459

we are but a gravy train in outer space (mander.xyz)

submitted 7 months ago by fossilesque@mander.xyz to c/science_memes@mander.xyz

19 comments fedilink hide all child comments

top 19 comments

sorted by: hot top controversial new old

[-] Chrobin@discuss.tchncs.de 12 points 7 months ago

Gravity isn't a force tho...

[-] JohnDClay@sh.itjust.works 16 points 7 months ago

I put it in my force balance equations, it's a force. It doesn't matter that it's from curving spacetime rather than exchanging particles, it still exerts force on things.

[-] Chrobin@discuss.tchncs.de 2 points 7 months ago

But the point of general relativity is that a free-floating observer is equivalent to an observer in free space. That means that falling due to gravity, which you call a force, is an unaccelerated movement, i.e. no force.

[-] JohnDClay@sh.itjust.works 1 points 7 months ago

If I take a relativistic frame of reference. If I take an 'absolute' non moving frame of reference, gravity shows up as a force. I use the later for calculating loads and statics, even though it's technically not correct. And in that case gravity shows up as a force.

[-] Chrobin@discuss.tchncs.de 0 points 7 months ago

I'm not trying to argue approximations. Physics is just approximations all the way down. But as a physicist, I also love arguing about technicalities, and that's also kinda the point of science communities for me.

[-] Zerush@lemmy.ml 13 points 7 months ago* (last edited 7 months ago)

Well, its a geometric deformation of space-time because the displacement by mass

[-] quicksand@lemm.ee 10 points 7 months ago

Yes it is. We just don't know what makes it work

[-] Chrobin@discuss.tchncs.de 3 points 7 months ago

In our current understanding of physics, it's an effect from the curvature of space and not a force. Quantizing gravity results in unphysical divergences. Whether there will be a way to model gravity as an exchange of particles, we can't know for sure. So according to our current knowledge, it's not a force.

[-] JillyB@beehaw.org 2 points 7 months ago

I'm no scientist, but there is some debate about whether it's a fundamental force. Some think it might be like centrifugal force which isn't "real" but shows up in a certain reference frame. Gravity might actually be a result of thermodynamics and entropy.

[-] oce@jlai.lu 1 points 7 months ago* (last edited 7 months ago)

There are many things than we experience as distinct forces but may not be actually if you change the reference (ex: centrifugal force is inertia) or if you go deeper into unification (ex: electrostatic force and magnetic force can be unified into electromagnetic force). But physics is about modeling reality in a convenient way for you current reference, we will never be certain to have the "real" final model independent from our observation bias.

[-] cynar@lemmy.world 8 points 7 months ago

Knowledge is knowing that tomato is a fruit.

Wisdom is still not putting it in a fruit salad.

Gravity isn't a force. Its effects can be mapped to an equivalent pseudo force and used as such. Outside of general relativity, or Quantum mechanics discussions, gravity is a force.

[-] bwrsandman@lemmy.world 2 points 7 months ago

But is it fundamental though?

[-] cynar@lemmy.world 5 points 7 months ago

We don't know. Right now, relativity and QM fundamentally disagree on what gravity is. Both are also hugely accurate in their predictions. QM treats it as a force comparable to EM or the strong force. GR says it's space itself moving. The force we experience is just a reaction to us trying to stay still, as space moves through us.

Beyond that, defining anything as fundamental is a challenge. How are you using fundamental?

[-] oce@jlai.lu 6 points 7 months ago

Depends on your definition. If you stop at quantum mechanics way of defining a force with boson exchange then you may also say gravity doesn't exist, because it's not included in the standard model for now.