Sean Kirkpatrick, director of the Pentagon’s All-domain Anomaly Resolution Office, wrote in a research titled “Physical Constraints on Unidentified Aerial Phenomena” and co-authored by Abraham Loeb, chairman of Harvard University’s astronomy department that there is a possibility that extraterrestrial motherships and smaller probes may be visiting Earth and other planets in our solar system.
The Pentagon is literally talking about the existence of alien motherships that release probes to earth.
“An alien mothership could potentially be a parent craft that releases many small probes during its close passage to Earth. In their research paper they suggest that 'Oumuamua' is possible such a mothership with probe capabilities.
These tiny probes would reach the Earth as the mothership passes by within a fraction of the Earth-Sun separation, just like ‘Oumuamua’ did,” the authors explained. Astronomers would not be able to notice the spray of mini-probes because they do not reflect enough sunlight for existing survey telescopes to notice them. source.