What are those lights in the sky?

Blinking means aircraft

Every aircraft flying at night has to show position lights, and they follow the same pattern worldwide:

• Red on the left wingtip (the port side).
• Green on the right wingtip (starboard).
• White on the tail, facing backward.

These burn steadily. The flashing comes from the anti-collision lights: a red beacon on the top and bottom of the fuselage, and bright white strobes on the wingtips. If you see red on the right and green on the left, the plane is coming toward you. Red and green together, with no white, means it’s heading straight at you. A single white light with a strobe usually means it’s flying away.

Helicopters carry the same lights. A helicopter is the light that blinks, moves slowly and sometimes stops altogether.

The “star” that doesn’t move

A very bright white light low in the sky that seems to hang in place, sometimes for minutes, is often an airliner on approach with its landing lights on, pointed more or less straight at you. Because it’s coming toward you rather than crossing your view, it barely appears to move. Near a busy airport you may see two or three of them in a line, each one a jet queued for the same runway. Give it a few minutes and it grows brighter, then turns or passes overhead with a roar.

Planets do the same trick without the roar. Venus in particular is bright enough to be mistaken for a plane at dusk. It doesn’t blink, and over an evening it drifts with the stars rather than flying anywhere. And slow red flashes in exactly the same place every night are obstruction lights on a radio tower, a wind turbine or a tall building, put there for pilots.

A steady light that glides silently: a satellite

Satellites don’t carry lights. You see them because they’re high enough to still be in sunlight after it’s dark where you are, which is why they show up in the first couple of hours after sunset and before sunrise. A satellite is a steady, silent point moving in a straight line at an even pace. It doesn’t blink, doesn’t turn, and often fades out partway across the sky as it passes into Earth’s shadow.

The brightest one: the space station

The International Space Station is one of the brightest things in the night sky when it’s visible, often about as bright as Venus. It crosses in a few minutes, steady and silent, with no flashing lights. NASA’s Spot the Station service lists when it will pass over you.

A line of lights: a Starlink train

A string of evenly spaced dots moving together across the sky is a batch of Starlink satellites shortly after launch. They’re released close together and spread out as they climb to their working orbit, so the “train” is only visible for a few days after each launch, usually around dusk and dawn. It’s one of the most reported strange sights in the sky, and it’s entirely ordinary.

Small, low and erratic: a drone

Drones flown at night carry their own lights. In the US, the rules for commercial drone pilots require anti-collision lighting visible for at least three statute miles when flying at night. A drone is the light that hovers, darts, climbs straight up or stops, usually low and close, and makes a high whine if you can hear it at all. A coordinated group forming shapes is a drone light show.

How to tell for sure

Open a live aircraft map, face the light, and look for a blip in that direction. If there’s an aircraft there, tap it for its type, operator, altitude and route. If there’s nothing, it may be a satellite, a planet, or an aircraft that isn’t broadcasting. Why some aircraft don’t appear. For the planes that keep you up after dark, see why planes fly over your house at night.