What Shape Is the Universe, Closed or Flat?
quantamagazine.org
What Shape Is the Universe, Closed or Flat?
1–10 of 27 posts
Re: What Shape Is the Universe, Closed or Flat?
#2Atheists are going to have a hard time if it turns out the Universe is shaped like a giant Pikachu :-)
Some models suggest our universe is just one "foam-bubble" in a big ocean of universes. Hell, the mole on your face may contain its own universes. It really could be "turtles all the way down", or Pikachus all the way down.
https://www.vice.com/en_us/article/j5yngp/the-universe-is-ma...
Because of our Earthly experience, we tend to assume there's an absolute limit to the quantity of "stuff", but perhaps that's not true: there is infinite stuff, we just can't touch most of it.
Re: What Shape Is the Universe, Closed or Flat?
#3The bubble shape makes much more sense to me than the linear plane shape. Whatever the truth is, the most accepted model today is most likely wrong;
Re: What Shape Is the Universe, Closed or Flat?
#4Time for Einstein Gravity Probe C.
Einstein suggested we could directly measure the curvature of the universe by comparing distances between probes located at angles to each other.
They would need to be pretty far apart from each other for this to work, but they can be very small: just an RTG and an antenna.
So hopeful light enough to build up an enormous velocity.
Re: What Shape Is the Universe, Closed or Flat?
#5Time for Einstein Gravity Probe C. Einstein suggested we could directly measure the curvature of the universe by comparing distances between probes located at angles to each other. They would need to be pretty far apart from each other for this to work, but they can be very small: just an RTG and an antenna. So hopeful light enough to build up an enormous velocity.
For the satellites to communicate to each other they need some combination of a powerful transmitter and a large receiving antenna, so that puts a limit on just how small they can be.
Re: What Shape Is the Universe, Closed or Flat?
#6Time for Einstein Gravity Probe C. Einstein suggested we could directly measure the curvature of the universe by comparing distances between probes located at angles to each other. They would need to be pretty far apart from each other for this to work, but they can be very small: just an RTG and an antenna. So hopeful light enough to build up an enormous velocity.
For the satellites to communicate to each other they need some combination of a powerful transmitter and a large receiving antenna, so that puts a limit on just how small they can be.
I was thinking a laser rather than radio. In radio terms: very very high gain.
The receiver can be a mylar reflecting dish, which would be lightweight.
Use a gyroscope to steer the entire probe (both for transmitting and receiving).
They only need to communicate very very sporadically, and you only need a single bit of data transmitted (amongst each other).
Make some kind of schedule where the probes face each other, measure distance (i.e. time between send and reply), then steer toward the next probe.
To earth you would basically use Hubble to read the data (and let each probe send duplicate data back to earth).
Re: What Shape Is the Universe, Closed or Flat?
#7Time for Einstein Gravity Probe C. Einstein suggested we could directly measure the curvature of the universe by comparing distances between probes located at angles to each other. They would need to be pretty far apart from each other for this to work, but they can be very small: just an RTG and an antenna. So hopeful light enough to build up an enormous velocity.
You are right but this has already been done using the CMB data and the universe seems flat with a 0.4% uncertainty. I don't think there is any need for artificial probes for it.
Source: https://arxiv.org/abs/1502.01589
Re: What Shape Is the Universe, Closed or Flat?
#8Seems like it would have to be open since the boundaries are permanently expanding. The set can’t contain its accumulation points if new points will always be created. Granted, infinite sets like aleph-0 and -1 are typically considered both open and closed, iirc. Been a while since I took topology.
Re: What Shape Is the Universe, Closed or Flat?
#9Seems like it would have to be open since the boundaries are permanently expanding. The set can’t contain its accumulation points if new points will always be created. Granted, infinite sets like aleph-0 and -1 are typically considered both open and closed, iirc. Been a while since I took topology.
I'm pretty sure when the article says 'closed' the really mean 'compact' in the topological sense.
If you have a topological space, the entire space is always both open and closed. https://en.wikipedia.org/wiki/Topological_space#Definition_v...
Re: What Shape Is the Universe, Closed or Flat?
#10Atheists are going to have a hard time if it turns out the Universe is shaped like a giant Pikachu :-) Some models suggest our universe is just one "foam-bubble" in a big ocean of universes. Hell, the mole on your face may contain its own universes. It really could be "turtles all the way down", or Pikachus all the way down. https://www.vice.com/en_us/article/j5yngp/the-universe-is-ma... Because of our Earthly experi…
What's up with the Pikachu references? I don't get the joke.