Did NASA Already Find Martian Life?

In 1992, astronomers discovered three objects roughly the size of Earth orbiting another star, the first known exoplanets. No one expected life on those objects because the star was a pulsar, the remains of a star that blew up as a supernova, and the “planets” had actually formed from the debris of that explosion.

Three years later, astronomers found the first true exoplanets orbiting the sun-like star 51 Pegasi. Now, the NASA Exoplanet Archive lists 4113 confirmed exoplanets with more than 3600 exoplanet candidates awaiting confirmation. Astronomers believe that we have only touched the tip of the exoplanet iceberg. Data suggests that our Milky Way galaxy alone contains some two hundred billion planets. As of now, there’s no solid evidence suggesting that life exists on any of them.

But some scientists believe that we already found life on another planet, one much closer to home. In 1976, NASA landed twin spacecraft on Mars, Viking 1 and 2. Each included automated laboratories designed to search for microscopic life on the Red Planet.

Both craft, which landed 4000 miles apart, included a simple test called the Labeled Release experiment. It added a nutrient broth to a small amount of Martian soil and checked to see if any metabolic byproducts, like carbon dioxide, were released. Every test by both landers reported positive results. However, the other experiments on both landers found no organic chemicals, which seemed to preclude any lifeforms. Since then, most scientists decided that some odd chemistry in the Martian soil falsely mimicked those life signs.

Viking Lander, credit NASA

But not all scientists. Gilbert Levin was the principal investigator for the Labeled Release experiment for both landers. In a recent article in Scientific American, he wrote “The Viking LR (experiment) sought to detect and monitor ongoing metabolism, a very simple and fail-proof indicator of living microorganisms. Several thousand runs were made, both before and after Viking, with terrestrial soils and microbial cultures, both in the laboratory and in extreme natural environments. No false positive or false negative result was ever obtained. This strongly supports the reliability of the LR Mars data.”

It may be decades or centuries before we confirm life on an exoplanet, if we ever do. But we may have already discovered life on another planet, right next door.