SPACETIME CRYSTAL: Scientists have proposed a way to build a clock that will keep perfect time forever.
Image: Berkeley Lab
The idea for an eternal clock that would continue to keep time even after the universe ceased to exist has intrigued physicists. However, no one has figured out how one might be built, until now.
Researchers have now proposed an experimental design for a "space-time crystal" that would be able to keep time forever. This four-dimensional crystal would be similar to conventional 3D crystals, which are structures, like snowflakes and diamonds, whose atoms are arranged in repeating patterns. Whereas a diamond has a periodic structure in three dimensions, the space-time crystal would be periodic in time as well as space.
The idea of a 4D space-time crystal was first proposed earlier this year by MIT physicist Frank Wilczek, though the concept was purely theoretical. Now a team of researchers led by Xiang Zhang of California's Lawrence Berkeley National Laboratory has conceived of how to make one a reality.
"The idea of creating a crystal with dimensions higher than that of conventional 3D crystals is an important conceptual breakthrough in physics, and it is very exciting for us to be the first to devise a way to realize a space-time crystal," Berkeley Lab physicist Tongcang Li, a member of the research group, said in a statement. [Twisted Physics: 7 Mind-Blowing Findings]
Zhang and his colleagues suggest that a space-time crystal could be constructed using an electric field to trap charged atoms (called ions), and taking advantage of the natural repulsion between two like-charged particles (positive and positive, or negative and negative), which is called Coulomb repulsion.
"The electric field of the ion trap holds charged particles in place and Coulomb repulsion causes them to spontaneously form a spatial ring crystal," Zhang said. "Under the application of a weak static magnetic field, this ring-shaped ion crystal will begin a rotation that will never stop. The persistent rotation of trapped ions produces temporal order, leading to the formation of a space-time crystal at the lowest quantum energy state."
In other words, the scientists would aim to create a ring of charged particles, with the resulting electromagnetic forces causing the structure to rotate perpetually. At its lowest quantum-energy state, also known as its ground state, the system has no disorder, or entropy, and there is no way for its entropy to increase over time. Thus, the crystal's temporal structure and timekeeping ability would continue even after the universe reached a state of "heat death," also known as thermodynamic equilibrium, when it had devolved into entropy.
The researchers describe their idea in a paper published recently in the journal Physical Review Letters.
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30 Comments
Add CommentThere is nothing but relative time. Our paradigm for time is based on our minute corner of the universe and can therefore not be considered 'perfect' in any sense.
Reply | Report Abuse | Link to thisWouldn't it require the magnetic field to remain for it to remain rotating? Otherwise it would slow down due to ... um... friction... with... aether... yeah... that's the ticket...
Reply | Report Abuse | Link to thisIn any case, the solution to the heat death of the universe has always been obvious: speed up 75% of the habitable solar systems in the galaxy or galaxies to nearly the speed of light and get them flying circles around our galaxy (presumably using some kind of hyper-advanced gravity manipulation technology), effectively putting the contents of the aforementioned systems into suspended animation as far as the rest of the universe is concerned. When the normal non-accelerated stars start going out, drop a few out of near-light-speed to inhabit until they start to go out, then drop a few more out and move to those, etc. The process could probably continue for a very long time, assuming the galaxy wasn't overpopulated, and only a small number of systems are dropped out each time, and nothing goes horribly wrong.
Note that this ignores any concerns about high-energy radiation, particularly radiation shifted to a different, deadlier, frequency by relativistic effects, or how ridiculously much kinetic energy mere space dust will have when it strikes anything moving at near-c speeds. I presume that any civilization sufficiently advanced to propel entire solar systems to nearly the speed of light and set them cartwheeling around a galaxy without hitting any other systems, can likely also deal with any other problems as well.
Wouldn't the half-life of the atoms that make up the crystal cause the crystal to degrade over time? How would you read the time from the crystal without increasing its entropy?
Reply | Report Abuse | Link to thisI have very little knowledge of physics. So this thing can get sucked into a black hole and still work? I though everything gets compressed down to almost nothing.
Reply | Report Abuse | Link to thisWho said our time was perfect? Time is relative to your inertial frame, it's the speed of light that is constant.
Reply | Report Abuse | Link to thisWho said anything about it getting sucked into a black hole?
Reply | Report Abuse | Link to thisIf a space time crystal could be invented then you could apply the sane theory to having a sub-universe or something like a artificial planet built the same way as the crystal. So a civilization could go unaffected by the outside forces, thus existing after the heat death.
Reply | Report Abuse | Link to thisI officially nominate this Clock for the Ignoble Award.
Reply | Report Abuse | Link to thisNot sure what catagory,but I don't suppose that matters because it like the whole Universe will (eventually) not exist.
The speed of light is constant? I thought it depended on the density of the Universe (or whatever it's passing through). Careful about making absolute statements like they're factual truth.
Reply | Report Abuse | Link to thisIn fact, I think that invites some thought experiments ...
Reply | Report Abuse | Link to thisNo, because any kind of civilisation would have entropy.
