Earth is constantly bombarded by material from space

Research suggests a 95-kilometer-wide (59-mile-wide) asteroid impact could boil the Earth's oceans

Even a 1-kilometer-wide (0.62-mile-wide) asteroid can trigger earthquakes and tsunamis on impact with oceans. The overwhelming majority of asteroids that reach Earth are much smaller and burn up in the atmosphere before reaching the ground.

Craters found on the moon and the calculated dates of these impacts, based on rocks returned by the Apollo missions, suggest that Earth was pummeled by asteroids for millions of years—a period known as the Late Heavy Bombardment.

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.

What would happen if a massive asteroid struck Earth?

While NASA states that no known asteroid currently threatens Earth, past impacts demonstrate that the risk is real. The agency has tested deflection technology to alter an asteroid's path, as this visualization imagines a worst-case collision scenario.

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.

As of 2025, over 131 million pieces of debris orbit Earth

These pieces range in size from a grain of sand to the size of a bus and orbit with an average speed of 10 kilometers per second.

Only 40% of city-destroying asteroids have been detected

Statistical modeling shows that while we have identified the majority of extinction-level asteroids, smaller asteroids that can cause significant damage remain elusive. Some asteroids, like the one that exploded over Chelyabinsk in 2013, can't be detected ahead of time since they come from the sun's direction.

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.

Defending Earth against asteroids

This three-minute video overview explains NASA's ambitious test to slightly alter the course of an asteroid by slamming a fast-moving space probe into its surface. Scientists hope to one day, if needed, use the technique to protect Earth from an asteroid impact.

There are trillions of pieces of space trash that are too small to be tracked

Although scientists monitor more than 24,000 pieces of large orbital debris, space junk can be as small as a paint fleck. The density of this trash is steadily increasing with the growth of the space industry on Earth.

Watch visualization of different-sized asteroid impacts

The animations range from a 4-meter-wide asteroid that would burn up in the atmosphere with the impact of 0.6 Hiroshima nuclear bombs to a 940-kilometer asteroid the size of the dwarf planet Ceres, which would produce a mass extinction event.

Because it loses more atmospheric gas to outer space than the cosmic dust it collects as it moves through space, the Earth loses about 50,000 metric tons of mass every year.

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.

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.

About 66 million years ago, an asteroid larger than Mount Everest struck Earth off the coast of the Yucatán Peninsula and wiped out at least 75% of all species, including nearly all dinosaurs.

About 20% of asteroids are metal worlds similar to Earth's core

The biggest of these (that we know of) is 16 Psyche. Measuring 140 miles across, its iron and nickel content is potentially worth 10,000 quadrillion dollars. NASA’s mission to Psyche—reaching the asteroid in 2029—will study it to learn about its formation.

Antimatter was discovered by examining debris from collisions between atmospheric gases and cosmic rays—high-energy matter particles from space.

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...

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.

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.

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.

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.

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...

Some cosmic rays possess energies as high as 100,000,000 teraelectron volts—more than 10 million times the energy of particles accelerated in the Large Hadron Collider.

If the Earth stopped spinning, 85% of the world's population would experience supersonic winds

The planet's equator moves about 470 meters per second—over 1,000 miles per hour—and air there would continue moving at this speed for several minutes if the ground stopped rotating. These conditions would cause tsunamis, global storms, and fling debris fast enough to destroy nearly all human-made structures.

By 2030, experts estimate a 1 in 1000 chance of a plane being hit by space debris

As more satellites and spacecraft are launched, the rate of space debris re-entering Earth's atmosphere, including those that do not burn up completely, increases. International space agencies and air traffic control systems will need to coordinate to develop standardized methods and technical solutions to prevent and minimize future crisis scenarios.

Why Earth's atmosphere constantly loses the universe's lightest elements to space

The masses of hydrogen and helium are too small for these gases to be held by Earth's gravitational force, particularly when these atoms are given energy from collisions with high-speed particles from the sun. Although the planet loses a meter-wide balloon's worth of hydrogen every second, it will still take billions of years to exhaust the planet of this element.

A modern-day version of the dinosaur-killing asteroid would kill billions of people

Such an asteroid would level Central America, trigger tsunamis, spark global fires, and plunge the planet into an artificial winter lasting over a decade. Bunkers would be insufficient for survival without years of provisions.

