A group of North American scientists have found water molecules on the surface of asteroids for the first time. The team, led by researcher Anicia Arredondo, used NASA’s Sofia Observatory to observe the asteroids Iris and Massalia and the finding could help scientists explain the origin of the substance in the emergence of rocky planets, like Earth, and others stars.
Importance
According to professor Roberto Dell’aglio Dias da Costa, from the Institute of Astronomy, Geophysics and Atmospheric Sciences (IAG) at the University of São Paulo, water is present in several space objects, such as Europa and Ganymede, moons of Jupiter that have more water than Earth. He states that this new discovery demonstrates that the substance may also be present in smaller celestial bodies.
According to the professor, a large part of the water present on Earth was obtained in the so-called “era of bombardment”, a period around 4 billion years ago in which a huge number of asteroids and comets collided with planets in the solar system. At the time, the Earth’s temperature was extremely high to retain the liquid, therefore, these external events were necessary to obtain the substance.
Discovery
According to Jane Gregório-Hetem, professor at IAG, the observational technique used by scientists was the same used to reveal water on the Moon, in which the spectral characteristic is observed at a wavelength of six micrometers (µm), which is specific of the water molecule.
For the professor, the new finding is also surprising because of the material that forms Iris and Massalia, silicate, responsible for the composition of around 90% of the Earth’s crust. Objects of this type are known as non-hydrated because they are composed of refractory materials and, due to their formation very close to the Sun, the presence of water in their structure is considered extremely difficult.
Water on Mars
Roberto Costa explains that water molecules have already been found in other space objects, such as Mars, but in different formats. While the water in asteroids was discovered on the surface, the substance is present in the red planet’s polar caps, which are mostly composed of frozen carbon dioxide (CO2), which is commonly used on Earth as dry ice.
He says that, despite the new discoveries, the water cycle in the Solar System still has a lot to be studied. “Mars has erosion marks on its surface, showing that there was once liquid water on the surface, but this water no longer exists. So what is the complete water cycle in the solar system? Much still needs to be understood in this area”, he explains.
Life outside Earth?
For Jane Gregorio-Hetem, the presence of water on other stars does not necessarily represent the existence of other forms of life outside Earth. She states that more in-depth studies on the topic are still needed by improving existing observational techniques, which can contribute to the analysis of other molecules, including those more complex than water.
“Finding water on these asteroids does not guarantee that we have other forms of life. Although water is always related to the forms of life that we know, studies are still needed to identify and also characterize other astrophysical environments that may contain other types of molecules”, he explains.