In Depth | Our Solar System - NASA Solar System Exploration
网页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; dozens of moons; and millions of asteroids, comets, and meteoroids.
In Depth | Sun – NASA Solar System Exploration
网页The Sun is the largest object in our solar system. Its diameter is about 865,000 miles (1.4 million kilometers). Its gravity holds the solar system together, keeping everything from the biggest planets to the smallest bits of debris in orbit around it.
What is a Planet? | Planets – NASA Solar System Exploration
网页A planet is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.
In Depth | Neptune – NASA Solar System Exploration
网页Dark, cold, and whipped by supersonic winds, ice giant Neptune is the eighth and most distant planet in our solar system. More than 30 times as far from the Sun as Earth, Neptune is the only planet in our solar system not visible to the naked eye.
In Depth | Pluto – NASA Solar System Exploration
网页Dwarf planet Pluto is a member of a group of objects that orbit in a disc-like zone beyond the orbit of Neptune called the Kuiper Belt. This distant realm is populated with thousands of miniature icy worlds, which formed early in the history of …
In Depth | Saturn – NASA Solar System Exploration
网页Saturn is the sixth planet from the Sun and the second-largest planet in our solar system. Like fellow gas giant Jupiter, Saturn is a massive ball made mostly of hydrogen and helium. Saturn is not the only planet to have rings, but none are …
In Depth | Earth – NASA Solar System Exploration
网页While Earth is only the fifth largest planet in the solar system, it is the only world in our solar system with liquid water on the surface. Just slightly larger than nearby Venus, Earth is the biggest of the four planets closest to the Sun, all of which are made of rock and metal.
10 Things to Expect in Planetary Science for 2021 - NASA Solar …
网页2021年1月28日 · Sending the first Artemis mission to the Moon in preparation for human missions, landing a new rover on Mars, and launching the James Webb Space Telescope into space, expanding our ability to see deep into the universe, are just a few of the things NASA has planned for 2021.
In Depth | Moons – NASA Solar System Exploration
网页There are hundreds of moons in our solar system – even asteroids have been found to have small companion moons. Of the terrestrial (rocky) planets of the inner solar system, neither Mercury nor Venus have any moons at all, Earth has one and Mars has its two small moons.
Asteroids, Comets & Meteors - NASA Solar System Exploration
网页Our solar system’s small bodies – asteroids, comets, and meteors – pack big surprises. These chunks of rock, ice, and metal are leftovers from the formation of our solar system 4.6 billion years ago. They are a lot like a fossil record of our early solar system.