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All of Earth's water in a single sphere (2019)

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Re: All of Earth's water in a single sphere (2019)

#131

Earlier quoted context omitted.

It would make Mars warmer. It would melt all the ice and CO2. It would give Mars an ocean. Of liquid rock. This is assuming that it doesn't destroy Mars completely. There might be enough fragments to make Solar System dangerous place and destroy life on Earth. Europa is the size of our Moon. Colliding it with Mars would be similar to the collision that formed our Moon.

But would it stay on Mars? I thought the issue was there was no dynamo in the core, which lets solar winds strip it away. How long would it stay?

It would stay molten for millions of years.

Not sure if Europa's water would be flung into space, make atmosphere, or make a boiling ocean.

Re: All of Earth's water in a single sphere (2019)

#132
post #59

I long assumed that the Earth is a "water planet" because water is mostly what you see from a distance. It wasn't until I did the math that I realized that is really about wet rocks in space vs dry rocks in space. Earth isn't made of water, it's just a damp rock. Or a bowling ball that you squirted a dozen times with a spray bottle.

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Re: All of Earth's water in a single sphere (2019)

#133
post #92

Earlier quoted context omitted.

Ceres could be taken apart with solar energy and rebuilt into a habitat much bigger than the Earth, never mind Mars. Ceres leads to the stars, Mars is just a dead end.

Is there reason to believe the stars are less of a dead end than Mars? It's easy to imagine us making a huge bet on interstellar travel, and just dying in interstellar space. Surely there's untold abundance in the stars, but if you can't actually reach it, then it may as well be a mirage. Whenever I consider the possibility of interplanetary colonization, I come back to the conclusion that the only way to make it fea…

I did a lot of analysis for the problem of "build a solar sail factory on a carbonaceous chondrite asteroid that makes sunshades to deploy at the L1 point", particularly from a chemical engineering point of view.

One interesting thing was that a lot of the chemistry involved was similar to the chemistry of decarbonization and carbon capture, particularly when you get CO2 as a waste product it is too precious to vent so you are going to feed it back into your "petrochemical" line.

Objects like Ceres are the norm once you get out to the outer solar system, the difference is that Ceres is close enough to the sun for solar energy to be a good power source. Centaur objects, the moons of outer planets, and Kuiper belt objects like Pluto are similar but when you get far from the Sun you need to use a different power source such as D-D fusion.

If a species became independent of sunlight it could take advantage of very generic objects that exist throughout interstellar space (comets, rouge planets, etc.) and make the journey in hops of (say) 100 years from one object to another. At that rate it would be possible to visit another star system in 10,000 years with a comfortable lifestyle. People like that might as well keep comet hopping but if they came across a star system I'd imagine they start some project like a Ceres megastructure because it is generic you can find some object like that and be able to establish a huge industrial base and population larger than the Earth with the same head end you've used all this time and same comfortable lifestyle.

Earth would be priority two if that for those people. Grabby aliens might have disrupted Ceres but left the dinosaurs alone. But Ceres is here, so they were not. Ceres is such an attractive target that it should be a SETI goal to look for hardware left behind. Would be hilarious if they stole the Deuterium.

Re: All of Earth's water in a single sphere (2019)

#134
post #105

Earlier quoted context omitted.

Earth isn't even really a "rock", it's mostly a ball of iron. It's a ball of iron covered with rocks (i.e. metal oxides) cover with water (i.e. hydrogen oxide).

I don't buy it. Even allowing counting iron as separate from what rocks can be composed of (and using mass instead of volume) you still have 30.1%+15.1%=45.2% of the Earth as oxygen and silicon (which are most certainly part of what makes a rock) at which point you've already disproved the claim Earth is more a ball of iron than a ball of rock. A ball of iron covered with a ball of rocks is a more fair statement thou…

https://s3-us-west-2.amazonaws.com/courses-images-archive-re...

Everything up to and including the mantle is either iron or has a lot of iron. But to your point the mantle also has a lot of silica. So I guess it depends on your definition of "mostly".

Re: All of Earth's water in a single sphere (2019)

#135
post #98

Earlier quoted context omitted.

Closer to a bowling ball that picked up a drop of beer from your hands.

This didn't sound right, so I did the math. The volume of all water is 1,386,000,000 km^3, which is then 1.386e+21 liters, or right about the same number of kilograms. The mass of Earth is about 5.972e+24 kg. So the percent fraction by mass is 0.0232%. A "drop" is typically estimated at 1/20th of one mL, which is then 0.05 grams. We can estimate the mass of a small-ish bowling ball at 5kg, or 5000 grams. 0.05 / 5000…

You'd have to use the volume of earth, not the mass. Google tells me that lava is ~3x denser than water.

Re: All of Earth's water in a single sphere (2019)

#136
post #71

Earlier quoted context omitted.

Well, spill a glass of water on your kitchen counter and you'll find it suddenly makes up a large percentage of the counter's surface as well!

I'm aware, notice my comment specifically states "the Earth's *surface* " not just "the Earth". However, my kitchen counter is a flat surface, it's common knowledge the Earth isn't flat and the average ocean depth is 3,682 meters

That was my point. The Earth isn't flat, but its surface is very smooth.

You give the average ocean depth at 3.7km, but the Earth's diameter is about 12,742km, making those bumps pretty insignificant. If you cover your countertop in sandpaper and spill water on it, the difference in coverage going to be almost negligible.

Re: All of Earth's water in a single sphere (2019)

#138

Earlier quoted context omitted.

The freezing-into-a-ball-of-ice is relevant here. A body that small can't hold on to water vapor at anything a human would consider a reasonable temperature; the average velocity of light gases at human-sane temperatures is high enough to overcome their escape velocity. See [1] for a log-log plot of what gases a body can hold onto - even Mars, which is much larger and denser than a Ceres-sized ball of water, has lost…

Given that water gets lighter when cooling down right above its fusion temperature, and that ice is a pretty good insulator. You'd have liquid water below an ice crust for a lot of time. It would eventually freeze entirely and be slowly eaten by the Sun's radiations. But that would take a pretty long time (well on a human scale).

Yeah, that's why I specified freeze over and not freeze through, although without doing the math I'm pretty sure it'd still freeze through on solar system timescales without radioactive (as in Earth's own mantle's case) or tidal (Enceladus, Europa, possibly Triton and Ganymede) heating.

Re: All of Earth's water in a single sphere (2019)

#139
post #71

Earlier quoted context omitted.

Well, spill a glass of water on your kitchen counter and you'll find it suddenly makes up a large percentage of the counter's surface as well!

I'm aware, notice my comment specifically states "the Earth's *surface* " not just "the Earth". However, my kitchen counter is a flat surface, it's common knowledge the Earth isn't flat and the average ocean depth is 3,682 meters

The earth is smoother than a billiard ball when accounting for relative size. Highly likely the earth is actually flatter than your countertop when accounting for size.

Re: All of Earth's water in a single sphere (2019)

#140
post #59

I long assumed that the Earth is a "water planet" because water is mostly what you see from a distance. It wasn't until I did the math that I realized that is really about wet rocks in space vs dry rocks in space. Earth isn't made of water, it's just a damp rock. Or a bowling ball that you squirted a dozen times with a spray bottle.

> Earth isn't made of water, it's just a damp rock. Or a bowling ball that you squirted a dozen times with a spray bottle.

Yeah, the image with the oceans being dry is wow-inducing... On further thought, of course it'd be very close a sphere, because gravity forces it to be. A sphere where e.g. a slice of it is water (imagine a clementine with one of its segments being water) would be very wobbly if even possible at all..

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