News / Science

"Why 'Impossible' UFO Movement Is Usually an Illusion"

"Objects that seem to accelerate, zig-zag or vanish at impossible speed are often showing us geometry, not physics. Line-of-sight error, parallax and a quirk of human vision explained."

By Track the Unknown · 31 October 2026

The claim that launches a thousand threads is always the same: it moved in a way nothing could move. Before anything can be called impossible, though, the movement has to be real — and our eyes and cameras lie about movement constantly. Here is how the common illusions work, and what genuinely impossible movement would look like.

Line-of-sight error

Imagine an aircraft flying a dead straight line at constant speed, but passing close to you rather than across your field of view. As it approaches, it appears slow and small. As it draws level, it appears to sweep sideways and accelerate violently. As it recedes, it slows again. Nothing about its motion changed — the geometry between you and it did.

This is the single most common explanation for "instant acceleration" in witness accounts, and it applies to dashcam and cockpit footage too. It is also why experienced pilots, who know they are watching a crossing target, are still routinely surprised by how fast something appears to move.

Parallax: the moving observer problem

If you are on a moving aircraft and the object is not where your brain assumes, the background and the object separate in ways that look dramatic. A distant cloud can appear to rush past a slower-moving object; a closer object can appear to streak. The Navy's GIMBAL and GOFAST videos, released by the Pentagon in 2020, have been argued over on exactly these grounds. The Navy confirmed the videos were genuine US Navy footage; it did not confirm they showed anything anomalous. Analysts disagree about how much of GOFAST's apparent speed is parallax and how much is the object's real motion — the answer depends on an altitude and distance that the footage alone does not settle. Both readings are on the table, and honest people land on different sides.

No reference points, no distance

Against a clear sky, a light has no scale. You cannot tell how far away it is, and without distance, apparent speed is meaningless. A modest aircraft at two kilometres can look like a rocket; a rocket at two hundred kilometres can look like it is drifting. Night makes it worse: the eye loses the depth cues that daytime clouds, terrain and haze provide.

Autokinesis: lights that move on their own

Stare at a small, stationary light in a dark sky for several seconds and it will begin to drift, wander or pulse. This is autokinesis, a well documented quirk of vision, and it is why unlit or distant lights in isolation so often get reported as manoeuvring. It also explains why a "cluster" of lights can appear to spread out and reform when each light stayed exactly where it was — see twinkling stars explained and aircraft lights explained.

What would actually count as impossible

Real impossible movement means measured angular speed combined with a known distance — from radar, infrared or triangulation — giving a real speed, a real turn radius and a real acceleration that known vehicles cannot produce. That requires more than one sensor and more than one vantage point. It is the standard AARO applies when it closes cases, and it is the standard a good sighting report should aim at: time, duration, direction, and anything the object passed behind.

A worked example

Suppose a light crosses about 30 degrees of sky — six full Moons' worth — in ten seconds. To the eye that is startlingly fast: three degrees per second, far quicker than anything you are used to watching. Now suppose a radar track later places it 5 kilometres away. Three degrees per second at that range works out at roughly 260 metres per second — about the cruising speed of a jet airliner. Same sky, same video, entirely different event once distance is known.

This is why single-sensor, single-witness footage cannot settle anything. Without a range, angular speed is a Rorschach test: it can be made to look like a slow drone or an impossible object simply by assuming a distance. Multi-sensor data — radar with infrared, two vantage points, a track that persists — is what turns a story into a measurement.

Why pilots still report

None of this means every report is an illusion. The geometry above explains a great deal, but it does not explain sensor-confirmed tracks with no identifiable source, and it does not explain why aircrew with instrument training and no incentive for embarrassment keep filing reports. The honest position is the uncomfortable one: perception is unreliable, and some cases are genuinely unresolved.

If you have seen something that still does not fit the usual explanations, the free sky checker is the fastest first step — and the glossary covers the terms you will see in the case files.

Resources

Tags: parallax, line of sight, autokinesis, gimbal, gofast, perception, motion, identification, science