Life on Mars

in Cornerstone

There Is Almost Definitely Life On Mars

New findings by NASA’s Mars rover Curiosity reveal the Martian past

Credit: NASA

It was a historic evening on August 6 PDT when NASA’s Mars rover Curiosity landed on the Red Planet.

Curiosity’s mission was to determine whether Mars had once offered environmental conditions favourable for microbial life. Curiosity began it’s work by sampling two mudstone slabs in an area known as Yellowknife Bay. Curiosity shocked the world when it found that these slabs had originated from an ancient riverbed containing mild water, the essential elements for microbial life and a chemical energy source used by microbes here on Earth.

We’d discovered that Mars had all the ingredients necessary for life. However we weren’t certain if they’d had the time to develop. Life may be spontaneously created but it doesn’t evolve in an instant. If the window for life’s evolution in Yellowknife Bay was too small, Mars may well of been an eternally dead planet.

Recent findings however have disputed that. With some recent samples taken from Gale Crater — scientists have extended the time Gale was habitable to an astounding 700 million years.

Artist interpretation of what Mars once looked like. Credit: Geekwire

A picture of Mar’s watery past

Using a little drill onboard and a SAM (Sample Analysis at Mars) module Curiosity can determine the age of Martian rocks. The process is known as radiometric dating and works the same as here on Earth. It’s done by comparing the ratio of potassium-40 to argon-40. Since potassium decays to argon at a known rate we can determine the age of the rock.

Curiosity can also determine the chemical composition of rocks on Mars, which are then compared to similar samples here on Earth. By comparing the formation of similar Earth rocks with the ones on Mars, geologists can determine the history of an area on Mars.

Combining these techniques researchers have revealed that the Gale Crater had groundwater and all the components necessary for life for 700 million years. This period of habitability ended roughly 3.1 billion years ago. When life on Earth was still single celled prokaryotic cells, like bacteria.

This crater may once have teemed with microbial life. Credit: NASA

The spread of life in the universe

Life existing elsewhere in the universe is not really news. The recent proliferation of habitable exoplanets, like the TRAPPIST-1 series, indicate life in our universe may be fairly common. We just haven’t found much of it yet.

Whether that means sentience is common is another story but extremophiles — or organisms that thrive in physically or geochemically extreme conditions, are likely to be found everywhere they can be found. Like on Earth trapped in giant underground crystals or keeping our underwater vents pumping.

The origin of life on Mars

This raises an interesting question. How did life get onto Mars? It’s easy to imagine it evolving spontaneously there. But did it also on Earth? One theory for the spread of life is known as Panspermia. It’s the the hypothesis that life exists throughout the Universe, distributed by meteoroids, asteroids, comets, planetoids, and also by spacecraft in the form of unintended contamination by microorganisms.

Still unexplained findings from research done in the 1970’s indicates this may be how life spreads. If true it seems likely we’d find life on Io, Europa or Callisto among other habitability candidates in our solar system. The European Space Agencies JUICE (JUpiter ICy moons Explorer) probe will land on Europa in 2030 and test for evidence of life.

Artists rendering of JUICE Credit: Bisbos

There’s still much research to be done before we can say with certainty life beyond Earth exists. However the more we find the more it seems to suggest there is.

Which given Kornreich’s estimate of 10 trillion galaxies in our universe each with 100 billion stars. It seems logical that life should exist elsewhere. Even modest estimates put into Drakes equation indicate billions of planets with life out there.

I guess perhaps it’s time to consider the implications of that.


Written by Andrew Walls

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