4 ms·

Also not an astrophysicist, but wouldn't we be able to work the consequence of the distance traveled into the prediction made before the experiment? There is a

Also not an astrophysicist, but wouldn't we be able to work the consequence of the distance traveled into the prediction made before the experiment? There is a possibility that our understanding of what effect the distance would have on the readings, but as long as you don't print things like it "confirms time ran slower" there's no real problem...

ggm 3y ago
Yes. I am sure the paper makes adjustments, error corrections. They're good scientists. But I'm a layperson. So, I guess the problems are headlines. Because the headline didn't say confirm, but it states positively Time ran slowly Outside of a dog, a cigar is a mans best friend. Inside of a dog, it's too dark to see. Inside of a slowly running time period, a second is still a second, surely? So I ask myself how inside the universe, we can make assertions about the relative speed a second "is" but remain inside the same system. The implications some other attribute of observed reality can remain unchanged, and confirm the "duration" of a second was different then, to now, based on observations made solely within this universe.. I'm struggling.
- quickthrower2 3y ago
  I was thinking the same thing. This explanation if right makes some sense: https://news.ycombinator.com/item?id=37245317 https://news.ycombinator.com/item?id=37245317 Basically is the same “time goes more slowly” as a atomic clock that is not on a jet plane
- 22c 3y ago
  Redshift isn't mentioned anywhere in the article except in the citation of the original paper https://www.nature.com/articles/s41550-023-02029-2 https://www.nature.com/articles/s41550-023-02029-2 but redshift here would be the key to making this determination.. I don't have access to the paper and it would probably be beyond me, but presumably you can make observations in redshifted light from quasars of different ages (or distances from the centre of the universe) and because we're fairly sure the properties of light haven't changed since the universe started, we use these subtle differences in redshifts like a sort of "cosmological GPS" and figure out that time must've been slower in the past
  - ggm 3y ago
    So I don't think this is an answer, certainly not THE answer, but I worry that aspects of the early universe like the local density of matter or electric fields were radically different to what we have now. If you imagine a beacon of light which is a signal from time "back then" which has to pass through both the early states of the universe with different densities of things between then and now, and us and them, AND has to be observed, I can think of ways both matter and energy could interfere with that signal differently across time. Consequently, the amount of red shift we see in modern times for more modern (ie closer) things reflects more modern states of the universe. As a correction factor, we'd be applying what we know, to what we infer, about the density in those times. This is why I express skepticism: It's very hard to believe there are no confounding factors in the states of being then, compared to now, which might lie inside the error/noise thresholds of their calculations. "it had to be time was different then" feels like "because I want it to" against all the sources of noise and conjecture, between then and now. I hasten to add I am not an astrophysicist. So, I can be put firmly back in my box and told to accept good science says otherwise.
    - 22c 3y ago
      I would say perhaps the key difference here is we're talking about cosmological scale observations. Yes, a few quasars might've had to pass through some gas clouds or an asteroid belt or space dust etc. but at the scale we're talking about, that's probably not going to skew the numbers too much. There's 190 quasars being measured here. Presumably more observations can be made over time and with other quasars involved but I don't think these scientists need more data to be confident in what they're seeing. If you think about a pebble getting in the way of old faithful, it's not going to make much difference if you're measuring how much water sprays out over a hundred years. Now you have 190 old faithfuls and they're all spraying out water in pretty much the same way, you don't really need to account for that pebble too much.
    - boomboomsubban 3y ago
      The general theory of relativity predicts that time would run slower, and if that was the case these ancient quasars would demonstrate certain properties when looked at by our telescopes. We then looked at ancient quasars, and the readings we got matched the predictions, with some amount of error. This can then be used as another piece of experimental data supporting the general theory of relativity, even though you are right that these readings could be achieved through some other bizarre set of circumstances.
- 22c 3y ago
  Also in terms of a second being a second, yes, presumably if you took a pocket watch back to the beginning of the universe, it would not operate observably slower. Imagine you had an inter-dimensional being that could traverse spacetime at will. They have 2 stopwatches, one is in their left hand at the center of the universe 12bn years ago, the other is in their right hand at the edge of the universe today. If they started both stopwatches at the same time, the one in their left hand would take longer to reach 5 seconds than the one in their right hand.

