My understanding as explained to me by CERN, You can build a Time Crystal but it is tough to observe it after. The object don't so much spin through infinity, as infinity spins through them. Building a Time Crystal changes how it moves through Space-Time. Since we are moving through Space-Time really quickly if you change for lack of a better word the inertia of matter by changing how it moves through Time it won't stand still for very long, (well not relative to you) this makes observation nearly impossible.
‘Time Crystals’ Could Upend Physicists’ Theory of Time
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Re: ‘Time Crystals’ Could Upend Physicists’ Theory of Time
#42Earlier quoted context omitted.
A satellite in orbit is always accelerating as well, and will remain in constant motion if the orbit is far enough out (i.e. well beyond atmospheric drag). I'm about half-way through this and it feels more and more like it was written by someone who would also ask why a permanent magnet can support a load against gravity without expending any energy - it's the same fundamental attribution error. EDIT: In fact finishi…
The difference here is that normally when you have something coasting in a circle like that, it's possible to remove energy from the system and have it stop doing that. For example, tidal forces are constantly removing energy from the Earth-Moon system. Here, the theory is that the system is already in its lowest-energy state, despite the fact that part of it is still in motion.
You hit the nail on the head, thank you.
Re: ‘Time Crystals’ Could Upend Physicists’ Theory of Time
#43This article doesn't seem fair to physics. For instance, it says: "How can something move, and keep moving forever, without expending energy? It seemed an absurd idea — a major break from the accepted laws of physics." I don't think that something moving forever is a major break from the laws of physics. Consider the following: (1) An asteroid flies through space forever (doesn't violate laws of physics) (2) A curren…
Yes. F=ma. There's no v in there.
Re: ‘Time Crystals’ Could Upend Physicists’ Theory of Time
#44This article doesn't seem fair to physics. For instance, it says: "How can something move, and keep moving forever, without expending energy? It seemed an absurd idea — a major break from the accepted laws of physics." I don't think that something moving forever is a major break from the laws of physics. Consider the following: (1) An asteroid flies through space forever (doesn't violate laws of physics) (2) A curren…
Yes. F=ma. There's no v in there.
yes there is, it's right in the v'(t)
Re: ‘Time Crystals’ Could Upend Physicists’ Theory of Time
#45Earlier quoted context omitted.
I think you're confusing forever with a really long time. (1) Asteroid's velocity is eventually overcome by external forces. (2, 3) Structure decays. (4) Bodies converge or diverge. (5) Radioactive decay. (6) You are observing a high energy system. (7) Etc.
I don't think I'm confusing forever with a really long time; I'm just assuming they're effectively the same. (Aside: nothing exists forever - even time crystals - because eventually the universe will be a bunch of infinitely far apart black holes or something. So I'm not sure how that assumption is relevant.)
The distinction still makes sense, I think. There are particles with a decay time so long they're practically stable (e.g. bound neutrons) and then there are stable particles.
The examples you gave above are forever; I just started assuming things like eternity and I can go on to assume no external forces/stuff in the way. (So not disagreeing with your initial statement, just adding.)
Re: ‘Time Crystals’ Could Upend Physicists’ Theory of Time
#46Is Noether's theorem preserved since we still have energy conservation? How? Very cool.
Re: ‘Time Crystals’ Could Upend Physicists’ Theory of Time
#47Earlier quoted context omitted.
I think you're confusing forever with a really long time. (1) Asteroid's velocity is eventually overcome by external forces. (2, 3) Structure decays. (4) Bodies converge or diverge. (5) Radioactive decay. (6) You are observing a high energy system. (7) Etc.
I don't think I'm confusing forever with a really long time; I'm just assuming they're effectively the same. (Aside: nothing exists forever - even time crystals - because eventually the universe will be a bunch of infinitely far apart black holes or something. So I'm not sure how that assumption is relevant.)
For me, the difference is whether these things a) have an external force being applied to them, or b) are slowing down and are only going on "forever" because the rest of the universe will collapse before they come to a standstill.
For example, even ignoring the fact that the sun is going to explode before the universe does, the earth's rotation around the sun is gradually getting slower and slower. If the sun, and the universe, did last forever then the earth would eventually come to a halt.
In the case of these crystals, my impression is that even in that hypothetical never-ending universe, the movement in these crystals would never slow down.
Re: ‘Time Crystals’ Could Upend Physicists’ Theory of Time
#48(Humor)
Something tells me that as soon as they build these, the cast from Time Bandits is going to bust through the wall and steal them.
Re: ‘Time Crystals’ Could Upend Physicists’ Theory of Time
#49Earlier quoted context omitted.
Wouldn't tidal forces influence Earth's orbit much more than gravitational radiation? Although I suspect both are far too small to measure on a human time scale.
If memory serves right, tidal forces are quite measurable. A centimetre a year or so extra in the distance between moon and earth.
Between the Moon and Earth, yes. I'm not so sure about between Earth and the Sun.
Re: ‘Time Crystals’ Could Upend Physicists’ Theory of Time
#50Earlier quoted context omitted.
> EDIT: In fact finishing it, I'm really confused as to what's new here. Since 1) the Nobel-winning physicist, 2) the peer reviewed journal AND 3) the main critic of his theory agree that there is something new there, you probably ARE confused as to what they really meant. I think an appeal to authority is appropriate here. Time and again I've seen simplistic comments in tech forums, putting down new scientific theor…
His criticism is probably aimed at the journalist, not the scientist.
Indeed so. The article does a poor job of explaining - whereas down the other comments on HN here I now actually grok the significance.