What it probably was
Venus, satellites, balloons, drones, clouds and cameras: the usual suspects.
How this site works. Every fact is in our own words with its source linked beside it. The pictures are our own drawings. We never say aliens have been found, because nobody has shown that they have; we show what was reported, then what the evidence says.
What did you see?
Pick the one that sounds most like your sighting, and we’ll show you the most likely everyday cause, with the source.
Probably: Venus (or another bright planet or star)
If you saw: A very bright, steady “star”, low in the sky around sunset or before dawn
Venus is one of the most confused objects in the sky, especially when it is low near the horizon. NASA Night Sky Network
Venus is the third brightest object in the sky, after the Sun and the Moon. NASA, Venus
A bright light such as Venus often seems to move, and can even seem to “follow” a car. Britannica
If you know the date, time and direction, free planetarium software such as Stellarium can show what was in the sky. NASA Night Sky Network
Probably: a Starlink satellite train
If you saw: A line of evenly spaced lights moving together across the sky
Before they spread out, a new batch circles Earth as a “train” that looks like a long string of bright lights. Skeptical Inquirer, Starlink
A satellite high overhead can still be in sunlight when it’s dark on the ground, which is why trains show up just after sunset or before sunrise. Skeptical Inquirer, Starlink
When the first trains appeared in May 2019 they were often reported as UFOs, including by airline pilots. Skeptical Inquirer, Starlink
If you know the date, time and direction, free planetarium software such as Stellarium can show what was in the sky. NASA Night Sky Network
Probably: sunlight glinting off a satellite
If you saw: A single light that flares up brightly for a moment, then fades
Sunlight flashing off a satellite’s solar panels can make a bright light that is often mistaken for a fast UAP or an “orb”. AARO FAQ
With a time and place, a sighting can be checked against air traffic, balloon-tracking and satellite-tracking records. AARO FAQ
Probably: a balloon
If you saw: A pale dot drifting slowly, maybe shining in daylight
High-altitude balloons for weather and research often have no markings and can look strange from some angles. AARO FAQ
The US National Weather Service alone launches hundreds of balloons a day; worldwide, thousands go up every day. AARO FAQ
In others, objects drifting at the speed and direction of the wind were judged almost certainly to be balloons. AARO imagery
If you saw it long after sunset, it is less likely to have been a sunlit balloon or an unlit aircraft. NASA Night Sky Network
Probably: a lenticular cloud
If you saw: A smooth, saucer-shaped cloud near hills that hardly moves
Lenticular clouds form downwind of hills and mountains, look a lot like science-fiction flying saucers, and are thought to be one of the most common explanations for UFO sightings worldwide. Met Office
They are quite unusual in the British Isles, but do sometimes appear. Met Office
Probably: a drone
If you saw: Small lights that hover, dart about and change direction
Drones can move erratically and fast, may have no visible lights, and are often too small for radar to classify. AARO FAQ
Some remote-control model aircraft are even built to look like flying saucers. NASA Night Sky Network
Investigators say the most useful thing is to record the time and the location of both you and the object. AARO FAQ
Probably: a rocket launch
If you saw: A glowing spiral or a long glowing plume high in the sky
Rocket launches can leave glowing spirals and lingering exhaust plumes high in the sky. AARO FAQ
With a time and place, a sighting can be checked against air traffic, balloon-tracking and satellite-tracking records. AARO FAQ
Probably: a meteor or fireball
If you saw: A bright streak that lasts a second or two
Other “UFOs” can be rocket launches, comets, military jets, weather balloons, satellites, meteors and fireballs, and odd clouds. NASA Night Sky Network
Check for recent meteor showers and things that are common in your area. NASA Night Sky Network
Probably: something the camera did
If you saw: Something in your photo that you didn’t see with your own eyes
Camera lenses can turn a single point of light into something that looks saucer-shaped. Britannica
Some photo “UFOs” are lens flare or other camera artefacts. NASA Night Sky Network
Reflections in windows and glasses can overlay one view on another. Britannica
Compressing video adds artefacts to it, so AARO wants original, uncompressed camera files. AARO FAQ
Still unidentified? Good. Write it down.
