In this installment of Weird Science, we're going to explore the universe — its nature, its past, present and future, and the strange science that tries to describe it all — with the strongest evidence yet that everything we see around us is simply a hologram, a study about how time may have no beginning or end in a 'rainbow' universe, and another study that shows the universe may collapse around us at any moment (or then again, it may not)...
Physicists give strongest evidence yet of holographic universe
So, when we deal with the universe on an every-day basis, it's in four dimensions — the length, width and height of space, and time. When physicists try to describe the behaviour of the universe, string theory introduces another six dimensions on top of that, but some recent ideas are simplifying things again, by saying that everything that goes on in the universe (4-D or 10-D) might actually be information on a two-dimensional surface at the edges of the cosmos.
Theoretical physicist Brian Greene gives a great short talk about the concept in this video:
Although plenty of physicists consider the holographic universe to be fairly likely, they haven't yet been able to show that is, without a doubt, what's happening. Now, though, two different scientific papers (here and here) are providing some pretty compelling evidence. They both look at black holes, but from two different perspectives — one using string theory and quantum gravity, and one looking at it from the two-dimensional model without gravity. In both instances, the computations of the internal energy of the black hole turned out to be the same.
The models used in the papers were simplified, apparently, but Juan Maldacena, the physicist who first proposed the holographic universe idea back in 1997, seems impressed by their findings. According to Nature, he has the hope that studies like these can lead us to a point where we can describe the entire universe just using quantum mechanics.
Does this affect our day-to-day lives? Well, no, not really. The concept of a holographic universe doesn't say that reality isn't real, or that it doesn't have consequences. It's just saying that all the actual 'action' of the universe happens much deeper down than we can perceive, and the hologram is just how we are able to perceive and relate to that action.
Pretty cool, huh?
In a 'rainbow' universe, there is no beginning and no end
Here's another mind-bender caused by the vastly different ways that Einstein's theories and quantum mechanics treat the universe.
Due to a concept called 'rainbow gravity', time may have had no beginning, and it may never end. The 'rainbow' part of this stems from the idea that different wavelengths of light, from gamma rays to radio waves, all experience gravity differently. So, based on their energy, photons of light travel through space along different paths. Now, this effect would be very, very small, so that we wouldn't notice it just by scanning the universe, but when it comes to extremely powerful events, like gamma ray bursts emitted from the cataclysmic explosion of a massive star, it's possible we could see this difference show up.
What's the implication of this? Well, if different wavelengths of light travel along different paths through the universe, tracing the universe backwards in time reveals two different possibilities in the distant past. Either the universe crunched down to nearly-infinite density, or it just got pressed together into some very high density. It doesn't ever reach the infinite-density 'singularity' predicted by the big bang theory. So, rather than the universe (and thus time) having a beginning, we may have expansions and contractions of space, but time just stretches back to infinity and stretches forward into infinity. Furthermore, the universe will look very different based on where you are in it. If we could communicate with aliens living far away, in a distant galaxy, we wouldn't be able to agree on where things are that lie between us.
There's no evidence yet that shows that's what's actually happening (and there are some critics who say the idea has nothing whatsoever to do with reality), but it's an interesting thing to contemplate.
The universe may collapse at any moment, but then again...
By now, we've probably all heard of the Higgs field and the Higgs particle (if you haven't, click here). Well, there's been some amazing discoveries about both the field and the boson over the past year or so, but it appears as though the field may spell the doom of us all. Oh, it's nothing that we'll be doing with it, so don't worry about the Large Hadron Collider. It's just that if a bubble happens to form in the the Higgs field, and that bubble happens to have a lower energy than the rest of the field, and if that bubble is big enough, it will expand in all directions at the speed of light and eventually engulf the entire universe.
Anything that the bubble envelopes as it expands will suddenly become billions of times heavier than it was before the bubble formed, and this will cause it all matter to crush together and the universe will collapse.
According to Jens Frederik Colding Krog, a PhD student at Denmark's Center for Cosmology and Particle Physics Phenomenology, a collapse may have already happened somewhere in the universe. One could be starting now, either here or far away, or one could start somewhere, billions of years from now. Noone knows. However, one thing the calculations he and his colleagues have done shows that a collapse is now more likely than ever before.
Don't panic, though. Their calculations depend on the universe having only the elementary particles that science knows about today. If researchers find any new ones, or if they show that the Higgs particle is made up of even smaller particles (and it could be made of ones called 'techni-quarks'), the entire idea collapses instead.
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Keep your eyes on the wonders of science, and if you spot anything particularly strange you'd like me to check out for next week, comment below or drop me a line on Twitter!
(Images courtesy: Wikimedia Commons)
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