6 ms·

this image makes me curious about something: imagine a distant galaxy, say ~1billion light years away (not 13 like in this new image). imagine a civilization

this image makes me curious about something: imagine a distant galaxy, say ~1billion light years away (not 13 like in this new image). imagine a civilization in this galaxy. any information takes ~1billion years to travel between us and them. but say ten years pass from our frame of reference here on Earth. in those ten years on Earth, did the civilization ~1billion years away also experience roughly ~10years from their point of view? I guess what I'm trying to ask is, in the time it took me to write this comment, could there be some part of the universe experiencing a much faster rate of time, relative to us? Did a civilization rise and fall somewhere? Does this question even make sense, or is it one of those things where relativity is so unintuitive that asking a question like this is nonsensical?

prox 4y ago
I once asked this question to a scientist and I believe the passage of time seems pretty uniform (in similar gravitational circumstances) The exception is the beginning of the universe where time might have been more fluid for the lack of a better word.
groffee 4y ago
There's a Star Trek episode addresses this sort of https://memory-alpha.fandom.com/wiki/Blink_of_an_Eye_(episode) https://memory-alpha.fandom.com/wiki/Blink_of_an_Eye_(episod... Also I remember a short story where scientists created a mini universe then find that they can take over conscious beings in this reality, and influence them. So a few minutes to the scientists is thousands of years in this simulation, and they use it to get new technology and such.
- drieddust 4y ago
  Hindus imagined this thousand of years ago. Uncountable universes(multiverse) are born when Supreme consciousness Vishnu breathes out. Inside each universe God Bharma is born with the responsibly of managing the affair. Brahma lives for his 100 years which is roughly 311 billion years. During this time many mini cycles of creation and dissolution takes place. When Bharma finally dies after completing his 100 years,that particular universe dies with him. After another 311 billion years another Brahma is born again and universe restarts. When supreme god Vishnu finally breathes in, multiverse stop existing and creation end till the time supreme god breathes out again.
  - Keyframe 4y ago
    That's beautiful. I always wondered if there's some lost knowledge from ye olde ancient past where people knew more (about what we consider scinetific facts now) than we thought they did when they came up with these stories.
    - drieddust 4y ago
      Hindus were thinking about time ranging from nano seconds to billions of years[0]. As far lost knowledge is concerned Indian civilization have faced numerous attacks especially on its knowledge system and wealth. During one such attack Nalanda university was destroyed, more than 10000 teachers were killed, and library with millions of books was set on fire which raged for 3 months. Invaders themselves recorded these event gleefully. As per them India was a land of idol worshipers.Here is summary article which contains links to primary sources[1]. It's through struggle and luck Indian civilization have survived although with lots of gaps. I am sure there were others great civilizations. But they are not here any more to tell the tale. [0] https://en.wikipedia.org/wiki/Hindu_units_of_time https://en.wikipedia.org/wiki/Hindu_units_of_time [1] https://www.myindiamyglory.com/2017/09/11/nalanda-9-million-books-burnt/ https://www.myindiamyglory.com/2017/09/11/nalanda-9-million-...
      - monroeclinton 4y ago
        I think the Greeks through Anaximander had the concept of "apeiron", or the infinite. Some of them believed the universe to be infinitely old, therefore they must have had the concept of one to infinity, including billions.
        drieddust 4y ago
        Yep ancient civilizations have thought about these concepts for a long time. Some got destroyed by floods, some by famine, but horrific destruction have happened when Abrahmic religions came on the scene with "holier than thou" philosophy which made destruction of others a religious duty. Hindus were obsessed with zero and infinity and to them it was the same as god itself. Shanti mantra(used to wish well to all living being) from īśopaniṣad says. > ओं | पूर्णमदः पूर्णमिदं पूर्णात्पूर्णमुदच्यते । पूर्णस्य पूर्णमादाय पूर्णमेवावशिष्यते ॥ > oṃ | pūrṇamadaḥ pūrṇamidaṃ pūrṇātpūrṇamudacyate | pūrṇasya pūrṇamādāya pūrṇamevāvaśiṣyate || > That is Whole and this is Whole, the perfect has come out of the perfect; having taken the perfect from the perfect, only the perfect remains. Let there be Peace, Peace, Peace. Verse above describes God superficially but it also describes zero and infinity[0]. This small text with only 18 verses and yet it is so profound. Similarly Buddhist philosophy which also came out from India is based on Shunya(zero). [0] https://en.wikipedia.org/wiki/Isha_Upanishad https://en.wikipedia.org/wiki/Isha_Upanishad
el_nahual 4y ago
> Did a civilization rise and fall somewhere? Yes. The same civilization! (wait for it) > or is it one of those things where relativity is so unintuitive that asking a question like this is nonsensical? The latter. One of the most unintuive aspects of relativity is the relativity of simultaneity. Basically, the order in which events happen in different places in the universe is relative. Imagine event A happening in galaxy A, event B happening in galaxy B, and event C happening in galaxy C. From the POV of one observer, events might happen in order ABC, while for other they may happen in order BCA. This doesn't mean that the observers simply see the events in different order because of their distance to them--it means that even when taking distance into account, one event happened before the other. So yes, a civilization rose while you wrote that comment. It also fell... from the POV of someone else. [1]: https://en.wikipedia.org/wiki/Relativity_of_simultaneity https://en.wikipedia.org/wiki/Relativity_of_simultaneity
