We know that liquid water is essential to the existence of life. It is possible that life could have established on Mars if the surface of the planet once had liquid water flowing and ponding. About 3.5 billion years ago, rocks formed that revealed the existence of life on Earth. Several billion years may have passed before life on Earth became established, though it could have occurred more quickly, and so scientists believe the same to be true for Mars.
During the first half billion years of the planet’s existence, life could have existed on much of Mars. Mars, however, may have had moist areas near warm volcanic regions after the first half billion years, suggesting there was some climate variability after that time and life may have been sustained there. A complicated multicellular organism could not have evolved in dark space, under the harsh conditions, and without the presence of physical evidence found on Earth 1 to 500 million years ago. Microbes would have been the most likely form of life on Mars, if it existed or existed in the past.
Volcanic activity likely contributed to the thicker atmosphere of early Mars, with more CO2 and water vapor. As a result of the higher atmospheric pressure, this Mars was warmer and drier. At the beginning of the Neolithic period, Mars’ environment was cold and wet, as it is today. Mars’ interior cooled greatly during the volcanism, causing its gases and water vapor to dwindle and its magnetic field to disappear. The martian surface was inundated with radiation after the atmosphere was left unprotected by the solar wind.
Life on Mars
We’ve been fascinated with the prospect that other worlds – much like Earth – may also contain living organisms for as long as humanity has watched the skies. The Moon remains a world of vast potential, even though it is completely barren and uninhabited.
In my opinion, the red planet, Mars, is the most intriguing possibility. Earth was definitely wetter a billion years ago, when liquid water definitely flowed on its surface. It is plausible that Mars may have once supported life, but that it may be still dormant and occasionally active, as evidenced by circumstantial evidence. Life is possible on Mars in these six ways. The current state of knowledge is as follows.
Listed below are 6 possibilities of life on Mars before Earth:
1. Life was never found on Mars.
Martian water conditions were similar to those on Earth, but the necessary conditions for life to form were never present. The inorganic processes that occur in geology and chemistry continued as usual, but there were no organic ones. Mars’ atmosphere was stripped away by the Sun three billion years ago, causing the planet’s surface to become dry and creating today’s Martian appearance.
This would be the most conservative position, and it would require at least one inorganic or contamination-related resolution for all three purportedly positive tests. The default assumption, however, is that this is indeed possible. The leading hypothesis is that Mars is devoid of life. However, there will be some convincing evidence that either there is life on Mars today, or that it has existed in the past.
2. Early on, Mars was alive, but it died.
Many aspects of this scenario are similar to those in the previous one. The world with: is easy to picture.
- As early Earth had a thick atmosphere
- Surface water that remains stable and liquid
- Geologically diverse continents
- Magnetic fields
- The length of the day is similar to ours
- Only marginally cooler than Earth’s current temperatures
It is possible to live. Even though the Earth formed more than a billion years ago, it only took a few hundred million years for life to evolve on the planet.
Martian life could have been extinguished if its atmosphere was lost, just as the loss of life on Earth was. It may be possible to validate this scenario by drilling down into the sedimentary rock of Mars and searching for fossils or metamorphosed carbon inclusions.
3. Under the surface of Mars, it still remains in a mostly-dormant state.
A more optimistic view of life on Mars is presented here, which is scientifically valid at the same time. Life may have been present early on Mars, and a few extremeophiles remained frozen and suspended in time when Mars lost its atmosphere. Biological life “wakes up” and can begin to perform its critical functions when the right conditions appear – perhaps underground, where liquid water flows occasionally.
If this holds true, then we may still find organisms beneath the Martian surface, perhaps in the shallow sands just a few feet or just a few inches below the surface of our spacecraft. Though we’re talking only about single-celled life, and perhaps not even a eukaryotic cell’s complexity, life on any other planet would still represent a major scientific advance. As part of this experiment, NASA’s Perseverance rover will collect soil samples from the Perseverance probe.
4. There was no life on Mars until Earth seeded it.
The fifth great mass extinction of Earth’s history took place 65 million years ago when a body impacting Earth made Chixulub crater, kicking up enough debris to damage the surface of the planet and create Chixulub crater. It’s likely that, just as with impactors on the Moon or Mars, small pieces of Earth were scattered into space, where some of them finally landed on Earth as meteorites.
Interestingly, a few impacts probably also affect other worlds like Mars: they might send Earth-borne material there. The Earth’s crust is among Earth’s richest sources of organic life, so it seems unreasonable that organic material would not reach Mars. Rather, Earth-based organisms could have survived on Mars, regardless of whether they thrived there. Maybe someday we will be able to determine whether life on Mars has a common ancestor with life on Earth. The possibility is intriguing and not easily dismissed.
5. Earth-based life has spread to Mars because of our modern space program.
The onset of the space age might have allowed Mars to become a desert planet – for billions of years at least. The chance is that stowaway organisms from Earth fell on the Martian surface when spaceborne materials weren’t completely decontaminated or sterilized.
Astrophysicists fear we will contaminate another world before even learning its true existence has taken place, but it is the astrobiologists’ worst nightmare. A worst-case scenario would be that Earth life arrived on Mars and outcompeted simple life from Mars, driving it to extinction immediately. Our biology-based fear of exploring other planets and foreign worlds is one of the main reasons we’re so conservative.
6. Mars may have been home to microbial life at one time
It may well be that life evolved on Mars before it established itself on Earth, if ancient microbes were found there.
Mars could have been a warmer and wetter place in the distant past, led NASA’s Curiosity rover, researchers said Tuesday (March 12).
Mars’ habitability window may have opened up some time ago, according to researchers. In contrast, the dates of the first signs of life on Earth may be comparable. The Curiosity team drew their conclusions from the material collected by the rover from the interior of a Martian rock. On Mars, Curiosity drilled 2.5 inches (6.4 centimeters) into John Klein, the deepest ever made by a robotic vehicle.
Curiosity’s analysis suggests the John Klein region was once a neutral-pH aqueous environment. As a result, the rover’s instruments detected several chemicals needed for life as we know it, including sulfur, nitrogen, hydrogen, oxygen, phosphorous, and carbon.
The mission scientists do not claim that life existed on the Red Planet previously. The Curiosity rover’s scientific gear includes no instruments to detect life on Mars, so they have not found any signs of microbes on Mars.
Although the John Klein deposits are of advanced age, they do allow for some interesting speculation. If life ever flourished on Mars, did it precede life on Earth? What are the chances that Earth life is descended from Mars?
Can life exist on Mars?
An asteroid impact may send some microbes off their home world and onto another world, where they may survive an interplanetary journey. Rocks from Mars can reach Earth much easier than rocks from Earth to Mars.
In the unlikely event that the future Mars mission discovers conclusive evidence of life, these are the kinds of questions scientists and laypeople will alike ask. In the meantime, Curiosity will continue cruising through Gale Crater and helps scientists further understand the Red Planet and its history.
Michael Meyer, lead scientist at NASA’s Washington headquarters for its Mars Exploration Program, said that Mars left its autobiography in Gale Crater’s rocks. “We’ve just begun to interpret the message,” he said.