For the first time, water molecules have been found by scientists on an asteroid’s surface.
The recent discovery might explain the origin of our tiny Blue Marble. Although astronomers and scientists are still unsure of the exact source of our water, a popular belief holds that asteroids that struck the planet gave it.
Studying the compositions of asteroids has helped astronomers understand how materials such as water are distributed across the solar system.
And since water is key to life, researchers hope it will provide an understanding of where else to look for potential life, both in the solar system and beyond.
‘Asteroids are leftovers from the planetary formation process, so their compositions vary depending on where they formed in the solar nebula,’ said astronomer Dr Anicia Arredondo, who was part of the discovery.
‘Of particular interest is the distribution of water on asteroids, because that can shed light on how water was delivered to Earth.’
The ‘unambiguous’ features were found on the asteroids Iris and Massalia, two asteroids that orbit the Sun and measure 124 and 84 miles wide in diameter respectively.
The water molecules were discovered after observations by the now retired Stratospheric Observatory for Infrared Astronomy (Sofia), which revealed that two of the asteroids reflected a specific wavelength of light indicating the presence of water molecules at their surface.
‘We detected a feature that is unambiguously attributed to molecular water on the asteroids Iris and Massalia,’ said Dr Arredondo.
‘We based our research on the success of the team that found molecular water on the sunlit surface of the Moon. We thought we could use Sofia to find this spectral signature on other bodies.’
Previous observations had detected some form of hydrogen both on the Moon and on asteroids, but the studies could not tell the difference between water and hydroxyl − its close chemical relative.
The researchers found roughly equivalent to a 12-ounce bottle, or 350ml, of water trapped in a cubic meter of lunar surface soil which was chemically bound in minerals.
The level of water on the asteroid is consistent with its abundance on the sunlit surface of the Moon.
‘Similarly, on asteroids, water can also be bound to minerals as well as adsorbed to silicate and trapped or dissolved in silicate impact glass,’ said Dr Arredondo.
Now the researchers are enlisting the premier infrared space telescope – Nasa’s James Webb Space Telescope – to investigate more targets, due to its precise optics.
Their aim is to look at another 30 targets to increase their understanding of the distribution of water in the solar system.
