What a mess this article is.
Proving our universe is one among many would be a fourth Copernican revolution
51–58 of 58 posts
Re: Proving our universe is one among many would be a fourth Copernican revolution
#52Earlier quoted context omitted.
According to current cosmological thought, the laws of physics at that shell are very close to if not identical to the laws of physics here. And yet, that shell is retreating from us faster than the speed of light. The shell is ever expanding, but we shall never see what that current shell will look like when it is 10 billion years. How can that be, you ask? It is quite simple. The speed of light is a limit on how fa…
It's also worth noting that, in a sense, the shell is actually shrinking. Every moment, more of our observable universe disappears "beyond the veil", so-to-speak, as the universe on our side of the edge transitions from near-light-speed to beyond light-speed outside the shell. (I know that's a sloppy way to use the speed of light, but it works for me.)
Small nitpick, that shell---the Hubble sphere---is shrinking due the accelerating expansion of space. Constant expansion cooresponds to a constant Hubble radius, and decelerating expansion with an expanding radius.
Re: Proving our universe is one among many would be a fourth Copernican revolution
#53> At first sight, the concept of parallel universes might seem too arcane to have any practical impact. But it may (in one of its variants) actually offer the prospect of an entirely new kind of computer: the quantum computer, which can transcend the limits of even the fastest digital processor by, in effect, sharing the computational burden among a near infinity of parallel universes. I'm far from an expert on quant…
I think the allusion is quantum mechanics -> many worlds interpretation -> quantum computers are executing in parallel universes. But quantum computers get their abilities from the quantum states and quantum operators, neither of which require any particular interpretation of quantum mechanics.
If we can form arbitrary size superposition we can put the universe in superposition - many worlds. If we cannot - limit to how big quantum computers we can build.
Re: Proving our universe is one among many would be a fourth Copernican revolution
#54Earlier quoted context omitted.
For now we can just by waiting. With every second we see just a little further. Tomorrow we might look out at the stars and see the tips of giant teeth. But, probably not.
You don't quite understand the concept of a light cone. Yes, we get new data all the time, and the extent of our horizon is growing. But it is always finite . You cannot look backwards past the big bang singularity, and you cannot look forwards beyond "now" for any value of "now".
No, you fail to understand a light cones end at finite points. If I travel 1 light year, then I observe a different light cone and it takes 1 year for somone that stayed behind to receive information from me. This effectively means you can see something before the light cone at your current location would observe it.
If you consider a light cone as all points out to infinity then that’s the entire universe. Instead at each point in time you have a different light cone that extends to the age of the universe.
In theory we can never see past a second limit based on the expansion of the universe, but that’s yet to be observed speculation without any consistent theory of what’s going on.
Re: Proving our universe is one among many would be a fourth Copernican revolution
#55The middle of the article reminded me of Asimov: The last question was asked for the first time, half in jest, on May 21, 2061, at a time when humanity first stepped into the light. The question came about as a result of a five dollar bet over highballs, and it happened this way... http://www.multivax.com/last_question.html
It always interested me that this could be Asimov's (1956) response to Arthur C Clarke's (1953), 9 Billion Names of God, where the stars went out.
Your comment led me to search for the latter title, if I could read it online. Instead, I found the following project. http://ninebillionnamesofgod.com/index.html
Re: Proving our universe is one among many would be a fourth Copernican revolution
#56> At first sight, the concept of parallel universes might seem too arcane to have any practical impact. But it may (in one of its variants) actually offer the prospect of an entirely new kind of computer: the quantum computer, which can transcend the limits of even the fastest digital processor by, in effect, sharing the computational burden among a near infinity of parallel universes. I'm far from an expert on quant…
Similarly, by the copernican principle, wouldn't our "local" quantum computer also then be burdened by the work being sent from a near infinity of parallel universes?
I think the answer to that is no and the reason involves entropy. Of all the possible universes most have very low probability, so when we "create" a bunch of parallel universes for our computer, those universes could already be existing which would interfere with the calculating (not in the sense of slowing it down because of too many things running on it, more like a radio channel with lots of interference from nearby channels), but this won't happen in practice as these universes will have very low corresponding probability.
On the other hand there is self interference, from poor engineering of the computer. I think this is a very significant problem now - but it will usually be described in terms of decoherence.
Re: Proving our universe is one among many would be a fourth Copernican revolution
#57Earlier quoted context omitted.
They couldn't transmit such a message; the part beyond "the wall" is moving away faster than light: the data would never reach us. From our perspective, their earlier era is "frozen" in time: red-shifted to zero. We cannot receive any "new" signal from them. Therefore, the seeming "faster than light" violation is not really the case. Relativity "fixes" it by mucking around with time. From a practical perspective, the…
> the part beyond "the wall" is moving away faster than light: the data would never reach us To nitpick, the wall itself is moving away at about one light-year per year. The photons that are not moving from our perspective because they are receding away from us at the speed of light will soon find themselves in a space where they are again moving towards us. "we routinely observe galaxies that have, and always have h…
Are you sure about that? While there may be a "neutral zone" where that's the case, it's only a small percent of the stuff that's beyond our senses.
Re: Proving our universe is one among many would be a fourth Copernican revolution
#58Earlier quoted context omitted.
It's also worth noting that, in a sense, the shell is actually shrinking. Every moment, more of our observable universe disappears "beyond the veil", so-to-speak, as the universe on our side of the edge transitions from near-light-speed to beyond light-speed outside the shell. (I know that's a sloppy way to use the speed of light, but it works for me.)
Small nitpick, that shell---the Hubble sphere---is shrinking due the accelerating expansion of space. Constant expansion cooresponds to a constant Hubble radius, and decelerating expansion with an expanding radius.
Good point, thank you.