How does gravity affect pressure under water?











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How different would being under water in Europa differ from being under water on Earth? Would it be possible to dive deeper on Europa with a submarine than on Earth and by how much?






gravity astrophysics atmosphere europa







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  • In order to answer this you'd need to know the density of Europa's oceans, which I don't believe anyone knows. Water pressure is created by the weight of the column of water above the depth in question, and this is directly related to its density. But if one assumes the density to be about equal to Earth's oceans, then the diving depth would simply be the ratio of Earth's and Europa's gravity (Earth = 9.78, Europa = 1.314).
    – BillDOe
    7 hours ago












  • @BillDOe How compressible do you think water is?
    – Rob Jeffries
    6 hours ago










  • @BillDOe Why do you think there would be a meaningful difference in density? (Obviously, if you get deep enough you'll start seeing effects but long before you get appreciable compression you'll get phase changes.)
    – Loren Pechtel
    26 mins ago















up vote
3
down vote

favorite












How different would being under water in Europa differ from being under water on Earth? Would it be possible to dive deeper on Europa with a submarine than on Earth and by how much?






gravity astrophysics atmosphere europa







share|improve this question
























  • In order to answer this you'd need to know the density of Europa's oceans, which I don't believe anyone knows. Water pressure is created by the weight of the column of water above the depth in question, and this is directly related to its density. But if one assumes the density to be about equal to Earth's oceans, then the diving depth would simply be the ratio of Earth's and Europa's gravity (Earth = 9.78, Europa = 1.314).
    – BillDOe
    7 hours ago












  • @BillDOe How compressible do you think water is?
    – Rob Jeffries
    6 hours ago










  • @BillDOe Why do you think there would be a meaningful difference in density? (Obviously, if you get deep enough you'll start seeing effects but long before you get appreciable compression you'll get phase changes.)
    – Loren Pechtel
    26 mins ago













up vote
3
down vote

favorite









up vote
3
down vote

favorite











How different would being under water in Europa differ from being under water on Earth? Would it be possible to dive deeper on Europa with a submarine than on Earth and by how much?






gravity astrophysics atmosphere europa







share|improve this question















How different would being under water in Europa differ from being under water on Earth? Would it be possible to dive deeper on Europa with a submarine than on Earth and by how much?






gravity astrophysics atmosphere europa




gravity astrophysics atmosphere europa






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited 10 mins ago









user22a6db72d7249

1031




1031










asked 7 hours ago









Muze

692118




692118












  • In order to answer this you'd need to know the density of Europa's oceans, which I don't believe anyone knows. Water pressure is created by the weight of the column of water above the depth in question, and this is directly related to its density. But if one assumes the density to be about equal to Earth's oceans, then the diving depth would simply be the ratio of Earth's and Europa's gravity (Earth = 9.78, Europa = 1.314).
    – BillDOe
    7 hours ago












  • @BillDOe How compressible do you think water is?
    – Rob Jeffries
    6 hours ago










  • @BillDOe Why do you think there would be a meaningful difference in density? (Obviously, if you get deep enough you'll start seeing effects but long before you get appreciable compression you'll get phase changes.)
    – Loren Pechtel
    26 mins ago


















  • In order to answer this you'd need to know the density of Europa's oceans, which I don't believe anyone knows. Water pressure is created by the weight of the column of water above the depth in question, and this is directly related to its density. But if one assumes the density to be about equal to Earth's oceans, then the diving depth would simply be the ratio of Earth's and Europa's gravity (Earth = 9.78, Europa = 1.314).
    – BillDOe
    7 hours ago












  • @BillDOe How compressible do you think water is?
    – Rob Jeffries
    6 hours ago










  • @BillDOe Why do you think there would be a meaningful difference in density? (Obviously, if you get deep enough you'll start seeing effects but long before you get appreciable compression you'll get phase changes.)
    – Loren Pechtel
    26 mins ago
















