this post was submitted on 24 Feb 2025
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[–] dessalines@lemmy.ml 24 points 1 day ago (4 children)

Never thought about it before, but I guess this makes portal guns impossible, since scenarios like this break conservation of energy.

[–] rainrain@sh.itjust.works 4 points 23 hours ago

Maybe conservation of energy is wrong.

[–] balsoft@lemmy.ml 11 points 1 day ago* (last edited 1 day ago) (1 children)

Well, the videogame kind are definitely impossible, but if the gravitational field could travel through the portal then it would probably still conserve energy. The gravitational interactions around vertical portals would be exceptionally weird. If they were close enough, you'd probably experience weightlessness while in between them, but I can't wrap my head around what would happen as they move further apart. That makes me hope someone tries to make a mod that models that in Portal...

[–] Daedskin@lemm.ee 1 points 36 minutes ago

My first instinct would be that it would equivalent to putting another celestial body the mass of the earth at the distance from the earth is from each portal. Since gravity is a wave, it, in theory, would affect a region beyond what would considered "around" the portals.

So if you put one portal on the ground, and another 100 meters up, it would be similar to there being a second earth 100 meters from the surface of the earth, experienced by the entire earth (once the gravitational wave propagated.) How that would evolve over time is too complex for my basic understanding of physics, but a simulation of it would be a neat experiment.

[–] SoulWager@lemmy.ml 4 points 1 day ago* (last edited 1 day ago)

Maybe entering the portal takes as much energy as it would take to climb the long way? If the other end is on the moon you have to enter at 10km/s or something else you fall right back out. Warning: I am not responsible for damage caused by extreme tidal forces.

[–] davel@lemmy.ml 14 points 1 day ago (1 children)

But you know it’s possible from firsthand experience. Whomsth’n’t reached terminal velocity by shooting the ceiling & floor and jumping in?