The thousands of objects orbiting Jupiter include 95 officially recognized moons

Io, Jupiter’s moon, is the most volcanically active body in the solar system

The innermost and third-largest of Jupiter’s four Galilean moons, Io’s volcanic activity is driven by tidal heating from Jupiter’s gravitational pull. Its atmosphere is very thin and primarily composed of sulfur dioxide, and its volcanic eruptions can exceed 1,000°C.

Galileo’s discovery of Jupiter’s moons led to multiple scientific advancements

Beyond challenging Earth-centric views upon their discovery in 1610, the Galilean moons were also later analyzed to contribute to early astrometry and astronomical interferometry. Measurements of eclipses were also used to estimate the speed of light.

ESA’s Juice and NASA’s Europa Clipper will search for habitability near Jupiter

Three of Jupiter’s moons—Ganymede, Europa, and Callisto—possess subsurface oceans that may support life. While Clipper will perform flybys of Europa, Juice will be the first spacecraft to orbit a moon in the outer Solar System.

Galileo's Jupiter discovery shattered Earth-centered universe beliefs

Using a telescope inspired by Dutch designs, Galileo spotted four moons orbiting Jupiter in 1610, providing undeniable evidence against geocentrism and fueled support for the heliocentric model. Galileo’s original telescope design stretched 20 meters long—a feat of optical engineering for its time.

Everything you need to know about Jupiter, the gas giant

NASA introduces you to the fifth planet from the sun, the gas giant Jupiter. When it comes to our solar system, Jupiter is the biggest kid on the block. Named after the king of the Ancient Roman gods, Jupiter is a planet of storms and chaos, most famously in its Great Red Spot, a hurricane larger than the earth itself.

Hot Jupiters are giant planets that orbit very close to their host star

Discovered in 1995, hot Jupiters are a class of exoplanets—planets orbiting stars other than the sun—with size and mass similar to Jupiter. They are most commonly found orbiting metal-rich stars and have become essential for testing theories of planetary system formation.

When it formed 4.5 billion years ago, Jupiter was twice its current size

Its original size was deduced from the orbits of its moons, Amalthea and Thebe. The planet's magnetic field was also 50 times stronger than today, or 400 times stronger than Earth's.

Observations of Jupiter's moons first demonstrated that light was not instantaneous

In 1676, Danish astronomer Ole Rømer noticed that eclipses of the moons occurred several minutes later when Earth and Jupiter were farther apart, reasoning that light needed more time to travel the greater distance. Lacking knowledge of Earth's orbital diameter, he was unable to calculate the speed of light.

Visualize water's abundance across the solar system, and its relative rarity on Earth

Despite covering almost three-quarters of its surface, water only makes up about 0.12% of Earth's volume. Water in some of Jupiter's and Saturn's moons comprises a larger share of those celestial bodies and of the total water in the solar system. For example, Jupiter's moon Ganymede is believed to harbor almost nine times Earth's oceans beneath its icy shell.

View a gallery of the best images of Jupiter from the Juno mission

Using the JunoCam, scientists have observed several of Jupiter's features, including cyclones, the Great Red Spot, and cloud bands and zones. The mission's effectiveness has resulted in its extension from July 2021 to September 2025.

The Hubble Space Telescope made discoveries within our solar system and across the universe

The observatory helped confirm the presence of water on Jupiter's moon Europa, and uncovered seasonal variations on planets like Uranus. It also observed exoplanets and gravitational lensing, proved the existence of supermassive black holes at the centers of galaxies, and detected the accelerated expansion of the universe.

Asteroids were discovered by 18th-century planet hunters

While looking for a planet between Mars and Jupiter to coincide with an apparent mathematical pattern in the distances of known planets from the sun, a group calling themselves the "Celestial Police" discovered multiple objects that fell into a new classification.

In 1994, fragments of comet Shoemaker-Levy 9 crashed into Jupiter

Hubble captured the collisions, which created massive black impact sites visible from space. It represented the first time scientists could prepare for, and observe, an interplanetary collision in real time, allowing them to gather valuable information about Jupiter's atmosphere.

Moon 101: NASA's complete overview of our lunar companion

From modulating our tides to impact our climate, Earth's lone natural satellite plays a key role forming the planet's habitat. Before diving into the rest of the resources on this page, check out NASA's overview of the basics of the Moon—how it got its name, its size and distance from Earth, its structure, and much more.

With the exception of Earth, the planets are named after Roman gods and goddesses

Mercury, Venus, Mars, Jupiter, Saturn, Uranus, and Neptune are named after the messenger of the gods, the goddess of love, the god of war, the king of gods, the god of agriculture, the god of the sky, and the god of the sea, respectively. "Earth" comes from Old English and Germanic words meaning "ground."

According to the Grand Tack model, Saturn stopped Jupiter's inward migration

The model suggests Jupiter migrated inward early in its formation and cleared debris from the inner orbits of terrestrial planets. Saturn's gravitational pull saved what was left of the inner solar system to form Mercury, Venus, Earth, and Mars.

Explore an interactive visualization of the solar system

This tool allows you to view the orbits of planets, dwarf planets, moons, asteroids, and other significant objects in the solar system. Clicking on an object reveals key facts and historical data.

Mar's moons, Phobos and Deimos, are thought to be captured asteroids

Of the two Martian moons, Phobos orbits more quickly, completing three revolutions a day. It gets 1.8 meters closer to Mars every year, and may crash into the planet in about 50 million years.