In order to answer this you'd need to know the density of Europa's oceans, which I don't believe anyone knows. Water pressure is created by the weight of the column of water above the depth in question, and this is directly related to its density. But if one assumes the density to be about equal to Earth's oceans, then the diving depth would simply be the ratio of Earth's and Europa's gravity (Earth = 9.78, Europa = 1.314).
– BillDOe
7 hours ago






In order to answer this you'd need to know the density of Europa's oceans, which I don't believe anyone knows. Water pressure is created by the weight of the column of water above the depth in question, and this is directly related to its density. But if one assumes the density to be about equal to Earth's oceans, then the diving depth would simply be the ratio of Earth's and Europa's gravity (Earth = 9.78, Europa = 1.314).
– BillDOe
7 hours ago














@BillDOe How compressible do you think water is?
– Rob Jeffries
6 hours ago




@BillDOe How compressible do you think water is?
– Rob Jeffries
6 hours ago












@BillDOe Why do you think there would be a meaningful difference in density? (Obviously, if you get deep enough you'll start seeing effects but long before you get appreciable compression you'll get phase changes.)
– Loren Pechtel
26 mins ago




@BillDOe Why do you think there would be a meaningful difference in density? (Obviously, if you get deep enough you'll start seeing effects but long before you get appreciable compression you'll get phase changes.)
– Loren Pechtel
26 mins ago










1 Answer
1






active

oldest

votes

















up vote
6
down vote



accepted










For a liquid, hydrostatic pressure is $rho g h$ where $rho$ is density (this is always the same for all water) g is gravitational acceleration and h is depth.



The gravitational acceleration on Europa is 1.3 (compared with 9.8 on Earth). But on Europa there is 20km of ice floating on the water.



As a rough estimate, the gravity in Europa is 1/10 that on Earth, so the pressure at the bottom of the ice/top of the water would be comparable to the pressure at 2km in the Earth's Oceans.



Since we can build submarines that can operate at 10km, we could reasonably suppose that we could operate submarines down to about 100km on Europa, which takes us to the rocky surface. However we have no way to pass through 20km of ice crust to reach the water layer. Building the submarine may be the easy part!






share|improve this answer

















  • 2




    A hot submarine could melt its way through, a bit like a dark stone on a glacier ;-)
    – Chappo
    5 hours ago










  • Nice answer. Is 20 km of ice a pretty good estimate? I thought it was a lot less certain.
    – userLTK
    3 hours ago






  • 1




    @Chappo Yup. Put a nuclear reactor (not merely a RTG) on board, melt your way down.
    – Loren Pechtel
    24 mins ago











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1 Answer
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active

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1 Answer
1






active

oldest

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active

oldest

votes








up vote
6
down vote



accepted










For a liquid, hydrostatic pressure is $rho g h$ where $rho$ is density (this is always the same for all water) g is gravitational acceleration and h is depth.



The gravitational acceleration on Europa is 1.3 (compared with 9.8 on Earth). But on Europa there is 20km of ice floating on the water.



As a rough estimate, the gravity in Europa is 1/10 that on Earth, so the pressure at the bottom of the ice/top of the water would be comparable to the pressure at 2km in the Earth's Oceans.



Since we can build submarines that can operate at 10km, we could reasonably suppose that we could operate submarines down to about 100km on Europa, which takes us to the rocky surface. However we have no way to pass through 20km of ice crust to reach the water layer. Building the submarine may be the easy part!






share|improve this answer

















  • 2




    A hot submarine could melt its way through, a bit like a dark stone on a glacier ;-)
    – Chappo
    5 hours ago










  • Nice answer. Is 20 km of ice a pretty good estimate? I thought it was a lot less certain.
    – userLTK
    3 hours ago






  • 1




    @Chappo Yup. Put a nuclear reactor (not merely a RTG) on board, melt your way down.
    – Loren Pechtel
    24 mins ago















up vote
6
down vote



accepted










For a liquid, hydrostatic pressure is $rho g h$ where $rho$ is density (this is always the same for all water) g is gravitational acceleration and h is depth.



The gravitational acceleration on Europa is 1.3 (compared with 9.8 on Earth). But on Europa there is 20km of ice floating on the water.



