NASA’s real-time science encyclopedia of deep space exploration. Our scientists and far-ranging robots explore the wild frontiers of our solar system.

2025年1月9日 · The Sun is the star at the heart of our solar system. Its gravity holds the solar system together, keeping everything – from the biggest planets to the smallest bits of debris – in its orbit.

The chromosphere has indeed proved to be an exciting and unique feature of the solar landscape. It is here that solar astronomers have found a host of transient exotic structures, including spicules, prominences, and plages.

Introduction. 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.

Venus rotates very slowly on its axis – one day on Venus lasts 243 Earth days. The planet orbits the Sun faster than Earth, however, so one year on Venus takes only about 225 Earth days, making a Venusian day longer than its year!

Pluto orbits the Sun about 3.6 billion miles (5.8 billion km) away on average, about 40 times as far as Earth, in a region called the Kuiper Belt.

2025年1月9日 · NASA’s real-time science encyclopedia of deep space exploration. Our scientists and far-ranging robots explore the wild frontiers of our solar system.

2025年1月9日 · How Cassini Changed Our View of ... Saturn. Overview: Before Cassini, scientists viewed Saturn’s unique features only from Earth and from a few spacecraft flybys. But over more than a decade orbiting the gas giant, Cassini studied the composition and temperature of Saturn’s upper atmosphere as the seasons changed there.

Overview: For decades, scientists didn’t know why Enceladus was the brightest world in the solar system, or how it related to Saturn’s E ring. Cassini found that both the fresh coating on its surface, and icy material in the E ring originate from vents connected to a global subsurface saltwater ocean that might host hydrothermal vents.

Image of Comet Hale-Bopp taken by Wally Pacholka on April 5, 1997 from the Joshua Tree National Park in California. On July 23, 1995, an unusually bright comet outside of Jupiter's orbit (7.15 AU!) was discovered independently by Alan Hale, New Mexico and Thomas Bopp, Arizona.