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Wonder if they also explored the possibility that we are in a black hole and the universe structure is recursive. Maybe the background radiation is the part of

Wonder if they also explored the possibility that we are in a black hole and the universe structure is recursive. Maybe the background radiation is the part of the hawking radiation that falls inward. And we perceive it infinite but it’s the dilatated space between the hevent horizon and the naked singularity at the center. And the big bang was the supernova that left the black hole. Trippinng!

dlwdlw 9y ago
I like this thought
hliyan 9y ago
That's a very interesting idea! Although, if the cosmic background radiation is the hawking radiation falling back toward the event horizon, where is the residual radiation left behind by the supernova (because in the traditional interpretation, CMB the afterglow of the big bang).
garmaine 9y ago
We are in a black hole. The event horizon of the entire universe is on the same order as the observable universe. We are inside the black hole of the universe.
- heavenlyblue 9y ago
  What?
  - joshlemer 9y ago
    The grandparent may be referring to the cosmic event horizon. https://en.wikipedia.org/wiki/Event_horizon#Cosmic_event_horizon https://en.wikipedia.org/wiki/Event_horizon#Cosmic_event_hor...
    - garmaine 9y ago
      Yes-ish. There are two reasons we are living inside an event horizon. First the accelerating expansion of the universe means that light emitted from earth now will never reach most of the observable universe. We can look up and see galaxies that are already beyond our cone of influence. That is the primary effect. But a secondary effect is that the mass of the universe (Big Bang remains) is sufficient even though not dense as to bend light emitted from it back onto a closed trajectory. So if there is any void beyond the cosmos that we see , observers in that void would see us—our entire observable universe—as a black hole.
      - raattgift 9y ago
        No, respectfully, not unless you radically redefine what you mean by "black hole". If by "black hole" you mean an object sourcing a Kerr-Newman-like metric, then you have the problem that the distribution of matter in the distribution we see is not at all like the interior region of such a metric. The metric one can infer from the bulk distribution of the visible matter is best described by a Robertson-Walker metric. Under time-reversal, galaxies in R-W fall through each observer-centric horizon, break up into dust and gas that in turn combines into denser higher-energy and lower-entropy states. While this might seem a little like a "white hole" (defined as a time-reversed BH), since under time-reversal a stellar BH has Hawking radiation rush into its vicinity becoming relatively dense at the time of the bust-up of the BH horizon, the difference is on the other side of that point a much lower entropy neutron star or similar body emerges from the high-entropy BH. Even stepping back a bit, macroscopically, galaxies are a lot more structured than either Hawking radiation; nor is Hawking radiation more structured than the cold relic fields crossing into optical detectability of an observer in time-reversed RW or time-reversed asymptotic de Sitter space. This is important: the densest phase of a universe like ours is (extremely) low entropy, while the densest phase of the black hole is (extremely) high entropy, especially if we measure just at their respective horizons. Entropy here is Boltzmannian: the log relationship between the observed macrostates and microstates that can produce them. (We could even test this directly by comparing the structures in the relic fields with Hawking radiation if we were to find sufficiently low-mass astrophysical black holes; we can however get some details from the ringing modes of BH mergers). Additionally, we can consider curvature. The extremely low bound on our universe's Weyl curvature allowed by indirect and direct gravitational wave observations (so far) completely precludes a Kerr-Newman-like