Mars may currently be hosting alien life forms on its surface despite the absence of a magnetic layer and liquid water, according to one physicist.

There are several Mars missions with the aim of finding signs of life on the Red Planet that have either already been launched or will begin in the coming years. So far, no life forms have been found on Mars, though recent data suggested that liquid water was once abundant on the planet. However, Brian Cox, a scientist and professor, recently pointed out one region of Mars that he believes is most likely to harbor life.

In his BBC show "The Planets," the TV physicist said microbes could live in Mars' Hellas Basin, known to be the largest visible impact crater in the solar system so far.

The crater spans 930 miles (1,500 kilometers) in diameter and has a depth of 5.6 miles (9 kilometers), according to the scientist. It is so massive that Mount Everest could be put inside it and still not reach the rim of the basin.

As for why exactly he believes Hellas Basin could be harboring life, Cox explained, "The air pressure is so high down there, that liquid water can exist."

"So I suppose it’s not impossible to imagine microbes coming up from deep below the surface to bask in the midday sun before disappearing back down below again," he continued.

However, the scientist emphasized that even if we eventually find life at the bottom of the Hellas Basin, they won't be the extraterrestrials depicted in movies. “But if life does exist out there, it will certainly only be simple life. There will be nothing anywhere near as complex as you or me, or even this plant," Cox said.

Unfortunately, the Hellas Basin has not yet been visited by a rover nor will it be the target landing site of future missions. NASA's Mars 2020 rover, which is set to launch in July 2020, is expected to touch down on Mars' Jezero Crater, according to a statement.

The space agency's Opportunity Rover landed on the Meridiani Planum, while its twin rover Spirit made its first step on Mars at the Gusev Crater. NASA's Curiosity, meanwhile, landed on the Gale Crater, which it is still exploring to date.

This self-portrait of NASA's Curiosity Mars rover shows the vehicle at the 'Mojave' site, where its drill collected the mission's second taste of Mount Sharp. Getty Images/NASA/JPL-Caltech/MSSS