Let's find a large ice comet and direct it towards Mars!
All of Earth's water in a single sphere (2019)
101–110 of 290 posts
Re: All of Earth's water in a single sphere (2019)
#102Earlier quoted context omitted.
> The largest sphere represents all of Earth's water. Its diameter is about 860 miles Should be a radius of 430 miles, no? The image is very non-intuitive, IMO, because it's making the water appear so small compared to the entire planet (which, duh, obviously the water is only part of earth), but also drawing the planet that small really hides how friggin big the earth is!
Yes. The fresh-water lakes and rivers sphere definitely does not look like it could fill the Great Lakes next to it. I am not saying it doesn't, I'm just saying it doesn't look like it could.
Average depth of Lake Michigan is around 300 feet. Longest dimension is about 300 miles. If you drew a map of Lake Michigan on a sheet of letter-sized paper, the paper would be thicker than the average depth of water.
Re: All of Earth's water in a single sphere (2019)
#103Fun fact: If you did this, everyone would die.
Plus every other nation on the earth would be mad at the US for taking it all
Re: All of Earth's water in a single sphere (2019)
#104We always talk about how scarce freshwater is but this image reprenstation has made it difficult to imagine how much supply do we have for an ever growing human population, the growing demand for water and how long will it last.
Does water leave earth when used?
Re: All of Earth's water in a single sphere (2019)
#105I 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 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).
Re: All of Earth's water in a single sphere (2019)
#106Earlier quoted context omitted.
We could probably terraform Mars if we crashed Europa into Mars.
And then we completely skew Mars's orbit until it crashes into the sun or is flung out of the solar system.
If we had the technology allowing us to move a full satellite through the solar system, we could probably do it in a way that would just make Mars a bit closer to the sun so that the weather gets nicer (sure, if it gets too close to earth it's going to mess up with both orbits, but we can as well correct it when it happens, right?)
Re: All of Earth's water in a single sphere (2019)
#107That's actually a lot bigger than I thought - The largest asteroid Ceres would be 1/3 the diameter of this water sphere (860mi)
That's a LOT of water.
Re: All of Earth's water in a single sphere (2019)
#108Re: All of Earth's water in a single sphere (2019)
#109Earlier quoted context omitted.
But would this sphere of water have enough mass to hold itself together as a sphere in space? Put aside it freezing into a ball of ice as a thought exercise.
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).
Re: All of Earth's water in a single sphere (2019)
#110I was curious how much of this water we lose to space via evaporation. Looking around, apparently not much; only few molecules achieve escape velocity. But can't find a good calculation yet.