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It's just so crazy to me to see a galaxy 420 million light years away. That is so much time for what we're seeing to have changed. I presume life can form withi

It's just so crazy to me to see a galaxy 420 million light years away. That is so much time for what we're seeing to have changed. I presume life can form within that window given the right conditions, so to some degree it just feels a bit sad that the distance is so great that we can't actually see what may exist in this moment that far away

vasco 2y ago
In another way it's really cool to be able to "see the past" even if all we see is always the past. At this level it is like a super power. If only some aliens had put a mirror somewhere far so we could see ourselves too. Or multiple mirrors at different distances. With enough mirrors and light bouncing around the size of the universe itself can be a "storage media" of the past with different photons all around carrying "how this location looked X years ago". "All" you have to do to know what happened is find the right photon to see whatever it is you want to see.
- steveoscaro 2y ago
  Well that sounds like a good premise for a scifi book or movie.
  - IngoBlechschmid 2y ago
    https://en.wikipedia.org/wiki/The_Hundred_Light-Year_Diary https://en.wikipedia.org/wiki/The_Hundred_Light-Year_Diary By Greg Egan, so highly recommended.
  - densh 2y ago
    You should check out Three Body Problem (the book, not the mediocre netflix adaptation).
    - steveoscaro 2y ago
      I love that book
- grahamj 2y ago
  You don't need mirrors, you just need to get in front of the photons. A time machine or warp drive will do :) Also the past is the only thing you can perceive, there effectively is no now.
  - densh 2y ago
    Is there a science fiction universe that explores a hypothetical warp drive that lets you travel very far relatively quickly, but the travel is only possible with simultaneous backwards time travel that's proportionate to the distance traversed? So you can hop across star systems but can't do a roundtrip A -> B -> A without significantly shifting time from the point of view of A backwards (irreversibly from the point of view of the traveler).
    - zzzr 2y ago
      [dead]
    - grahamj 2y ago
      Consider: - I leave Earth and travel 1ly at speed c - I arrive one year later - An Earth telescope will see the destination as it was when I left - It will take another year to see me arrive So in a way that's already happening because I'm traveling quite quickly - twice as fast as it seems from Earth's perspective - and I arrive in what appears from Earth to be the past.
      - densh 2y ago
        Relativity is so hard to wrap you head around.
- ujikoluk 2y ago
  For prior art in this field, see: https://github.com/yarrick/pingfs https://github.com/yarrick/pingfs "pingfs is a filesystem where the data is stored only in the Internet itself, as ICMP Echo packets (pings) travelling from you to remote servers and back again." Also https://en.wikipedia.org/wiki/Delay-line_memory https://en.wikipedia.org/wiki/Delay-line_memory Storing data as acoustic waves gave a higher capacity in practice, as propagation is slower thus fitting a larger number of symbol per time unit.
  - lloeki 2y ago
    From chainsaws to ICMP echo packets (and more) http://tom7.org/harder/ http://tom7.org/harder/
- ConcernedCoder 2y ago
  In theory, couldn't we focus on a perfect spot near a black hole where the light has been warped 180 degrees around it... i.e. if the black hole is 100 light years away, you'd see ( with perfect zoom, of course ) a picture of the earth 200 years ago...? I understand that we'd have to account for the movement of objects, of course, but with computers, seems like a small hurdle...
deleted 2y ago
[deleted]
gary_0 2y ago
Given that the speed of light is the speed of causality, technically it's not really 420 million years in the "past" in any meaningful sense. The present is relative, not universal. The collected light we see in our telescopes is a lie about a particular universe that will never be, at least in any tangible way. On a cosmic scale, every spot in the universe sees its own unique sequence of events going on around it, all of it rendered virtually immutable by the relative slowness of c. It's a beautiful nightmare, isn't it? https://en.wikipedia.org/wiki/Relativity_of_simultaneity https://en.wikipedia.org/wiki/Relativity_of_simultaneity
- nullwriter 2y ago
  Absolutely mind blowing - I've not thought of this and will be reading about it
  - andrewflnr 2y ago
    Don't think about it too much. It's wrong. Relativity of simultaneity only kicks in when you have reference frames moving at noticeably different velocities. Which is... not entirely wrong in this case due to the expansion of the universe, but would be equally true of a nearby reference frame moving away equally fast. It's nothing to do with light travel time. Ed: I've slipped into the fallacy a bit. Reference frames don't have locations, so they can't be "nearby". Just pretend I said "reference frame of a nearby object".
- conductr 2y ago
  I’ll admit I’m severely undereducated in this stuff, probably less than an average high schooler these day but nevertheless I feel like I’ve considered this before and never knew it had a name. Which makes me feel not completely stupid. > whether two spatially separated events occur at the same time – is not absolute, but depends on the observer's reference frame. But What I don’t understand about this is why is “time” framed as observer based? In my mind, the events do happen at the same time and just are unable to be observed as such. I feel like time is a figment of our imagination, it’s just a measurement. In my pea brain time makes sense more as a constant and the other things are something else that impacts the latency of observance
0xDEAFBEAD 2y ago
It might be possible to build a powerful telescope to see life on planets that are closer to us, though: https://www.palladiummag.com/2024/10/18/its-time-to-build-the-exoplanet-telescope/ https://www.palladiummag.com/2024/10/18/its-time-to-build-th...
- Sander_Marechal 2y ago
  Ohh I love the idea of a massive telescope that's just compromised of thousands of individual satellites!
- Tepix 2y ago
  Or go for the gravitational lens provided by our sun (580 AU out).

