Water is a ubiquitous molecule that is essential for life as we know it. It covers 71% of the Earth’s surface and makes up approximately 60% of the human body. But where did all this water come from? Recent observations using the Atacama Large Millimeter Array (ALMA) Observatory have shed light on the origins of water in the solar system, providing us with a new and intriguing narrative.
In a study published in the journal Nature Astronomy, scientists were able to detect water particles in the star system V883 or Yonis using ALMA. The system contains a well-known baby star with a large disc, and inside the disc, the scientists discovered a unique isotope of water. This discovery connects previous findings from Earth, comets, and interstellar space, suggesting that most, if not all, of the water on Earth originated from interstellar space.
The water discovered in V883 is potentially billions of years older than the solar system itself, which is a mind-blowing revelation. It suggests that we are not just made of stardust, but also ancient galactic water, possibly even older than most stars in the galaxy.
However, it’s important to note that not all water is the same. Water can have various isotopes, including heavy water, which contains heavier hydrogen or oxygen molecules. By looking at the different types of water in interstellar space, scientists have identified specific ratios between isotopes, such as the terium oxide, which contains two deteriums instead of two hydrogens.
The precise calculation of the terium to hydrogen ratio in water on Earth is known with extreme precision, allowing for comparisons with water found elsewhere. Previous assumptions that water on Earth may have come from comets were proven to be incorrect, as cometary water contains a different ratio of terium to hydrogen than that found on Earth. However, certain asteroids coming from the asteroid belt contain a similar ratio, suggesting they may have contributed to some of the water on Earth.
It’s believed that all the water in the solar system was already present when the Sun and planets were formed, and that the molecules of water came from the original molecular cloud. Observations of various molecular clouds, such as the Orion Nebula and the Carina Nebula, have discovered water that is similar in ratio to that found in asteroids on Earth, suggesting that water was already in existence in the interstellar space when stars were forming.
Despite having many theories and propositions, there was not enough observational evidence to prove the origin of water. This new study provides valuable evidence that water in the solar system may have come from interstellar space, which could help us understand the origin of life on Earth.
The study focused on a baby star located in the Orion molecular cloud, approximately 1,300 light-years away from Earth. The baby star shows what early stars like our Sun may have looked like in the first few thousand years of their existence, and is a very active object, accreting a significant amount of material and possessing a jet that expels material into space.
The scientists detected areas around the star system where the frostline, also known as the snowline, can be seen. The frostline is a specific boundary around a star where the temperature drops low enough for volatile compounds like water to condense into ice. Beyond the frostline, water can exist in solid form, while inside the frostline, it exists in a gaseous form.
The detection of the frostline in the V883 system provides evidence that water was present during the early stages of planet formation, and that it may have played a crucial role in the formation of rocky planets like Earth. The presence of water in the disc surrounding the baby star suggests that it could have been the key ingredient in the formation of planets within the habitable zone.