There is no denial the charm of alien artifacts. Science fiction is awash with the material remains of extraterrestrial civilizations, which appear in everything from classic Arthur C. Clarke books to game franchises such as Mass effect AND Outer Wilds.
The discovery of the first interstellar objects in the solar system over the past decade has sparked speculation that they may be alien artifacts or spacecraft, although the scientific consensus remains that all three objects have natural explanations.
That said, scientists have expected the possibility of encountering alien artifacts since the dawn of the space age.
“In the history of technosignatures, the possibility of artifacts in the solar system has existed for a long time,” says Adam Frank, a professor of astrophysics at the University of Rochester.
“We’ve been thinking about this for decades. We’ve been waiting for it to happen,” he continues. “But being responsible scientists means adhering to the highest standards of evidence and not crying wolf.”
This raises some tantalizing questions: What is the best way to search for alien artifacts? And what should we do if we actually identify it? Given that these technosignatures can run the gamut from minuscule specks of alloy to massive spaceships – or perhaps some material unimaginable to Earthlings – it’s demanding to know what to expect.
To meet this challenge, researchers are currently working on a range of techniques to search for signs of alien remnants throughout the solar system, including in Earth’s orbit.
For example, Beatriz Villarroel, an assistant professor of astronomy at the Nordic Institute of Theoretical Physics, focused on a largely untapped observational source: historical images of the sky taken before the human space age.
By studying archival photographic observations recorded by telescopes before the launch of Sputnik in 1957, Villarroel created a portrait of the sky before it was dotted with our satellites. As project manager of the Vanishing & Appearing Sources during the Century of Observations (VASCO) project, she was initially looking for any evidence that stars or other natural objects might disappear in these archival plates.
Instead, Villarroel found inexplicable “transitioners” that look like artificial satellites in orbit around Earth, long before Sputnik was launched, which – she and her colleagues informed in 2021
“Then I realized that it was actually a fantastic archive, used not to look for disappearing stars, but to look for artifacts,” she says.
Last year, Villarroel and her colleagues published three more studies on the search for near-Earth alien artifacts in Publications of the Pacific Astronomical Society, Monthly Notices of the Royal Astronomical SocietyAND Scientific reports which sparked a lively discussion among scientists. Scientists suggest a number of alternative explanations for transients that may include instrumental errors, meteorites, or nuclear test debris.
The mystery could potentially be solved with a dedicated artifact search mission in geosynchronous orbit, an environment approximately 30,000 km above Earth. Villarroel, however, doubts that any federal space agency will agree to such a mission in the near future due to the controversial nature of the topic.
“There is such a great taboo that no one will take such results seriously until such a probe is dismantled,” he adds.
Frank says he agrees that stigmatizing the search for otherworldly artifacts – and the search for alien life more broadly – is counterproductive. However, he believes that opposition to research on alien artifacts is a fit and natural part of scientific research.