PROOF of alien life may come with the discovery of planets rich in an incredibly noxious and foul-smelling gas known as phosphine, astrobiologists have announced.
Alien species depicted by Hollywood blockbusters over the years have taken all shapes and sizes. But a group of researchers at the Massachusetts Institute of Technology (MIT) believe ETs could be incredibly “stinky” to boot.
MIT researchers have proposed in a recently published study simple organisms are responsible for the production of phosphine.
On Earth, phosphine is one of the most toxic and repulsing gases known to man.
Sometimes dubbed “swamp gas”, phosphine is typically found in incredibly unpleasant locations such as foul marshes and heaps of penguin dung.
But on planets far outside of the solar system, alien bacteria that do not require oxygen to thrive could be churning out the gas.
The molecular astrobiologist argued astronomers now need to consider new and bizarre scenarios if we are to find alien life one day.
Dr Sousa-Silva, who led the phosphine study, said: “Here on Earth, oxygen is a really impressive sign of life. But other things besides life make oxygen too.
“It’s important to consider stranger molecules that might not be made as often, but if you do find them on another planet, there’s only one explanation.”
Creatures that do not rely on oxygen to grow are known as anaerobic organisms or anaerobes.
Here on Earth, anaerobes are commonly single-celled bacteria that process hydrogen, for instance, instead of oxygen.
MIT’s researchers have suggested phosphine cannot be naturally produced on a rocky planet without life in the mix.
There are, however, examples of the gas being produced spontaneously and without life on the planets Jupiter and Saturn.
As a result, the researchers believe phosphine to be a good indicator of life on a planet – a so-called biosignature.
Dr Sousa-Silva said: “So we started collecting every single mention of phosphine being detected anywhere on Earth, and it turns out that anywhere where there’s no oxygen has phosphine, like swamps and marshlands and lake sediments and the farts and intestines of everything.
“Suddenly this all made sense: It’s a really toxic molecule for anything that likes oxygen.
“But for life that doesn’t like oxygen, it seems to be a very useful molecule.”
The MIT researchers are now in the process of assembling a database of biosignature that could lead to the discovery of alien life.
The researchers analysed more than 16,000 candidates including phosphine.
But before the MIT team could publish their discovery, they needed to rule out any non-biological processes that lead to the creation of phosphine.
The researchers considered factors such as plate tectonics, lightning strikes and even meteor impacts.
Ultimately, after “several years” of trying to understand the process, the MIT team concluded life most likely needs to be part of the equation.
At the same time, the researchers concluded even trace amounts of phosphine comparable to the amounts released on Earth should be detectable by space telescope such as NASA’s upcoming James Webb Space Telescope.
The MIT researchers are positive space telescopes will be able to detect the gas on planets up to 16 light-years or 94,058,006,000,000 miles from Earth.
Dr Sousa-Silva said: “I think the community needs to invest in filtering these candidates down into some kind of priority.
“Even if some of these molecules are really dim beacons, if we can determine that only life can send out that signal, then I feel like that is a goldmine.”
What does NASA have to say about the possibility of alien life on other worlds?
The US space agency is at the forefront of deep space exploration, driven by a desire to know how the universe has evolved.
One way in which NASA scans the cosmos for signs of life is by hunting down habitable exoplanets.
NASA said: “No life beyond Earth has ever been found; there is no evidence that alien life has ever visited our planet. It’s all a story.
“This does not mean, however, that the universe is lifeless.
“While no clear signs of life have ever been detected, the possibility of extraterrestrial biology – the scientific logic that supports it – has grown increasingly plausible.”