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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)

#281

Post by sfink »

margalabargala wrote: post #279
sfink wrote: post #204

Earlier quoted context omitted.

We could, but I would describe it as "mathematically accurate". Which is not incompatible with "unreasonably narrow", given that the definition of "exponential" has recently gotten polluted enough that it is now often synonymous with "fast growing". But what's the point of arguing over definitions if we're going to start with a baseline of saying that there is no basis upon which to argue definitions other than recen…

No; to characterize "exponential" as "fast-growing" is a misunderstanding of what I'm saying. "Faster than linear" would be a good descriptor. > > there are others which allow x^2 to be described as "exponential". > Those same definitions allow x 1000 to be described as "exponential". (x 1000000 would be "more exponential"!) > If you're describing something as exponential, then either you're just saying "fast growing…

Um, ok. Your position baffles me, because you clearly understand what exponential means mathematically, yet you insist that the word means something else colloquially. Specifically "faster than linear". Usually, people who (mathematically) misuse the term do so because they don't understand what it actually means, but that's not what is happening here.

If it's going to mean something precise, such as

> The slope of the derivative is positive and linear.

then why not pick the precise thing that the word already means?

Is x*log(x) also exponential to you? If so, then why not use the word that already exists: superlinear? If not... oh wait, the above definition I quoted wouldn't even cover x^2, since the slope of its derivative is constant, not linear. So I'm just completely confused; I can't figure out which (mathematically) non-exponential functions you would like to label as exponential. x*1000, no. x^3, yes. x^2, I don't know. x*log(x), I don't know. x^2*log(x), I don't know.

> "Exponential" in the colloquial sense means that the derivative has a positive slope.

"Exponential" in the colloquial sense means that the speaker isn't using a mathematical sense, and so isn't considering first or second derivatives. I don't buy the argument that the colloquial sense accepts x^3 and rejects x^2, and in fact I bet I could find someone using it for a linear relation ("My workload has gone up exponentially since you laid off half the team!")

> "Exponential" in the mathematical sense, means the derivative is a function of x.

No it doesn't. x^2 is not mathematically exponential, yet its derivative is a function of x. Exponential means the derivative is exponential. But that's just a detail that doesn't really change the core of your message.

The main purpose of the mathematical definition is to exclude polynomials. The main purpose of the colloquial definition seems to be something like an impressive or important increase.

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

#282

Post by lenocinor »

card_zero wrote: post #215
hn_throwaway_99 wrote: post #178

Earlier quoted context omitted.

Does any of that water, though, ever make it onto the Earth's surface? I'm guessing not, or only miniscule amounts over geologic time through volcanism. For all intents and purposes, I think only counting "surface" water is more useful and intuitive. It's essentially any water that can participate in the hydrologic cycle on Earth, and that water locked beneath the crust doesn't really "matter" for what I think the in…

We don't have access to any part of the planet below a depth of 2.5 miles, so the image should compare the volume of accessible water to the volume of accessible Earth, except then it would fail in its dishonest mission to make people say "gosh that sphere looks relatively small compared to the other sphere, I must restrict myself to ten-second showers." Even if it was accessible water to accessible non-water I don't…

I think a neat follow-up image would be a sphere containing the top 2.5 miles of Earth’s crust for comparison to the water.

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

#283

Post by mistercow »

syndicatedjelly wrote: post #187
mistercow wrote: post #152

I think it’s important to keep in mind that if you did this same visualization on a planet with ten times Earth’s radius, but the same ocean depth and water distribution, then the water blobs would seem even smaller in comparison to the planet. I’m just not sure it’s a particularly useful illustration to compare the volume of water on a planet to that of the planet itself.

Why is this confusing? We aren't comparing planets by amount of water they have. I thought the goal of this visualization was just to make a point - the amount of fresh water in rivers and lakes appears to be the size of a large metropolis in radius. Seems like a cool way to show scale of water resources

Well, let me put it this way: that apparently little fresh water sphere? If the ISS passed over that spot, it would hit that.

