<p>There will be tides, but they will be not very large.  It's pretty easy to get a good estimate of their size.</p>

<p>There are two things that control tides on Earth and both will be present anywhere else: The tidal forces from celestial bodies, and the size of the body of liquid in which the tides are raised along with resonances int he body of liquid.  Taking them in turn.</p>

<p>The tidal force is a bit funny, since the size of the tides raised on a planet by a celestial body is </p>

<p>(1) <em>proportional</em> to the mass of the celestial body raising the tide, </p>

<p>(2) <em>inversely proportion to the <strong>cube</strong> of the distance away</em>,</p>

<p>(3) <em>inversely</em> proportional to the surface gravity of the planet,</p>

<p>(4) and (roughly) <em>proportional</em> to the diameter of the body of liquid in which the tides are being raised.</p>

<p>That inverse cube of the distance means that the ability of a body to raise a tide drops off very quickly with distance.</p>

<p>Comparing Earth and Neptune: The Sun is 30 times further from Neptune than Earth, so Solar tides will be roughly 27,000 times smaller on Neptune.  They can be completely ignored.</p>

<p>Triton (Neptune's largest moon) is the jackpot, since it's a third as massive as Earth's Moon, and about the same distance away.  Neptune is 17 times more massive than Earth and four times the diameter.  So Triton tides of Neptune will be about fifteen times smaller than lunar tides on Earth.</p>

<p>All the other moons are much smaller or further away or both and will raise completely negligible tides.</p>

<p>So from gravitational effects alone, Triton will raise small tides and nothing else will be measurable without good instruments and a lot of care.</p>

<p>(Note, I'm talking about tides in oceans comparable in size to the planet -- for smaller bodies of liquid, the tides will scale down.)</p>

<p>On Earth, tides vary all over the place, and this is due to the configuration of the body of water and resonance effects.  Basically, if a body of water has a resonance -- a natural period for sloshing back and forth -- that matches the period of the tidal force, the tide can build up like repeated pushes to a kid in a swing.</p>

<p>Additionally, there can be a funnel effect with two arms of land coming together, or shallowing water that can amplify the tides. (E.g., the Bay of Fundy.)  Since as far as we know, Neptune has no land, it's effectively an planetary ocean and will get the full effect of the gravitational tides, but no resonances.</p>

<p>So, bottom line: Small Triton tides and nothing else.</p>

CC BY-SA 4.0
2019-02-02T16:19:21.197Z
Thanks for this Mr. Mark. This helped. But one more doubt emerged in my mind while reading your answer. Do neighbouring planets affect tides ?
Gamira
CC BY-SA 4.0
2019-02-02T16:25:27.720Z
Sure, but they are *very, very* small effects because of the inverse cube of the distance.
Mark Olson
CC BY-SA 4.0
2019-02-05T15:04:59.160Z
Minor nit - if a putative Neptune-sized planet had "oceans" of some low-density fluid, the physical effect would be greater than for, say liquid water.  Otherwise, nice clean explanation.
Carl Witthoft
CC BY-SA 4.0
2019-02-02T15:56:04.220Z
2019-02-02T15:56:04.220Z
Mark Olson
<p>Neptune's largest moon, Triton, is about a third the mass of Earth's moon, and roughly the same distance away from its primary, so it will indeed have noticeable tidal effect on Neptune's atmosphere and oceans. </p>

<p>Neptune's other moons are all tiny (all of them together being about 0.5% of Triton's mass), so while they do exert tidal forces, those effects would be dwarfed by Triton even when all the small moons are on the same side of Neptune. </p>

CC BY-SA 4.0
2019-02-01T17:23:05.207Z
2019-02-01T17:23:05.207Z
Russell Borogove
<p>I mean, we experience tides here on earth because of combined effect of gravitational field of moon and sun. So I thought that tides could also occur on other planets. </p>

<p><em>Let us consider Neptune where the gas transits into a slushy ice and water layer. The water-ammonia ocean serves as the planet's mantle, and contains more than ten times the mass of Earth. Also it has <strong>14</strong>  moons. What I was thinking was that more moons would mean more tidal effect would be seen even if distance from sun has increased.</em></p>

<p>But then I thought that the moons of Neptune would all have different orbits and different time periods of rotation. So this will definitely impact the extent of tides. </p>

<p>-To what extent will this affect tides?</p>

<ul>
<li>And how will tides formed on Neptune be different than that             formed on earth? I mean, how will they vary in properties?</li>
</ul>

CC BY-SA 4.0
2019-02-01T16:07:25.770Z
Every extended body experiences tides to one degree or the other.
AtmosphericPrisonEscape
CC BY-SA 4.0
2019-02-03T03:07:14.020Z
You might want to check out https://farside.ph.utexas.edu/teaching/336L/Fluid/node161.html
irchans
CC BY-SA 4.0
2019-02-05T15:03:29.863Z
Tidal forces happen whenever there's a body orbiting a rotating body. (or vice versa).  The magnitude of observed motion is a separate question.
Carl Witthoft
<tidal-forces><neptune>
Do tides occur on planets like Neptune, having water?
Gamira
# Do tides occur on planets like Neptune, having water?

