AARO Information Paper: Forced Perspective and Parallax in UAP Reports

A report of an object the size of a football field, or one that crossed the horizon in seconds, rests on an estimate of distance that the observer usually never states. This short paper from the All-domain Anomaly Resolution Office is about that hidden estimate.

What this record is

This is “Effect of Forced Perspective and Parallax View on UAP Observations,” an AARO Information Paper dated May 2024. It runs to four pages with three figures. The first is a tourist photograph using forced perspective, the second shows a featureless sphere at an unknown range, and the third is a diagram of an aircraft passing over a river with an object suspended above it. AARO’s Chief of Staff reviewed it on 6 February 2025 under the FY2024 National Defense Authorization Act and released it in full as case number 330UAP000016. The Office of the Secretary of Defense later passed it to the National Archives. It is a teaching document written for a general reader. It discusses no particular case.

What it says

The introduction sets out the claim carefully. No single explanation fits every report, but forced perspective and parallax “can frequently explain excessively large sizes or high speeds described in UAP reports,” especially when the observer is far from the object and moving fast relative to it.

Forced perspective is the trick behind holiday photographs of people “holding” the Eiffel Tower or propping up the Leaning Tower of Pisa, which the paper gives as roughly 190 feet tall against a person of five to six feet. The illusion is easy to see through in those photos because everyone knows how big a person and a tower are. In the sky there is usually nothing of known size to compare with. Observers fall back on clouds, trees or buildings, whose own distance they may misjudge, and the error gets worse when the object has no windows, propellers, wings or other features that would hint at its size. Size and distance are tied together: a 10-foot featureless sphere looks smaller if the observer assumes it is closer, and larger if they assume it is farther away.

Parallax is explained with the familiar exercise of holding up a thumb and closing each eye in turn, so that the thumb seems to jump against the background. A moving observer gets the same effect continuously. In the paper’s diagram, an aircraft passes three points while a stationary object hangs above a river. From the first point the object appears against the right bank, from the second against the water, and from the third against the left bank. The object seems to cross the river in the opposite direction to the aircraft, and the faster the aircraft flies, the faster the object seems to go. A footnote says the effect vanishes when the observer is directly above the object. The paper says electronic sensors on aircraft are just as vulnerable as eyes, because they are often too far away to get an exact range.

The summary guards against overreach. Not every fast-moving UAP is explained this way, single-observer reports remain “critical to consider,” and observers should still estimate range, size and speed. The paper hopes that people who understand these effects will describe what they saw with more context.

Context

This paper sets out, in plain language, the reasoning behind several of AARO’s case resolutions. The office’s 2025 resolution of the Navy’s “Go Fast” video, released in the same Office of the Secretary of Defense series, rests on the parallax argument. It concluded that the apparent high speed came from the jet’s own motion over the ocean, and that the object was far higher above the water than it looked (see the Go Fast video). AARO gave a similar explanation for the apparent speed in its analysis of the Aguadilla video. The same range problem lies behind the physics argument in the Loeb-Kirkpatrick constraints paper: if an object seems to move impossibly fast yet produces no fireball or sonic boom, the distance estimate is the likeliest thing to have gone wrong.

Status

This is an explanatory paper, not a case file, and it sets out standard optics rather than new findings. It is also careful about its own limits and does not claim that parallax or forced perspective accounts for any specific unresolved report. Its value on this site is as a tool for readers. When a report says “enormous” or “impossibly fast,” the first question to ask is how the witness knew the distance. Before the National Archives transfer, the site carried only an automatically generated placeholder entry for this paper.

Sources

• National Archives catalog entry: https://catalog.archives.gov/id/499915948
• PDF of the record: https://catalog.archives.gov/medialz/electronic-records/rg-615/493468580/016_Parallax_Paper.PDF
• Series: Records from the Office of the Secretary of Defense Relating to Unidentified Anomalous Phenomena: https://catalog.archives.gov/id/493468580
• National Archives, Record Group 615 UAP records: https://www.archives.gov/research/topics/uaps/rg-615