In Depth | Our Solar System – NASA Solar System Exploration
Our solar system formed about 4.5 billion years ago from a dense cloud of interstellar gas and dust. The cloud collapsed, possibly due to the shockwave of a nearby exploding star, called a …
In Depth | Sun – NASA Solar System Exploration
The Sun formed about 4.6 billion years ago in a giant, spinning cloud of gas and dust called the solar nebula. As the nebula collapsed under its own gravity, it spun faster and flattened into a …
In Depth | Earth's Moon – NASA Solar System Exploration
During a "full moon," the hemisphere of the Moon we can see from Earth is fully illuminated by the Sun. And a "new moon" occurs when the far side of the Moon has full sunlight, and the side …
If the temperature of the nebula was below 200 K, hydrogen was probably in the form of molecules, rather than as charged particles protons and electrons as it is found now in the …
In Depth | 1P/Halley – NASA Solar System Exploration
Halley's orbit period is, on average, 76 Earth years. This corresponds to an orbital circumference around the Sun of about 7.6 billion miles (12.2 billion kilometers). The period varies from …
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 | Europa – NASA Solar System Exploration
Jupiter’s large Galilean moons – Io, Europa, Ganymede, and Callisto – likely formed out of leftover material after Jupiter condensed from the initial cloud of gas and dust surrounding the …
RTG power sources are enabling the Galileo mis-sion to Jupiter, the international Ulysses mis-sion studying the Sun’s polar regions, and the Cassini mission to Saturn.
307 Temporary Redirect - NASA Solar System Exploration
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In Depth | Enceladus – NASA Solar System Exploration
Oct 9, 2008 · The moon creates a ring of its own as it orbits Saturn—its spray of icy particles spreads out into the space around its orbit, circling the planet to form Saturn’s E ring.