Astrophysicist Neil deGrasse Tyson speaks during the Clinton Global Initiative's annual meeting in New York, Sept. 28, 2015. Reuters

Renowned astronomer Seth Shostak wants you to know there are probably tons of aliens out there, but they don't look like the green space men you might have in mind. Shostak, the senior astronomer at the SETI Institute in California, said there are likely many common misconceptions about aliens because of what we know from movies and TV shows that don't reflect reality.

“Think what were gonna do in this century, which is invent thinking machines,” Shostak said while speaking to Neil deGrasse Tyson last week during a National Geographic Star Talk. “The aliens have probably already done that, so the real aliens probably look like machines.”

Shostak pointed out that roughly 30 percent of all Americans believe in “UFO phenomena.” You can count Shostak, who hosts the SETI Institute’s weekly science radio show, “Big Picture Science,” as a believer, too.

"Seth claims to have developed an interest in extraterrestrial life at the tender age of ten, when he first picked up a book about the solar system," the SETI Institute website reads. "This innocent beginning eventually led to a degree in radio astronomy, and now, as Senior Astronomer, Seth is an enthusiastic participant in the Institute’s SETI observing programs. He also heads up the International Academy of Astronautics’ SETI Permanent Committee."

Shostak has been spreading his message about what aliens could look like for years. He has said that alien life could exist on billions of planets in the universe.

“It doesn’t seem unreasonable to think that we are not alone, if all those planets are completely sterile, you’ve got to think, wow there must be something really special and miraculous about Earth – but generally those people are not scientists,” he told the Guardian last year.

For whatever it's worth, DeGrasse Tyson, the popular TV astrophysicist, also believes in aliens.

"At the moment, life on Earth is the only known life in the universe, but there are compelling arguments to suggest we are not alone. Indeed, most astrophysicists accept a high probability of there being life elsewhere in the universe, if not on other planets or on moons within our own solar system. The numbers are, well, astronomical: If the count of planets in our solar system is not unusual, then there are more planets in the universe than the sum of all sounds and words ever uttered by every human who has ever lived. To declare that Earth must be the only planet in the cosmos with life would be inexcusably egocentric of us," he wrote in 2003 in NASA's Astrobiology magazine.