cwkoss 4y ago
Does time move faster the deeper you are in a gravity well? If a civilization was trying to compete with another in another galaxy, could they coalesce as much matter as they could into a single star, increasing gravity, and relativistically experience more time in their star system than the other civilization?
- jungturk 4y ago
  Yes, it does (from the point of view of observers outside the gravity well), and yes they could. They could also accelerate themselves to relativistic speeds to accomplish the same feat.
- lovehashbrowns 4y ago
  I think they’d just need to travel slower through space to experience more time relative to the other civilization. Then that civilization could take more that time to develop a civilization-ending laser or whatever. Then for gravity, the less gravity that civilization experiences the slower time moves for them relative to their competitor. So I think the goal would be to send star matter to the other civilization so their time slows down relatively speaking. I’m no expert, though. Happy to take corrections.
- SAI_Peregrinus 4y ago
  Yes. You can actually measure this just by the mass difference of a mountain here on Earth, with a sufficiently accurate pair of clocks. http://www.leapsecond.com/great2016a/index.htm http://www.leapsecond.com/great2016a/index.htm
- arthens 4y ago
  Would that not achieve the opposite effect? If interstaller thought us anything, the closer you are to a black hole the slower time gets. When they got close to the black hole they only spent a few hours there but lost years compared to our frame of reference.
jungturk 4y ago
Yes, the two settings (aka "reference frames" in special and general relativity) can experience time at different rates. https://en.wikipedia.org/wiki/Time_dilation https://en.wikipedia.org/wiki/Time_dilation
mabbo 4y ago
Time will pass for them very very closely to the same rate it does for us. But here's something fun: the space between us and them is stretching, so in a billion years when the light arrives at our position, the time between photons will be longer than when they left (so things will appear slower) and the photons will be at a longer wavelength making it more red.
colechristensen 4y ago
There are situations where time passes differently like with high speeds and in gravity wells, but except for unusual circumstances, time will pass mostly at the same rate for life on any two planets across the universe. Because on relativistic scales they’ll be in very nearly exactly the same inertial frame. Like maybe a few nanoseconds over ten minutes difference. One could probably come up with a standard deviation statistic, but whatever it would be would be way below a perceptual difference. (We can measure the difference in the flow of time with a clock on a table compared to another on the floor, but of course that’s way less than could be felt)
mannerheim 4y ago
Depends on their velocity relative to Earth. The unintuitive bit of relativity is that you observe the other as experiencing time more slowly - this is the origin of the twin paradox (i.e., shouldn't each twin observe the other as having aged less?) whose resolution comes from the fact that the second twin is in a non-inertial reference frame once he changes directions to return to Earth.
perihelions 4y ago
Reality is much crazier than that. Some of the distant galaxies are causally disconnected from us: they're receding faster than the speed of light (by one out of the several definitions), and will (probably) continue to do so, so no information can travel between us. No causal interaction is possible. It's as if they were practically no longer a part of this universe -- they can't affect anything here, and nothing here can affect them. (I'm not certain on this point, but I think some of the high-redshift galaxies we can see in deep field images are now causally disconnected. We're receiving some of their old light, but we can't send anything back anymore -- they've faded out into infinite redshift). edit: Here's an article about this idea by Ethan Siegel, and its HN discussion thread (thanks 'petilon for helping me remember the author): https://medium.com/starts-with-a-bang/the-disappearing-universe-d7447467c63a https://medium.com/starts-with-a-bang/the-disappearing-unive... ("The Disappearing Universe") https://news.ycombinator.com/item?id=7896776 https://news.ycombinator.com/item?id=7896776 (64 comments)
- joelcollinsdc 4y ago
  Can you provide a link with this info? I’m only a casual follower of this stuff but it seems hard for me to believe
  - tambourine_man 4y ago
    He’s referring to the cosmic event horizon “ In an expanding universe, the speed of expansion reaches — and even exceeds — the speed of light, preventing signals from traveling to some regions. A cosmic event horizon is a real event horizon because it affects all kinds of signals, including gravitational waves, which travel at the speed of light.” https://en.m.wikipedia.org/wiki/Event_horizon https://en.m.wikipedia.org/wiki/Event_horizon
    - davidvarela_us 4y ago
      I was just going to ask about gravity. TIL that gravity travels at the speed of light. Thanks!