ggm 3y ago

Yes. I am sure the paper makes adjustments, error corrections. They're good scientists. But I'm a layperson. So, I guess the problems are headlines. Because the headline didn't say confirm, but it states positively Time ran slowly Outside of a dog, a cigar is a mans best friend. Inside of a dog, it's too dark to see. Inside of a slowly running time period, a second is still a second, surely? So I ask myself how inside the universe, we can make assertions about the relative speed a second "is" but remain inside the same system. The implications some other attribute of observed reality can remain unchanged, and confirm the "duration" of a second was different then, to now, based on observations made solely within this universe.. I'm struggling.

quickthrower2 3y ago
I was thinking the same thing. This explanation if right makes some sense: https://news.ycombinator.com/item?id=37245317 https://news.ycombinator.com/item?id=37245317 Basically is the same “time goes more slowly” as a atomic clock that is not on a jet plane
22c 3y ago
Redshift isn't mentioned anywhere in the article except in the citation of the original paper https://www.nature.com/articles/s41550-023-02029-2 https://www.nature.com/articles/s41550-023-02029-2 but redshift here would be the key to making this determination.. I don't have access to the paper and it would probably be beyond me, but presumably you can make observations in redshifted light from quasars of different ages (or distances from the centre of the universe) and because we're fairly sure the properties of light haven't changed since the universe started, we use these subtle differences in redshifts like a sort of "cosmological GPS" and figure out that time must've been slower in the past
- ggm 3y ago
  So I don't think this is an answer, certainly not THE answer, but I worry that aspects of the early universe like the local density of matter or electric fields were radically different to what we have now. If you imagine a beacon of light which is a signal from time "back then" which has to pass through both the early states of the universe with different densities of things between then and now, and us and them, AND has to be observed, I can think of ways both matter and energy could interfere with that signal differently across time. Consequently, the amount of red shift we see in modern times for more modern (ie closer) things reflects more modern states of the universe. As a correction factor, we'd be applying what we know, to what we infer, about the density in those times. This is why I express skepticism: It's very hard to believe there are no confounding factors in the states of being then, compared to now, which might lie inside the error/noise thresholds of their calculations. "it had to be time was different then" feels like "because I want it to" against all the sources of noise and conjecture, between then and now. I hasten to add I am not an astrophysicist. So, I can be put firmly back in my box and told to accept good science says otherwise.
  - 22c 3y ago
    I would say perhaps the key difference here is we're talking about cosmological scale observations. Yes, a few quasars might've had to pass through some gas clouds or an asteroid belt or space dust etc. but at the scale we're talking about, that's probably not going to skew the numbers too much. There's 190 quasars being measured here. Presumably more observations can be made over time and with other quasars involved but I don't think these scientists need more data to be confident in what they're seeing. If you think about a pebble getting in the way of old faithful, it's not going to make much difference if you're measuring how much water sprays out over a hundred years. Now you have 190 old faithfuls and they're all spraying out water in pretty much the same way, you don't really need to account for that pebble too much.
  - boomboomsubban 3y ago
    The general theory of relativity predicts that time would run slower, and if that was the case these ancient quasars would demonstrate certain properties when looked at by our telescopes. We then looked at ancient quasars, and the readings we got matched the predictions, with some amount of error. This can then be used as another piece of experimental data supporting the general theory of relativity, even though you are right that these readings could be achieved through some other bizarre set of circumstances.
22c 3y ago
Also in terms of a second being a second, yes, presumably if you took a pocket watch back to the beginning of the universe, it would not operate observably slower. Imagine you had an inter-dimensional being that could traverse spacetime at will. They have 2 stopwatches, one is in their left hand at the center of the universe 12bn years ago, the other is in their right hand at the edge of the universe today. If they started both stopwatches at the same time, the one in their left hand would take longer to reach 5 seconds than the one in their right hand.