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Um. What? Is this the new "the earth is flat"? Space is infinite. I believe it goes on forever in every direction. Whether you can see whatever is out there fr

Um. What? Is this the new "the earth is flat"? Space is infinite. I believe it goes on forever in every direction. Whether you can see whatever is out there from here in no way proves that it isn't...

crazydoggers 6y ago
That’s not known. This article refers to the observable universe which is bound by the speed of light. Whether the universe is infinite or not is an open question. It might be finite but unbounded. Spacetime geometry is complicated.
- permille42 6y ago
  Neither the title nor the summary say anything about the "observable universe". They make broad claims beyond that. The detail of the article in no way mentions that there could very well be infinite duplicates of what we see out there beyond observable distance.
  - crazydoggers 6y ago
    Because this is an article that’s using the layman terminology. The scientists involved surely understand the difference. In fact read the Wikipedia article and you’ll see the old estimate of 2 trillion for the observable universe. https://en.m.wikipedia.org/wiki/Observable_universe https://en.m.wikipedia.org/wiki/Observable_universe
  - Cederfjard 6y ago
    This is the first sentence in the lead paragraph: >How dark is the sky, and what does that tell us about the number of galaxies in the visible universe?
joering2 6y ago
We have no proof Universe is infinite, but we can also argue that the building blocks of Universe - atoms? - cannot come in unlimited quantity. At least it sounds more reasonable that way. Unless of course we are all in a symultation and our whole Universe takes up half a sq. inch of a silicone chip.
- permille42 6y ago
  This is my point. We have no evidence either way, so it seems strange to me to blindly claim "this is everything".
  - ObjectiveZen 6y ago
    Did you not blindly claim space is infinite? That seems the stranger assumption. If I’m standing in a forest counting all the trees I can see, I’d certainly take into account that there are some trees I can’t see, but I wouldn’t assume there exists an infinite forest of trees.
    - permille42 6y ago
      You're right. The earth is clearly flat and that is a sensible assumption if you haven't left your local area or been in space or seen a picture from space. Or not. Flat earthers are quacks. It is the same principle essentially. It is illogical to think "hey if I keep walking that way I'll hit a wall eventually". That is why flat earthers are quacks from the beginning. The same principle applies to space. What quack seriously thinks that eventually there is just a wall in space or that it wraps around? Wrapping around makes zero sense in 3-dimensional space.
      - perl4ever 6y ago
        The universe appears to be fairly flat, but according to: https://en.wikipedia.org/wiki/Shape_of_the_universe https://en.wikipedia.org/wiki/Shape_of_the_universe ...if the universe was like a "3-torus", it could be both flat and finite: https://en.wikipedia.org/wiki/Three-torus https://en.wikipedia.org/wiki/Three-torus If you ever played the classic game "asteroids", you might remember how everything wrapped around at the edges of the screen. A 3-torus would be like that, only in 3D. On the other hand, one could imagine the universe as a 3-sphere, which I believe would mean it would be both locally curved and finite in volume. https://en.wikipedia.org/wiki/3-sphere https://en.wikipedia.org/wiki/3-sphere There are also other possibilities, like something analogous to a Klein bottle with an extra dimension. There are a bunch of possibilities for "flat and finite" as well as "positively curved and finite" that I can't begin to visualize. There is even supposedly such a (hypothetical) thing as a negatively curved, (commonly described as saddle shaped) yet finite universe. But regardless, the current belief about the real universe is that it is at least very close to flat, but not known to be finite or infinite.
ObjectiveZen 6y ago
Perhaps space is infinite, but that doesn’t necessarily mean there is infinite matter.
sandgiant 6y ago
The set of natural numbers is also infinite. That doesn't mean you can't learn something by counting from 0 to 10. :)

crazydoggers 6y ago

That’s not known. This article refers to the observable universe which is bound by the speed of light. Whether the universe is infinite or not is an open question. It might be finite but unbounded. Spacetime geometry is complicated.

permille42 6y ago
Neither the title nor the summary say anything about the "observable universe". They make broad claims beyond that. The detail of the article in no way mentions that there could very well be infinite duplicates of what we see out there beyond observable distance.
- crazydoggers 6y ago
  Because this is an article that’s using the layman terminology. The scientists involved surely understand the difference. In fact read the Wikipedia article and you’ll see the old estimate of 2 trillion for the observable universe. https://en.m.wikipedia.org/wiki/Observable_universe https://en.m.wikipedia.org/wiki/Observable_universe
- Cederfjard 6y ago
  This is the first sentence in the lead paragraph: >How dark is the sky, and what does that tell us about the number of galaxies in the visible universe?

joering2 6y ago

We have no proof Universe is infinite, but we can also argue that the building blocks of Universe - atoms? - cannot come in unlimited quantity. At least it sounds more reasonable that way. Unless of course we are all in a symultation and our whole Universe takes up half a sq. inch of a silicone chip.

permille42 6y ago
This is my point. We have no evidence either way, so it seems strange to me to blindly claim "this is everything".
- ObjectiveZen 6y ago
  Did you not blindly claim space is infinite? That seems the stranger assumption. If I’m standing in a forest counting all the trees I can see, I’d certainly take into account that there are some trees I can’t see, but I wouldn’t assume there exists an infinite forest of trees.
  - permille42 6y ago
    You're right. The earth is clearly flat and that is a sensible assumption if you haven't left your local area or been in space or seen a picture from space. Or not. Flat earthers are quacks. It is the same principle essentially. It is illogical to think "hey if I keep walking that way I'll hit a wall eventually". That is why flat earthers are quacks from the beginning. The same principle applies to space. What quack seriously thinks that eventually there is just a wall in space or that it wraps around? Wrapping around makes zero sense in 3-dimensional space.
    - perl4ever 6y ago
      The universe appears to be fairly flat, but according to: https://en.wikipedia.org/wiki/Shape_of_the_universe https://en.wikipedia.org/wiki/Shape_of_the_universe ...if the universe was like a "3-torus", it could be both flat and finite: https://en.wikipedia.org/wiki/Three-torus https://en.wikipedia.org/wiki/Three-torus If you ever played the classic game "asteroids", you might remember how everything wrapped around at the edges of the screen. A 3-torus would be like that, only in 3D. On the other hand, one could imagine the universe as a 3-sphere, which I believe would mean it would be both locally curved and finite in volume. https://en.wikipedia.org/wiki/3-sphere https://en.wikipedia.org/wiki/3-sphere There are also other possibilities, like something analogous to a Klein bottle with an extra dimension. There are a bunch of possibilities for "flat and finite" as well as "positively curved and finite" that I can't begin to visualize. There is even supposedly such a (hypothetical) thing as a negatively curved, (commonly described as saddle shaped) yet finite universe. But regardless, the current belief about the real universe is that it is at least very close to flat, but not known to be finite or infinite.

ObjectiveZen 6y ago

Perhaps space is infinite, but that doesn’t necessarily mean there is infinite matter.

sandgiant 6y ago

The set of natural numbers is also infinite. That doesn't mean you can't learn something by counting from 0 to 10. :)