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3 votes
Accepted

Another universe due to a rogue wave fluctuation

It's exactly that scenario is mentioned in wiki, on universe heat death : It is suggested that, over vast periods of time, a spontaneous entropy decrease would eventually occur via the Poincaré ...
Agnius Vasiliauskas's user avatar
2 votes
Accepted

Could the universe have a form of a $T^3$-torus?

A universe with toroidal spatial surfaces is not in obvious conflict with general relativity, which is a local theory. Nor is it in conflict with the FLRW solution, which is separately applicable to ...
Sten's user avatar
  • 4,735
-1 votes

Is observable universe an explanation against Olbers' paradox?

Olbers posed the supposed paradox in 1823. It wasn't until more than a century later that interstellar extinction, or the attenuation of light due to non-luminous matter absorbing photons, was ...
pygosceles's user avatar
-1 votes

The inner workings of the Olbers paradox

Answers ignoring the effect of interstellar matter, modeled here by the Beer-Lambert attenuation law, are incorrect. The assertion that Olbers's Paradox proves a finite size of the universe is ...
pygosceles's user avatar
3 votes
Accepted

Cosmic web shape

It looks like a neutral net: It should be random on the largest scale, but there is clearly structure from dynamic interactions on large scales. You really can't say what it would look if it looked ...
JEB's user avatar
  • 33k
1 vote

Why does the total gravitational potential in the universe exactly equal the total mass energy RIGHT NOW?

First of all, it's extremely difficult to even define the total energy of the universe, and all sorts of different features (dark energy, dark matter, the energy of the cosmic microwave background, ...
Eric Smith's user avatar
  • 8,958
2 votes

Does going to the other side of Milky Way galaxy mean seeing different observable universe?

Keep in mind that the observable universe is growing at the speed of light, as more and more light is able to reach us over time. If you sent a probe to some distant location, it would indeed see a ...
Sten's user avatar
  • 4,735
1 vote

Does going to the other side of Milky Way galaxy mean seeing different observable universe?

As long as you took account of the journey time (hundreds of thousands of years) then the CMB would look the same from the other side of our galaxy as it does from Earth. The size of our galaxy is ...
gandalf61's user avatar
  • 51.7k
0 votes

Solve Friedmann equation for non-zero curvature and non-zero cosmological constant

Assuming that $\rho$ is a function of $R$ only and does not explicitly depend on time, we can write $$\dot{R}= \frac{dR}{dt} = \sqrt{\frac{8\pi G}{3c^2} \rho(R) R^2 - kc^2 + \frac{c^2\Lambda}{3} R^2}$$...
Lenard Kasselmann's user avatar
1 vote
Accepted

Can we measure temperature in an isothermal Universe?

Recording an experimental result generates entropy. In a perfectly isothermal universe at maximum entropy, this is impossible. Thus no experiment of any kind is theoretically possible in such a ...
John Doty's user avatar
  • 20.5k
1 vote

Can we measure temperature in an isothermal Universe?

If by "isothermal universe" you mean the state like in the "heat death of the universe", then no, because there is no thermometer, only chaotic, feature-less, gas-like system. But ...
Ján Lalinský's user avatar
-1 votes

The Universe as a four-dimensional sphere?

The universe can be modelled extremely well as a 3-sphere expanding at the speed of light. The 3-sphere is the surface of a 4-dimensional ball of spacetime. This makes many correct predictions and ...
John Hobson's user avatar

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