Planetary & Solar-System Phenomena
Fireballs and Meteorite Falls
A fireball is an especially bright meteor, and a meteorite is a piece that survives the fall and reaches the ground.
Every day small space rocks strike the atmosphere; a few are bright enough to be seen from far away.
- Observe
A brilliant streak that may flare, fragment and sometimes produce a boom.
- Measure
Camera networks, satellites and infrasound measure brightness, path and energy.
- Model
Entry models predict where fragments fall.
- Explain
Space rocks turn motion into light and heat in the atmosphere.
What is it?
A meteoroid is a small rock or piece of metal in space. When it enters the atmosphere at tens of kilometers per second it heats the air around it and glows, and the streak is called a meteor. A fireball is a meteor brighter than about magnitude −4, roughly as bright as Venus. If a meteor breaks up with a visible explosion it is often called a bolide. If any of it survives to the ground, the piece is a meteorite.
Most meteors are tiny. Larger ones can fragment high in the atmosphere, sometimes producing a sonic boom minutes after the flash. Only a small fraction of fireballs drop meteorites that can be found.
How does it happen?
- Stage 1MeteoroidA rock in space
- Stage 2MeteorIt glows in the atmosphere
- Stage 3FireballExceptionally bright
- Stage 4MeteoriteA piece reaches the ground
What do we actually observe?
- Entry
- Typical entry speeds range from about 11 to 72 kilometers per second. The glow begins around 100 kilometers up as air compresses and the surface melts and vaporizes.
- Fragmentation
- Stress from air pressure can break the object apart, causing brightening flares and, sometimes, shock waves that reach the ground.
- Sound
- Sound travels far slower than light, so a boom can arrive several minutes after the flash.
- Dark flight
- Below roughly 20 kilometers, surviving fragments slow, stop glowing and fall as dark rocks.
How do scientists detect it?
- Fireball camera networks. Networks such as the Global Meteor Network and NASA's all-sky cameras triangulate paths.
- Government satellite sensors. NASA's CNEOS database lists bolides detected by US government sensors.
- Weather radar and GOES. Falling meteorites can show up on weather radar, and GOES lightning sensors sometimes record bolides.
- Eyewitness reports. The American Meteor Society collects reports that help locate falls.
On 15 February 2013 a roughly 20-meter object entered over Chelyabinsk, Russia. Its airburst injured more than a thousand people, mostly through broken glass, and fragments were later recovered from a nearby lake.
Why does it matter?
- Meteorites are samples of the early Solar System and of asteroids we have not visited.
- Tracking entries helps assess the impact hazard.
The SpaceWeatherTracker connection
Meteor showers, which SpaceWeatherTracker follows, produce many meteors and occasional fireballs. Most fireballs, though, are unrelated to showers and can occur any night.
Related phenomena
Primary family: Planetary & Solar-System Phenomena
Fireballs and Meteorite Falls: common questions
What is the difference between a meteor and a meteorite?
A meteor is the streak of light. A meteorite is the rock that survives and lands on the ground.
Should I look for a meteorite after a bright fireball?
Only a small fraction of fireballs drop meteorites. If you search, respect land ownership and local law, and use reported fall locations rather than guessing.