You may want to put aside plans to build a flux capacitor: the "toy" explosion created in the lab suggests that time travel may, after all, be impossible.
Igor smolinov and Yu in a new study
Ju Hung of the University of Maryland used advanced materials to simulate the birth of the universe, which can bend light in an unusual way.
Their device supports the idea that the forward "time arrow" cannot go back to itself to undo events that have already occurred.
Smolyaninov says time travel is not possible in real life so far, and this new material suggests it is impossible. (
Physicists predict that time will end after Five Billion years. ")
The new material represents space and time. The new Big Bang simulator is only one inch (20 micrometers)wide.
It is made of alternating gold and plastic, pieced together in a way that creates a super material, an engineered substance that can manipulate light.
Over the past few years, researchers have used supermaterials to make "sci-fi" devices such as invisible cloaks and super lenses, which allow scientists to "see" structures that are smaller than the wavelength of visible light.
Supermaterials have also attracted the interest of astrophysicists, who have recently used these foreign substances to make artificial black holes and multi-universe simulators. (
See also "the existence of the universe, may be explained with new materials. ")
According to Smolyaninov and Hung, their supermaterials are the "reasonable" representation of our universe, especially the early universe at the time of the big explosion, which was about 13 years old.
7 billion years ago.
Because of their unique way of bending light by supermaterials, the equation describing the passage of particles through time is similar to the equation describing the motion of photons and quantum particles, called plasma, produced by free electron waves through materials.
"In this material, [the movement]plasmons]
It looks like the motion of particles in Minkowski space, "says Smolyaninov, referring to the theoretical model of space-time that physicists sometimes use to study the universe.
Therefore, the super-material device is our four-
Dimensional Universe: horizontal motion through a hypermaterial plane is roughly similar to motion through a three dimensional space, while vertical motion represents movement through time.
The universe is too chaotic for time?
In this experiment, scientists triggered the big bang with a green laser.
Events in super material.
The laser caused a series of plasma in the gold atom.
These plasma radiate from one point to the outside, just as scientists think the material particles that radiate from one point after the Big Bang. (
Related article: The Big Bang of "atomic accelerator prompt" flows out of the "liquid" universe. ")
Scientists have found that the path of radiation plasma is tilted as they move further.
This is consistent with the second law of thermodynamics, which states that unless there is any intervention, the system becomes more disordered over time.
Scientists call system entropy a measure of disorder, so another way to state the second law of thermodynamics is to say that entropy increases over time in our universe.
In the toy model, what is equivalent to time travel is that the plasma completes a cycle that runs along exactly the same path as it has traveled before.
But once the plasma excitation element deviates from that path, part of the reason is that entropy makes the cycle no longer possible.
This result is described in a paper published in arXiv this month.
This suggests that particles in our universe may also not be able to move backwards in time.
But smoliyanov admitted that the experiment was far from perfect: "I'm not sure to what extent this applies to real life.
Is Toy Big Bang too simplistic?
Andreas Albrecht, a cosmologist at the University of California, Davis, did not participate in the study, and he doubted whether the supermaterial could accurately reflect the early universe.
"The Minkowski space is a space without matter," Albrecht said . ".
"But there's something in the universe, so we know it's not Minkowski space.
Albrecht called the team's big bang simulator a "cool" achievement, but he didn't think it would teach physicists anything about the universe, these things are not known from observation data or models based on equations and computer simulations.
"We have a better model of the universe, we can [create with]
Albrecht said: "normal computer, so I can't feel [material]
Provides any insight into the universe that cannot be obtained more directly.
Lawrence Claus, a theoretical physicist at Arizona State University, is also skeptical about the discovery, saying the new Big Bang model is too simplistic.
"I don't think [this model]
Krauss said in an email: "This clarifies a more difficult question of what is possible in the real universe, where there may be arbitrary state equations . " Reference physicists use to describe different equations of the state of matter in the cosmic age, which are not explained in toy models.
While new experiments and our daily experience seem to rule out the possibility of time travel, there are still many unknowns in the universe and physicists can imagine that time travel is possible. (
Also see "every black hole contains another universe? ")
For example, the laws of physics may vary depending on where a person is in the universe, and the Earth may happen to be where the entropy increases in the universe, which will make time travel impossible.
"Maybe life is attached to these patches with rising entropy because we need the arrow of time to exist," says Albrecht of UC Davis . ".
As Albert Einstein once quipped, the reason for the time is that "nothing will happen at the same time.
Or, Albrecht says, "you can imagine a universe where entropy loops up and down.
He said: "If entropy is not constant in this hypothetical universe, then the arrow of time may move backwards, events such as the broken cup being once again intact or the human reverse aging are not only possible, but also natural.
Residents of such a universe may not notice anything wrong at all.
"If this happens, we will change our thinking about the past and the future and will not notice anything special," Albrecht said . ".