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.

Simulations show unidentified asteroids around Venus may pose a threat to Earth

A new study suggests that Venus' co-orbital asteroids—space rocks that lag ahead or behind the planet—could potentially destroy cities if they strike Earth. While no observed co-orbitals currently pose a threat, observational bias prevents observation of those of greater risk.

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.

Experiments suggest nuking a metal-rich asteroid may strengthen it

Scientists exposed meteorite samples to proton irradiation at CERN to mimic the effects of a nuclear detonation. The material exhibited greater resistance to breaking after the exposure, suggesting nuclear weapons may better serve to deflect asteroids, not break them.

Space weather phenomena, including solar flares, coronal mass ejections, and solar wind, are driven by the sun's magnetic field and can affect Earth's ground- and space-based technological systems.

The sun emits a continuous stream of plasma known as the solar wind

Composed of charged particles—electrons and ions—the solar wind is deflected around the Earth by the planet's magnetic field. More powerful solar storms, known as coronal mass ejections, are short-lived but produce huge clouds of plasma that disrupt technology upon reaching Earth.

If particle accelerators did create black holes by packing tremendous energy into a small volume, then trillions would be created in Earth's atmosphere daily by cosmic rays.

About 10% of the radiation people are exposed to each year comes from outer space, with higher percentages for those living at higher elevations or who fly often.

Scientists have proposed using lasers to push space trash into Earth's atmosphere

Such projects would allow most debris to burn up and no longer pose a risk to active satellites, telescopes, and astronauts on space stations. Enacting these plans would require substantial investments from private and governmental space agencies and overcoming international laws that prevent the removal of another country's space equipment.

Ballistic experiments show that tardigrades are unlikely to be an alien species

Those fired from guns at speeds as high as 825 meters per second (1,845 mph) could be resuscitated after impact. Shock pressure from greater speeds tore apart the samples, suggesting they could not survive asteroid impacts if brought to Earth from outer space.

Protecting astronauts against space radiation

Outside the protective atmosphere of Earth, astronauts are constantly bombarded by radiation, which, among other dangers, increases the risk cancer. While those of us on Earth can mitigate the effects of similar radiation by limiting exposure,...

In 1962, the US detonated a nuclear weapon in space, which produced an electromagnetic pulse that disabled three low Earth orbit satellites and damaged electrical equipment in Hawaii.

Who owns outer space?

More and more material ends up in Earth's orbit, posing threats to orbiting space stations and satellites. A 1960s treaty technically made space the common property of humankind, but with increasing chances of conflict in space, things can seem anarchic. This video breaks down the brewing tensions in space.

Simulate the impact of an antimatter bomb, which releases energy from the annihilation of matter with antimatter, around the world.

Asteroids are artifacts of water's presence in the solar system

Asteroids contributed to planet formation and carried water from the solar system's outer reaches toward the center. They were also early providers of the necessary elements and conditions for life to evolve on Earth.

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.

In 2022, NASA's OSIRIS-REx spacecraft touched down on an asteroid

Dust of asteroid Bennu, slightly wider than the Empire State Building is tall, was found to be rich in carbon, nitrogen, and organic compounds essential for life. The presence of magnesium-sodium phosphate indicated Bennu may have broken off from a primitive ocean world.

Every day, lightning releases several Hiroshima bombs' worth of energy into the atmosphere

If all this lightning struck one location at once, the bolt would be the diameter of the center circle of a basketball court, turning the entire court into a crater. Its heat would ignite surfaces for miles around, and its shockwave would demolish buildings.

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.

The weight of Earth's atmosphere is equivalent to a 33-foot deep, global ocean

Because air is made up of gas molecules with mass, it is not weightless. On the planet's surface, we are effectively living in what is the equivalent of the bottom of an invisible ocean of these particles pressing against us, just as water molecules do when we are submerged.

Interactions between solar storms and Earth's magnetic field create auroras

Solar storms on the Sun's surface produce clouds of electrically charged particles, some of which make their way to Earth. Those trapped in Earth's magnetic field accelerate toward the north and south poles, colliding with atmospheric atoms and molecules in the process, which produces light.