It doesn’t seem likely that there was water on Earth before the solar system it is in. But a recent study in the journal Science that was reviewed by experts backs this up.
Astronomers came to this conclusion by showing that water in our solar system had to have come from the huge cloud of gas and dust that came before and was needed for the Sun to form. This means that there was water before the Sun exploded into a star, and that water got to Earth through “wet rocks” like asteroids and comets.
One of the people who wrote the study is Ted Bergin, who teaches astronomy at the University of Michigan in Ann Arbor. He thinks there is “a magnificent story to be told” about the past 4.6 billion years.
The Earth was made up of tiny pieces that were smaller than the width of a human hair. Astronomers call this “dust,” and Bergin says that astronomers are “very creative people.”
At this distance from the Sun, these dust particles would get so much heat from the Sun that they would be too hot for water to freeze on them. Bergin says this shows that when the Earth was made, it was dry. Where did the water come from? That’s an interesting question.
Bergin thinks we need to ask a bigger question: Where did the water in the universe come from? He says, “The universe is made of atoms, not water.” So, at some point in time, those atoms in the universe linked up through chemistry to make water.
Luckily, astronomers can use tools from Earth to study that chemical. They can make the same conditions that cause water to be made. This is done with the help of a method called “isotope fingerprinting.”
This is done with the help of a method called “isotope fingerprinting.” Deuterium is the second type. There are about 100,000 hydrogen atoms for every deuterium atom, so the ratio of these two elements is more or less the same all over the solar system. This much hydrogen and deuterium might be in water.
"Chemistry, according to Bergin, “tells us that there can be an excess of deuterium under extremely exact conditions.” This is known as a “isotopic fingerprint.” Deuterium is plentiful on Earth and in comets and asteroids."
"The isotopic fingerprint is only observable at very low temperatures, between 10 and 20 degrees above absolute zero (-441 degrees Fahrenheit). As a result, Bergin writes, “we already know one thing: whatever the source of the water was, it was extraordinarily, incredibly cold.” This is due to the Earth’s deuterium surplus. As a result, we must analyse how stars and planets form and ask, “Where is it that cold?”
Only two places in the huge, violent system where stars first form can have temperatures this low: the protostar’s cloud of gas and dust or the accretion disc that is just starting to form around it. One more surprise is that water can also be made chemically, through a process called ionisation. By looking at a detailed model of this chemical event, the researchers found that the disc isn’t able to move it.
Bergin says this shows that the disc can’t make water, but the cloud of gas and dust, which are the most likely places to find water, can. Given this, water with an isotopic signature could only have come from gas and dust about a million years before the sun.
But this makes me wonder how this water got to Earth in the first place. Bergin says that planets are made from the same cloud of gas and dust that gets squeezed together and then bursts into flames to make a star.
The cloud sent rocks into space, where they hit the subatomic particles that eventually formed Earth. Even though some of them didn’t have water, they crashed into the Earth and merged with it. From far away, more stones were thrown at us. These pebbles were cold enough to hold water.
"Therefore, Bergin claims, “when the Earth was birthing, these boulders from larger distances provided the water.” The seas, the atmosphere, and the lovely world we have today were all produced as a result of the water that had previously been a component of the rocks simply evaporating through volcanoes."
Reference: You may read the original article on Earth.com here.
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