WEBVTT - Where Does Earth's Water Come From?

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<v Speaker 1>Welcome to brain Stuff, a production of iHeartRadio, Hey brain

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<v Speaker 1>Stuff Lauren vogelbom Here. A water surrounds us, falling from

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<v Speaker 1>rain clouds, rushing down river beds, and pouring from faucets,

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<v Speaker 1>and yet many of us have never stopped to wonder

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<v Speaker 1>where does water come from? The answer is a complicated one,

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<v Speaker 1>stretching way beyond the water cycle and all the way

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<v Speaker 1>back to the very origins of the universe. It's essential

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<v Speaker 1>to understand that water isn't just a liquid that happens

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<v Speaker 1>to cover our planet. It's a medium for pretty much

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<v Speaker 1>all life as we know it. A water's unique properties,

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<v Speaker 1>such as its ability to dissolve many substances and its

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<v Speaker 1>solid state being less dense than its liquid state, which

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<v Speaker 1>is why ice expands as it freezes and floats in

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<v Speaker 1>liquid water, make it invaluable. A water acts as a solvent,

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<v Speaker 1>a temperature regulator, and a means of transportation for new

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<v Speaker 1>tents and waste. And devoid of the water cycle, the

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<v Speaker 1>complex chain of life on Earth from microbes to mammals

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<v Speaker 1>would cease to exist. But let's go back, like way back.

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<v Speaker 1>Shortly after the Big Bang, neutrons and electrons swarmed in

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<v Speaker 1>ten billion degree heat within minutes, hydrogen and then helium

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<v Speaker 1>unknown as the lighter elements had taken shape from these

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<v Speaker 1>atomic building blocks in a process called nucleosynthesis. Lithium made

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<v Speaker 1>a cameo as well, but generally the heavier elements didn't

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<v Speaker 1>appear until much later, when the lighter elements underwent fusion

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<v Speaker 1>inside of stars and during supernova Over time, stars sent

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<v Speaker 1>wave after wave of these heavier elements, including oxygen, out

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<v Speaker 1>into space, where they mixed with the lighter elements. Of course,

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<v Speaker 1>the mixing of hydrogen and oxygen atoms and the subsequent

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<v Speaker 1>formation of water are two different things. That's because even

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<v Speaker 1>when hydrogen and oxygen atoms get together, they still need

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<v Speaker 1>a spark of energy to form water. The process is

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<v Speaker 1>a violent one, and so far nobody has found a

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<v Speaker 1>way to safely create water on Earth. So how did

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<v Speaker 1>our planet come to be covered with the stuff. The

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<v Speaker 1>simple answer is we still don't know, but we have

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<v Speaker 1>a few ideas. One theory states that nearly four billion

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<v Speaker 1>years ago, the early Solar System was overrun by millions

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<v Speaker 1>of asteroids and comets, which slammed into the surface of

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<v Speaker 1>our relatively young planet. A quick glance at the Moon's

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<v Speaker 1>crater pocked surface gives us an idea of what conditions

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<v Speaker 1>of early Earth might have been. The theory goes that

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<v Speaker 1>these crash landing celestial bodies weren't solid rock, but rather

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<v Speaker 1>the equivalent of cosmic sponges, loaded with water that was

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<v Speaker 1>released on impact. While astronomers have confirmed that water rich

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<v Speaker 1>asteroids and comets exist, some scientists think that the theory

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<v Speaker 1>doesn't hold water huh. They question whether enough collisions could

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<v Speaker 1>have taken place to account for all of Earth's water. Also,

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<v Speaker 1>a researchers from the California Institute of Technology found that

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<v Speaker 1>water from the comet hail Bop is different from normal

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<v Speaker 1>Earth water. Ours has the chemical formula H two OH.

