Read about the dangerous comet behind the Perseids meteor shower

Stellar photos from around the world of the 2020 Perseids

The annual Perseids meteor shower occurs in the Northern Hemisphere's summer, peaking usually around mid-August. The phenomenon is caused by the Earth's passing through a comet's debris trail of ice and dust, providing a weekslong spectacle for...

Explore an interactive solar system with 3D visualizations of meteor showers—streams of dust-like debris left behind from comets or asteroids that burn up in Earth's atmosphere.

A 101 on the science and history of meteor showers

Bits of rock, ice, and dust flying through space called meteors burn up in a spectacular display when they hit our atmosphere 60 miles up at an average of 30,000 mph. Some of these are isolated objects, but others are recurring phenomena caused by...

Explore a guide to observing comets

Binoculars or telescopes can be used to see vivid tails, glowing comas, and brief bursts of brightness from these celestial objects. For photography, a DSLR or mirrorless camera with a wide-aperture lens, long exposure settings, and accessories such as tripods and star trackers is recommended.

Find which comets are currently visible in the night sky

Incorporating sightings reported in the Comet Observation database and information from NASA's Jet Propulsion Laboratory, this list provides a finder chart, star map, tracker, simulated orbit, and key properties for each comet, all viewable based on a user's input position on Earth.

Shooting stars, or meteors, are fragments of asteroids and comets that burn up as they enter Earth's atmosphere, creating streaks in the sky called meteor showers.

View a gallery of notable comets

The collection features 1973's Kohoutek, which had been dubbed the "comet of the century," 1965's Ikeya-Seki—one of the brightest comets of the millennium—and 2002's NEAT, a comet that survived a coronal mass ejection as it passed near the sun.

Visualize the anatomy of a comet

The solid nucleus holds the frozen molecules, which are heated into a gaseous state once the comet is within three times Earth's distance from the sun. The surrounding coma, from which comets get their name, is a spherical cloud that can grow larger than Jupiter, from which tails develop.

Tracking the latest meteorite falls on Earth

Roughly 50 tons of meteorite material arrives on Earth every day, and many of the larger objects survive the hot temperatures of the atmosphere and make landfall. This tracker compiles data from survey sites across the globe to present the latest...

The ancient Greeks and Romans viewed comets and meteors as divine omens

Both considered the appearance of a comet or its fragments as a precursor to significant events, such as the birth of a notable figure or the death of a ruler. One observed in 44 BCE was believed to be a sign of the deification of Julius Caesar after his assassination.

A comet's tails point away from the sun, rather than trailing its motion

The ion tail, composed of gases ionized by solar radiation and pushed by the solar wind, points away from the sun. In contrast, the dust tail is pushed away by radiative pressure and curves away from the comet's motion. As the comet approaches the sun, both tails get longer.

Shooting stars are streaks of light produced by meteoroids

As these rocks enter Earth's atmosphere at high speeds, friction causes them to burn up, briefly leaving streaks of light. The color of these fireballs can be used to determine the composition of the meteoroid, if it does not reach the ground and become a meteorite for analysis.

Dark comets appear to be rocky asteroids but move like comets

Cometary orbits are known to exhibit accelerations independent of gravity that result from forces related to the release of gases. Dark comets exhibit this behavior but lack visible clouds of frozen material that have turned into a gas—the coma the comets display—indicating minor quantities of escaping subsurface ice.

The importance of the mesosphere, the coldest part of Earth's atmosphere

Atmospheric gases are dense enough in this region to begin burning up debris traveling toward Earth's surface, producing meteor showers, or shooting stars. Although we normally associate decreasing temperatures with increasing altitude, temperatures increase beyond the mesosphere layer due to the absorption of high-energy ultraviolet radiation and X-rays.

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.

Comets serve as time capsules of the early solar system

The frozen objects preserve the molecular composition of the solar system's formation, dating back about 4.6 billion years. Spectral analysis of the gases they release when heated upon approaching the sun in eccentric orbits reveals this composition and helps assess solar system formation models.

The Oort cloud, our solar system's theoretical icy shell

Recurring comets lead astronomers to believe they originate from an extremely distant, icy shell encapsulating the solar system. They call it the "Oort cloud," and this giant swarm of icy objects is as fascinating as it is is massive. Home of comets and a tremendous number of planetesimals, this NASA site introduces you to the Oort.

Halley's comet is named after the astronomer who predicted its next appearance

Edmund Halley realized that historical accounts of a celestial object passing in the night sky in 1531 and 1607 referred to the same object he observed in 1682. By applying Newtonian mechanics to his observational data, he calculated its orbit and accurately predicted its return in 1758.

NASA monitors potentially hazardous asteroids and comets

Established in 2016, the Planetary Defense Coordination Office characterizes and tracks asteroids and comets passing within 30 million miles of Earth. Over 40,000 near-Earth asteroids have been discovered, although estimates suggest that about 14,000 more such objects remain to be found.

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.

Explore an interactive forecast of the future of the universe, from the return of Halley's Comet to the last light in the cosmos.

The composition of comets earned them the nickname 'dirty snowballs'

The icy relics of the solar system are composed of rock, gravel, dust, and frozen molecules, such as carbon dioxide, carbon monoxide, methane, ammonia, and water. Once close to the sun, these compounds sublimate into gases, creating a fuzzy cloud that earned the comets another nickname in history: hairy stars.

Our solar system is currently traveling through a 'dark matter hurricane'

The phenomenon refers to a stream of cosmic debris, including stars and dark matter, leftover from a small galaxy that passed too close to the Milky Way and was torn apart. There are over 30 such streams known in our galaxy, and the stream intersecting the solar system is predicted to continue to do so for millions of years.

