A scientist working with NASA revealed how alien life can be discovered on Mars. According to the scientist, this can be done by making sure that Martian organisms do not have genetic similarities to those found on Earth.

Recently, planetary scientist Pascal Lee of the SETI Institute and head of NASA's Haughton-Mars Project hosted an Ask-Me-Anything event on Reddit. Many of the questions she answered were related to the search for alien life on the Red Planet.

Dragon On Mars
Photo taken by the Mars Reconnaissance Orbiter NASA/JPL/UArizona

Earth's Tree Of Life

According to Lee, alien life is classified as that which does not fit onto Earth's Tree of Life model. For scientists, the Tree of Life is a genetic tree that shows the connections between all living organisms found on Earth.

When it comes to searching for life on Mars, Lee noted that the goal is to ensure that the evidence found on the Red Planet does not fall into the Tree of Life. This means that the living organisms found on Mars should not have genetic connections with Earth-based lifeforms in order to be considered as truly alien.

Confirming Alien Nature Of Samples

This can be determined by conducting genetic testing on live or recently deceased samples. Unfortunately, Lee noted that this technique wouldn't work on fossilized samples.

"The only way to establish that life found on Mars is alien would be to do genetics on it and show that it does not belong to Earth's Tree of Life. In order to do genetics on it, we have to find it alive (or dead only very recently; not fossilized)," he explained.

Moreux Crater
The peak of the Moreux crater ESA/DLR/FU

Finding Alien Life On Mars

According to Lee, the area on Mars that is most likely hiding alien life is below the planets' surface. As noted by the scientists, areas that are shielded from Mars' harsh surface environment, such as underground lava tubes, most likely have the right conditions to support life. Lee explained that exploring Mars' subsurface world is the only way to find live samples that can be subjected to genetic testing.

"Until we explore the interiors of Mars' volcanoes (lava tubes) and/or drill deep into the Martian subsurface, we are unlikely to find any signature of life we can establish as alien, which is the main point of the search to begin with," he stated. "No amount of fossil finding at the surface of Mars will tell you for sure that you've found alien life."