Hello! Question,
Would the water pressure in different oceans on different planets be the same as the oceans here on earth? If yes, please explain and if no please explain as well.
Thank you!
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TL:DR: Yes, it depends on the gravity of the planet.
Water pressure exerted on an object is dependent on the weight of a column of water above the object.
Weight is a force dependent on 2 things, mass and acceleration due to gravity (f = ma).
The mass of that column is its volume multiplied by the density, and as (liquid) water is incompressible, the density is 1kg/L. On earth, the acceleration due to gravity is ~10m/s²
This means if you were 1m under water and had an area of 1m² there would be 1m³ column of water pressing down on you with a mass of 1,000kg. Multiply that by acceleration due to gravity, that’s 10,000N of force, divide that then by the surface area (pressure is force/area) you have your water pressure. The pressure will increase with depth as more water will be above you pressing down.
As I mentioned, water is incompressible, meaning its density won’t change. The only other variables are depth and acceleration due to gravity.
Another planet may have higher or lower gravity dependent on that planets mass, meaning the pressure per unit depth will be higher on more massive planets and lower on less massive planets than Earth.
You’ll need to be a bit more specific on what exactly you’re asking.
Water pressure changes depending on depth so even on earth water pressure in the ocean can be anything from 1 atmosphere of pressure to thousands of atmospheres.
Do you mean if the *minimum* pressure is different on other planets or do you mean if the rate of pressure *increase* as you dive is the same?
Pressure exerted by water is a function of the depth of the water, plus the pressure of the atmosphere above it. Pressure will be different depending on where you are in the ocean.
Given that both gravity and atmospheric pressure on other planets is different, the relative pressure of bodies of water at comparable depths will also be different.
Thinking about different planets, you have several different things to consider.
* Gravity of the planet.
* Weight of atmosphere above the “water”
* Density of the water (and the solutes dissolved in in) since it is unlikely to be pure H2O
* Depth below the surface of that water
You need a temperature / pressure combination that allows liquid water.
**That gives some big picture possibilities**
**Huge planet like Jupiter** but with a rocky surface that allows liquid water at some point near the “surface” would have a huge weight of atmosphere above it. The “water” at this pressure likely has many things dissolved in it (more dense). We might guess at 200X earth’s surface pressure where the atmosphere changes from gas to liquid.
**Small moon like Ceres** would have less atmosphere and less gravity.
The **pressure profile would be much less than earth**.
Is there a video of different water pressure on different gravities out there?
I think the simplest explanation is an equation:
P=D*g*h
P is pressure (or pressure head when dealing with more than just static pressure)
D is density of the fluid (usually represented by the Greek letter rho, but I don’t have that on my keyboard)
g is acceleration due to gravity (~10 m/s^(2) on Earth)
h is height of the fluid column above you (be that air or water or oil) aka depth below the surface
So, gravity has an effect. Different planets with different gravities will exert a different pressure under the same depth of water. A different fluid will exert a different pressure than water because of differing densities (easily seen with air vs water. You live under a roughly 100 km tall column of air without noticing it, but 2 metres under water is very noticeable).
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