Unidentified Aerial Phenomena (or UAPs, formerly known as UFOs) are back in the news, with the U.S. Defense Department’s recent publication of (mostly old) case files, and the release of Steven Spielberg’s new film Disclosure Day on June 12. It’s unlikely that either will move us any closer to unraveling the mystery of UAPs. What might help, though, is a method for determining which of the thousands of sightings reported every year are truly worth investigating.
Toward that end, we have proposed a rating scale meant to help citizens and scientists alike assess the reliability of UAP reports based on the type and quality of evidence. This won’t solve most cases (more than half of the sightings reviewed by the U.S. government’s All-domain Anomaly Resolution Office (AARO) lack sufficient data for rigorous analysis). But it might help us reduce the number of “false alarms.”
We start from the premise that most UAP reports stem from misunderstandings — people seeing unfamiliar objects in the sky that, if investigated fully, would have an ordinary explanation. These objects range from balloons and drones (which together accounted for 91% of sightings between 1996 and 2024 that could be resolved by the AARO) to meteors, flocking birds, and even rare atmospheric phenomena such as “sprites” and “elves.”
It isn’t that people who mistakenly report ordinary objects as UAPs are dumb or dishonest. Most of the time, they’ve just seen something strange (to them) and want to know what it is. If you’ve never seen a bright fireball in the night sky or a train of Starlink satellites, it might well look like something from a sci-fi movie.
Nor do we outright dismiss the idea that UAPs could be aliens. It’s entirely possible that other spacefaring civilizations exist in our galaxy, and even though the distances between stars are great, what would a 10,000-year journey matter to beings that live (perhaps in a dormant state) 100 times that long? The possibility that even one reported UAP could be evidence of advanced extraterrestrial life accounts for the ongoing public interest in the subject and makes it worth serious scientific and governmental investigation.
A proposed reliability scale for UAP reports
How, then, does our rating scale rank reported sightings? We categorize them according to the quality of their evidence, considering such factors as the number of observers, whether there is supporting evidence (such as photos and video), and whether witnesses (or a third party) have made some kind of effort to find an ordinary explanation for what they saw or experienced.
- 10 — Long-duration sighting by multiple individuals/groups at different locations or recorded evidence from multiple sensors; physical evidence; reviewed by experts, and so far unexplained
- 9 — Long-duration sighting by multiple individuals/groups at different locations or recorded evidence from multiple sensors; physical evidence
- 8 — Long-duration sighting by multiple individuals/groups at different locations or recorded evidence from multiple sensors; reviewed by experts, and so far unexplained
- 7 — Long-duration sighting by multiple individuals/groups at different locations or recorded evidence from multiple sensors; plausibly explained, but the explanation is disputed
- 6 — Long-duration sighting by multiple individuals/groups at different locations or recorded evidence from multiple sensors
- 5 — Long-duration sighting by one person or group, with recorded evidence
- 4 — Long-duration sighting (more than ~10 seconds) by one person or group, no recorded evidence
- 3 — Short-duration sighting by one person or group, with recorded evidence
- 2 — Short-duration sighting by one person or group, researched but no recorded evidence
- 1 — Short-duration sighting (under ~10 seconds) by one person or group, not researched
- 0 — Sighting explained beyond a reasonable doubt as a known phenomenon or object
That last step — attempting to find an ordinary explanation, which is required to rise from Category 1 in our scale to Category 2 and above — may be the most important in reducing the number of false alarms. Some UAP reporting organizations, such as the National UFO Reporting Center and Enigma Labs, offer likely explanations for some cases submitted online. Future systems using artificial intelligence will undoubtedly be able to explain even more. But even today, you might find your own explanation for a mysterious light in the sky with a bit of online research.
A “Before You Report” checklist
Toward that end, we urge UAP witnesses to take the time to do a simple self-guided check before reporting a sighting. Below is a list of possible UAP explanations along with sources you can check for each.
- Airplanes: FlightRadar24 or ADS-B Exchange
- Weather balloons: SondeHub Tracker
- Rocket launches or re-entries: U.S. Launch Range Locations or Vapor Tracers
- Meteors: American Meteor Society
- Satellites: N2YO.com Real Time Satellite Tracking or Starlink Satellite Map
- Military aircraft: This map of U.S. military bases to see where tests and overflights may have taken place. Many bases post notices of these events, and can answer queries through their public information offices.
- Unusual cloud formations: Cloud Appreciation Society
- Stars or planets: Stellarium Star Map
- Birds: BirdCast bird migration forecasts in real-time
- Drones: Interactive Map of UAV Drones over the USA (a very limited list of the estimated 8,500 public and private drones flying in U.S. airspace on any given day)
For a sighting to be classified higher on our scale (Category VIII and above) requires a thorough, in-depth investigation by expert outside reviewers. This is particularly true for information collected by advanced sensors, whose specific capabilities (and possibilities for error) are often known only to a relatively small group of specialists.
We suggest that this type of review be conducted by neutral parties (not associated with the UAP witness), consistent with the tradition of scientific peer review, and that it include people with professional backgrounds in science, engineering, psychology, and other relevant fields. These expert reviews could be done by the AARO or by a standing committee in a respected body such as the American Institute of Aeronautics and Astronautics or the U.S. National Academy of Sciences. Although it was not tasked to examine evidence for particular UAP claims, the 2023 NASA Unidentified Anomalous Phenomena Independent Study could be a model for such an effort.
Whoever the expert reviewers are, we should keep in mind that UAP sightings, by their very nature, pose a problem for scientific study, as they cannot be reproduced in a lab setting. Physical evidence is helpful, but also rare. Credibility in many cases hinges on the reliability of witness testimony, and positive proof will be difficult to come by even under the best circumstances.
Fortunately, there are a number of individuals and groups, including Metabunk, Skeptoid, the American Institute of Aeronautics and Astronautics, and the Society for UAP Studies, making good-faith efforts to evaluate UAP evidence scientifically, with a critical eye. We are fully aware that even in cases where a plausible explanation is offered, arguments may continue. As a result, many cases are likely to rise no higher than Category VII, including some that have become famous in the UAP literature. In some cases, there’s likely never to be a final, authoritative verdict.
To illustrate how our suggested rating scale might be applied, we rated two well-known UAP cases in a recent paper: the Council Bluffs case (Iowa, 1977) and the Nimitz “Tic Tac” encounters from 2004.
We encourage everyone to keep an open mind about UAP and remember that even the most experienced observer can misinterpret what they’ve witnessed (veteran astronaut Scott Kelly’s remarks to the 2023 NASA study panel are instructive here). We hope that our rating scheme — or something like it — could help shed light on a mystery that continues to captivate the public.
This article Could UAPs be aliens? Use this 11-point scale to evaluate the evidence is featured on Big Think.