prox 4y ago

I once asked this question to a scientist and I believe the passage of time seems pretty uniform (in similar gravitational circumstances) The exception is the beginning of the universe where time might have been more fluid for the lack of a better word.

groffee 4y ago

There's a Star Trek episode addresses this sort of https://memory-alpha.fandom.com/wiki/Blink_of_an_Eye_(episode) https://memory-alpha.fandom.com/wiki/Blink_of_an_Eye_(episod... Also I remember a short story where scientists created a mini universe then find that they can take over conscious beings in this reality, and influence them. So a few minutes to the scientists is thousands of years in this simulation, and they use it to get new technology and such.

drieddust 4y ago
Hindus imagined this thousand of years ago. Uncountable universes(multiverse) are born when Supreme consciousness Vishnu breathes out. Inside each universe God Bharma is born with the responsibly of managing the affair. Brahma lives for his 100 years which is roughly 311 billion years. During this time many mini cycles of creation and dissolution takes place. When Bharma finally dies after completing his 100 years,that particular universe dies with him. After another 311 billion years another Brahma is born again and universe restarts. When supreme god Vishnu finally breathes in, multiverse stop existing and creation end till the time supreme god breathes out again.
- Keyframe 4y ago
  That's beautiful. I always wondered if there's some lost knowledge from ye olde ancient past where people knew more (about what we consider scinetific facts now) than we thought they did when they came up with these stories.
  - drieddust 4y ago
    Hindus were thinking about time ranging from nano seconds to billions of years[0]. As far lost knowledge is concerned Indian civilization have faced numerous attacks especially on its knowledge system and wealth. During one such attack Nalanda university was destroyed, more than 10000 teachers were killed, and library with millions of books was set on fire which raged for 3 months. Invaders themselves recorded these event gleefully. As per them India was a land of idol worshipers.Here is summary article which contains links to primary sources[1]. It's through struggle and luck Indian civilization have survived although with lots of gaps. I am sure there were others great civilizations. But they are not here any more to tell the tale. [0] https://en.wikipedia.org/wiki/Hindu_units_of_time https://en.wikipedia.org/wiki/Hindu_units_of_time [1] https://www.myindiamyglory.com/2017/09/11/nalanda-9-million-books-burnt/ https://www.myindiamyglory.com/2017/09/11/nalanda-9-million-...
    - monroeclinton 4y ago
      I think the Greeks through Anaximander had the concept of "apeiron", or the infinite. Some of them believed the universe to be infinitely old, therefore they must have had the concept of one to infinity, including billions.
      - drieddust 4y ago
        Yep ancient civilizations have thought about these concepts for a long time. Some got destroyed by floods, some by famine, but horrific destruction have happened when Abrahmic religions came on the scene with "holier than thou" philosophy which made destruction of others a religious duty. Hindus were obsessed with zero and infinity and to them it was the same as god itself. Shanti mantra(used to wish well to all living being) from īśopaniṣad says. > ओं | पूर्णमदः पूर्णमिदं पूर्णात्पूर्णमुदच्यते । पूर्णस्य पूर्णमादाय पूर्णमेवावशिष्यते ॥ > oṃ | pūrṇamadaḥ pūrṇamidaṃ pūrṇātpūrṇamudacyate | pūrṇasya pūrṇamādāya pūrṇamevāvaśiṣyate || > That is Whole and this is Whole, the perfect has come out of the perfect; having taken the perfect from the perfect, only the perfect remains. Let there be Peace, Peace, Peace. Verse above describes God superficially but it also describes zero and infinity[0]. This small text with only 18 verses and yet it is so profound. Similarly Buddhist philosophy which also came out from India is based on Shunya(zero). [0] https://en.wikipedia.org/wiki/Isha_Upanishad https://en.wikipedia.org/wiki/Isha_Upanishad

el_nahual 4y ago

> Did a civilization rise and fall somewhere? Yes. The same civilization! (wait for it) > or is it one of those things where relativity is so unintuitive that asking a question like this is nonsensical? The latter. One of the most unintuive aspects of relativity is the relativity of simultaneity. Basically, the order in which events happen in different places in the universe is relative. Imagine event A happening in galaxy A, event B happening in galaxy B, and event C happening in galaxy C. From the POV of one observer, events might happen in order ABC, while for other they may happen in order BCA. This doesn't mean that the observers simply see the events in different order because of their distance to them--it means that even when taking distance into account, one event happened before the other. So yes, a civilization rose while you wrote that comment. It also fell... from the POV of someone else. [1]: https://en.wikipedia.org/wiki/Relativity_of_simultaneity https://en.wikipedia.org/wiki/Relativity_of_simultaneity

cwkoss 4y ago

Does time move faster the deeper you are in a gravity well? If a civilization was trying to compete with another in another galaxy, could they coalesce as much matter as they could into a single star, increasing gravity, and relativistically experience more time in their star system than the other civilization?