Reply | Report Abuse | Link to thisWell what good is an eternal time clock if it can't even survive getting sucked into a black hole?
Reply | Report Abuse | Link to thisWhat an accurate representation of man and his inconceivable arrogance.
Reply | Report Abuse | Link to thisMy understanding is that nothing is constant but the fact that nothing is constant.
Reply | Report Abuse | Link to thisIf you read the sutras of the Buddha you would learn that not only does the universe exist or at some point "won't exist", it concurrently exists and does not exist at this moment or any moment.
Reply | Report Abuse | Link to thisActually, the confirmed speed of light in a vacuum is a constant - just under 300,000 km/sec. The speed of light through a transparent medium such as glass or air does vary. Please see
Reply | Report Abuse | Link to thishttp://en.wikipedia.org/wiki/Speed_of_light
Great attempt, but merely for the chemistry's point of view. If there is no space left, space we now call "empty", then space and therefore time stops. There is no fourth dimension if the first three are gone, therefore no time.
Reply | Report Abuse | Link to thisAlso I would expect when (spacial) pressure increases or decrease the atomic bonds will be stronger or weaker, respectively. Perpetual machine kick-ass nonetheless.
How do we know that we will have the technology for that by then?
Reply | Report Abuse | Link to thisCareful about making absolute statements like they're factual truth.
Reply | Report Abuse | Link to thishttp://en.wikipedia.org/wiki/Speed_of_light
You mean:
Reply | Report Abuse | Link to thishttp://en.wikipedia.org/wiki/Variable_speed_of_light
If someone in a previous universe prior to the beginning of our universe had created such a crystal, that crystal should still exist somewhere in the universe if the premius of this article is correct.
Reply | Report Abuse | Link to thisThat is, based on the premise of this article.
Reply | Report Abuse | Link to thisThe stronger gravity is, the slower time moves, so, inversely as the matter of the universe dissipates, there will be less gravity and time will speed up. When all matter is gone, time will move at infinite speed, or not at all. Since there will be no one to observe it and measure it, time will no longer exist.
Reply | Report Abuse | Link to thisYep - at that rate it'd seem like you could wait forever for something to happen...
Reply | Report Abuse | Link to thisCan we use this technology of making an eternal clock to survive the Heat Death of the universe, to make an eternal account of our human history in the 4th dimension to make sure we have a legacy that extends through space and time? I think it might be cool for it to be found by the next generation of life when the universe begins anew.
Reply | Report Abuse | Link to thisReading this I get the eerie feeling that somebody is pulling my leg...
Reply | Report Abuse | Link to thisHow anything material, thus composed of atoms, can be eternal, when electrons, protons, neutrons and all that stuff have a half life, and will finish by disintegrating? Exchanging old atoms by newer ones, going back in time, as the giant cylinder spaceship in Arthur C. Clarke's "Rendezvous with Rama"? Who wants to live forever?
Reply | Report Abuse | Link to thisAs you say, the speed of light has been slowed down to a crawl in a Bose Einstein condensate.
Reply | Report Abuse | Link to thisI may have only taken AP Physics in high school, but I'm pretty sure the speed of light doesn't change; only the frequency and wavelength of light changes when passing through different materials or environments. What I have to ask though, for the sake of being thorough, is what does the "death" of the Universe entail? As far as my knowledge goes, the Universe is made of a fabric of space-time. So, if the Universe were to cease to exist, wouldn't it's components cease to exist as well? And wouldn't this "clock" be within the Universe, and so would cease to exist as well? Even if this clock existed in a higher state than the 3rd Dimension, couldn't it be possible that a 4th dimensional aspect exists within the Universe, but we are simply incapable of detecting it? If this was so, and if the Universe would cease to exist, wouldn't this 4th Dimension would be included in that cessation? Please inform me of the details, because I'm just hypothesizing all of this based on my limited background in physics.
Reply | Report Abuse | Link to thisI never attended any physics class, so I like to check facts with http://en.wikipedia.org/wiki/Speed_of_light
Reply | Report Abuse | Link to this"The speed at which light propagates through transparent materials, such as glass or air, is less than c. The ratio between c and the speed v at which light travels in a material is called the refractive index n of the material (n = c / v). For example, for visible light the refractive index of glass is typically around 1.5, meaning that light in glass travels at c / 1.5 ~ 200,000 km/s; the refractive index of air for visible light is about 1.0003, so the speed of light in air is about 90 km/s slower than c."
Also see
http://en.wikipedia.org/wiki/Speed_of_light#In_a_medium
I recall seeing an experiment where a dense plasma, I think, was use to slow the propagation of light so much that you could watch as a laser beam took a couple of seconds to propagate a distance of about a meter. I think this was done without any thermal absorption and randomly directed reemission of light as occurs in opaque materials, which is why it takes many thousands of years for a photon (quanta of energy) emitted within the Sun to reach its surface.
I'm also suspicious of the persistence of any electric fields or charged atoms beyond the "heat death" of the universe when all energy has been dispersed... See
http://en.wikipedia.org/wiki/Heat_death_of_the_universe