The journey begins with trail-like hydrogen and oxygen gas in the middle of the stars and ends with oceans and ice caps on planets, with icy moons orbiting the gas reservoirs and icy comets and asteroids orbiting the stars. We do.
Without water, life could not exist on Earth. Understanding the history of water in the universe is important for understanding how planets like Earth formed. Astronomers usually refer to water’s journey from forming as individual molecules in space to reaching the surfaces of planets.
The journey begins with trail-like hydrogen and oxygen gas in the middle of the stars and ends with oceans and ice caps on planets, with icy moons orbiting the gas reservoirs and icy comets and asteroids orbiting the stars. We do. The beginning and end of this trail are easy to see, but the middle remains a mystery.
I am an astronomer who studies the formation of stars and planets using observations from radio and infrared telescopes. In a new paper, my colleagues and I describe the first measurements made of this hidden central part of the water pathway and what these findings mean for water found on Earth-like planets. How Planets Are Formed The formation of stars and planets are closely related. The so-called emptiness of space – or the interstellar medium – actually contains large amounts of gaseous hydrogen, small amounts of other gases and dust particles.
Due to gravity, some parts of the interstellar medium become more dense as particles attract each other and form clouds. As the density of these clouds increases, molecules collide more frequently and form larger molecules, including water that forms on dust grains and encases the dust in ice. Stars begin to form when parts of the collapsing cloud reach a certain density and become hot enough for hydrogen atoms to begin fusing together.
Since only a small fraction of the gas initially collapses into the newborn protostar, the rest of the gas and dust form a flat disk of material orbiting around the newborn star. Astronomers call this the proto-planetary disk. As icy dust particles collide with each other inside a proto-planetary disk, they begin to coalesce. This process continues and eventually forms the familiar objects of space such as asteroids, comets, rocky planets like Earth and gas giants like Jupiter or Saturn.
Two Theories for the Source of Water There are two possible routes that water might have taken to arrive in our Solar System. The first, called chemical succession, is when water molecules that originally formed in the interstellar medium are transported without change to the proto-planetary disk and all the bodies that form from them. The second principle is called chemical reset. In this process, the heat from the proto-planetary disk and the formation of the newborn star breaks apart water molecules, which re-form as the proto-planetary disk cools.
To test these theories, astronomers like me look at the ratio between normal water and a special type of water called semi-heavy water. Water is generally composed of two hydrogen atoms and one oxygen atom. Semi-heavy water is made up of one oxygen atom, one hydrogen atom and one atom of deuterium – a heavier isotope of hydrogen that has an extra neutron in its nucleus.
The ratio of semi-heavy to normal water is a guiding light for the journey of water – measuring the ratio can tell astronomers a lot about the source of water. Chemical models and experiments have shown that about 1,000 times more semi-heavy water would be produced in the cold interstellar medium than in a protoplanetary disk. This difference means that by measuring the ratio of semi-heavy to normal water at a location, astronomers can tell whether that water went through chemical inheritance or chemical reset.
Measuring water during planet formation The ratio of semi-heavy to normal water in comets is almost entirely consistent with the chemical legacy, meaning that the water has not undergone any major chemical changes since it first formed in space Is. Earth’s ratio sits somewhere between the legacy and reset ratios, making it unclear where the water came from.
To determine exactly where the water on the planets comes from, astronomers needed to find a Goldilocks proto-planetary disk—that’s the right temperature and size to help observe water. Doing so has proven incredibly difficult. It is possible to detect semi-heavy and normal water when water is gas; Unfortunately for astronomers, much of the proto-planetary disk is very cold and consists mostly of ice, and it is almost impossible to measure the ratio of ice to water at interstellar distances.
A breakthrough came in 2016, when my colleagues and I were studying proto-planetary disks around a rare type of young star called Fu Orionis stars. Most young stars consume material from the proto-planetary disk around them. FU Orionis stars are unique in that they consume matter about 100 times faster than typical young stars and, as a result, emit hundreds of times more energy.
Due to this high energy output, the proto-planetary disks surrounding FU Orionis stars are heated to very high temperatures, which convert ice into water vapor far away from the star. Using the Atacama Large Millimeter/submillimeter Array, a powerful radio telescope in northern Chile, we discovered a large, hot proto-planetary disk around the Sun-like star V883 Ori, about 1,300 light-years from Earth in the constellation Orion .
V883 Ori emits 200 times more energy than the Sun, and my colleagues and I considered that it was an ideal candidate to observe the semi-heavy to normal water ratio. Completing the waterway In 2021, the Atacama Large Millimeter/submillimeter Array measured V883 Ori for six hours. The data revealed a strong signature of semi-heavy and normal water coming from V883 Ori’s proto-planetary disk. We measured the ratio of semi-heavy to normal water and found that the ratio was similar to that found in comets as well as those found in young protostar systems. The new results show definitively that a large proportion of the water on Earth formed billions of years ago before the Sun ignited.
Confirming this missing piece of water’s pathway through the universe provides clues to the origins of water on Earth. Scientists have suggested that most of the water on Earth came from comets impacting the planet. The fact that there is less semi-heavy water on Earth than comets and V883 Ori, but more than the chemical reset theory would produce, means that water on Earth came from more than one source.
Disclaimer:Prabhasakshi has not edited this news. This news has been published from PTI-language feed.