7 ms·
There is a couple of things to keep in mind. First, like others mentioned, they are way off in the effect size, for this kind of time dilation you need 80% the
by tsbinz 6y ago
There is a couple of things to keep in mind.
First, like others mentioned, they are way off in the effect size, for this kind of time dilation you need 80% the speed of light, not 8%.
Second, when looking at time dilation caused by velocity, it is always necessary to say who observes what since observers that move relative to each other won't agree on which clock runs at what speed. If the star moved at 80% of the speed of light, someone on that star would say "When a 100 minutes pass here, only 60 minutes pass on Earth" while an observer on Earth would say "When 100 minutes pass here, only 60 minutes pass on that star". So both observers would say that the other's clock is running slower than their own.
This answers a part of your last question - time dilation always makes clocks appear to tick slower than your clock if they move relative to you.
There are other effects that can make things appear "sped up", there's all kind of odd things happening when you go to high relativistic speeds ...
- eru 6y ago> Second, when looking at time dilation caused by velocity, it is always necessary to say who observes what since observers that move relative to each other won't agree on which clock runs at what speed. Interestlingly, the universe does have a preferred velocity (and thus a preferred inertial frame). It's the speed and direction that makes the cosmic background radiation not have a dipole. https://astronomy.swin.edu.au/cosmos/c/Cosmic+Microwave+Background+Dipole https://astronomy.swin.edu.au/cosmos/c/Cosmic+Microwave+Back...
- tinco 6y agoSo this velocity must be relative to some common point/area right? Like the center of the event that caused it? When they say "300,000 years after the big bang" how do they count that, is that seconds in some periodic movement inside matter or radiation?
- brnt 6y agoThere is no center to the source of the background radiation, as it is was created at a moment the universe was still a fairly homogeneous soup (apparently) with these photons being created (and absorbed) everywhere roughly in equal quantity. Only after the universe became transparent did these photons become free, and since they were produced roughly homogenously in that soup there are everywhere in the same quanitity: a background radiation. Since they were not produced in a localized event, they won't have a center. But since they're everywhere, they are a sort of absolute reference for how fast you're going (actually that's a new and interesting idea for me too, pretty neat).
- jstanley 6y agoBut if they're a reference for how fast you're going, aren't they also a reference for what direction you're going? Can you then not look backwards at the direction they have come from and work out the point that they all appear to originate from? And then haven't you found the centre?
- ben_w 6y agoThey are coming at you from every direction at once. What you’re asking is analogous to asking where the center of the Earth is on a map of the surface, and arguing it must exist because of how things on the horizon change when you move.
- brnt 6y agoImagine an omnipresent and homogeneous field, let's say an infinite field of corn. By looking at the corn, you can see how fast you're going, without that observation requiring the field to have a center.
- stallmanite 6y agoThis is a great analogy, finally “clicked” for me after trying to understand this concept for a while. Thank you.
- thedufer 6y agoThe reference velocity is the one such that you see an equal amount of cosmic background radiation in every direction. If you're moving relative to it, you'll see extra radiation from in front of you (much like how you see extra cars moving in the opposite direction from you on a highway).
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- onemiketwelve 6y agoI never got a real answer to this thought experiment. It's something I always thought about but I've been too lazy and dumb to figure out. So say two people are hanging out in space and their watches are synced to 12:00, then one person blasts off, turns around then comes back. `Clocks slow down when they move in relation to you` So to the "stationary" person, the clock of the person who zoomed off would be behind. But since it's relative, to the "zoomer" the stationary person went out and back. So then to the zoomer the stationary person's watch would be slower. But which one is it? Do they end up showing the same time?
- mb7733 6y agoThings aren't symetrical because only one of the two underwent acceleration. So one of them was not in an inertial frame of reference. This is a famous paradox, see here for a full discussion/resolution: https://en.wikipedia.org/wiki/Twin_paradox https://en.wikipedia.org/wiki/Twin_paradox