What Was That Moving Light in the Sky? A Quick Identification Guide

You step outside, look up, and see a light moving across the sky. What is it? This guide will help you identify the most common things people see overhead — from satellites to shooting stars.

Steady Light Moving in a Straight Line

Most likely: a satellite

If you see a steady, non-blinking light moving smoothly across the sky in a straight line, you’re almost certainly watching a satellite. Characteristics:

No blinking or flashing — steady brightness throughout
Moves across the sky in 2–6 minutes depending on the pass geometry
Appears during twilight — roughly 20–90 minutes after sunset or before sunrise
May gradually fade as it enters Earth’s shadow

If it’s exceptionally bright (brighter than any star), it’s likely the International Space Station. Use the Tonight tool to confirm.

Very Bright, Slow-Moving Light

Most likely: the ISS or a large satellite

The ISS is by far the brightest artificial satellite. It can reach magnitude -4 or brighter — rivaling Venus. Key characteristics:

Unmistakably bright — brighter than anything else in the sky except the Moon
Steady, white light with no blinking
Takes 3–6 minutes to cross the sky
Visible in twilight hours only

Check the ISS pass page to see if it matches a predicted pass for your location.

Line of Lights Moving Together

Most likely: a Starlink train

A string of evenly spaced lights moving in formation is almost certainly a recently launched batch of SpaceX Starlink satellites. They look like:

10–60 bright dots in a line, all moving the same direction
Evenly spaced, like pearls on a string
Most dramatic 1–5 days after a SpaceX Starlink launch
The line gets more spread out over subsequent days

Check the launch schedule to see if a Starlink mission launched recently. Read the full Starlink train guide for more details.

Blinking or Flashing Light

Most likely: an airplane

Airplanes have navigation lights that blink in a regular pattern — typically a combination of red, green, and white lights. Key differences from satellites:

Blinks or flashes at regular intervals
Red and green lights may be visible (port and starboard)
Sound — you’ll often hear engine noise, especially below 20,000 feet
Moves slower than satellites relative to the sky
Navigation lights stay on throughout the entire crossing

Some satellites can also appear to flash — tumbling rocket bodies or satellites catching sunlight at different angles — but they flash irregularly, not in the steady pattern of aircraft lights.

Brief, Bright Streak

Most likely: a meteor (shooting star)

A quick streak of light lasting 1–3 seconds is a meteor — a tiny piece of space debris burning up in the atmosphere:

Very fast — crosses a portion of the sky in a second or two
May leave a brief trail that fades in a couple of seconds
Random direction — can appear anywhere in the sky
Some are colorful — green, blue, or orange depending on composition

During meteor showers (Perseids in August, Geminids in December, etc.), you’ll see many more per hour, and they’ll appear to radiate from a specific point in the sky.

Light That Suddenly Appears and Fades

Most likely: an Iridium flare or satellite glint

Some satellites produce brief, very bright flashes (called “flares” or “glints”) when their reflective surfaces catch sunlight at just the right angle:

Appears suddenly in a specific part of the sky
Brightens dramatically over a few seconds, then fades
May be much brighter than any star, briefly rivaling Venus
Stationary or slow-moving during the flare

The original Iridium satellites were famous for predictable, brilliant flares. While most have been deorbited, other satellites still produce similar glints.

Hovering Bright Light (Not Moving)

Most likely: a planet or bright star

If the light isn’t moving at all, it’s probably Venus, Jupiter, or a bright star like Sirius:

Venus appears in the west after sunset or east before sunrise. It’s extremely bright and can look unusual near the horizon.
Jupiter is the second-brightest planet and can appear anywhere along the ecliptic
Sirius (the brightest star) twinkles dramatically when low on the horizon, sometimes appearing to flash colors due to atmospheric refraction

Planets and stars don’t move noticeably over minutes — they track slowly with Earth’s rotation over hours.

Multiple Lights in a Pattern (Stationary)

Most likely: a drone, helicopter, or tower lights

If you see a group of colored lights that seem to hover in one area:

Drones often have colored LED lights in geometric patterns
Helicopters have navigation lights and a bright spotlight
Cell towers and radio masts have steady red lights at various heights

Still Not Sure?

If you saw something you can’t identify:

Note the time, direction, and duration of the sighting
Check the Tonight tool — enter your location and see if any satellite passes match your sighting
Check the launch schedule — a recent Starlink launch explains most “line of lights” sightings
Consider the time of night — satellites are only visible during twilight. Deep nighttime sightings are typically aircraft, meteors, or drones.

Most “UFO” sightings turn out to be Starlink trains, the ISS, or rocket launches viewed from a distance during twilight. The night sky is more active than most people realize!