Proof of alien life? Stinky gas could be evidence aliens are real, astronomers announce
Nature & Science

Proof of alien life? Stinky gas could be evidence aliens are real, astronomers announce

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.

Clara Sousa-Silva from MIT’s Department of Earth, Atmospheric and Planetary Sciences speculates rocky planets with phosphine in their atmosphere may be home to alien life.


Proof of alien life: Alien on an exoplanet

Proof of alien life: A noxious gas called phosphine is good indicator of life on a planet (Image: GETTY)

Proof of alien life: Alien exoplanet in space

Proof of alien life: MIT researchers consider phosphine a strong biosignature (Image: GETTY)

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.

If we can determine that only life can send out that signal, then I feel like that is a goldmine

Clara Sousa-Silva, Massachusetts Institute of Technology

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.”





Proof of alien life: Alien planet in deep space

Proof of alien life: Astronomers hope space telescopes can detect the noxious gas (Image: GETTY)

Proof of alien life: James Webb Space Telescope

Proof of alien life: NASA’s James Webb Space Telescope could detect phosphine on exoplanets (Image: GETTY)

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 telescope such as ’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.”

Could alien life exist on the Red Planet Mars?

Mars is believed to have once resembled a young Earth with a hotter and more humid climate, liquid water on the surface and a thicker atmosphere.

Today the planet is a barren desert lashed by intense radiation from the Sun.

Scientists are, however, hopeful simple microbial life developed on Mars many millions of years ago.

NASA is sending its Mars 2020 rover to the Red Planet next year to search for evidence of alien life in ancient rock and soil samples.

NASA said: “If Mars once had liquid water, or still does today, it’s compelling to ask whether any microscopic life forms could have developed on its surface.

“Is there any evidence of life in the planet’s past? If so, could any of these tiny living creatures still exist today?

“Imagine how exciting it would be to answer, ‘Yes!’”

December 21, 2019: On December 19 we published the above article with the headline “Proof of alien life? Stinky gas is surefire evidence aliens are real, astronomers announce”. The article incorrectly stated researchers at the Massachusetts Institute of Technology consider the gas phosphine to be a definite sign of extraterrestrial life on rocky planets rather than a possible indicator of life. The article and headline have since been amended to accurately report the study published by Dr Clara Sousa-Silva and her team. 

Dr Sousa-Silva does not believe the presence of phosphine on other planets is definitive evidence of alien microbes but speculates the possibility based on its creation on Earth. Phosphine is created on Earth by anaerobic life and humans for industrial purposes. The article now also points out examples of phosphine are present in the solar system where no known biological life exists. 

We are happy to set the record straight.