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The place where the Earth is now seems very dry so if the Earth formed as a dry rock around a hot young star, then how did this water get here? The beginning premise (Earth as a dry rock) is ridiculous but then leads to a logical yet pointless question (where did the water come from?). The video suggests Earth's water source is an extremely complex issue but its only complex if you assume the Earth didn't start out with the same constituents we see in almost all other hard bodies in the solar system. |
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In other words, its a complex issue when you start with the wrong assumption.
Begin by thinking Earth was a dry molten rock with no water and then it becomes necessary to add water. But if the Earth is built out of the same Rock/Ice Rock material the rest of the solar system is made of then voila problem solved. If you want to see a bunch of videos (like the above) with some good science peppered with not so good science click here. This is why I keep saying if you start with the wrong premise it doesn't matter what your models or math suggests because they are then nothing more than a reflection of your preexisting expectations. |
The late heavy bombardment did NOT look like this. Meteors weren't showering down like raindrops.
Many years would pass between each impact. The impacts were energetic (high velocity) and relatively frequent and with a thin early atmosphere small impactors made it to the surface without burning up. Impact energy was far too infrequent and localized to create a molten surface but as our planet grew ever larger internal compression forces along with internal radiogenic heat were significant enough to heat and melt rock. |
This image is a little more like what early Earth might have looked like except for the ridiculous barrage of meteorites.
Consider this scenario. The Earth was similar in composition to Enceladus, Europa, Ganymede, Pluto and to a greater degree Mars but Earth was much larger. It was a planet constructed of water ice, rock and iron but the proportions were a bit different. Why? Because we are closer to the Sun, hence more of the lighter (volatile) gasses like H2O were slowly baked away. |
This scenario allows for more rocky material but still lots of water ice during the formation of our planet.
The spin speed (orbital velocity) of objects was faster so impacts were more energetic creating some minor local surface molten conditions which would have cooled quickly same as occurs today. The Earth's volume is larger and the mass is denser than outer solar system objects (moons) creating more compressional energy in turn forming a molten mantle and core. Lighter materials like water rose to the surface of Earth cooling and creating the crust quickly trapping the internal heat in a blanket separating water from molten rock. |
Consider these two models of Enceladus and Europa. The only real difference between them and Earth is their size and proximity to the Sun and because of that proximity their densities are much less than Earth.
Since they are far beyond the asteroid belt's frost line they are encased in a crust of ice but below that ice crust is a world that looks very much like the early Earth (small metal core, large rocky hot mantle, thin crust covered by water and ice). Put Enceladus, Europa, Ganimede or even Callisto in Earths orbital path and their ice crust would melt to water. |
Earth existed as a mostly covered in water world long before the LHB.
Wiki quote about the time of the LHB. As more data has become available, particularly from lunar meteorites, this theory (LHB), while still controversial, has gained in popularity... Consistent with the cataclysm hypothesis, none of their ages was found to be older than about 3.9 Ga. Nevertheless, the ages do not "cluster" at this date, but span between 2.5 and 3.9 Ga. The latest science findings indicate, the solar system developed 4.5682 Ga, the Moon was formed 60 million years after the solar system or 4.51 byr, the Earth was covered in water 4.4 Ga, the magnetic field developed at least 4.2 Ga and the LHB occurred between 2.5 to 3.9 byr. According to this science paper in Nature the LHB began 3.68 byr and lasted 200 myr or ended 3.48 byr. The Earth was covered in water 4.4 byr while the LHB started 3.68 byr, in other words, the LHB did NOT deliver oceans of water to Earth. Stated another way, the Earth was an ocean world 780 million years before the LHB began. Universe-Sci About three billion years ago, small pockets of free oxygen started to appear in the oceans, and then about 2.4 billion years ago, a rapid increase in atmospheric oxygen took place. During this period of about 200 million years, the amount of free oxygen in the atmosphere suddenly jumped by about 10,000 times. |
The moon formed very early on from multiple impactors.
Earth's water and atmosphere were protected by a magnetic field at least within the first 350 million years. Based on the fact Ganymede has a magnetic core I'm suggesting the Earth's magnetic core existed prior to 4.2 Ga although its not yet scientifically proven. A recent study released September 19th, 2017 shows that Mars had an atmosphere almost as thick as Earth's 4 Ga which means it had oceans of water, just like Earth, prior to the LHB. |
Section NWA 7533 of a Martian meteorite, Black Beauty has been dated to 4.4 billion years old and is loaded with evidence of water existing on Mars' surface at that time. Both Earth and Mars were covered in water 4.4 Gya or 500 million to 1.5 billion years prior to the LHB. All this information put together indicates the Earth was a ball of rock covered by water/ice prior to the LHB. The LHB did not deliver the water to Earth indicated by event timing and deuterium ratios. Earth formed as a ball of rock and ice before the Sun even ignited. |
Below are a series of images migrating from under ocean thermal vents creating mineral mounds surrounded by marine life to volcanoes punching through the surface of the ocean to hot spring pools filled with extremophiles (single celled organisms that thrive in extreme conditions) to volcanically driven erupting geysers to geysers building earthen mineral mounds housing extremophile life forms.
