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Not allowing excavation to the core solves weird gravity issue as well. Astroneer had super weird gravity at their planet core. You can get stuck oscillating th

Not allowing excavation to the core solves weird gravity issue as well. Astroneer had super weird gravity at their planet core. You can get stuck oscillating there.

reactordev 1y ago
If you really wanted to go for realism, there would be NO GRAVITY at the core. :P As you dig down you would get lighter and lighter on your feet. Any mass you are below (within the sphere of Earth) will exert a gravitational pull in one direction, while the mass above you (also within the Earth) will exert an equal and opposite pull.
- ricardobeat 1y ago
  That's how it's implemented in the game!
- lsaferite 1y ago
  Yeah, I'm mostly aware of that. Weird didn't mean 'wrong' in this case, just weird for a terrestrial-bound human. :)
  - reactordev 1y ago
    There’s all sorts of weird physics in the universe ;)
- nomdep 1y ago
  If you REALLY want to aim for realism, gravity should depend on all quads on the planet. So, if you were to build a huge floating island, the gravity between it and the planet would be less than the usual
  - DrewADesign 1y ago
    If you really truly wanted to aim for realism, digging to the core would require a huge budget and an international coalition that would get bogged down in politics and mismanagement and it would never happen.
    - reactordev 1y ago
      30 year pension plan.
- hdjrudni 1y ago
  If earth was just full of water.... as you swam deeper and deeper there would be more and more pressure upon you. Would there be a point where that pressure would start to lessen as the water is pulled in all directions?
  - chii 1y ago
    > pressure would start to lessen as the water is pulled in all directions? the pressure would never lessen, just increase slower. The gravity at the center is zero, but the mass above you is not exerting just gravity force (which gets cancelled out by the opposite side), but also pressure (from the weight of it falling down). This means the water pressure would steadily climb, but at a slower rate as you move nearer to the center, and will be at maximum at the very center.
    - reactordev 1y ago
      Correct. Gravity would be net zero but the pressure would be the entire worlds oceans.
  - posix86 1y ago
    Awesome question!
- b3lvedere 1y ago
  Just a thought; I do wonder in reality if there is an actual single physical point that has any form of material but totally zero gravity. I think anything, as longs its size is above the planck length, has some gravity.
  - Filligree 1y ago
    If nothing else, your own body will exert some gravity on you.
- noahbp 1y ago
  >As you dig down you would get lighter and lighter on your feet. Fun fact: Gravity doesn't decrease the entire way down! Only when you get to the core does it decrease monotonically: https://physics.stackexchange.com/questions/18446/how-does-gravity-work-underground https://physics.stackexchange.com/questions/18446/how-does-g...
jacquesm 1y ago
That actually sounds pretty close to what I would expect to happen IRL. After all the mass is mostly all around you at that point and depending on how far you are towards the core you might build up speed, overshoot the target and then do it all over again. But hollow planets are hard to come by so this is just my imagination, I'm sure someone has worked out exactly what would happen.
- gizmo686 1y ago
  Newton worked this out in what is now know as the shell theorem. If you have a hollow spherically symmetric body, then any point inside of the body experiences no net gravitational force. In contrast, points outside of the shell experience the same force as if the body were a point mass. For ideal (spherically symmetric) planets where a point is underground, you can divide the planet into 2 regions. The shell of the planet "above" the point has no net effect, while the shell below has the full effect, resulting in the gravity falling towards 0 as you approach the center. In practice, planets are not actually spherically symmetric, but are close enough for it to be a good approximation.
  - jacquesm 1y ago
    That's super interesting, thank you for posting this!
Aeolun 1y ago
I think the outer wilds did this perfectly. I seem to remember falling towards the core and gravity just disappearing.
rcxdude 1y ago
Astroneer does deliberately make it weirder, though, it's not just a simple gravity implementation.

Not allowing excavation to the core solves weird gravity issue as well. Astroneer had super weird gravity at their planet core. You can get stuck oscillating there.

reactordev 1y ago

If you really wanted to go for realism, there would be NO GRAVITY at the core. :P As you dig down you would get lighter and lighter on your feet. Any mass you are below (within the sphere of Earth) will exert a gravitational pull in one direction, while the mass above you (also within the Earth) will exert an equal and opposite pull.

ricardobeat 1y ago
That's how it's implemented in the game!
lsaferite 1y ago
Yeah, I'm mostly aware of that. Weird didn't mean 'wrong' in this case, just weird for a terrestrial-bound human. :)
- reactordev 1y ago
  There’s all sorts of weird physics in the universe ;)
nomdep 1y ago
If you REALLY want to aim for realism, gravity should depend on all quads on the planet. So, if you were to build a huge floating island, the gravity between it and the planet would be less than the usual
- DrewADesign 1y ago
  If you really truly wanted to aim for realism, digging to the core would require a huge budget and an international coalition that would get bogged down in politics and mismanagement and it would never happen.
  - reactordev 1y ago
    30 year pension plan.
hdjrudni 1y ago
If earth was just full of water.... as you swam deeper and deeper there would be more and more pressure upon you. Would there be a point where that pressure would start to lessen as the water is pulled in all directions?
- chii 1y ago
  > pressure would start to lessen as the water is pulled in all directions? the pressure would never lessen, just increase slower. The gravity at the center is zero, but the mass above you is not exerting just gravity force (which gets cancelled out by the opposite side), but also pressure (from the weight of it falling down). This means the water pressure would steadily climb, but at a slower rate as you move nearer to the center, and will be at maximum at the very center.
  - reactordev 1y ago
    Correct. Gravity would be net zero but the pressure would be the entire worlds oceans.
- posix86 1y ago
  Awesome question!
b3lvedere 1y ago
Just a thought; I do wonder in reality if there is an actual single physical point that has any form of material but totally zero gravity. I think anything, as longs its size is above the planck length, has some gravity.
- Filligree 1y ago
  If nothing else, your own body will exert some gravity on you.
noahbp 1y ago
>As you dig down you would get lighter and lighter on your feet. Fun fact: Gravity doesn't decrease the entire way down! Only when you get to the core does it decrease monotonically: https://physics.stackexchange.com/questions/18446/how-does-gravity-work-underground https://physics.stackexchange.com/questions/18446/how-does-g...

jacquesm 1y ago

That actually sounds pretty close to what I would expect to happen IRL. After all the mass is mostly all around you at that point and depending on how far you are towards the core you might build up speed, overshoot the target and then do it all over again. But hollow planets are hard to come by so this is just my imagination, I'm sure someone has worked out exactly what would happen.

gizmo686 1y ago
Newton worked this out in what is now know as the shell theorem. If you have a hollow spherically symmetric body, then any point inside of the body experiences no net gravitational force. In contrast, points outside of the shell experience the same force as if the body were a point mass. For ideal (spherically symmetric) planets where a point is underground, you can divide the planet into 2 regions. The shell of the planet "above" the point has no net effect, while the shell below has the full effect, resulting in the gravity falling towards 0 as you approach the center. In practice, planets are not actually spherically symmetric, but are close enough for it to be a good approximation.
- jacquesm 1y ago
  That's super interesting, thank you for posting this!

Aeolun 1y ago

I think the outer wilds did this perfectly. I seem to remember falling towards the core and gravity just disappearing.

rcxdude 1y ago

Astroneer does deliberately make it weirder, though, it's not just a simple gravity implementation.