A recent NASA discovery on the red planet could give us a clue as to what any potential alien neighbors may look like. On Thursday, scientists released images from a NASA satellite that show what look to be dark fingers of water flowing down Martian slopes and craters. The flows appear during the late spring and summer periods and suggest that Mars may indeed have liquid water. If so, scientists think that this water would be salty based on past Martian soil samples. Any liquid water would probably be hidden underground, safe from quick evaporation in the thin atmosphere or from freezing to a solid in the frigid surface temperatures.
Where there is liquid water, many scientists assume there is also the best possibility for life. Even in temperature extremes and the absence of sun light, complex ecosystems have thrived in the darkest depths of Earth's oceans. This latest discovery has led at least one scientist on the NASA panel to suggest the same could be true on Mars. Although more research needs to be done at the seven sites of suspected water flow on Mars, Lisa Pratt, biogeochemist at Indiana University and panel participant, said "It is our first chance to see an environment on Mars that might allow for the expression of an active biological process."
According to one popular theory, the key to the existence of alien life in another planet's underground ocean would be the presence of hydrothermal vents. If enough heat and the right chemicals were escaping from the Martian planet's core, then there is the possibility that an ecosystem supporting complex lifeforms may exist. What would creatures in this ecosystem look like? Probably at least as alien as the bizarre lifeforms in the extreme environments around Earth's deep hydrothermal vents.
Here's a few examples of strange creatures closer to home that may turn out to look quite similar to aliens we may one day discover on Mars.
The building block of a Martian ecosystem might be a microscopic organism like Earth's halobacterium. This single-celled species thrives in environments of high salt concentrations. They could potentially survive the destructive ultra violet light on Mars, and may provide a food source for larger organisms by creating proteins from amino acids. On Earth ancient halopaths contain the oldest recovered DNA; one estimate put a specimen at over 250 million years old.
One of the largest animals that can live near Earth's hydrothermal vents is Riftia pachyptila. These extreme worms are found at depths of several miles on the ocean floor and reach a length of nearly eight feet. Tolerant of extremely high levels of hydrogen sulfide, a poisonous chemical compound found in volcanic gases, giant tube worms shocked science a decade ago as being one of the few large animals capable of living without the sun's energy. Perhaps an alien species of worms could inhabit the neighborhoods of Martian hydrothermal vents.
Using another volcanic gas for energy, the deep sea mussels convert methane into food. They are a key organism in our deep vent ecosystems as they attract other animals like shrimp, limpets, and crabs. Colonies of mussel-like organisms could become a staple prey for larger predators roaming subsurface Martian oceans.
Another extremophile found here on Earth that could be confused for an alien, the Pompeii worm can survive temperatures as high as 176 degrees Farenheit. Their resilience to heat comes from a symbiotic relationship with a bacteria that feeds on the worm's mucus in exchange for providing it some insulation. What strange hybrids would have to be possible to survive the harsh conditions of Mars?
Although not usually found at a hydrothermal vents, this last creature could probably survive there or Mars for that matter. The tardigrade has been found from the deep sea to the peaks of the Himalayas. Also known as the water bear, this animal can survive higher temperatures than any other known organism, as well as extremely cold environments close to absolute zero. Tardigrades have also lived through a space launch (Foton M-3) where they were exposed to the vaccuum of space and solar radiation for ten days. If the water on Mars is subject to periodic icing, the water bear could live there too as it is capable of changing its body composition from 85% water to just 3%, and thereby resist freezing to death. What's more, they can survive this dehydrated, death-like state for years and even decades.
Put together, all these extreme survival abilities of the tardigrade make it the most likely prototype for an alien lifeform. Indeed, some scientists have even theorized that life on Earth actually originated from sources outside our planet. NASA scientist's Richard Hoover claims that meteorites (perhaps chunks of Mars?) could have carried organisms with tardigrade-like resiliency to get things started long ago on primordial Earth.