vasco 2y ago

In another way it's really cool to be able to "see the past" even if all we see is always the past. At this level it is like a super power. If only some aliens had put a mirror somewhere far so we could see ourselves too. Or multiple mirrors at different distances. With enough mirrors and light bouncing around the size of the universe itself can be a "storage media" of the past with different photons all around carrying "how this location looked X years ago". "All" you have to do to know what happened is find the right photon to see whatever it is you want to see.

steveoscaro 2y ago
Well that sounds like a good premise for a scifi book or movie.
- IngoBlechschmid 2y ago
  https://en.wikipedia.org/wiki/The_Hundred_Light-Year_Diary https://en.wikipedia.org/wiki/The_Hundred_Light-Year_Diary By Greg Egan, so highly recommended.
- densh 2y ago
  You should check out Three Body Problem (the book, not the mediocre netflix adaptation).
  - steveoscaro 2y ago
    I love that book
grahamj 2y ago
You don't need mirrors, you just need to get in front of the photons. A time machine or warp drive will do :) Also the past is the only thing you can perceive, there effectively is no now.
- densh 2y ago
  Is there a science fiction universe that explores a hypothetical warp drive that lets you travel very far relatively quickly, but the travel is only possible with simultaneous backwards time travel that's proportionate to the distance traversed? So you can hop across star systems but can't do a roundtrip A -> B -> A without significantly shifting time from the point of view of A backwards (irreversibly from the point of view of the traveler).
  - zzzr 2y ago
    [dead]
  - grahamj 2y ago
    Consider: - I leave Earth and travel 1ly at speed c - I arrive one year later - An Earth telescope will see the destination as it was when I left - It will take another year to see me arrive So in a way that's already happening because I'm traveling quite quickly - twice as fast as it seems from Earth's perspective - and I arrive in what appears from Earth to be the past.
    - densh 2y ago
      Relativity is so hard to wrap you head around.
ujikoluk 2y ago
For prior art in this field, see: https://github.com/yarrick/pingfs https://github.com/yarrick/pingfs "pingfs is a filesystem where the data is stored only in the Internet itself, as ICMP Echo packets (pings) travelling from you to remote servers and back again." Also https://en.wikipedia.org/wiki/Delay-line_memory https://en.wikipedia.org/wiki/Delay-line_memory Storing data as acoustic waves gave a higher capacity in practice, as propagation is slower thus fitting a larger number of symbol per time unit.
- lloeki 2y ago
  From chainsaws to ICMP echo packets (and more) http://tom7.org/harder/ http://tom7.org/harder/
ConcernedCoder 2y ago
In theory, couldn't we focus on a perfect spot near a black hole where the light has been warped 180 degrees around it... i.e. if the black hole is 100 light years away, you'd see ( with perfect zoom, of course ) a picture of the earth 200 years ago...? I understand that we'd have to account for the movement of objects, of course, but with computers, seems like a small hurdle...

deleted 2y ago

[deleted]

gary_0 2y ago

Given that the speed of light is the speed of causality, technically it's not really 420 million years in the "past" in any meaningful sense. The present is relative, not universal. The collected light we see in our telescopes is a lie about a particular universe that will never be, at least in any tangible way. On a cosmic scale, every spot in the universe sees its own unique sequence of events going on around it, all of it rendered virtually immutable by the relative slowness of c. It's a beautiful nightmare, isn't it? https://en.wikipedia.org/wiki/Relativity_of_simultaneity https://en.wikipedia.org/wiki/Relativity_of_simultaneity

nullwriter 2y ago
Absolutely mind blowing - I've not thought of this and will be reading about it
- andrewflnr 2y ago
  Don't think about it too much. It's wrong. Relativity of simultaneity only kicks in when you have reference frames moving at noticeably different velocities. Which is... not entirely wrong in this case due to the expansion of the universe, but would be equally true of a nearby reference frame moving away equally fast. It's nothing to do with light travel time. Ed: I've slipped into the fallacy a bit. Reference frames don't have locations, so they can't be "nearby". Just pretend I said "reference frame of a nearby object".
conductr 2y ago
I’ll admit I’m severely undereducated in this stuff, probably less than an average high schooler these day but nevertheless I feel like I’ve considered this before and never knew it had a name. Which makes me feel not completely stupid. > whether two spatially separated events occur at the same time – is not absolute, but depends on the observer's reference frame. But What I don’t understand about this is why is “time” framed as observer based? In my mind, the events do happen at the same time and just are unable to be observed as such. I feel like time is a figment of our imagination, it’s just a measurement. In my pea brain time makes sense more as a constant and the other things are something else that impacts the latency of observance

0xDEAFBEAD 2y ago

It might be possible to build a powerful telescope to see life on planets that are closer to us, though: https://www.palladiummag.com/2024/10/18/its-time-to-build-the-exoplanet-telescope/ https://www.palladiummag.com/2024/10/18/its-time-to-build-th...

Sander_Marechal 2y ago
Ohh I love the idea of a massive telescope that's just compromised of thousands of individual satellites!
Tepix 2y ago
Or go for the gravitational lens provided by our sun (580 AU out).