solution, where Weyl curvature will be very large. Our imaging of ever older galaxies does not reveal them to be spaghettified. Finally, it's worth noting that while Kerr-Newman and Robertson-Walker can have optical horizons so can many other solutions. For example, there are optical horizons in the Gödel solution but we obviously aren't in a Gödel universe. There are also many solutions which cannot have optical horizons; a torus or Klein bottle universe is clearly different from a Euclidean one, although all of those can be everywhere flat and horizon-free. So I don't think one should promote the presence of optical horizons into the defining characteristic of a metric.
- yaks_hairbrush 9y ago
  There a germ of the right idea here, but our universe is really more of a black hole backwards. Within the event horizon of a black hole, the singularity is always in the future. Within our universe, we see a singularity in our past. In short, our universe looks more like a white hole than a black hole.
  - evincarofautumn 9y ago
    Couldn’t we just be perceiving time backward? I’m no physicist, but AIUI the equations work either way. As a sci-fi–head, sometimes I just like to speculate—“What if the ‘point’ of the universe is the singularity of the big bang?” (Yeah, pun intended.) If we’re in a simulation, maybe it’s the final result of the computation. If we’re in a black hole, maybe it’s in the past of the universe within, but in the future of the one without. All good material for a short story, one of these days…
  - garmaine 9y ago
    Black hole does not imply singularity.
    - tigershark 9y ago
      Why not? You can’t have a black hole without a singularity. A black hole is formed only when >3 solar masses collapse in a singularity. Maybe the opposite is theoretically possible, the so called naked singularity in which a singularity is not hidden by an event horizon.
      - garmaine 9y ago
        A black hole is a region that light cannot gravitationally escape. It has nothing to do with singularities which often but not always exist inside of a black hole. Small black holes often have singularities just to have enough mass density to capture light. It is not required though — imagine a binary system of two neutron stars that are each just below the mass threshold to collapse into a singularity. It would be a black hole to external observers. Oddly larger black holes require less mass density. More oddly still as you approach the size of the observable universe, the required mass density crosses the cosmic mass density, meaning light emitted from Earth cannot gravitationally escape the universe created by the Big Bang, meaning we exist inside of a black hole as big as the observable universe. I’m not sure why I’m being so heavily down voted for stating this fact you can find in any cosmology textbook.
neilsimp1 9y ago
I've always liked toying with the idea (in my own head, not an astrophysicist) that space is cyclical, or in your words, recursive. I love animations where it zooms out farther and farther into space, until it gets to the point where galaxies start to resemble molecular structures. And then of course The Simpson's did a couch gag where exactly this happens and they zoom out and out into space until it finally zooms out of Homer's own head.
- v_lisivka 9y ago
  Drop me line at vlisivka@gmail.com if you want to talk further about that.
- pbhjpbhj 9y ago
  Learning of atoms initially I was given an orbital model, like a solar system, who caused/allowed me to form a similar idea (I think it's quite common?) that solar systems could be atoms in a super-universe. I was so annoyed as a teenager to find that atoms aren't really little solar systems.
  - samstave 9y ago
    When I was ten years old I was meditating and thinking about how each one our consciences are a neuron in gods brain... I will never forget that epiphany as it was before I had studied any philos etc
v_lisivka 9y ago
We are inside of infinite number of recursive black holes. We are inside infinite number of Homer heads. But we are too small to view whole picture even for level above.

