The White House has tapped Avi Loeb, a Harvard astrophysicist, to lead a team of scientists who will study the national security risks of UFOs. 

Loeb gained attention in 2017 for proposing that an interstellar object that passed near Earth, which many scientists thought to be a comet or ice chunk, could be a thin "light sail" detached from an extraterrestrial spacecraft, the Associated Press reported. 

While his theories have been praised in UFO circles, he often came into conflict with other academics who accused him of making unsubstantiated claims and bringing these claims to the public without peer review. 

Loeb's team will report to a White House panel that's studying UFOs, which are now often called unidentified anomalous phenomena, or UAP.