If you saw: None of these, or I’m really not sure
AARO, the US government’s UAP office, says many cases are labelled “unidentified” simply because the sensors didn’t collect enough information to say what they were. AARO FAQ
NASA’s team said eyewitness reports can be interesting and compelling, but can’t be reproduced and usually lack the details needed for a firm answer. NASA UAP study
Investigators say the most useful thing is to record the time and the location of both you and the object. AARO FAQ
Phone photos carry useful hidden data, such as GPS position and time stamps. AARO FAQ
Your local astronomy club can help, so note the date and time, how long you watched, its path and speed, and how bright it was. NASA Night Sky Network
This is a friendly first guess, not a verdict. Plenty of things fit more than one description.
Planets and stars
Venus is one of the most confused objects in the sky, especially when it is low near the horizon. NASA Night Sky Network
Venus is the third brightest object in the sky, after the Sun and the Moon. NASA, Venus
A bright light such as Venus often seems to move, and can even seem to “follow” a car. Britannica
Sirius, Jupiter and Mercury are also often reported as UFOs, and bright planets lined up near the horizon can look like a formation of strange lights. NASA Night Sky Network
AARO says bright planets like Venus and Jupiter, and meteors, can look as if they are hovering or manoeuvring. AARO FAQ
Satellites and Starlink
Sunlight flashing off a satellite’s solar panels can make a bright light that is often mistaken for a fast UAP or an “orb”. AARO FAQ
Starlink is a network of thousands of low-orbit internet satellites, launched in groups of fifty or more. Skeptical Inquirer, Starlink
Before they spread out, a new batch circles Earth as a “train” that looks like a long string of bright lights. Skeptical Inquirer, Starlink
A satellite high overhead can still be in sunlight when it’s dark on the ground, which is why trains show up just after sunset or before sunrise. Skeptical Inquirer, Starlink
When the first trains appeared in May 2019 they were often reported as UFOs, including by airline pilots. Skeptical Inquirer, Starlink
In 2022, pilots reported pulsing “racetrack” lights circling far away; amateur investigators matched every video they could date and place to Starlink satellites. Skeptical Inquirer, Starlink
Balloons and bags
High-altitude balloons for weather and research often have no markings and can look strange from some angles. AARO FAQ
The US National Weather Service alone launches hundreds of balloons a day; worldwide, thousands go up every day. AARO FAQ
Windblown plastic bags, foil party balloons and birds can look odd because of their small size and unpredictable motion; even radar can be fooled. AARO FAQ
Drones, planes and rockets
Drones can move erratically and fast, may have no visible lights, and are often too small for radar to classify. AARO FAQ
Some remote-control model aircraft are even built to look like flying saucers. NASA Night Sky Network
Ordinary planes can look strange from unusual angles, in poor visibility or through infrared cameras. AARO FAQ
Rocket launches can leave glowing spirals and lingering exhaust plumes high in the sky. AARO FAQ
A CIA history declassified in 2014 says U-2 and later OXCART spy-plane flights accounted for more than half of all UFO reports in the late 1950s and most of the 1960s. Britannica
Clouds
Lenticular clouds form downwind of hills and mountains, look a lot like science-fiction flying saucers, and are thought to be one of the most common explanations for UFO sightings worldwide. Met Office
They are quite unusual in the British Isles, but do sometimes appear. Met Office
Cameras, eyes and radar
Camera lenses can turn a single point of light into something that looks saucer-shaped. Britannica
Some photo “UFOs” are lens flare or other camera artefacts. NASA Night Sky Network
Reflections in windows and glasses can overlay one view on another. Britannica
Compressing video adds artefacts to it, so AARO wants original, uncompressed camera files. AARO FAQ
Judging the distance and speed of a light in a blank sky is very unreliable, because there is nothing to compare it with. Britannica
Radar is more reliable in some ways, but can’t always tell aircraft from meteor trails, rain or layers of warm and cold air. Britannica
And the rest
Other “UFOs” can be rocket launches, comets, military jets, weather balloons, satellites, meteors and fireballs, and odd clouds. NASA Night Sky Network
At least some sightings have been hoaxes. Britannica
Most psychologists who have studied “alien abduction” stories doubt they involve aliens, and point to a common experience called sleep paralysis. Britannica
Our view: none of this means people who report UFOs are silly. Venus has fooled pilots, police officers and astronomers. If it fools you, you are in excellent company.