The below sequence of images presents a rough idea of how I see the early earth evolving from water world to earth world to living world >>>>>>>>>> Enjoy the music while you view the below images |
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The guy in this video is extremely annoying but its an informative video.
>>>>>>>>>> Since water ice is abundant in our solar system, it seems, the most likely scenario is our Earth was constructed of material that was heavily laden with water ice much like we see at Pluto and many of the moons around Jupiter and Saturn. Mars is our neighbor and was once covered with water when the planet was internally hotter but now has vast quantities of that water locked up as ice just below the surface dirt. |
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“The signature of water is present nearly everywhere on the lunar surface, not limited to the polar regions as previously reported,” says lead author Shuai Li. Although the bulk of the water mapped in the study could be attributed to solar wind, there were exceptions. For example, higher-than-average concentrations of water were found in lunar volcanic deposits near the moon’s equator, where background water in the soil is scarce. |
The primary difference being bodies closer to the Sun have more of the water ice boiled or evaporated away depending on temperature and magnetic atmospheres. We have a nice strong magnetic field protecting us from the Sun's solar wind and this magnetic field likely existed from Earth's earliest times protecting its water content. |
Early multiple smaller impactors which created the Moon were probably constructed mostly of the same stuff as Earth and so would have also had lots of water ice along with rock and metals.
Water was already largely on Earth before the Moon forming impacts (plural) but that water supply was added to by these impacts. The moon had to form early or else it wouldn't have been around to take all the impacts from the LHB, it doesn't have an atmosphere but it does have subsurface water ice. If a Theia (Mars) sized object hit Earth to form our Moon, the Moon wouldn't have so much water and neither would the Earth. |
This image isn't even close to what the asteroid belt looks like there's lots of space between each asteroid.
The average distance between objects in the asteroid belt is 600,000 miles (965,600 km). This image demonstrates one aspect of the belt which I'd like to describe in a little detail. >>>>>>>>>> Below image is of Ceres, Vesta and other asteroid belt objects. Almost one-third of the entire mass of the asteroid belt is accounted for by Ceres alone. Beyond that, some 200 asteroids are larger than 100 km (62 miles) in diameter, while 0.7–1.7 million asteroids have a diameter of 1 km (2/3 of a mile) or more. |
This happened in the early solar system, planets formed before the Sun ignited so all the icy rocky metal materials were mostly in place at the time the Sun turned on.
This is an artist rendition of a protoplanetary disk. I'm asking you to consider what happened prior to this moment. Prior to this star's ignition, these planets were moons and the star was a planet. |
This is HL-Tauri a protoplanetary disk around a young forming star.
This system is assumed to be only 100 degrees Kelvin (it could be more) and planets are forming in the gaps at temperatures where all the water ice is still frozen rock hard. While today our inner solar system is constructed mainly of hard rock bodies those bodies didn't start out that way. Their volatile gasses had to be liquefied then vaporized then escape into space. All material in the solar system was pretty much the same and since we see a lot of evidence beyond the frost line that ice water was a major constituent of solar system construction material then it is inevitable that the inner solar system was the same stuff. Simply add some time and heat and the material's rock to ice ratios change. |
Every billion years the Sun gets approximately ten percent hotter, it was 30% cooler at ignition than it is today.
As the Sun grew larger and hotter it had sufficient time to bake away more volatile gasses from the surface of inner bodies but early on the ratio of water ice relative to rock/metal was significant. A gravitationally large enough planet like Earth, with a magnetosphere evaporating water could hold onto its water vapor as an atmosphere. The molten metal core set up a magnetic field that shielded the water's evaporation process from the Sun as the compressed hot rock bubbled outward it broke through an ever thinning layer of water creating volcanoes. |
Wiki Quote
Study of zircons has found that liquid water must have existed as long ago as 4.404 ± 0.008 Ga, very soon after the formation of Earth.[10][11][12][13] This requires the presence of an atmosphere. The cool early Earth theory covers a range from about 4.4 to 4.0 Ga. In fact, recent studies of zircons (in the fall of 2008) found in Australian Hadean rock hold minerals that point to the existence of plate tectonics as early as 4 billion years ago. If this holds true, the previous beliefs about the Hadean period are far from correct. That is, rather than a hot, molten surface and atmosphere full of carbon dioxide, Earth's surface would be very much like it is today. The action of plate tectonics traps vast amounts of carbon dioxide, thereby reducing greenhouse effects, and leading to a much cooler surface temperature, and the formation of solid rock, and possibly even life.[14] |
The asteroid belt with its inner and outer type ring shows the barrier beyond which the Sun's atmospheric heat is insufficient to rapidly sublimate ices into gasses.
As the Sun grew hotter, this ice/snow zone moved outward. In other words volatile gasses like H2O which are liquid and gas on Earth start to act more like solids at this frost line. The Earth actually orbits inside the Sun's atmosphere. This image does a fairly good job of depicting this fact. |
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