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<v Speaker 1>It's one atom of oxygen linked together with two atoms

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<v Speaker 1>of the common hydrogen one isotope, which has in its

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<v Speaker 1>nucleus only one proton a butt. Most of the water

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<v Speaker 1>on the hail Bop is what's called semi heavy water,

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<v Speaker 1>a form of water in which there's still one atom

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<v Speaker 1>of oxygen, but one of the atoms of hydrogen is

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<v Speaker 1>a different isotope called hydrogen two or deuterium. It has

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<v Speaker 1>a proton and a neutron in its nucleus. The semi

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<v Speaker 1>heavy water's chemical formula is h DO, and its higher

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<v Speaker 1>mass gives it slightly different chemical and physical properties. So

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<v Speaker 1>either the comets asteroids that hit Earth were very different

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<v Speaker 1>from the hail BOP or Earth got its H two

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<v Speaker 1>oh some other way. More recently, astronomers may have revealed

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<v Speaker 1>that the former may actually be true. Using observations from

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<v Speaker 1>the Stratospheric Observatory for Infrared Astronomy or SOPHIA, which is

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<v Speaker 1>a converted seven to forty seven aircraft that flies at

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<v Speaker 1>high altitude with an infrared telescope sticking out of the

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<v Speaker 1>tail section. A researchers found that when the comet Wordinin

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<v Speaker 1>made its closest approach with Earth in December of twenty eighteen,

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<v Speaker 1>it was venting very ocean like water vapor into space.

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<v Speaker 1>Wordenin belongs to a specific family of comets called hyperactive

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<v Speaker 1>comets that vent more water vapor into space than others.

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<v Speaker 1>The researchers deduced that its water is ocean like by

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<v Speaker 1>comparing the ratio of observed H two O and HDO

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<v Speaker 1>in that water vapor. Earth's oceans have a very specific

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<v Speaker 1>ratio of those two hydrogen isotopes. And here's that wordinan

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<v Speaker 1>shares that same ratio as Observing infrared wavelengths from the

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<v Speaker 1>ground is impossible because Earth's atmosphere blocks these wavelengths. Only

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<v Speaker 1>space telescopes and Sophia, which flies above most of the atmosphere,

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<v Speaker 1>can make reliable observations of comets. Another theory states that

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<v Speaker 1>a young Earth was bombarded by oxygen and other heavy

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<v Speaker 1>elements produced within the Sun. The idea is that the

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<v Speaker 1>oxygen combined with hydrogen and other gases released from the

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<v Speaker 1>Earth itself in a process known as degassing, thus forming

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<v Speaker 1>Earth's oceans and atmosphere along the way. And a team

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<v Speaker 1>of scientists from Japan's Tokyo Institute of Technology has devised

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<v Speaker 1>yet another theory, which states that a thick layer of

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<v Speaker 1>hydrogen may have once covered Earth's surface, eventually interacting with

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<v Speaker 1>oxides in the crust to form our planet's oceans. Finally,

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<v Speaker 1>computer simulations reported on in twenty seventeen suggested a closer

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<v Speaker 1>origin or at least some water on our planet. This

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<v Speaker 1>theory states that water could develop deep inside Earth's mantle

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<v Speaker 1>and eventually escape via earthquakes or other geological processes. Water

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<v Speaker 1>is so essential to life on Earth that a lot

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<v Speaker 1>of research is devoted to finding it on other planets

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<v Speaker 1>and moons, because where we find it, we may find

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<v Speaker 1>alien life. However, here on our planet, a water's availability

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<v Speaker 1>and quality are under threat. Pollution, over extraction, and climate

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<v Speaker 1>change are just some of the challenges facing our planet's

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<v Speaker 1>water resources. Addressing these issues is not only a scientific endeavor,

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<v Speaker 1>but also a societal one. After all, while we can't

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<v Speaker 1>say with certainty how water came to Earth, we are

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<v Speaker 1>fortunate it did. Today's episode is based on the article

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<v Speaker 1>where does water come From? On howstiffworks dot com, written

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<v Speaker 1>by job An Adabury and Ian O'Neil. Brain Stuff is

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<v Speaker 1>production of iHeartRadio in partnership with ho stuffworks dot Com

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<v Speaker 1>and was produced by Tyler Klang. For four more podcasts

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<v Speaker 1>from my heart Radio, visit the iHeartRadio app, Apple Podcasts,

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<v Speaker 1>or wherever you listen to your favorite shows.