions of years ago. It shares many similarities with Pluto, the best known world of the Kuiper Belt. Like our own moon, …
In 1943, astronomer Kenneth Edgeworth hypothesized that many small, icy bodies exist in a disc in the region beyond Neptune, having condensed from widely spaced ancient material, and that from time …
In Depth | Our Solar System – NASA Solar System Exploration
Our solar system consists of our star, the Sun, and everything bound to it by gravity – the planets Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune; dwarf planets such as Pluto; …
Bibliography - NASA Solar System Exploration
Apr 23, 2024 · Scott S. Sheppard's Neptune's Known Satellites Page: http://www.dtm.ciw.edu/users/sheppard/satellites/nepsatdata.html Scott S. Sheppard's Pluto's Known …
Mars By the Numbers - NASA Solar System Exploration
Oct 21, 2025 · Mars is the fourth planet from the Sun, and the seventh largest. It’s the only planet we know of inhabited entirely by robots.
In Depth | 1P/Halley – NASA Solar System Exploration
At aphelion in 1948, Halley was 35.25 AU (3.28 billion miles or 5.27 billion kilometers) from the Sun, well beyond the distance of Neptune. The comet was moving 0.91 kilometers per second (2,000 mph).