In a series of tweets, Kaku said there's a possibility that UFOs are millions of years more technologically advanced than humans.
"I think it is a legitimate scientific question to ask where these UFO sightings come from," Kaku tweeted. "Imagine if the aliens are millions of years more advanced than us. New laws of physics open up, so keep an open mind." (Related: NASA gets serious about UFOs: New chief orders scientists to investigate UFOs.)
Earlier this year, Kaku told reporters at the Guardian that humans are on track to discover alien life within the century due to technological advancements such as the James Webb Space Telescope.
But Kaku cautioned his colleagues who are attempting to reach out to aliens.
"There are some colleagues of mine that believe we should reach out to them. I think that’s a terrible idea," he told the Guardian. "We all know what happened to Montezuma when he met Cortes in Mexico so many hundreds of years ago. Now, personally, I think that aliens out there would be friendly but we can’t gamble on it. So I think we will make contact but we should do it very carefully."
As legend has it, Montezuma accidentally ceded the entire Aztec Empire to Cortes, a Spanish conquistador, over a language misunderstanding.
Kaku apparently fears that were people to find and contact aliens, earthlings could be the Aztecs and aliens the Spaniards. If people send a message such as "we come in peace" upon discovering them, the aliens may interpret it to mean "come rule us."
The Aztec Empire was eventually destroyed by the Spanish so Kaku may have concerns for the future of humanity. "Now, personally, I think that aliens out there would be friendly but we can't gamble on it. So I think we will make contact but we should do it very carefully," Kaku said.
In 2004, Navy pilots spotted something extremely unusual off the West Coast – group of objects flying in erratic, inexplicable flight patterns. (Related: Former head of Pentagon's AATIP confirms UAPs (UFOs) are real.)
Years later, the puzzling UFO encounter was revealed by the New York Times, with multiple eyewitnesses ping forward over the years to describe what they saw. Seen in the infrared video was an odd oblong unidentified object, which was nicknamed "Tic Tac."
Navy pilot Chad Underwood talked to Intelligencer about what he recorded. "You're not going to see it with your own eyes until probably 10 miles, and then you're not going to be able to visually track it until you're probably inside of five miles, which is where [commanding officer who first made visual confirmation of the UFO] Dave Fravor said that he saw it," Underwood told Intelligencer.
"The thing that stood out to me the most was how erratic it was behaving. It was just behaving in ways that aren’t physically normal. That's what caught my eye. Because, aircraft, whether they're manned or unmanned, still have to obey the laws of physics."
What puzzled Underwood the most was that the "Tic Tac" bore no resemblance to any conventional aircraft. "Well, normally, you would see engines emitting a heat plume. This object was not doing that," he said. And it certainly was no bird. "You don't see birds at 5,000 or 10,000 or 20,000 feet. That's just not how birds operate."
There has been a spike in UFO sightings across the nation with 7,200 UFO sightings last year, an increase of over 1,000 from 2019.
Earlier this year, the Department of Defense launched an investigation into how the unidentified aerial phenomena – the government's preferred term for UFOs – were being monitored by the military.
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