- 3366 - EARTH - The deeper we go the more we learn? More historical artifacts lie in the ocean than in all of the world's museums combined. Whether it's a Viking sundial used for navigation or a jadeite gift to ancient gods, a lot of the world's history can be found at the bottom of the seas.
--------------------- 3366 - EARTH - The deeper we go the more we learn?
- How could water have arrived on Earth since being closer to the Sun “Early Earth” would have all its water evaporated? So where did all the water come from? Water covers 70% of the planet. It got here somehow?
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- Analysis of asteroid “Itokawa” suggest that Earth's water may have been created by the sun. This water may have rained on the fledgling Earth in the form of dust grains produced by the interaction of the “solar wind“, the stream of charged particles emanating from the sun, with various bodies , asteroids, in the solar system.
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- The solar winds are streams of mostly hydrogen and helium ions which flow constantly from the sun out into space. When those hydrogen ions hit an airless surface like an asteroid or a space borne dust particle, they penetrate a few tens of nanometers below the surface, where they can affect the chemical composition of the rock. One inch has 24,500,000 nanometers.
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- Over time, this space weathering effect of the hydrogen ions can eject enough oxygen atoms from materials in the rock to create water, which remains locked within the asteroid.
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- This mechanism may be the missing link explaining the abundance and chemical composition of water on Earth that has long baffled scientists. Earth's surface is 70% covered with water. That's much more than any other planet in the solar system.
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- But none of the existing theories can fully explain all of it. A dominant view suggests that asteroids rich in carbon, which pummeled the young Earth some 4.6 billion years ago, delivered this water to the planet.
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- But detailed chemical analysis of meteorites known as “carbonaceous chondrites“, which are chunks of these carbon-rich asteroids, revealed that the water locked inside them doesn't quite match the chemical fingerprint of Earth's water.
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- This discrepancy in what scientists call “isotopic composition” led researchers to believe that there must be at least one additional source of our planet's life-giving liquid. Isotopes are forms of chemical elements that differ just by the number of uncharged neutrons they contain.
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- The carbonaceous chondrites tend to have water that contains more deuterium, a form of hydrogen with one neutron, while Earth's hydrogen is mostly a lighter form called “protium” that has no neutrons.
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- In search of the additional source of Earth's water, the team of researchers analyzed the composition of a rocky type of asteroid rich in silicon oxide using a novel technique called the “atom probe tomography“. Using this technique, the researchers measured the atomic structure of these grains one atom at a time to detect individual water molecules.
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- The samples analyzed in this study came from the asteroid Itokawa, visited by the Japanese probe Hayabusa, which delivered tiny pieces of this space rock to Earth in 2010.
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- The evidence came from the first 50 nanometers of the surface of dust grains on Itokawa. This asteroid orbits the sun in 18-month cycles. It allowed us to see that this fragment of space-weathered rim contained enough water that, if we scaled it up, would amount to about 4.4 gallons for every cubic meter (35 cubic feet) of rock.
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- The particles produced in the interaction of Itokawa's dust and the solar wind had more of the lighter form of hydrogen than the carbon-rich asteroids. That strongly suggests that fine-grained dust, buffeted by the solar wind and drawn into the forming Earth billions of years ago, could be the source of the missing reservoir of the planet's water.
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- The findings also suggest that water might be locked in the surface rocks of many space bodies, including the moon and asteroids. If so, this could be good news for future human exploration in deep space, as necessary supplies might be easier to find than scientists fear.
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- One of the problems of future human space exploration is how astronauts will find enough water to keep them alive and accomplish their tasks without carrying it with them on their journey.
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- The same space weathering process which created the water on Itokawa will have occurred to one degree or another on many airless worlds. That could mean that space explorers may well be able to process fresh supplies of water straight from the dust on the planet's surface.
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- Our planet may have been covered by a vast ocean and had no continents at all 3.2 billion years ago? Continents appeared later, as plate tectonics thrust enormous, rocky land masses upward to breach the sea surfaces.
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- Around 4.5 billion years ago, high-speed collisions between dust and space rocks formed the beginnings of our planet which was a bubbling, molten sphere of magma that was thousands of miles deep.
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- Earth cooled as it spun; eventually, after 1,000 to 1,000,000 years, the cooling magma formed the first mineral crystals in Earth's crust. Earth's first water may have been carried here by ice-rich comets from outside our solar system, or it may have arrived in dust from the cloud of particles that birthed the sun and its orbiting planets, around the time of Earth's formation.
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- When Earth was a hot magma ocean, water vapor and gasses escaped into the atmosphere. It then rained out from the atmosphere as conditions got cool enough.
