Spacetime analogs is an emerging field of physics in which scientists investigate systems having mathematical links with general relativity, and test their theories about the early behavior of the universe. The latest in a series of such experiments is one that uses spacetime analogs to model the end of time theory, dubbed the “Big Crunch,” at which the universe is predicted to contract and eventually collapse into a black hole.

An example of a spacetime analog is the behaviour of light in electromagnetic space, which is mathematically analogous to its behavior in spacetime. Recent developments have enabled scientists to use metamaterials to manipulate electromagnetic space and create electromagnetic analogs to the multiverse, quantum foam and the big bang.

Now University of Maryland visiting research scientist Igor Smolyaninov and colleagues have developed an experiment using metamaterials to model the end of time.

Metamaterials can be manipulated and forced to behave as various analogs, such as a system with two dimensions of space and one of time, or one with one dimension of space and two of time. The experiments designed by Smolyaninov and colleagues used a metamaterial comprising stripes of polymethyl methacrylate (PMMA), which were deposited on a gold film.

Laser light traveling through the metamaterial is described by mathematical equations that are used to describe space and time. In the gold film the movement of photon-electron waves (plasmons) followed the equations representing a universe with two space dimensions and one time dimension, but in the metamerial they followed the equations of a universe with one space dimension and two time dimensions In the “end of time” experiment the photons became very hot, experiencing a sudden rise in energy and frequency, described as a “higher harmonic generation.”

Smolyaninov analyzed what happened when the metamerial was placed at various orientations to the gold and discovered that if they were placed end on, with a space dimension perpendicular to a time dimension, time stops, which is essentially a simulation of “end of time”.

When the metamaterial boundary is perpendicular to the “space-like direction” the scientists observed a Rindler horizon, which produces Hawking radiation. If it is perpendicular to the “time-like direction” time ends. The electromagnetic field diverges at the interface between the two materials.

The experiment is described in the July 20 edition of arXiv, the physics preprint journal. Future experiments planned include adding quantum dot semiconductors to a metamaterial to allow the researchers to simulate the center of a black hole and look for an analog for Hawking radiation, predicted to exist at the edge of black holes.

**Explore further:**
Who cares about the fourth dimension?

**More information:**
Hyperbolic metamaterial interfaces: Hawking radiation from Rindler horizons and the "end of time" arxiv.org/abs/1107.4053

## hemitite

## emsquared

## Darkboy

Because, like many end-of-time theories, it is speculation. According to inflation (the most accepted model in the community), the rate of expansion was very high at the first moments of the universe, then it slowed down and it is going through an upward slope again. Maybe it will be slowed to the point where gravity will dominate and the whole universe will contract itself to another "singularity", similar to that of the Big Bang. It is also in perfect agreement with general relativity, since it was one of the three solutions described by Friedmann.

## hemitite

## Sanescience

Oops, created a tiny little universes with trillions of civilizations that grew great and powerful yet ultimately were powerless to prevent it from vanishing again, all in a blip of time in our universe.

## FroShow

It's also possible for there to be multiple "Big Crunches". Each occurring in a region of space that has been isolated from the rest of the universe due to an accelerated expansion. The "Big Rip" and "Big Crunch" could both happen.

## Callippo

Both these concepts are quite substantial turnaround after last century of physics, based on abstract formal models and Big Bang cosmology. The dense particle environment in the role of vacuum can model the metamaterials naturally, because it exhibits the fluctuations of both positive, both negative curvature, like the fluctuations of dense gas.

## DavidMcC

Well you might ask! I suspect it has to do with Abhay Ashtekar's prediction, based on his version of "spin foam" quantum gravity. However, there are other versions, that might not predict the collapse of everything.

## DavidMcC