The search for life on Mars seems to have been in the forefront of many civilians, scientists, and government's minds for decades upon decades. We have visualized, recently, it in movies like the Martian...but what ways are we currently searching for life on the red planet?
For some time, we have been searching for signs of life by investigating portions of Mars where "sediment accumulated long ago, like the ancient lake-bed environment that NASA's curiosity rover discovered inside Mars' 96-mile-wide Gale Crater." The idea behind this is that because, on Earth, habitats like these provided archeologists with rich findings that informed them about the life that was there long ago.
But, this method hasn't turned out to be as fruitful as expected. Why? Well, because Mars is not Earth.
The researchers behind a "Perspectives" piece that was published online Dec. 18 in the journal Nature Geoscience write: "We must recognize that our entire perspective on how life has evolved and how evidence of life is preserved is coloured by the fact that we live on a planet where photosynthesis evolved."
One important thing to keep in mind is how long Mars has been cold. Because of its size relative to Earth, its core cooled much faster than Earth's. In fact, if Mars did ever support life it would have had to have done so a billion years earlier than Earth...which is a little unlikely (but not hopeless). "Mars may have been cold, arid, oxidizing and generally inhospitable at the surface for much of its history; however, hydrothermal conditions in the near surface or subsurface might have been considerably more clement," said the researchers.
This information will be used to re-tool our approach to the hunt for life on Mars. In 2020, NASA plans to launch a life-hunting Mars rover that will collect rock samples to bring back to Earth. Jack Mustard, a geology professor at Brown University in Rhode Island, said he'd like the 2020 rover to investigate exposed "mineralized fracture zones." He goes on to explain to Space.com that "These would be places where there was fluid flow in the crust, and where you get mixing between different fluids from different sources that have potentially different concentrations of important elements, as well as dissolved hydrogen, for example."
By prioritizing spots like these, where subsurface life may have once been successful, we may be able to find evidence of life on Mars. Space.com also mentions you wouldn't have to dig deep, "NASA's Spirit rover stumbled onto one inside Mars' Gusev Crater back in 2008 when its wonky wheel scraped away some surface dirt."
Although, as previously mentioned, the chance for life on Mars is not guaranteed it is interesting and exciting to see new methods being applied to the search.
The above image is a picture was taken by the Viking Lander 1 on February 11, 1978 on Sol 556. The large rock just left of the center is about two meters wide. This rock was named "Big Joe" by the Viking scientists. The top of the rock is covered with red soil. Those portions of the rock not covered are similar in color to basaltic rocks on Earth. Therefore, this may be a fragment of a lava flow that was ejected by an impact crater. The part of the Lander that is visible in the lower left is the cover of the nuclear power supply. This image is in the public domain.