Stars appear to twinkle because turbulence in the motion of molecules in Earth's atmosphere causes light to bend and wiggle rapidly on its way to the surface—a phenomenon called scintillation.

The Neil Gehrels Swift Observatory is a NASA spacecraft with telescopes designed to study gamma ray bursts—the most powerful explosions in the universe, which result from supernova explosions during the formation of neutron stars and black holes.

The next five asteroid approaches

Asteroids are zinging by our planet regularly, and some of them you can see without a telescope. Here's a regularly updated list of the next five asteroid approaches.

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.

Deep Impact was the first mission to probe beneath a comet's surface

The NASA mission sent a probe to deliberately crash into comet Tempel 1, producing an explosion equivalent to 4.7 tons of TNT. The payload included a compact disk with more than 625,000 names of people who participated in the "Send Your Name to a Comet!" campaign.

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.

NASA's Stardust mission collected and returned samples from a comet

Launched in 1999, the spacecraft traveled to comet Wild 2 and captured more than 10,000 dust particles from its coma using a tennis racket-like mesh covered in aerogel. It also took pictures of the comet before returning to Earth and releasing the collection canister during its 2006 flyby.

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.

As of 2025, scientific evidence strongly supports 3I/ATLAS being a comet

Claims of alien technology would require the celestial object to transmit measurable technological signals, which were not detected by the world's largest fully steerable radio telescope. Previous telescope observations identified that 3I/ATLAS's chemical composition, structure, and orbital characteristics are consistent with those of an interstellar comet.

Visualize the impact of approximately 9,000 metric tons of satellites and space debris orbiting Earth—70% of which, including the International Space Station and the Hubble Space Telescope, do so in low Earth orbit.

Visualizing Earth's space garbage

An unsavory byproduct of humanity's brilliant exploration of space, the Moon, and more, is the rapid production of space debris floating around in orbit. Its estimated over 25,000 objects are in orbit, a number that grows everyday as satellites are decommissioned, rockets enter orbit, and more. Now, you can visualize what this debris looks like from a zoomed-out perspective with this brief video.

Space trash is making low Earth orbit increasingly dangerous for spacecraft

Millions of fragments from satellites, rockets, and other spacecraft that are no longer operational move thousands of meters per second as they circle Earth. Even a piece of debris a centimeter in size can cause mission-ending damage to space stations, telescopes, and astronauts.

You are 65,000 times more likely to be struck by lightning than to be hit by space trash

In 2023, about 1,500 pieces of space junk fell to Earth, with most consisting of payload fragmentation debris. The vast majority that falls back to Earth burns up before reaching the surface, making it three times less likely to be struck by space trash than by a meteorite.

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

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.

Explore a series of NASA visualizations tracking satellites and space debris

The series illustrates the population of objects orbiting Earth as of February 2024, using data from US Space Command. These include active satellites, defunct spacecraft, rocket bodies and debris fragments larger than roughly 10 centimeters in low Earth orbit.

Colorful thunderstorm phenomena can be viewed from the International Space Station

Transient luminous events are lightning-related phenomena that occur in the atmosphere above storm clouds. These events often look like columns of red light resulting from electrical discharge, but may also appear as purple tendrils or long blue jets.

Earth is constantly bombarded by material from space

Most of this matter is composed of small particles, with any smaller than 33 feet in diameter burning up in the atmosphere. Larger asteroids can reach the ground, and those larger than several thousand feet cause global damage, including earthquakes and tsunamis.

Watch a simulated flight through Jupiter's Great Red Spot

Since its discovery over 350 years ago, the anticyclonic storm—with a high-pressure center and flows opposite to the low-pressure system underneath it—has fascinated astronomers due to its size, which is larger than Earth's, and its prominent features, including winds that surpass 250 miles per hour.

Simulate asteroid impact, mitigation, and defense scenarios

Tens of thousands of asteroids are in orbit in our solar system, and only a fraction come close enough to concern humanity. This simulator allows you to see the big picture scenarios of an asteroid impact, strategies to mitigate its destruction, and how Earth could defend itself.

The faint triangle of light occasionally seen above the horizon, known as zodiacal light, is due to sunlight reflecting off ice and dust scattered throughout the inner solar system.

Jupiter may have affected the trajectory of the asteroid that wiped out the dinosaurs

Despite its reputation as Earth’s cosmic shield, Jupiter’s gravity pulls more asteroids into Earth-crossing orbits. Simulations show that Earth experiences over three times more asteroid impacts because of Jupiter’s influence than if Jupiter didn’t exist.

Explore the night's sky from anywhere

Stellarium Web is a planetarium running in your web browser. It shows a realistic star map, just like what you see with the naked eye, binoculars or a telescope. Using its interface, you can click on object's visible at your location on the Earth...

As seen in the dark region of the Horsehead Nebula, clouds of space dust can block some forms of light from reaching telescopes, impairing observations and data collection.

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.

Explore Earth's atmosphere and what its layers contain in this interactive adventure

In this interactive, users can move from Earth's surface up through its atmosphere, exploring the natural phenomena found in each layer, including atmospheric rivers, auroras, and meteor showers. Artificial structures such as weather balloons and the International Space Station can also be found on the adventure.

Aurora-like magenta streaks across the sky may not be auroras

The phenomenon, known as STEVE (Strong Thermal Emission Velocity Enhancement), has only been observed alongside auroras. Rather than light emitted by gases energized by collisions with ionized particles from the sun, STEVE is a high-velocity, high-temperature stream of particles that glows. (Some readers may experience a paywall.)