The existence of parallel universes may seem like something cooked up by science fiction writers, with little relevance to modern theoretical physics. But the idea that we live in a “multiverse” made up of an infinite number of parallel universes has long been considered a scientific possibility – although it is still a matter of vigorous debate among physicists. The race is now on to find a way to test the theory, including searching the sky for signs of collisions with other universes.
It is important to keep in mind that the multiverse view is not actually a theory, it is rather a consequence of our current understanding of theoretical physics. This distinction is crucial. We have not waved our hands and said: “Let there be a multiverse”. Instead the idea that the universe is perhaps one of infinitely many is derived from current theories like quantum mechanics and string theory.
The universes predicted by string theory and inflation live in the same physical space (unlike the many universes of quantum mechanics which live in a mathematical space), they can overlap or collide. Indeed, they inevitably must collide, leaving possible signatures in the cosmic sky which we can try to search for.
Whether we will ever be able to prove their existence is hard to predict. But given the massive implications of such a finding it should definitely be worth the search.
(Score: 2) by Zz9zZ on Thursday September 03 2015, @08:21PM
I do like these thought experiments, and if they can manage some real experiments that'd be pretty great. However, since we don't even understand gravity fully I think hopping to the multiverse is a bit of a stretch. Headline grabbing journalism courtesy of some over-excited scientists.
Whether we're in a multiverse or not, at least their research is pushing the bounds of human knowledge farther out.
~Tilting at windmills~
(Score: 2) by Mr Big in the Pants on Thursday September 03 2015, @08:40PM
I also love how he refers to it not just being a consequence of "maths" but a consequence of "theoretical physics" and then refers to string theory...
...which current almost exclusively resides in the realm of mathematics with little if any experimentation backing it up.
This is a complete load of hog wash. It reads as if it is a lame PR attempt to bolster bad press or something?!
(Score: 2) by Zz9zZ on Thursday September 03 2015, @09:34PM
Yeah, although he referenced quantum mechanics as well. The article is not a waste, just a layman's intro to the multiverse concept with the news that they may be able to experimentally test for it. At worst just driving web traffic, but it was well written.
~Tilting at windmills~
(Score: 0) by Anonymous Coward on Thursday September 03 2015, @11:32PM
Fuck the Journal of Quantum Physics, I get my quantum cosmology information from theconversation.com.
(Score: 5, Interesting) by VortexCortex on Thursday September 03 2015, @10:36PM
I do like these thought experiments, and if they can manage some real experiments that'd be pretty great.
Well, technically this universe is our only currently possible experiment. The tests are already being conducted. Some researchers have identified at least four possible footprints of collisions with another universe in our cosmic microwave background radiation, [quantamagazine.org] but will need correlation from even higher resolution data before the signal is strong enough to make an affirmative statement scientifically.
So, yes, it is pretty great that we're managing to perform some real experiments in this universe -- That is to say: We're lucky that entropy in this universe is low enough to allow for meaningful structures to last long enough for complex organisms to emerge and therefore for science itself to be possible -- of course, according to the Anthropic Principal, said observations are only made in universes where they're possible. The interesting thing to think about, IMO, is that this universe might NOT have been one conducive to our existence until after a universal collision occurred (apart from the one that may have ignited our big bang). Just look at inflationary period, then WHAM it slows down... If I were a sufficiently powerful overseer I might even try to configure matter at a grand scale in order to imprint the pattern of life upon my universe itself such that were it to collide with other universes, even after my universe's heat death, it would copy the equation of meaningful existence therein, or at least set up the proper initial conditions required, or at the very least add the proper amount of randomness to the otherwise uniform radiation such that complexity in the form of stars and galaxies could form. One experiment down, a possibly unbounded number to go...
It could be that there is too much chaos in the sky to detect past collisions, or hypothetical imprinted messages from other universes beyond. That would be disappointing, but that level of chaos may turns out to be the reason we're able to be thinking organisms instead of less complex crystals -- or at least why we exist at the scale we do (where the chaos to order ratios are just right for life). Life needs a certain amount of randomness in its structure, thus error tolerance/correction is key. By the grace of His noodly appendage in our holy scriptures is writ, RFC1122:1.2.2, "Be liberal in what you accept, and conservative in what you send".
Ramen, and may you go with Arxiv. [arxiv.org]
(Score: 2) by Zz9zZ on Thursday September 03 2015, @11:02PM
I think you missed your calling as a philosopher ;)
My point was that the hypothesis ventures too far past our current scientific knowledge. Astronomers may find proof of the multiverse only later to find out that our theory of gravity is incomplete, and the updated version explains the observations. It feels like trying to understand superconductivity before fully grasping basic electricity.
Since we're updating our theory of the atom http://phys.org/news/2015-08-theory-radiationless-revolution.html [phys.org] I think it is safe to say solving the grand mystery of the universe may be a tad ambitious (though don't let my hesitation stop anyone! :D ). Not trying to be a buzz-kill, trying to add a little grounding to the conversation.
~Tilting at windmills~
(Score: 2) by urza9814 on Friday September 04 2015, @05:55PM
On the other hand, if astronomers *aren't* searching for proof of the multiverse, they might not find the data which could lead to that updated theory of gravity.
This isn't a video game where you get the entire tech tree laid out before you and you just have to choose where to go. If we really knew with any certainty where the research was going to lead, we wouldn't need to research it! :)