A series of missions to the moons of Jupiter and Saturn has revealed their potential to harbour life. Nina Notman looks to the skies
After a series of mission failures, July 1965 saw the first successful flybys of Mars. The US Mariner 4 became the first spacecraft to take close up pictures of another planet, beaming 22 images of the impact-cratered Martian surface back to Earth. Since then, more than 20 successful missions have explored the red plant’s atmosphere and surface.
Thanks to the images and data collected– and by telescopes, both on earth and in space – we now know that billions of years ago, Mars had the three critical ingredients for life. It had an abundance of the chemical building blocks, liquid water on its surface and an energy source (volcanic activity) to power the chemical reactions that make life possible (on Earth that energy source is the sun). Today, the inhospitable surface of Mars is thought to be unsuitable for life, but the possibility of life existing deep beneath its frozen surface hasn’t been ruled out. To date though, no evidence of life – ancient or otherwise – has been found. Mars being habitable, it turns out, doesn’t mean it actually has a habitat.
The search for Martian life is ongoing, with a further three missions to Mars planned to launch over the next few years. Longer-term, a number of space agencies are also aiming to collect samples from Mars and return them to Earth for more in-depth analysis. And the search for signs of extraterrestrial life is stretching to the depths of our solar system and beyond.
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