A fireball in the sky last night was most likely a very bright meteor, a fragment of a comet or asteroid burning up as it hit the atmosphere. Most fireballs are visible for only a few seconds. A slow light that crawled across the sky for a minute or more, breaking into pieces, was more likely space debris or a rocket stage coming back down. Either way, the most useful thing you can do now is write it down and report it.
Reports matter. The American Meteor Society (AMS) collects fireball reports from around the world, and when several people report the same event it can sometimes work out the object's actual path through the atmosphere.
What is a fireball?
The AMS defines a fireball as a very bright meteor, generally brighter than magnitude −4, about as bright as Venus in the morning or evening sky. A bolide is a fireball that explodes in a bright flash at its end, often breaking visibly into pieces. NASA's Center for Near Earth Object Studies uses a slightly stricter test, magnitude −3 or brighter when seen straight overhead, and notes that the words fireball and bolide are often used interchangeably.
Meteoroids hit the atmosphere at 11 to 72 km per second, according to the AMS. That speed is why a fireball is so brief, and why it can glow green, yellow or blue as different elements vaporise. The green light file covers why some fireballs look green, and the orange lights file covers slower, warmer-coloured ones.
How common are fireballs?
Common across the planet, rare for any one person. The AMS says several thousand meteors of fireball brightness occur in Earth's atmosphere every day, but most happen over oceans or uninhabited land, and many are masked by daylight. Its rule of thumb for experienced observers is one fireball of magnitude −4 for every 20 hours or so of watching, and one of magnitude −6 or brighter for every 200 hours. On its report form, the AMS calls seeing a fireball extremely rare and often a once-in-a-lifetime event.
Fireball or space debris?
Re-entering satellites and rocket stages also light up like fireballs, and the two get confused. The difference comes down to time and angle.
| Check | Meteor fireball | Space debris re-entry |
|---|---|---|
| How long | A few seconds. The AMS asks people not to report anything over 30 seconds. | Can take minutes, travelling hundreds of kilometres. |
| Speed | 11 to 72 km per second. | Roughly 8 km per second. |
| Path | A short, fast streak. | Almost horizontal, following the curve of the Earth. |
| Pieces | One head, sometimes ending in a flash and fragments (a bolide). | Slows and breaks into pieces that travel on together. |
| Where to report | The American Meteor Society. | Keep your own record. The AMS does not accept reports of rocket launches, satellites or aircraft. |
The speed and path figures for space debris come from Michael J. I. Brown of Monash University, writing in The Conversation. The meteor figures and the reporting limits come from the AMS.
Did it make a sound?
Rarely. The AMS says a very bright fireball, usually brighter than magnitude −8, that reaches below about 50 km and explodes can produce sonic booms heard on the ground. Sound travels slowly, so a boom arrives 1.5 to 4 minutes after the flash, and the AMS suggests listening for a full 5 minutes. Some witnesses also report hissing or crackling at the same moment as the fireball. The AMS calls these electrophonic sounds and says they have never been validated scientifically.
Did anything land?
Probably not. The AMS says a fireball generally has to be brighter than about magnitude −8 to −10 to drop a meteorite at all. The glow stops 15 to 20 km up, after which any stones fall unseen, and they are probably not hot when they land. Only a handful of witnessed meteorite falls occur each year.
The fireball report card
Write these down before you sleep. They are the details the AMS asks observers to remember.
- TimeDate and time to the minute, with your time zone.
- PlaceWhere you stood: address or nearest town, and whether you were outside or in a car.
- Start and endThe compass direction and height above the horizon where it appeared and where it vanished. Stack fists at arm's length up from the horizon to judge height. Constellations work if you know them.
- DurationCount it out if you can. Seconds, not "a while".
- BrightnessCompare it with things you know. On the AMS scale, bright Venus is magnitude −4.5, the first-quarter Moon −9.4 and the full Moon −12.6.
- Colour and shapeColours, length across the sky, a tail or glowing train, pieces breaking off, a flash at the end.
- SoundAnything at the same moment, and anything in the 5 minutes after.
- EvidenceDashcam, doorbell or phone footage, with the original file kept untouched. Names of other witnesses. The evidence checklist covers metadata.
How to report a fireball to the American Meteor Society
The AMS takes reports through an online form at fireball.amsmeteors.org. The International Meteor Organization's fireball site, fireball.imo.net, opens the same form. It is interactive, asks about your sighting step by step, and leaves room for your own description at the end.
The AMS sets some limits. It asks people not to report sightings that lasted more than 30 seconds, recurring events, slow blinking objects, or lights crossing the sky in twos or threes. It will not accept reports of aircraft, rocket launches, satellites or sky lanterns. As of late September 2026 much of the AMS website is offline after a cyberattack, but the report form is working.
Keep your own copy too. The report builder saves your notes as a clean record and shows other places to send them. If the light does not fit a fireball, the sky identifier checks satellites and planets for that minute, the flashing light file covers lights that blinked, and how to report a UFO sighting covers the other routes. In Canada, see how to report a sighting in Canada.
Sources
- American Meteor Society, Fireball FAQs (archived copy, December 30, 2025; the live AMS site is partly offline)
- American Meteor Society, Report a Fireball (form checked September 29, 2026)
- American Meteor Society, home page notice on the cyberattack
- International Meteor Organization, fireball report form
- NASA JPL Center for Near Earth Object Studies, Fireballs introduction
- The Conversation, Comet, rocket, space junk or meteor? Here's how to tell your fireballs apart, Michael J. I. Brown, May 11, 2025
Common questions
What was the fireball in the sky last night?
Most likely a bright meteor, a fragment of comet or asteroid that burned up in a few seconds. If it lasted a minute or more and broke into a slow line of pieces, it was more likely space debris re-entering.
How do I report a fireball?
Use the American Meteor Society's online form at fireball.amsmeteors.org. Have the time, your location, where it started and ended, how long it lasted, its brightness and its colour ready.
Was it a meteor or space junk?
Time it. Meteors last a few seconds and move at 11 to 72 km per second. Space debris moves at roughly 8 km per second, nearly level, and can take minutes to cross the sky.
Can a fireball reach the ground?
Rarely. The AMS says a fireball usually has to be brighter than about magnitude −8 to −10 to drop a meteorite, and the pieces fall unseen for the last 15 to 20 km.
