Following the discovery of evidence of flowing water on Mars earlier this week, NASA scientists are seriously considering what the finding means for the ongoing search for extraterrestrial life.
Researchers have been trying to answer the question of whether or not life could survive on the Red Planet for years. There has been some compelling evidence that the ingredients necessary for life to exist as it does on Earth could have been on Mars at one point or another, including Allan Hills 84001, a suspected Martian meteorite discovered in Antarctica in 1984. The meteorite was full of minerals that could not have formed without water being present, and scientists also discovered structures that looked suspiciously like fossilized bacteria in 1996. The discovery was announced by President Bill Clinton to the surprise of people around the world.
Since landing the first research rover on the Martian surface, however, scientists have found little evidence of the conditions that would support life. Extensive satellite images showed giant fluvial formations, but there was no evidence that any rivers had flowed in thousands of years.
Opportunity came along in 2004 and changed everything, however. The rover took samples from the bed of what researchers believe was an ancient ocean. They discovered some of the same minerals that had been found in the sediments of a prehistoric ocean in the middle of Australia.
The discovery proved that it had been more than three billion years since Mars had oceans covering its surface. In addition to this ancient sea, other discoveries from Opportunity revealed that there were likely all different types of water present on Mars at one point, including salt and fresh water, hot springs, and acidic water. While these discoveries do not equate to confirming the presence of life on the Red Planet, they mean that the chances of life having existed at least at one point during its multi-billion year history may not be so slim.
There is, to this day, still no proof of life on Mars. There is, however, a multitude of information that suggests it is well within the realm of possibility. One of the biggest selling points is that there is virtually no place on Earth where there is water, but no life. By following water on the surface of the Red Planet, NASA scientists believe they have the best chances of finding evidence of living beings.
Curiosity came along a few years after Opportunity and discovered even more promising evidence of potential life on Mars. The newer rover was quick to discover tiny patches of ice on the Martian surface, which confirmed the existence of H2O on the planet, even if it had been frozen for millions of years.