UAP Researchers Search For “Transient Events” In Earth’s Shadow, Finding Unexplained Events

Since 2017, the Vanishing & Appearing Sources during a Century of Observations (VASCO) project has attempted to look for stars and other sources of light that have appeared and disappeared from view or have dimmed unusually over the 20th and 21st centuries, known as “transient events”. The team has previously found that around 100 stars have disappeared from view without an explanation (though other teams have suggestions as to where they went).

“These short-lived transients (lasting less than one exposure time of 50 minutes) are absent in images taken shortly before the transients appear and in all images from subsequent surveys,” the team explained in a recent pre-print paper. “In some cases, multiple transients appear in a single image, exhibiting characteristics not easily accounted for by prosaic explanations (e.g., gravitational lensing, gamma ray bursts, fragmenting asteroids, plate defects).”

In the latest study from the group, they focused on transient star-like objects observed in the pre-Sputnik era, or before any satellites had been launched into orbit by humans. The team identified transients captured by the Palomar Observatory Sky Survey (POSS-I), which scanned the skies from November 19, 1949, to April 28, 1957. By focusing on this timeframe, they could eliminate any transient events that are due to reflections from human-made satellites, a common source of bright objects in the night sky.

The team is motivated directly to study UAP phenomena – a topic which scientists have generally steered well clear of. The general consensus is that while alien life is possible, or even probable according to some, there is no real scientific evidence of alien life coming anywhere near Earth. Nevertheless, transients are real phenomena that warrant investigation in their own right, and the team attempted to narrow down their source.

“Given the unusual nature of these events and their potential implications, it is important to further test the hypothesis that some transients may originate from reflective artificial objects in Earth orbit,” the team explains of their motivation in the new paper. “Searches for extraterrestrial probes were proposed as early as the 1960s, but to date only a few searches for NTAs have been attempted or proposed.”

The latest paper identified a number of interesting transient events for which they could not provide an explanation, including a bright but short-lived transient event on July 19, 1952, in which three stars vanished within 50 minutes.

“Notably, this particular event coincides in time with one of the most extensively documented aerial anomalies in historical records: the Washington D.C. ‘UFO flap’ of July 1952, which unfolded over two consecutive weekends (July 18–19 and 26–27),” the team writes. “While this may be a coincidence, the temporal proximity invites further scrutiny — especially given the rarity of both phenomena.”

While this is all pretty speculative and unlikely to be resolved due to the event taking place over 70 years ago, the team offers up an intriguing statistical analysis that might warrant further attention, potentially showing that these might not be something as simple as photographic plate defects.

“One of the most revealing tests involves Earth’s shadow. No matter how asymmetric or irregular the distributions of plate defects may be, they have no plausible reason to avoid the Earth’s shadow. In contrast, transients associated with solar reflections would,” the team explains. 

In short, if the transients were just plate defects, then we would see them no matter where the astronomical equipment was pointed. But according to their analysis, there were far fewer transients detected in Earth’s shadow compared to the rest of the sky.

“At 80,000 km altitude, we expect N = 339 transients in shadow out of 106,339 total, corresponding to a fraction of f_exp = 0.00319 ± 0.00017. However, we find only N = 79 transients in shadow, yielding fobs = 0.00074 ± 0.000084,” the team explains. “The difference in these observed fractions is also highly significant, with a significance level of 12.7σ, computed by combining the Poisson uncertainties in quadrature.”

According to the team, this makes it more likely that the transient events are caused by light reflecting off a source. Which is somewhat odd, given that the period studied was pre-satellite. That’s not to say that the transient events are some sort of alien probe. In fact, given a lack of evidence for such a phenomenon, you can place a pretty solid bet that it is caused by something else. A separate paper by the team, for instance, found that they were associated with nuclear weapons tests. But it is certainly intriguing, and may offer clues to scientists looking to study these odd, transient phenomena. 

“Our results motivate continued investigation of historical sky surveys and the application of similar alignment-based detection methods to modern deep-sky imaging,” the team concludes. “Whether or not these events ultimately point to the existence of NTAs [non-terrestrial artifacts], the identification of statistically improbable, spatially aligned transients in pre-satellite data represents a novel observational anomaly deserving of further scientific attention. Future work may help clarify whether these transients constitute a new class of astronomical phenomena—or represent the first hints of artificial activity near our planet.”

The study is published in Monthly Notices of the Royal Astronomical Society.