This is the point: everything on the surface of the Earth is essentially two dimensional at this scale. Seeing a sphere with a 400 km radius placed on the Earth doesn’t give any better intuitions for the scale of water resources than simply reading the number “35 quintillion liters”. If you think it’s given you a better intuition, you’ve been misled.

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

#285

Post by mckravchyk »

TheRealPomax wrote: post #182

The problem with this sphere is that people are terrible at understanding the mind boggling scale represented by "height" here. It looks like a tiny drop that "fits on the US". Instead it has a diameter of 860 miles. That's a ball of water that reaches all the way to outer space... ...and then keeps going for another 800 miles.

156 x Mt. Everest

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

#286

Post by mckravchyk »

When you look at the image you can't help but think how it would look like if a giant ball of water was dropped like this on the surface. Apart from the flood / water destroying / reshaping the surface of the entire continent, anyone has an idea how it would the impact look like?

I am probably way off, but I imagine solid ice sinking deep into the ground with water starting to turn into vapor in the upper layers and the vapor generated inside exploding out from the ball as it gradually shrinks and deforms.

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

#287

Post by WarOnPrivacy »

abduhl wrote: post #273
WarOnPrivacy wrote: post #258

Earlier quoted context omitted.

> Hydrogen and oxygen ions inside minerals in rock is far too much of a stretch of imagination to call as water. Agreed and to follow that thread to the end: We can't impact that water in a meaningful way. We can't pollute it in dozens of ecosystem-altering ways. We can't alter it's ability to host systems that sustain life. We can't bulk-melt the frozen part & in turn alter the salinity + elevation of a liquid part.…

Are you sure we can’t do any of these things, or are you just not thinking big enough? Give me a couple million dollars of VC money and I bet I could have an MVP that could conceivably accomplish at least one of these. I’d obviously need to raise another round of funds to find a market for such a product before taking the necessary steps to fit my product into that particular market (after raising more funds again, o…

If you had the means to reach the mantle economically, there are a lot of other uses you'd be put to first. Magma geothermal comes to mind.

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

#288

Post by rtkwe »

dredmorbius wrote: post #270
rtkwe wrote: post #263

Earlier quoted context omitted.

It does separate liquid fresh water from surface lakes and rivers which makes me believe the middle ball includes reasonably accessible ground water.

My read is that the two smaller spheres are non-exclusive, and that the smallest is included in the 2nd. The breakout is for comparison: surface freshwater (total) and surface freshwater (lakes and rivers) relatively.

Yes they're pretty clearly subsets of each other. There's a better graphic on this page: https://www.usgs.gov/special-topics/water-science-school/sci... Direct link: https://d9-wret.s3.us-west-2.amazonaws.com/assets/palladium/...

That one actually has percentages on the subsets too for interesting differences like glacier and icecap volume vs ground water (which I think still excludes the kind of deep mantle water mentioned up thread because it's not usably extractable).

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

#289

Post by Sparkyte »

littlestymaar wrote: post #106
wildzzz wrote: post #97

Earlier quoted context omitted.

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?)

It doesn't have to be near the sun to have heat or be warmed by the Sun. It is still currently in the goldilocks zone, same with Venus. The difference is how well each planet traps heat. No atmosphere no heat for mars, highest peak surface temperature is 70 fehrenheit or 20 celsius. Not much but enough green house gas and you could raise it by 20 degrees or more. Other thing to consider is that you don't need to move Mars, you could create artificial magnetospheres.

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

#290

Post by [deleted] »

tejohnso wrote: post #155
RIMR wrote: post #123

Earlier quoted context omitted.

The ballpark math is easy to do in your head too. The diameter of Earth is 8,000 miles, and the deepest point in the ocean, the Mariana Trench, is only 7 miles deep. It's immediately apparent that the oceans are tiny by comparison to the rest of the mass that is Earth.

Neil DeGrasse Tyson says the earth scaled down to the size of a billiard ball would be smoother than any billiard ball ever made.

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