Neptune is the farthest planet from the sun, orbiting 30 times farther than Earth and taking 165 years to complete one revolution.

Reaching 2,400 kilometers per hour (1,500 miles per hour), Neptune's winds are the strongest in the solar system.

Explore a 3D interactive visualization of Neptune, the smallest of the solar system's giant planets.

A return to Uranus

There's been only one mission to Uranus before—Voyager 2 passed by the ice giant in 1986 before heading off into interstellar space. NASA's recent planned itinerary for space missions lists Uranus as the highest priority over the next decade. The seventh planet is 20 times as far from the sun as Earth, and researchers say its study will shed light on how the outer half of the Solar System formed.

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.

Astronomers inferred Neptune's existence through mathematics while attempting to explain irregularities in Uranus' orbit, but Neptune had been directly observed 234 years earlier by Galileo.

Excluding using another planet's gravity to redirect the object, it takes less energy for a spacecraft to leave the solar system than to hit the sun.

A look at Uranus, our distant icy cousin

NASA provides a profile of the seventh planet from the sun and the third largest—Uranus. More than just a punchline, the planet is cold, windy, and utterly inhospitable. It's also a lovely blue-green, due to the large amounts of methane it contains, with faint rings and two dozen moons. Learn more about this not-so-gentle gas giant.

Simulate the precession of Mercury's perihelion—the gradual shift in the closest point of Mercury's path around the sun as its elliptical orbit rotates.

Differences in the tilts of planetary orbits make perfect alignment impossible

Mercury deviates within 7 degrees of the ecliptic that marks the path of the sun, with the other planets varying from 3 degrees to approximately flat. Even an alignment within 1 degree between all eight planets is estimated to occur only once every 13.4 trillion years.

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

Since 1989, storms resembling Jupiter's Great Red Spot have been observed on Neptune, but darker and lasting no more than a few years.

The 45 planets astronomers think are most likely to host alien life

The list includes familiar names like Proxima Centauri b (4 light-years away) and four planets in the TRAPPIST-1 system (about 40 light-years away), but even the nearest of those would take humanity roughly 114,000 years to reach at current spacecraft speeds. The list's real near-term value is as a targeting guide for the James Webb and upcoming Nancy Grace Roman space telescopes.

Although no such planet exists in our solar system, the most common subtype of exoplanet in the galaxy is the sub-Neptune world, which is larger than Earth but smaller than the ice giants.

How scientists study Earth's geocorona, the farthest portion of the planet's exosphere

Seen via ultraviolet radiation scattered by neutral hydrogen in the region, observations by the ESA/NASA Solar and Heliospheric Observatory indicate that the geocorona extends roughly 50 times Earth's diameter above its surface. At this distance, the geocorona extends beyond the Moon's orbit.

Why the sun's equator rotates once every 24.5 days, but the poles take over 34 days

Just like the Earth, linear speeds on the surface of the sun decrease from the equator to the poles. However, rotation time also appears to vary with depth, with the radiative zone beneath the convection zone rotating about once every 26.6 days. Measurement uncertainty has prevented measurement of the rotation of the solar core.

In 2025, astronomers confirmed that Neptune has auroras, which were observed at mid-latitudes because its magnetic field is tilted 47 degrees from its rotation axis.

Why parts of the Earth are colder when the planet is closer to the Sun

The Earth orbits the Sun in an elliptical shape, and winter in the Northern Hemisphere occurs when the Earth reaches the point in its orbit closest to the Sun, known as perihelion. The lower temperatures result from the hemisphere tilting away from the Sun.

As of 2026, 14 of Neptune's 16 moons have been named for mythological figures, with Triton, the largest of them, orbiting backward, or in retrograde.

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."

View a gallery of photographs of Neptune taken during NASA missions.

In 1676, Danish astronomer Ole Rømer determined that light did not travel instantaneously by observing a delay in the appearance of solar eclipses on Jupiter when it was farther from Earth.

While the sun, moon, and stars rise and set from east to west due to Earth's rotation, the moon's eastward revolution around the Earth causes its shadow to move from west to east during a solar eclipse.

An overview of Venus, from its retrograde rotation to its volcanic surface

Boasting over 1,600 major volcanoes—more than any other planet in the solar system—Venus rotates in the opposite direction as Earth, potentially due to a major collision during its formation that flipped the planet upside-down. The planet's rotation also makes days on Venus last longer than its entire year.

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.

Planets' high orbital speeds prevent them from falling into their host star

Although the gravitational force attracts a planet and the star it orbits around, the large speed the planet orbits with, which is acquired during its formation process, causes it to continuously miss the star as it orbits around it. This is analogous to theoretically throwing a baseball horizontally faster and faster until it's fast enough to orbit the Earth while attempting to fall to its surface.

While published images have suggested that Neptune is much bluer than Uranus, the two ice giants are a similarly pale shade of greenish-blue.

Comets can be categorized based on their orbital period

Short-period comets orbit around the sun once every 200 years or less and are made up of Jupiter-family (less than 20 years) and Halley-type (between 20 and 200 years) comet subgroups. Long-period comets have orbits greater than 200 years, while exocomets originate in solar systems outside our own.

Everything you need to know about the planets in our solar system

NASA provides a re-introduction to our solar systems's planets, and a few other neighborhood residents. In the Milky Way galaxy, there are more planets than stars. We’ve discovered thousands of planets orbiting distant stars, but it all started with the current lineup of eight planets orbiting our own star—the sun. Learn more here.