jungturk 4y ago
Yes, it does (from the point of view of observers outside the gravity well), and yes they could. They could also accelerate themselves to relativistic speeds to accomplish the same feat.
lovehashbrowns 4y ago
I think they’d just need to travel slower through space to experience more time relative to the other civilization. Then that civilization could take more that time to develop a civilization-ending laser or whatever. Then for gravity, the less gravity that civilization experiences the slower time moves for them relative to their competitor. So I think the goal would be to send star matter to the other civilization so their time slows down relatively speaking. I’m no expert, though. Happy to take corrections.
SAI_Peregrinus 4y ago
Yes. You can actually measure this just by the mass difference of a mountain here on Earth, with a sufficiently accurate pair of clocks. http://www.leapsecond.com/great2016a/index.htm http://www.leapsecond.com/great2016a/index.htm
arthens 4y ago
Would that not achieve the opposite effect? If interstaller thought us anything, the closer you are to a black hole the slower time gets. When they got close to the black hole they only spent a few hours there but lost years compared to our frame of reference.

jungturk 4y ago

Yes, the two settings (aka "reference frames" in special and general relativity) can experience time at different rates. https://en.wikipedia.org/wiki/Time_dilation https://en.wikipedia.org/wiki/Time_dilation

mabbo 4y ago

Time will pass for them very very closely to the same rate it does for us. But here's something fun: the space between us and them is stretching, so in a billion years when the light arrives at our position, the time between photons will be longer than when they left (so things will appear slower) and the photons will be at a longer wavelength making it more red.

colechristensen 4y ago

There are situations where time passes differently like with high speeds and in gravity wells, but except for unusual circumstances, time will pass mostly at the same rate for life on any two planets across the universe. Because on relativistic scales they’ll be in very nearly exactly the same inertial frame. Like maybe a few nanoseconds over ten minutes difference. One could probably come up with a standard deviation statistic, but whatever it would be would be way below a perceptual difference. (We can measure the difference in the flow of time with a clock on a table compared to another on the floor, but of course that’s way less than could be felt)

mannerheim 4y ago

Depends on their velocity relative to Earth. The unintuitive bit of relativity is that you observe the other as experiencing time more slowly - this is the origin of the twin paradox (i.e., shouldn't each twin observe the other as having aged less?) whose resolution comes from the fact that the second twin is in a non-inertial reference frame once he changes directions to return to Earth.

perihelions 4y ago

Reality is much crazier than that. Some of the distant galaxies are causally disconnected from us: they're receding faster than the speed of light (by one out of the several definitions), and will (probably) continue to do so, so no information can travel between us. No causal interaction is possible. It's as if they were practically no longer a part of this universe -- they can't affect anything here, and nothing here can affect them. (I'm not certain on this point, but I think some of the high-redshift galaxies we can see in deep field images are now causally disconnected. We're receiving some of their old light, but we can't send anything back anymore -- they've faded out into infinite redshift). edit: Here's an article about this idea by Ethan Siegel, and its HN discussion thread (thanks 'petilon for helping me remember the author): https://medium.com/starts-with-a-bang/the-disappearing-universe-d7447467c63a https://medium.com/starts-with-a-bang/the-disappearing-unive... ("The Disappearing Universe") https://news.ycombinator.com/item?id=7896776 https://news.ycombinator.com/item?id=7896776 (64 comments)

joelcollinsdc 4y ago
Can you provide a link with this info? I’m only a casual follower of this stuff but it seems hard for me to believe
- tambourine_man 4y ago
  He’s referring to the cosmic event horizon “ In an expanding universe, the speed of expansion reaches — and even exceeds — the speed of light, preventing signals from traveling to some regions. A cosmic event horizon is a real event horizon because it affects all kinds of signals, including gravitational waves, which travel at the speed of light.” https://en.m.wikipedia.org/wiki/Event_horizon https://en.m.wikipedia.org/wiki/Event_horizon
  - davidvarela_us 4y ago
    I was just going to ask about gravity. TIL that gravity travels at the speed of light. Thanks!