(Asked by: username_0 on 2019-02-01)

I mean, we experience tides here on earth because of combined effect of gravitational field of moon and sun. So I thought that tides could also occur on other planets.

*Let us consider Neptune where the gas transits into a slushy ice and water layer. The water-ammonia ocean serves as the planet's mantle, and contains more than ten times the mass of Earth. Also it has **14** moons. What I was thinking was that more moons would mean more tidal effect would be seen even if distance from sun has increased.*

But then I thought that the moons of Neptune would all have different orbits and different time periods of rotation. So this will definitely impact the extent of tides.

-To what extent will this affect tides?

* And how will tides formed on Neptune be different than that formed on earth? I mean, how will they vary in properties?

**Tags:** tidal-forces, neptune

> **Comments:**
> **username_1**: Every extended body experiences tides to one degree or the other.  
> **username_2**: You might want to check out https://farside.ph.utexas.edu/teaching/336L/Fluid/node161.html  
> **username_3**: Tidal forces happen whenever there's a body orbiting a rotating body. (or vice versa).  The magnitude of observed motion is a separate question.  

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## 2 answers

### Answer by username_4 on 2019-02-02. Score: 8

There will be tides, but they will be not very large. It's pretty easy to get a good estimate of their size.

There are two things that control tides on Earth and both will be present anywhere else: The tidal forces from celestial bodies, and the size of the body of liquid in which the tides are raised along with resonances int he body of liquid. Taking them in turn.

The tidal force is a bit funny, since the size of the tides raised on a planet by a celestial body is

(1) *proportional* to the mass of the celestial body raising the tide,

(2) *inversely proportion to the **cube** of the distance away*,

(3) *inversely* proportional to the surface gravity of the planet,

(4) and (roughly) *proportional* to the diameter of the body of liquid in which the tides are being raised.

That inverse cube of the distance means that the ability of a body to raise a tide drops off very quickly with distance.

Comparing Earth and Neptune: The Sun is 30 times further from Neptune than Earth, so Solar tides will be roughly 27,000 times smaller on Neptune. They can be completely ignored.

Triton (Neptune's largest moon) is the jackpot, since it's a third as massive as Earth's Moon, and about the same distance away. Neptune is 17 times more massive than Earth and four times the diameter. So Triton tides of Neptune will be about fifteen times smaller than lunar tides on Earth.

All the other moons are much smaller or further away or both and will raise completely negligible tides.

So from gravitational effects alone, Triton will raise small tides and nothing else will be measurable without good instruments and a lot of care.

(Note, I'm talking about tides in oceans comparable in size to the planet -- for smaller bodies of liquid, the tides will scale down.)

On Earth, tides vary all over the place, and this is due to the configuration of the body of water and resonance effects. Basically, if a body of water has a resonance -- a natural period for sloshing back and forth -- that matches the period of the tidal force, the tide can build up like repeated pushes to a kid in a swing.

Additionally, there can be a funnel effect with two arms of land coming together, or shallowing water that can amplify the tides. (E.g., the Bay of Fundy.) Since as far as we know, Neptune has no land, it's effectively an planetary ocean and will get the full effect of the gravitational tides, but no resonances.

So, bottom line: Small Triton tides and nothing else.

> **Comments:**
> **username_0**: Thanks for this Mr. Mark. This helped. But one more doubt emerged in my mind while reading your answer. Do neighbouring planets affect tides ?  
> **username_4**: Sure, but they are *very, very* small effects because of the inverse cube of the distance.  
> **username_3**: Minor nit - if a putative Neptune-sized planet had "oceans" of some low-density fluid, the physical effect would be greater than for, say liquid water.  Otherwise, nice clean explanation.  

---

### Answer by username_5 on 2019-02-01. Score: 7

Neptune's largest moon, Triton, is about a third the mass of Earth's moon, and roughly the same distance away from its primary, so it will indeed have noticeable tidal effect on Neptune's atmosphere and oceans.

Neptune's other moons are all tiny (all of them together being about 0.5% of Triton's mass), so while they do exert tidal forces, those effects would be dwarfed by Triton even when all the small moons are on the same side of Neptune.


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