Faster than light ???

[Gmetric]

Sabine has something to say about it.





If you need a refresher on the Higgs field, boson and mechanism see the videos below in order of ease.

This link give a brief explanation of the mass defect and binding energy

http://ne.phys.kyushu-u.ac.jp/seminar/M ... mass_E.htm

And Just for clarity, when she refers to the condensed Higgs field and condensate, I believe she is referring to the vacuum expectation value VEV
See here https://en.m.wikipedia.org/wiki/Vacuum_ ... tion_value

For the Higgs field see here

https://simple.m.wikipedia.org/wiki/Higgs_field

And the videos - the second has a good explanation of VEV

[helicon]

Thanks Arry. Pretty cool stuff

[Lady Fraktor]

Lots to go through, thank you for the links Arry

[AntennaGuy]

I can't compete with Dr. Hossenfelder on knowledge of relativity, but I'm not (yet) persuaded that her argument against the veracity of the customary paradox involving special relativity and causality being violated by faster-than-light communication of information (thereby excluding FTL communication) is correct. Over short distances (mere handfuls of light years, heh!) mostly-empty space is pretty darn nearly flat. It seems to me that the paradox can be legitimately evaluated within such a context, in which case arguments from special relativity alone (i.e., ignoring gravity and the universe's background frame of matter) should be valid. Well, I suspect we'll hear more about this later, as genuine theorists offer their thoughts. I miss NFA.

[ThinkerX]

That is an interesting dodge. Whether that dodge can work with QM is another matter.

Were he still with us, Fritz would likely have some...interesting...comments.

That said, I posted a bit of speculation here in times past about negating the 'strong attractive force' in a microscopically small area and using the energy (not far shy of a matter/anti-matter reaction) to power a slower than light starship.

[Gmetric]

I can't compete with Dr. Hossenfelder on knowledge of relativity, but I'm not (yet) persuaded that her argument against the veracity of the customary paradox involving special relativity and causality being violated by faster-than-light communication of information (thereby excluding FTL communication) is correct. Over short distances (mere handfuls of light years, heh!) mostly-empty space is pretty darn nearly flat. It seems to me that the paradox can be legitimately evaluated within such a context, in which case arguments from special relativity alone (i.e., ignoring gravity and the universe's background frame of matter) should be valid. Well, I suspect we'll hear more about this later, as genuine theorists offer their thoughts. I miss NFA.

Thanks for your input FWIW, and without further investigation, I’m with you and need further persuasion. I think we all miss nFA. What we need is another retired resident expert who has the time to go through all this stuff. I’m sadly not a genuine theorist nor do I have enough time to post deeply thoughtful or insightful posts, at the moment. Sorry about that.

This is her intitial backreaction post about it in 2020
http://backreaction.blogspot.com/2020/0 ... e.html?m=1

[SkyHiker]

That's a really weird mix of special relativity, philosophy and Higgs stuff that I know nothing about. Relativity and quantum fields still don't mix very well AFAIK.

In GR, observing object that move away from us faster than the speed of light is not abnormal. Objects that were 46 Gly away at t=0 are now crossing the particle horizon at a recession velocity 3 times the speed of light, and we observe them with near-infinite redshift. That is in a flat ΛCDM universe. Gödel cooked up a model of the universe where time travels in circles, you can arrive before you left. So, in GR there are much weirder things possible than with inertial frames in SR.

This is nitpicking a bit, Sabine presents it in a very nice way of course but I don't think I'm going to watch that video a second time.

[Gmetric]

That's a really weird mix of special relativity, philosophy and Higgs stuff that I know nothing about. Relativity and quantum fields still don't mix very well AFAIK.

In GR, observing object that move away from us faster than the speed of light is not abnormal. Objects that were 46 Gly away at t=0 are now crossing the particle horizon at a recession velocity 3 times the speed of light, and we observe them with near-infinite redshift. That is in a flat ΛCDM universe. Gödel cooked up a model of the universe where time travels in circles, you can arrive before you left. So, in GR there are much weirder things possible than with inertial frames in SR.

This is nitpicking a bit, Sabine presents it in a very nice way of course but I don't think I'm going to watch that video a second time.

Can’t say much at the moment as I’m on lunch and am at work. But, as always, thanks for your input, Henk. If I understand you right, I think we can but you in the “need more persuasion” camp along with AntennaGuy and myself?

[SkyHiker]

Can’t say much at the moment as I’m on lunch and am at work. But, as always, thanks for your input, Henk. If I understand you right, I think we can but you in the “need more persuasion” camp along with AntennaGuy and myself?

Yup. But don't ask me, what do I know. I finally understand GR and cosmology to some intermediate level.

I just watched it for a 2nd time, this time not bailing out halfway and heard the comoving coordinate arguments, then she said with a straight face that if she wanted to learn something new, she goes to Brilliant, lol. That was a good one!

Time as we know it from cosmology emerges from the theory of symmetric spaces - you just look at the properties of a homogeneous and isotropic universe, apply differential geometry and add some assumptions et voila. In the quantum world it is quite different. In the Big Think ER=EPR link that we saw a while ago it is theorized that quantum entanglement is the result of an Einstein Rosen bridge. Van Raamsdonk built a space time model based on that idea. It is confusing. If you search the internet for if time is an emergent property or not, you will find many yes- and no-responses (no, not time, space is emergent).

So far, I just read the popular links, don't understand much of it and I'm glad I am not the only one. The ER=EPR folks are trying to explain quantum physics and relativity using wormholes, and if that means time can run in closed loops, great. Others are using quantum physics (gravitons, Higgs fields) to explain spacetime. Who knows. But those ideas are pretty remote from Alice and Bob in spaceships one of which moves faster than light.

As an aside, any opinions on a faster than light question that I have: How can static gravity cross an event horizon as gravitational waves cannot? We should be able to sense mass from outside the visible universe and inside the Schwarzschild radius of black holes according to their differential geometric model origins, but that means that static gravity travels faster than light somehow. Or does it? I searched the internet for an answer and the opinions are all over the place. Anyway, it's all fascinating and we can't rule anything out.

[AntennaGuy]

Re:

... How can static gravity cross an event horizon as gravitational waves cannot? We should be able to sense mass from outside the visible universe and inside the Schwarzschild radius of black holes according to their differential geometric model origins, but that means that static gravity travels faster than light somehow. Or does it? I searched the internet for an answer and the opinions are all over the place. Anyway, it's all fascinating and we can't rule anything out.

At the risk of being completely wrong (or at least overly simplistic), allow me to respond with these comments & questions: Does gravity need to "cross" the event horizon at all? If (ok, possibly ignoring particle physics too much) gravity is considered as direct consequence of the curvature of spacetime, then the effect of gravity on matter is a local one (like the matter being at a location in a potential well), and not like that matter being subject to radiation (photons, gravitons, etc.) illuminating it at some velocity. If there is literally no radiation involved, then there is no barrier for gravity to cross (so to speak) to travel from its source (such as a black hole) to its target, for there is no traveling at all.