Harvard's Top Alien-Hunting Astronomer Has an Explanation for UFOs Spotted Above Ukraine

Avi Loeb, who leads a team of scientists looking for evidence of alien technology for Harvard, has reasoned that scientists observed artillery shells.
Motherboard explores UFOs, UFO culture, and the paranormal.

In September, Ukrainian astronomers published a report detailing what they thought were unexplained aerial phenomena, or UAPs, flying above the war-torn region. Now, alien-hunting Harvard astronomer Avi Loeb has weighed in on the science out of Kyiv with a paper posted online on Wednesday and found a down-to-earth explanation for the puzzling observations, which the Ukrainians attributed to so-called “phantom” UAPs.


Loeb is the head of the Galileo Project at Harvard University, a program that uses scientific rigor to search for evidence of extraterrestrial life and technology, and former chair of the school’s astronomy department. He’s gained accolades and notoriety in equal measure in recent years for feats such as getting the U.S. military to confirm that an interstellar object entered Earth’s atmosphere using classified data, and for hypothesizing that alien technology zipped by our planet in 2017. 

Loeb told Motherboard on the phone that people constantly ask him to comment or study unidentified aerial phenomena. He claimed the authors of the initial paper out of Kyiv had contacted him with their work but that he hadn’t looked at it. The skies above Kyiv, Loeb said, are the last place people should be looking for UAPs right now. 

“In science, we’re trying to minimize the noise so that we can pick up the signal and therefore Ukraine would be the last palace on earth where I would search for unidentified aerial phenomena… The noise level is so high,” he said.

Ukraine is at war, and during a war there’s lots of stuff flying through the sky. Drones, aircraft, and artillery shells, and satellites would conflict with any observations made of the sky. “It’s sort of like saying, ‘I want to find the stars that are in the Milky Way galaxy and I will look during the daytime,” Loeb said.


But everything changed when Sean Kirkpatrick, the newly appointed head of the Pentagon’s All-Domain Anomaly Resolution Office (AARO) showed up at Loeb’s home, he said, and asked him to look into the phenomenon of UAPs. According to Loeb, Kirkpatrick didn’t mention the Kyiv report specifically. Loeb recalled it later that evening and decided to work through its observations in the morning. Within an hour he concluded that they got the distance to their dark objects wrong by “a factor of ten,” he said in a writeup of his observations on Medium.

The Ukrainian UAP paper identified two kinds of objects it labeled phantoms and cosmics. Phantoms were dark objects and cosmics were luminous. He focused on the phantoms at first because, if they’re dark, it means they’re blocking light and probably in earth’s atmosphere. The paper suggested that these phantoms were 3-12 meters in length and moving at speeds of up to 15 km per second at a distance of up to 10-12 km.

According to Loeb, an object that fits that description would cause an incredible disruption to the atmosphere—“a huge fireball,” Loeb said. According to Loeb, the energy released by such an object would be equivalent to the amount of energy consumed by everyone on Earth. “They certainly don’t claim to see a fireball. The objects are dark. They call them phantoms. They don’t see anything. So, they made a mistake.”


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Objects moving through space displace the matter around them. When a bullet leaves a gun it displaces air and makes a distinctive cracking noise. When a jet goes faster than the speed of sound, the waves of pressure create a sonic boom. And, according to Loeb, with regard to meteors “a tenth of the kinetic power is radiated away in the optical band.” Anything of the size and speed described in the Kyiv paper would create such a noise and cause a similar explosion of sound and light.

Instead, Loeb believes that the explanation for “phantom” UAVs in Ukraine is something much more common during war: artillery. 

“If the Phantom objects are ten times closer than suggested, then their angular motion on the sky corresponds to a physical velocity that is ten times smaller, v ∼ 1.5 km s−1, and their inferred transverse size would be ∼ 0.3–1.2 meters, both characteristic of artillery shells,” he wrote in his paper on the subject. As for the luminous object observed by the Ukrainian astronomers, Loeb concludes that it’s likely a satellite. 

Both Russia and Ukraine have launched artillery shells during the war, and this simple explanation makes a lot of sense. When reached for comment, however, B.E. Zhilyaev—one of the Ukrainian authors of the original paper—stood by their findings. His team published the data, but are not in the business of speculating on what that data means, he said.


“I have read the article by Avi Loeb, I know his comment,” Zhilyaev said. “Avi Loeb is a theorist. We are experimenters. We observe, process and determine the characteristics of data. Our publication contains just such data. We are not in the business of interpretation. Avi Loeb is trying to interpret our data. This work contains a discovery. Bright and dark objects. Our work can be repeated and verified, although this is a challenging experiment. Our characteristics of the objects are very similar to those of US military pilots and Canadian civilian pilots.”

“My reply is simple,” Loeb said after reading Zhilyaev’s response. “Being an experimentalist or a theorist is not relevant. All scientists, whether they are experimentalists or theorists, must use logic.” Logically, Loeb said, the fact that the objects were dark means that they blocked the light coming from the sky. 

“The required electromagnetic interaction with light implies that the phantom objects must also interact with air molecules,” he said. “There is no logical way for the phantom objects to block light but not air molecules because the cross-section for electromagnetic interaction of air molecules with matter is larger than for light with matter.”

A popular refrain from people in the UAP community when faced with evidence like this will say that whoever or whatever is behind the phenomenon have access to technology beyond our understanding. But Loeb maintains that advanced technology must still, in effect, follow the laws of physics. 

“I say that is not possible,” Loeb said. “Because how do you detect these objects? You detect them by the fact that they’re dark. In order for them to be dark in the background of the day sky, they must block light. Light is electromagnetic, it requires an electromagnetic interaction… So if they block light, they must collide with air molecules. You can not, on the one hand, say an object is blocking light and at the same time say it will go through air without pushing it. That is not possible.”

UAPs, the new name for UFOs, have become big news in the last few years. The Pentagon declassified several videos of strange objects observed by Navy Pilots after the images had already been leaked to the press. Congress created the AARO to try to figure out what’s going on and politicians and military officers have come forward to share their experiences and weigh in.

In this environment, Loeb has become one of the most well-known figures in the scientific community who is keeping his mind open to the possibility of alien intelligence while applying rigorous science. Indeed, he is currently organizing an expedition to search for remnants of an interstellar object on the ocean floor. Most likely, it’s a meteor that will tell us a lot about the universe beyond our cosmic doorstep. It could also be alien technology, Loeb says, but the former outcome wouldn’t be so bad either. 

The Pentagon’s Office of the Director of National Intelligence, which coordinates with the AARO, did not respond to Motherboard’s request for comment.