In a draft paper, a Harvard astronomer and a Pentagon official suggest that the extraterrestrial spaceship could be exploring our galactic neighborhood by using “dandelion seeds” – small spacecraft that can gather and send back information similar to the way humans send spacecraft to explore planets.
Avi Loeb, the astronomer at Harvard University, and Sean M. Kirkpatrick, the director of the Pentagon’s All-domain Anomaly Resolution Office (AARO), established in July 2022 by the Department of Defense (DoD) to detect and study “objects of interest,” released the draft, “Physical Constraints on Unidentified Aerial Phenomena,” on March 7. It is not an official Pentagon document but was carried out in partnership with the DoD. It has not been peer-reviewed.
In the draft paper, Loeb and Kirkpatrick looked at Unidentified Anomalous Phenomena (UAPs), the government’s preferred term for UFOs, confined by known physics. The authors suggest the dandelion seed probes could reach Earth for exploration without being detected by astronomers as they would likely be too small to reflect enough sunlight for survey telescopes to detect.
Equipped with a large surface-to-mass ratio of a parachute, technological dandelion seeds could slow down in the Earth’s atmosphere to avoid burnup and then pursue their objectives wherever they land.
Aliens would likely want to explore rocky planets with an atmosphere in the solar system, the authors propose. From a distance, Venus, Earth, and Mars would all look appealing, with Earth being of greatest interest once aliens found signatures of liquid water. The alien civilization that created the probes would not need to be on the mothership. It would be unlikely that it could even communicate with the probes.
The alien civilization may not even exist anymore. Most stars in the solar system formed billions of years before the sun. A habitable planet with intelligent life could have been sending out probes long before Earth formed. Searching for “resembles checking our mailbox for any packages that may have accumulated over time there, even if the senders are not alive anymore,” Loeb said.
You can read the full draft version below.