Track the location of the Voyager probes, currently between 13 and 15 billion miles away from Earth.

Evidence for a ninth planet in our solar system

Is there a massive ninth planet on the edge of our solar system? Many of our solar system's most distant objects tend to swing out in one direction, hinting at evidence for a previously unknown ninth planet potentially larger than Earth. This theoretical planet's orbital period is estimated to be roughly 20,000 years, revolving around the sun at a distance of 60 billion miles. Experts break down the evidence in this quick video.

Track the location of the Voyager probes, currently between 13 and 15 billion miles away from Earth.

There may be as many as 300 million potentially habitable planets in our galaxy

The estimate comes from a study using data from the Kepler space telescope—a project aimed at finding exoplanets—and considers exoplanets similar in size to Earth around sun-like stars. These have a greater potential to possess liquid water.

The Oort Cloud is a shell of icy objects surrounding the solar system, from which many comets originate

Proposed in 1950 by Jan Oort, the theoretical structure is believed to be the origin of comets with periods of more than 200 years. Leftover planetary building blocks from the early solar system formed the Oort Cloud after being flung out by the gravity of planets like Jupiter.

Comets in Pluto's orbit contributed to its demotion from planetary status

In 2006, the International Astronomical Union formally defined a planet as an object in orbit around the sun with a nearly spherical shape and an orbital path clear of significant debris. Because Pluto shares its neighborhood with comets from the Kuiper Belt, it was reclassified as a dwarf planet.

Anticipating moon tourism by 2000, Pan Am issued 'First Moon Flights' club cards

More than 93,000 cards were issued between 1968 and 1971, creating a waitlist that began when Gerhard Pistor, an Austrian journalist, visited a Viennese travel agency to request a flight to the moon. The cards were issued at no cost and numbered in the order they were issued.

Explore the known asteroids, comets, and spacecraft involved in asteroid studies within our solar system with 'Eyes on Asteroids,' a 3D visualization from NASA.

In 2023, there were nearly as many payloads in LOE as trackable pieces of debris

In 2021, the European Space Agency estimated that more than 130 million space debris objects larger than 1 millimeter were in low Earth orbit, though only about 22,000 were being tracked. As of late 2025, the tracked total exceeds 49,000.

Apollo astronauts left items in the moon's 'toss zone,' including golf balls, family photos, and bags of human waste, to make room for lunar rocks.

While the sun's gravity keeps the planets in orbit, their gravity also pulls on the sun, causing it and everything else in the solar system to orbit around a mutual balance point called the barycenter—the true center of the solar system.

Most of the observable universe's volume consists of voids and supervoids—enormous regions of space with little to no galaxies, stars, or light.

Meet the 56 signers of the Declaration of Independence—most of whom didn't put pen to paper until August 2, 1776—and see their original signatures.

Memecoins are a type of cryptocurrency—a form of digital currency with a wide variety of uses—created around popular 'memes,' or viral internet jokes.

The hormonal disorder PCOS was renamed PMOS in 2026, a move designed to improve care and research by shifting the focus to the hormonal causes of this condition that affects 1 in 8 women.

SpaceX's S-1 or 'prospectus' revealed many previously unknown details about the company, including its unprofitability despite doing $18.7B in revenue in 2025, exactly how many voting shares Elon Musk will have in the company (roughly 85%), and more.

See the 25 of the best photos of auroras from around the world.

The syncytiotrophoblast is the outer layer of the placenta and the largest human cell, spanning an area about twice that of a king-sized bedsheet.

Poison ivy was sent to Europe in the 1600s as an exotic, ornamental oddity, where it was purposefully grown in the English royal gardens at Kew, the Faculty of Medicine in Paris, and a few other locations.

Some Pokémon have been named after real and fictional organisms, while some real-world species have been named after Pokémon, such as Chilicola charizard and Binburrum zapdos.

The Nasdaq's 'Magnificent 7' companies are responsible for roughly 40% of the Nasdaq 100 index's gains, while the remaining 93 companies account for the other 60%.

The Mona Lisa's celebrity status and repeated restorations have obscured what made the painting so revolutionary for its time

See a 3D reconstruction of Tenochtitlan, the Aztec capital that was home to an estimated population of 200,000 to 400,000.

Quincy Jones' 'Big Band Bossa Nova' helped introduce bossa nova—a jazz-influenced Brazilian genre—to the US

See photos of Meteora, a mountainous site in central Greece, home to 14th-century monasteries perched atop soaring outcroppings.

Domino's Pizza's 30-minute delivery guarantee was responsible for the chain's 1980s surge, but it was discontinued after the company was found liable for delivery driver accidents.

Search a massive database of over 4 decades of clues from the TV quiz show 'Jeopardy!'

Roughly 43 million US borrowers owe roughly $1.7T in student debt, the second-largest source of consumer debt behind mortgages.

Researchers believe the brain consolidates memories, processes emotions, and plans for the future during dream states

The Russia-Ukraine conflict is the largest ground war in Europe since World War II in casualties, forces mobilized, and displacement of civilians.

Explore a list of the 100 best novels of all time, compiled by some of the world's best living writers, including Salman Rushdie, Stephen King, and Jennifer Egan.

Double world record holder Hunter Ewen helped conquer his fear of balloons, called globophobia, by training to win Guinness World Record titles for balloon inflation.