As a rough estimate, the gravity in Europa is 1/10 that on Earth, so the pressure at the bottom of the ice/top of the water would be comparable to the pressure at 2km in the Earth's Oceans.



Since we can build submarines that can operate at 10km, we could reasonably suppose that we could operate submarines down to about 100km on Europa, which takes us to the rocky surface. However we have no way to pass through 20km of ice crust to reach the water layer. Building the submarine may be the easy part!






share|improve this answer

















  • 2




    A hot submarine could melt its way through, a bit like a dark stone on a glacier ;-)
    – Chappo
    5 hours ago










  • Nice answer. Is 20 km of ice a pretty good estimate? I thought it was a lot less certain.
    – userLTK
    3 hours ago






  • 1




    @Chappo Yup. Put a nuclear reactor (not merely a RTG) on board, melt your way down.
    – Loren Pechtel
    24 mins ago













up vote
6
down vote



accepted







up vote
6
down vote



accepted






For a liquid, hydrostatic pressure is $rho g h$ where $rho$ is density (this is always the same for all water) g is gravitational acceleration and h is depth.



The gravitational acceleration on Europa is 1.3 (compared with 9.8 on Earth). But on Europa there is 20km of ice floating on the water.



As a rough estimate, the gravity in Europa is 1/10 that on Earth, so the pressure at the bottom of the ice/top of the water would be comparable to the pressure at 2km in the Earth's Oceans.



Since we can build submarines that can operate at 10km, we could reasonably suppose that we could operate submarines down to about 100km on Europa, which takes us to the rocky surface. However we have no way to pass through 20km of ice crust to reach the water layer. Building the submarine may be the easy part!






share|improve this answer












For a liquid, hydrostatic pressure is $rho g h$ where $rho$ is density (this is always the same for all water) g is gravitational acceleration and h is depth.



The gravitational acceleration on Europa is 1.3 (compared with 9.8 on Earth). But on Europa there is 20km of ice floating on the water.



As a rough estimate, the gravity in Europa is 1/10 that on Earth, so the pressure at the bottom of the ice/top of the water would be comparable to the pressure at 2km in the Earth's Oceans.



Since we can build submarines that can operate at 10km, we could reasonably suppose that we could operate submarines down to about 100km on Europa, which takes us to the rocky surface. However we have no way to pass through 20km of ice crust to reach the water layer. Building the submarine may be the easy part!







share|improve this answer












share|improve this answer



share|improve this answer










answered 7 hours ago









James K

31.9k247104




31.9k247104








  • 2




    A hot submarine could melt its way through, a bit like a dark stone on a glacier ;-)
    – Chappo
    5 hours ago










  • Nice answer. Is 20 km of ice a pretty good estimate? I thought it was a lot less certain.
    – userLTK
    3 hours ago






  • 1




    @Chappo Yup. Put a nuclear reactor (not merely a RTG) on board, melt your way down.
    – Loren Pechtel
    24 mins ago














  • 2




    A hot submarine could melt its way through, a bit like a dark stone on a glacier ;-)
    – Chappo
    5 hours ago










  • Nice answer. Is 20 km of ice a pretty good estimate? I thought it was a lot less certain.
    – userLTK
    3 hours ago






  • 1




    @Chappo Yup. Put a nuclear reactor (not merely a RTG) on board, melt your way down.
    – Loren Pechtel
    24 mins ago








2




2




A hot submarine could melt its way through, a bit like a dark stone on a glacier ;-)
– Chappo
5 hours ago




A hot submarine could melt its way through, a bit like a dark stone on a glacier ;-)
– Chappo
5 hours ago












Nice answer. Is 20 km of ice a pretty good estimate? I thought it was a lot less certain.
– userLTK
3 hours ago




Nice answer. Is 20 km of ice a pretty good estimate? I thought it was a lot less certain.
– userLTK
3 hours ago




1




1




@Chappo Yup. Put a nuclear reactor (not merely a RTG) on board, melt your way down.
– Loren Pechtel
24 mins ago




@Chappo Yup. Put a nuclear reactor (not merely a RTG) on board, melt your way down.
– Loren Pechtel
24 mins ago


















 

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