Extremophiles : The formidable creatures
When scientists first started to understand the origins of life, and the conditions that support it, they had realised that organisms can survive, propagate in certain ambient conditions, exception to this rule were many animals but, there was a limit to the extremeness, and that’s a thing many people scientists believed. Until, In the 1960s, heat resistant bacteria were discovered in hot springs in Yellowstone National Park and that changed everything.
None of the thousands of planets found in other star systems is a good match for our own Earth. Still it is not impossible for those worlds to harbour life. Maybe it already exists, or maybe, converse to our perception of ‘little green creatures’, they could be robust microorganisms lurking in the labyrinth of gases like hydrogen ,methane , conditions like extreme temperatures and pressure ,or spine-chilling cold. And this idea has been backed by certain creatures found on earth called extremophiles.
The variety of bacteria that was found here(Yellowstone national park) were Thermus aquaticus
Since then scientists have discovered many microorganisms like that in other niches like extreme cold (psychrophile), extreme pressure conditions, etc. And the search continues to this day.
A Ray of Hope
These microorgasenisms have enabled scientist to formulate certain theories about extraterrestrial life.
Also scientist have tried to simulate the conditions found on mars, and are trying to see if life can bloom among it.
It all boils down to one thing that is “We believe that there is only one way to make life.”
Life could have happened differently on other planets, though it makes the discovery of life much more difficult. The carbon based life on earth may be different from those we are trying to find. Scientists at NASA are planning missions to Mars and Saturn's icy moon Enceladus that may yield conclusive evidence of life on those worlds.
There are still vast ecosystems that mankind has not yet explored. It would be interesting to see what bounties lie there for us.
In the year 2003 Thermococcus gammatolerans ,an extremophile was discovered that can survive lethal doses of radiation. This points towards the possibility of life on the planets where there is an absence of atmosphere.
They are an interesting species who are famed for their extreme survival skills and adaptability.
Also known as Water Bears, tardigrades can survive ,in case of flooding by inflating its body as a balloon and staying over the surface of water. In case of drought or cold ,they can replace most of the water in their body with a sugar known as trehalose. These sugars do not form damaging crystals, as in case of water at low temperatures.
These robust beings have successfully survived in 100 year old samples in museums and also. Many tardigrades survived a 12 day journey into the cold vacuum of space, done under the project TARDIS, protected by a UV filter almost all survived. Most of the ones without the filter did not.
What Next ?
All the facts mentioned in the previous paragraphs indicate the fact that, still we have not found the true limit of life. It makes us difficult for us to predict life on other planets, and since our knowledge about the environments of other planets are limited, we cannot hope for earth-like life to exist on those planets. And if it existed, then it is in extinct form.
Similar to Earth, other planetary bodies might have different environments with varying ranges for each parameter. Further expeditions to these planets would shed some light.
Depending on the planetary body, different extremophiles or polyextremophiles( could survive more than one extreme conditions) could persist. Like for example
halopsychrophiles have a high probability of surviving on the moons of Jupiter, which likely have saline subsurface oceans. These life forms would also need to withstand high pressures.