Despite being called 'ice giants,' Uranus and Neptune do not contain plentiful frozen water—the term refers to their abundance of elements heavier than hydrogen and helium.

The moon is moving 3.8 centimeters farther away from Earth each year

Driven by tidal forces, the effect is minimal and slow, ensuring stable tidal patterns and lunar cycles. Earth's rotation slows down as the Moon gains orbital momentum, slowly lengthening the day over time.

Enough sunlight hits Earth in just 90 minutes to power the planet for an entire year

Despite this, in 2023, only 5.1% of electricity in the US came from solar energy. Solar panel technology has nonetheless made significant advancements since the 19th century, largely due to NASA's efforts in the space race.

Earth is the only planet in our solar system with fire

And while the sun seems like fire, and other planets have volcanoes, the sun and lava aren't the same thing as fire. To produce fire, a planet needs three ingredients: oxygen, fuel, and heat. No other planet has all three.

Voyager 1 captured Earth as a 'Pale Blue Dot' from 6 billion kilometers away

On Feb. 14, 1990, NASA's Voyager 1 space probe took the farthest photo of Earth ever captured. Earth appears so small in the image that it takes up less than a single pixel out of 640,000 in the photo's frame.

Visualizing the history of Saturn and its rings

Every 13 to 16 years, Saturn's rings become far less visible because its plane becomes exactly even with Earth's. This visual-rich essay explores the history of humanity's perception of Saturn, from Galileo's first sighting (and dubbing the rings "ears") to the idea that the rings won't last more than a few hundred millions years more. Explore this fascinating planet here.

The Earth orbits the sun within the Orion Spur arm of the Milky Way galaxy

The solar system is roughly halfway between the galaxy's outer rim and its center, which is located about 25,000 light years away. The Milky Way is itself one of hundreds of thousands of galaxies in the Virgo Supercluster.

Visualize the size of countries on the sun and other planets

Pluto is roughly the size of Australia. What about Namibia and Nepal? How small would North America appear on the sun? Compare the relative size of continents and countries with this easy-to-use interactive.

Asteroids are often unobserved until they are days away from Earth

Even those large enough to cause local or regional damage are too small, dim, and far away to be observed readily from cosmological distances. New tools, like NASA's NEO Surveyor telescope, aim to address gaps in detection systems.

NASA plans to bring down the ISS at a location farthest from land

Point Nemo is located in the South Pacific Ocean at coordinates 48°52.6'S 123°23.6'W, approximately 2,688 kilometers (1,670 miles) from Ducie Island, Motu Nui, and Maher Island. The location has served as an underwater graveyard for hundreds of satellites and is expected to be harbor the International Space Station in 2030.

Over thousands of years, the frequency of solar eclipses is greatest around the Arctic and Antarctic Circles and lowest near the equator.

The solar system formed between 4.5 and 4.6 billion years ago

Its age is best estimated by studying meteorites from the early formation period of the planetary system, including Erg Chech 002 (4.565 billion years old) and NWA 11119 (4.5648 billion years old). Solar analysis and stellar evolution models estimate the sun's age to be approximately 4.57 billion years.

As of 2025, humans have only dug 0.2% the way to Earth's center

The Kola Superdeep Borehole revealed two billion-year-old fossils and underground water, but the immense temperature and pressure prevented further tunneling. Beyond those depths, scientists know of Earth's interior by analyzing how seismic waves move.

Units involving light, such as light-seconds and light-years, describe the distances traveled by light across that amount of time.

What is the Kuiper Belt?

The Kuiper Belt is a collection of extraterrestrial objects that might've been a planet if it hadn't been for Neptune. Still, the belt is a fascinating collection of dwarf planets, rocks, ice, and comets. Extending beyond Neptune's orbit, the Kuiper Belt provides an endless selection of interesting objects and anomalies for astronomers to explore.

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.

Earth's smooth, continuous motion as it orbits the sun prevents detectable motion

Although humans are sensitive to acceleration, Earth's nearly circular orbit around the sun and its slow spin relative to its size produce negligibly small, minimally changing accelerations. However, the changing seasons and the day-night cycle are evidence of Earth's movement through space, as verified by satellites and telescopes.

There may be over one trillion comets in the Kuiper Belt

Named after Gerard Kuiper, who theorized the existence of a band of icy objects beyond Neptune in 1951, direct evidence for its existence did not arrive until 1992, when the first trans-Neptunian object, besides Pluto and its moon Charon, was observed. Comets with periods of less than 200 years originate from this belt.

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.

NASA's Near-Earth Object Surveyor can detect asteroids coming from the sun

Telescopes directed at the sun or lacking heat shields may become damaged, limiting our ability to monitor potentially dangerous objects coming from that direction. The NEO Surveyor is built to overcome this problem and spot asteroids that reflect as little as 5% of incoming light.

Earth's core is about 2.5 years younger than its surface according to relativity

Due to differences in where objects are located within gravitational fields, time will run at different rates, which has major impacts on technology that relies on synchronization. For example, GPS satellites run about 38 microseconds faster every day than clocks on Earth's surface, resulting in GPS discrepancies of about six miles, were it not for software corrections.

How neutron stars resemble Earth, including harboring an atmosphere and 'mountains'

These stars maintain an atmosphere of hydrogen, helium, and carbon at approximately 2,000,000 degrees Celsius (3,600,000 degrees Fahrenheit), only a few thousandths of a millimeter thick, which envelops "mountains" about a millimeter high. Its interior consists of an inner and an outer crust surrounding inner and outer cores, all held together by enormous gravitational forces despite spinning multiple times a second.