Experts have unearthed the ‘strongest evidence yet’ for aliens on other planets after pieces of an asteroid were found to contain the building blocks of life.
In 2020, a NASA spacecraft collected a sample from an asteroid called Bennu as part of a nail-biting mission that took place more than 200 million miles away.
Once it had returned to Earth samples of the dust were sent to laboratories around the world, including in the UK, to be studied by scientists.
Now, analysis has revealed that traces of ancient brine within the sample contain minerals crucial to life and which kicked off the chemical processes that led to a lush and fertile Earth.
And experts say this is the ‘strongest evidence yet’ that the building blocks for life as we know it are spread across the solar system – and have been there for billions of years.
The discovery has been published across two papers – one which indicates Bennu was part of a long-lost wet, salty world which originated at the dawn of the solar system, and another which reveals a ‘suite’ of organic materials that were detected in the sample.
Among them are all five nitrogenous bases – molecules required for building DNA and RNA – and amino acids, which are the building blocks of proteins.
Professor Sara Russell, from the Natural History Museum, was one of the scientists studying the ‘dust’.
Experts have unearthed the ‘strongest evidence yet’ for aliens on other planets after pieces of an asteroid were found to contain the building blocks of life
In 2020, a NASA spacecraft collected a sample from an asteroid called Bennu as part of a nail-biting mission that took place more than 200 million miles away. Once it had returned to Earth samples of the dust were sent to laboratories around the world, including in the UK, to be studied by scientists
Analysis has revealed that traces of ancient brine within the sample contain minerals crucial to life and which kicked off the chemical processes that led to a lush and fertile Earth
She said: ‘One of the interesting things we found in there was a whole range of salts. That includes sodium chloride, which is what we put on our chips, and loads of other salts like phosphates and carbonates.
‘We think these actually formed a briny, salty water that may have been underground in the asteroid.
‘This sort of salty fluid would be a perfect place to make organic molecules. And in the early solar system there would have been millions of asteroids like Bennu, so it could have been really important for “seeding” the Earth and other planets with all these ingredients they can use for life.’
She said although there isn’t any evidence for life elsewhere in the solar system yet, ‘now we know there were there were all of these ingredients around’.
‘I imagine that whatever rained down on Earth would have also rained down on Mars and on the moons of the giant planets, and they might have been really great environments for life to begin,’ she added.
‘I think it’s likely that the fact we’ve found these things in abundance means that life may have begun elsewhere.
‘This is really strong evidence that these building blocks for life were widespread throughout our solar system.’
The two new studies, which appear in the journals Nature and Nature Astronomy, are among the first published analyses of the Bennu samples.
Scanning electron microscope images of trona found in samples of the asteroid Bennu returned by NASA’s OSIRIS-REx mission
Earth-originating examples of minerals found in Bennu samples. Foreground, left to right: calcite, gaylussite, sylvite with halite, villiaumite
Some of these crucial ‘building blocks’ have not been detected in meteorites that have fallen to Earth – most likely because their composition would have been altered after burning through the atmosphere and they would have been easily contaminated after hitting the ground.
Bennu consists of pieces of a larger asteroid that formed nearly 4.6 billion years ago, around the same time as the solar system.
By understanding the composition of the Bennu samples, scientists can gain insights into the conditions of that time, helping answer questions about how the solar system – and Earth – formed.
‘It’s interesting that although Bennu had everything needed for life, it did not form,’ Professor Russell added.
‘The complex and delicate conditions needed to catalyse life really bring into focus the abundance of biodiversity here on Earth.’
Co-lead author Tim McCoy, curator of meteorites at the Smithsonian Museum in Washington said: ‘This extraordinary work, done at the scale of microns, will help us understand what happens at the scale of planets.’
