Mars missions by NASA and other space agencies are currently ongoing, hoping to find definite proof of life on the Red Planet.

Evidence born from decades of spacecraft exploration has shown that Mars once had the capacity to host life like Earth. Water is believed to have existed on the Red Planet billions of years ago in the form of rivers, lakes and possibly an ocean. One study even theorized that some lifeforms on Earth could have made their way to Mars by accident and thrived on Martian soil.

However, Mars is now little more than a cold, barren wasteland following the loss of its global magnetic field. Similar to Earth's own magnetic field, Mars' field once protected it from solar radiation, which destroyed the planet's atmosphere once there was nothing to stop it.

But despite the planet having no global magnetic field and water at the moment, scientists still believe that life exists there and likely just hiding underground to the fatal radiation on the Martian surface.

"If Mars had life 4 billion years ago, Mars still has life. Nothing has happened on Mars that would've wiped out life," Michael Finney, co-founder of The Genome Partnership, a nonprofit organization that runs the Advances in Genome Biology and Technology conferences, said, via

"So, if there were life on Mars, it may have moved around, it may have gone into hiding a bit, but it's probably still there," Finney said last month during a panel discussion at the Breakthrough Discuss conference at the University of California, Berkeley.

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

One hint of possible lifeforms still existing on Mars is the presence of methane, a well-known biosignature for life. NASA's Curiosity found methane in the Gale Crater, and data from the lander showed that the gas' concentrations in the air undergo cycles from season to season.

On Earth, microbes and other organisms produce methane, so scientists are hoping to find evidence of them lurking under Mars' surface.

“With these new findings, Mars is telling us to stay the course and keep searching for evidence of life,” Thomas Zurbuchen, associate administrator for the Science Mission Directorate at NASA Headquarters, in Washington, said in a statement on NASA's website last year. “I’m confident that our ongoing and planned missions will unlock even more breathtaking discoveries on the Red Planet.”

NASA has made finding life and biosignatures on Mars its priority, with the space agency launching the 2020 Mars rover next summer. The 2020 ExoMars rover, a collaboration between the European Space Agency and the Russian Roscosmos State Corporation, will also be heading to the Red Planet around the same time, with a similar goal.