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- Australian outback preserves a hydrothermal system dating to 3.2 billion years ago that records the entire ocean crust from the surface down to the heat engine that drove circulation.
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- Preserved in that craggy seafloor were different versions, or isotopes, of oxygen. The scientists uncovered something unexpected through their analysis of more than 100 sediment samples. They found that 3.2 billion years ago, oceans held more oxygen-18 than oxygen-16, that is more common in the modern ocean.
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- Their computer models showed that on a global scale, continental land masses leach oxygen-18 from the oceans. In the absence of continents, the oceans would carry more oxygen-18. And the ratio between these two oxygen isotopes hinted that at the time, there were no continents at all. This value is different than the modern ocean in a way that can be explained most easily by a lack of emergent continental crust.
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- The Earth was once ocean covered. The prospect of this ancient water world Earth also offers a new perspective on another intriguing question: where the planet's earliest forms of life appeared and how they evolved.
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- There are two major camps for the origin of life: hydrothermal vents and ponds on land. The number of environments on land for life to emerge and evolve was really small or absent until sometime after 3.2 billion years ago
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- About 70 percent of the Earth's surface is covered with water, yet the oceans largely remain a mystery for scientists. More is known about the moon's surface than the depths of the ocean. In fact, 12 people have stepped foot on the moon, but only three have been to the Mariana Trench, the deepest part of the ocean, at roughly 7 miles deep.
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- Though 94 percent of life on Earth is aquatic, and about two-thirds of all marine life remains unidentified. New species are constantly being discovered, raising more questions about marine life. New species include a striking red species of sea dragon that remained undiscovered despite living in shallow waters off the western coast of Australia.
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- Other recent discoveries have included what may be the world's ugliest fish, as well as a ghostly octopod and a "ninja" shark with a dimly glowing head. It's not just the flora and fauna of the oceans that remain mysterious to scientists; there are a handful of sounds from the depths of the oceans that scientists cannot explain with any certainty.
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- "The Bloop" may be the most famous underwater sound, captured in 1997 by hydrophones set out by the National Oceanic and Atmospheric Administration (NOAA). It is one of the loudest ocean sounds ever recorded, and while the noise is consistent with an underwater ice quake, a large iceberg fracturing, no one knows for sure what made the sound.
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- Oceans have lakes, and rivers, that exist underwater. How is this possible?? When seawater seeps through thick layers of salt, the salt dissolves and forms depressions in the seafloor. Dissolved salt also makes the water in that area denser. It will settle into the depressions. These underwater lakes and rivers, also known as brine pools, are similar to their land-based counterparts, they have shorelines, and even waves.
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- There are even waterfalls in the ocean. The Earth's largest known waterfall lies between Greenland and Iceland, underwater. An underwater waterfall with 175 million cubic feet of water dropping a whopping 11,500 feet.
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- The waterfall is formed by the temperature difference between the water on each side of the Denmark Strait. When the colder, denser water from the East meets the warmer, lighter water from the West, the cold water flows down and underneath the warm water.
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- The Denmark Strait cataract is more than three times the height of Angel Falls in Venezuela, which is considered Earth's highest aboveground uninterrupted waterfall. The Denmark Straight cataract carries almost 2,000 times the amount of water of Niagara Falls at peak flow.
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- Warmer oceans, more acidic waters, pollution and human interference are threatening marine life across the globe. Coral reefs contain some of the most delicate ocean residents. Yet coral has a way to naturally protect itself: "sunscreen."
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- Over millions of years, corals in Australia's Great Barrier Reef developed protective barriers that help them survive in the sun. The oceans are rich with more than just marine life.
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- Dissolved gold can be found in the water of all oceans. But although the oceans hold nearly 20 million tons of gold, it is so dilute that its concentration is on the order of parts per trillion.
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- There is undissolved gold in and on the seafloor. Mining for this gold, located at least a mile or two underwater and encased in rock, may not be worthwhile, as there currently isn’t a cost-effective way to mine or extract gold from the ocean. NOAA estimates that if all of the gold were extracted from the world's oceans, each person on Earth could have 9 lbs. of the precious metal.
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- More historical artifacts lie in the ocean than in all of the world's museums combined.
Whether it's a Viking sundial used for navigation or a jadeite gift to ancient gods, a lot of the world's history can be found at the bottom of the seas.
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- That does not include the vast number of shipwrecks lying on the ocean floor, estimated to number 1 million, with the majority of the wrecks still undiscovered.
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- The ocean holds many secrets about human history and the planet's origins. The deeper we go the more we learn.
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December 4, 2021 EARTH - the more we learn/ 3362
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