What-If 0054: "Drain the Oceans: Part II"

[Flumble]

I'd say it's more unrealistic to believe that the Netherlands could conquer the Earth and New Netherlands

Good, good, keep that thought. *twiddles thumbs and grins mischievously*

[teelo]

What if the original portal on Earth was then moved to just above the surface of Venus, facing down?

[Fire Brns]

Would it eventually freeze? Going off mean temperatures (because they're the best data I can find for the effort I'm prepared to put in), you're adding 1.3 billion cubic kilometers of water at 67C above the Mars surface mean, for a total of ~5 * 10^24 joules (5 yottajoules). That's about six years' worth of the energy received by Mars from the Sun. It'd certainly drag the surface temp up to above-zero, and the huge pile of water vapour added would likely thicken the atmosphere up to the point where you just need a gas mask rather than a pressure suit. Water vapour is also one of the best greenhouse gasses known, what with forming clouds and all.

Do you mean 67F? The ocean doesn't average 155F.

Below the first 150-200 meters nothing receives any sunlight and relies of hydrothermal vents for heat. Because so much deep water remains unheated the average temperature of the ocean is right above freezing where liquid water is at it's densest state*. If the ocean was 67F or 19C just from thermal expansion the sea level would be (If I am mathing right) close to 100 meters higher and I would be typing this in a diving suit.


*Water is most dense at 4C.

[mathmannix]

(If I am mathing right)

Did you just verb math?

Because that is awesome.

[gmalivuk]

He verbed math, but didn't successfully read the post he was responding to.

Specifically, he missed the part where it was 67C above Mars's surface temperature.

[Fire Brns]

Specifically, he missed the part where it was 67C above Mars's surface temperature.

That makes much more sense. My previews post is irrelevant then.

[rmsgrey]

Any sort of portal that just sticks two pieces of spacetime together is going to mess up the existing equilibrium states - the gravitational gradient between the bottom of the Challenger Deep and somewhere in the Martian atmosphere is going to be fairly steep - though I'm pretty sure the water pressure would still win out... More interesting would be what happens to the water after it squirts through - in the vicinity of the portal, it'll be like having the planet Earth hanging just over Mars (with a cavorite sheet with a hole in between them)...

Sounds like an interesting theoretical exercise to explore someday...

[Davidy]

The total amount of water on Earth is about 2,551,000 Mi³. The surface area of Mars is 55,910,000 Mi². If all of Earth's water was dumped on Mars, it would cover the entire surface to a depth of about 22 Miles.

3. this is an exponent
2. so is this

[gmalivuk]

The total amount of water on Earth is about 2,551,000 Mi³. The surface area of Mars is 55,910,000 Mi². If all of Earth's water was dumped on Mars, it would cover the entire surface to a depth of about 22 Miles.

Where did you get that volume number? It's off by a factor of about 150. (And yet, your depth figure is only off by a factor of about 4, which is closer, but which also means that whatever calculation you used lost a factor of almost 40.)

[Copper Bezel]

Erm. Your surface area is right, but your volume is wrong, and it still doesn't come out to the number you posted. What happened there?

Several people have done the math and come to a bit over 9km (~6 miles,) but if you're still not convinced (and please don't take this the wrong way,) let me Wolfram that for you.

Edit: Ninja'd.

[Davidy]

The total amount of water on Earth is about 2,551,000 Mi³. The surface area of Mars is 55,910,000 Mi². If all of Earth's water was dumped on Mars, it would cover the entire surface to a depth of about 22 Miles.

Where did you get that volume number? It's off by a factor of about 150. (And yet, your depth figure is only off by a factor of about 4, which is closer, but which also means that whatever calculation you used lost a factor of almost 40.)

You're right. I mistakenly used Earth's fresh water volume. The total water volume is 332,500,00 Mi³. That amount would cover Mars (if it was a smooth sphere) to a depth of 4.558 miles. The same amount of water covering a smooth Earth would be 1.6 miles deep.

[gmalivuk]

That's... still wrong.

[Davidy]

That's... still wrong.

Okay, correct it please. Apparently I suck at math.

[Copper Bezel]

That's the thing - there's no obvious error to get what you're getting.

Using the numbers you started with, 332,500,000 / 55,910,000 = 5.95 miles. I get 1.7 miles for Earth, though. How do you math? = /

[brenok]

Okay, the volume of water on Earth is 332,500,000 cubic miles.

Mars' radius is 2104 miles.

The volume of a spherical shell is 4/3 pi (R³ - r³)

V = 4/3 pi (R³ - r³)

3.325 * 10 ⁸ = 4/3 pi (R³ - 2104³)

R = 2110 mi

R - r = 6 miles

Applying it to Earth (Earth's radius is 3956.6 mi):

3.325 * 10 ⁸ = 4/3 pi (R³ - 3956.6³)

R = 3958.3

R - r = 1.7 miles

[gmalivuk]

That's... still wrong.

Okay, correct it please. Apparently I suck at math.

The rough calculation would be to simply divide. Some number of cubic miles of volume divided by some number of square miles of area gives some number of miles of (approximate) depth, which isn't the number you came up with despite having the correct values for the other two.

[FierceContinent]

There is an anime series called Aria that is set in the future on a flooded/terraformed Mars.
There are some not-very-good-science reasons given for how they maintain the gravity and heat and air.
The main focus is on girls training to be gondoliers in Neo-Venosa, an exact re-creation of Venice.
There are three seasons and Nothing. Ever. Happens.

[Mikeski]

Nothing. Ever. Happens.

...but in a really good way.

[Flumble]

[...]

The thermal mass of the Earth's oceans is far, far greater than the thermal mass of the atmosphere of Mars plus the upper few kilometres of its crust. The new mean temperature would be very close to 4C, which is the average temperature of the oceans on Earth.

Also, having read a lil' more: the vapour pressure of water at 4C is about 800Pa. That's tiny by Earth standards, but on Mars, where average atmospheric pressure is 600Pa, it means the oceans would outgas until a large fraction of the atmospheric pressure is due to water vapour. The greenhouse effect would be immense.

Oops, I had totally missed out on this post.

While the heat capacity of the oceans may outnumber that of Mars by far, we're not talking about dropping the oceans onto Mars within a matter of hours. Could you tell me if that situation still applies when a small stream of water enters Mars' atmosphere?
I guess (part of) the water indeed evaporates but the vapour will probably also leave the atmosphere, as said elsewhere in this topic (or the other).

[Omelas]

I have been desperately looking for ways to keep the new Martian ocean from freezing. The Dutch already dominate the world speed skating competitions. The last thing we need is for them to possess a planet sized track.

The temperature gain of the new ocean from the water dropping onto Mars is only in the 5C range, not really enough to stave off the impending Ice Rink of Doom.

I had looked at crashing Phobos into the planet, but there's not enough energy in it's orbit to lose to tidal heating or even just crashing it into the surface. It just gives the Zambonis a big divot to smooth over.

Although while it was liquid, having two moons with short periods (7.5hour Phobos/30hour Demos) and a 24hour Martian day would make for some very interesting tides. I wonder if you could surf them like the tidal bores on the Amazon and Severn rivers?

[paddyfool]

Further subquestion: if earth's water was to be portalled onto Mars in this way, and to have the kinetic energy that it would usually do due to earth's orbit and rotation around the sun, would the additional mass and differing velocities affect Mars' orbit in any tangible way, and to what extent would this depend on which side of Mars the portal appeared on, and the relative positions of Earth and Mars in their orbits around the sun?

Also, how would this differ for a variety of other solar bodies? Could you make Jupiters moons crash into the gas giant with a good dousing of earth oceans, for instance?