Michio Kaku, the renowned theoretical physicist who is never shy to offer his visions of humanity's future, has urged fellow scientists to “keep an open mind” about UFOs and the possibility of extraterrestrial life, saying it’s a “legitimate scientific question to ask where these UFO sightings come from.”

Kaku’s comments came in a recent tweet, in which he said: “Many physicists are skeptical because the stars are so far away, but that assumes ET is only a century ahead of us. Imagine if the aliens are millions of years more advanced than us; new laws of physics open up, so keep an open mind.” 

Kaku has previously said he thinks it’s likely we’ll make contact with an extraterrestrial civilization within this century. However, he also believes that we should be cautious about making the first move since we may be meddling with a force that is light-years ahead of us. If we take a look at history, this power dynamic between freshly acquainted civilizations doesn’t always end well. 

“It’s a bad idea to advertise our existence,” Kaku said in an interview with Stephen Colbert back in April.

“Look what happened to Cortés and Montezuma,” he added. “Montezuma in Mexico made the biggest mistake in history. He assumed that Cortés was a god. Cortés was a pirate! A blood-thirsty pirate carrying smallpox, armed with steel, the horse, written language, gunpowder. The Aztecs were a Bronze Age civilization with no written language, no horse, no steel, totally vulnerable to smallpox — it was no contest.”

Although Kaku suspects that extraterrestrial life will come in peace without violent colonial intentions, he thinks it’s not worth the risk just yet.

“I think it's a good idea to keep our presence a secret, so the aliens don't put us in their sights. Who knows what the aliens believe in?” he mused.

Kaku's comments come at a time of renewed interest in UFOs. After decades of near-silence on the topic, the Pentagon recently confirmed the existence of a number of high-profile UFO – or as they are known officially, Unidentified Aerial Phenomena (UAPs) – sightings and released them to the public. In June 2021, the US Office of the Director of National Intelligence published a much-anticipated UFO report that complied dozens of sightings reported by military personnel over the past 17 years. While the report's findings were largely inconclusive, it suggests that authorities are finally taking UFO reports seriously.