51–60 of 96 posts
"That solution is the graviton: a spin-2 particle that couples to itself and all other particles with equal strength." So, has this been discovered recently? I was under the impression that the graviton was theoretical?
> When bootstrapping, physicists determine how elementary particles with different amounts of “spin,” or intrinsic angular momentum, can consistently behave. In doing this, they rediscover the four fundamental forces that shape the universe. They have derived gravity through quantum mechanics? What rock have I been living under?
> They have derived gravity through quantum mechanics? Sort of! The problem is that the solutions of the existing quantum field theories are not renormalizable so infinities arise in the solutions. The whole point of quantum gravity is to find realizable solutions.
Err, not on any clock I've ever seen! But points for effort.
"That solution is the graviton: a spin-2 particle that couples to itself and all other particles with equal strength." So, has this been discovered recently? I was under the impression that the graviton was theoretical?
Earlier quoted context omitted.
Not a physicist by any means, but from the article it talks about gravity in the context of the graviton (as one plausible solution to the problem mentioned). Which is still hypothetical, so it's not like they've proven gravity from first principle or anything.
As a layman reading this, it’s funny. Because I do not need gravity proven to me from first principles ;)
Earlier quoted context omitted.
> not always the way they are and that they evolved spontaneously over time But how did they get any way at all? How and why do they evolve? > multiverse. i.e. we just got a random set of self consistent laws. This raises even more questions. Why are there any multiverses with any laws at all? From where did the stuff in the multiverses come from? What initiated this chain of multiverse creation, or why is it inevita…
I don’t think what you’re asking for is possible, and the answer lies more in the realm of philosophy than in physics. You can always keep asking the question ‘why?’ At some point, either you have just accept something as fundamental, or the answer justifies itself, or you have an infinite regress of whys.
Only very low-level ontological questions meet this criteria, like "why is there something rather than nothing," but even then, I am open to the possibility that there are reasonable explanations for these things that we just can't articulate yet.
Earlier quoted context omitted.
As a layman reading this, it’s funny. Because I do not need gravity proven to me from first principles ;)
And yet, funnily enough, your phone needs a more thorough understanding of gravity than you do. The GPS system must correct for relativistic effects that cause the atomic clocks to shift relative to ground.
The content of the article is very interesting and worth reading, but the framing feels circular. Some laws of nature are fundamental and other laws are inevitable consequences of those laws. If the inevitable laws were not inevitable, then they would be fundamental. As our knowledge and explanatory power grows, some laws that first appeared fundamental have been explained in terms of deeper laws, but we must still a…
“This is rather as if you imagine a puddle waking up one morning and thinking, 'This is an interesting world I find myself in — an interesting hole I find myself in — fits me rather neatly, doesn't it? In fact it fits me staggeringly well, must have been made to have me in it!'"
> And the hour hand on a clock must spin around twice before it tells the same time again. Err, not on any clock I've ever seen! But points for effort.
Wondering if anyone could recommend a layman's introduction to "spin". I've read the Wikipedia article, I broadly understand it, but just curious as to how it was discovered, why it is considered an "intrinsic" form of angular momentum, and why it is so fundamental a concept in our universe.
Objects with spin can be point-like but carry angular momentum. The electron is one such particle. It is "intrinsic" because it has no known moving parts. If it had moving parts, and that motion had net angular momentum, we would refer to it in many contexts as "orbital angular momentum". Spin should seem counterintuitive. There are no macroscopic objects that I am aware whose spin you can feel with your hands. Our r…
This is where I get stuck. The particles are all excitations of a quantum field. So what does spin mean in that context?