dlwdlw 9y ago

I like this thought

hliyan 9y ago

That's a very interesting idea! Although, if the cosmic background radiation is the hawking radiation falling back toward the event horizon, where is the residual radiation left behind by the supernova (because in the traditional interpretation, CMB the afterglow of the big bang).

garmaine 9y ago

We are in a black hole. The event horizon of the entire universe is on the same order as the observable universe. We are inside the black hole of the universe.

heavenlyblue 9y ago
What?
- joshlemer 9y ago
  The grandparent may be referring to the cosmic event horizon. https://en.wikipedia.org/wiki/Event_horizon#Cosmic_event_horizon https://en.wikipedia.org/wiki/Event_horizon#Cosmic_event_hor...
  - garmaine 9y ago
    Yes-ish. There are two reasons we are living inside an event horizon. First the accelerating expansion of the universe means that light emitted from earth now will never reach most of the observable universe. We can look up and see galaxies that are already beyond our cone of influence. That is the primary effect. But a secondary effect is that the mass of the universe (Big Bang remains) is sufficient even though not dense as to bend light emitted from it back onto a closed trajectory. So if there is any void beyond the cosmos that we see , observers in that void would see us—our entire observable universe—as a black hole.
    - raattgift 9y ago
      No, respectfully, not unless you radically redefine what you mean by "black hole". If by "black hole" you mean an object sourcing a Kerr-Newman-like metric, then you have the problem that the distribution of matter in the distribution we see is not at all like the interior region of such a metric. The metric one can infer from the bulk distribution of the visible matter is best described by a Robertson-Walker metric. Under time-reversal, galaxies in R-W fall through each observer-centric horizon, break up into dust and gas that in turn combines into denser higher-energy and lower-entropy states. While this might seem a little like a "white hole" (defined as a time-reversed BH), since under time-reversal a stellar BH has Hawking radiation rush into its vicinity becoming relatively dense at the time of the bust-up of the BH horizon, the difference is on the other side of that point a much lower entropy neutron star or similar body emerges from the high-entropy BH. Even stepping back a bit, macroscopically, galaxies are a lot more structured than either Hawking radiation; nor is Hawking radiation more structured than the cold relic fields crossing into optical detectability of an observer in time-reversed RW or time-reversed asymptotic de Sitter space. This is important: the densest phase of a universe like ours is (extremely) low entropy, while the densest phase of the black hole is (extremely) high entropy, especially if we measure just at their respective horizons. Entropy here is Boltzmannian: the log relationship between the observed macrostates and microstates that can produce them. (We could even test this directly by comparing the structures in the relic fields with Hawking radiation if we were to find sufficiently low-mass astrophysical black holes; we can however get some details from the ringing modes of BH mergers). Additionally, we can consider curvature. The extremely low bound on our universe's Weyl curvature allowed by indirect and direct gravitational wave observations (so far) completely precludes a Kerr-Newman-like solution, where Weyl curvature will be very large. Our imaging of ever older galaxies does not reveal them to be spaghettified. Finally, it's worth noting that while Kerr-Newman and Robertson-Walker can have optical horizons so can many other solutions. For example, there are optical horizons in the Gödel solution but we obviously aren't in a Gödel universe. There are also many solutions which cannot have optical horizons; a torus or Klein bottle universe is clearly different from a Euclidean one, although all of those can be everywhere flat and horizon-free. So I don't think one should promote the presence of optical horizons into the defining characteristic of a metric.
yaks_hairbrush 9y ago
There a germ of the right idea here, but our universe is really more of a black hole backwards. Within the event horizon of a black hole, the singularity is always in the future. Within our universe, we see a singularity in our past. In short, our universe looks more like a white hole than a black hole.
- evincarofautumn 9y ago
  Couldn’t we just be perceiving time backward? I’m no physicist, but AIUI the equations work either way. As a sci-fi–head, sometimes I just like to speculate—“What if the ‘point’ of the universe is the singularity of the big bang?” (Yeah, pun intended.) If we’re in a simulation, maybe it’s the final result of the computation. If we’re in a black hole, maybe it’s in the past of the universe within, but in the future of the one without. All good material for a short story, one of these days…
- garmaine 9y ago
  Black hole does not imply singularity.
  - tigershark 9y ago
    Why not? You can’t have a black hole without a singularity. A black hole is formed only when >3 solar masses collapse in a singularity. Maybe the opposite is theoretically possible, the so called naked singularity in which a singularity is not hidden by an event horizon.
    - garmaine 9y ago
      A black hole is a region that light cannot gravitationally escape. It has nothing to do with singularities which often but not always exist inside of a black hole. Small black holes often have singularities just to have enough mass density to capture light. It is not required though — imagine a binary system of two neutron stars that are each just below the mass threshold to collapse into a singularity. It would be a black hole to external observers. Oddly larger black holes require less mass density. More oddly still as you approach the size of the observable universe, the required mass density crosses the cosmic mass density, meaning light emitted from Earth cannot gravitationally escape the universe created by the Big Bang, meaning we exist inside of a black hole as big as the observable universe. I’m not sure why I’m being so heavily down voted for stating this fact you can find in any cosmology textbook.

neilsimp1 9y ago

I've always liked toying with the idea (in my own head, not an astrophysicist) that space is cyclical, or in your words, recursive. I love animations where it zooms out farther and farther into space, until it gets to the point where galaxies start to resemble molecular structures. And then of course The Simpson's did a couch gag where exactly this happens and they zoom out and out into space until it finally zooms out of Homer's own head.

v_lisivka 9y ago
Drop me line at vlisivka@gmail.com if you want to talk further about that.
pbhjpbhj 9y ago
Learning of atoms initially I was given an orbital model, like a solar system, who caused/allowed me to form a similar idea (I think it's quite common?) that solar systems could be atoms in a super-universe. I was so annoyed as a teenager to find that atoms aren't really little solar systems.
- samstave 9y ago
  When I was ten years old I was meditating and thinking about how each one our consciences are a neuron in gods brain... I will never forget that epiphany as it was before I had studied any philos etc

v_lisivka 9y ago

We are inside of infinite number of recursive black holes. We are inside infinite number of Homer heads. But we are too small to view whole picture even for level above.