Finding Dark Energy in a Supercomputer
Written by Fraser Cain
Dark energy is probably the most influential force in the cosmos, overwhelming the pull of dark matter, and absolutely dominating the meager impact of regular matter. And scientists have absolutely no idea what it is. But a new supercomputer simulation by cosmologists at Durham University might give astronomers a few places to look; to know how to measure this mysterious force.
When dark energy was discovered in 1998, it came as a complete surprise. By measuring the distance to supernovae, astronomers were hoping to calculate the rate at which the Universe's expansion is slowing down. Instead of slowing down, though, they found that the expansion of the Universe is actually accelerating. Instead of coming together in a big crunch, it looks like dark energy will spread the Universe out faster and faster.
Physicists now believe that dark energy makes up 70% of the Universe, with the remaining amount made of mostly dark matter, and a sprinkling of regular matter. Since that discovery, astronomers haven't been able to find the source of this dark energy.
So a new simulation, run on Durham University's Cosmology Machine supercomputer could help astronomers in their search. The simulation looked at the tiny ripples in the distribution of matter in the Universe made by sound waves a few hundred thousand years after the Big Bang. These ripples have long since been destroyed by the 13.7 billion years of the lifetime of the Universe, but the simulations show they might have survived in some conditions.
By changing the nature of dark energy, the researchers found that the ripples changed in length. In other words, if astronomers can find the ripples in the real Universe, this can help constrain the parameters for dark energy.
Durham University Professor Carlos Frenk said, "the ripples are a gold standard. By comparing the size of the measured ripples to the gold standard we can work out how the Universe has expanded and from this figure out the properties of the dark energy."
An upcoming ESA mission called the SPectroscopic All-sky Cosmic Explorer (SPACE) should have the capabilities to detect these ripples, and so help put some constraints on the nature of dark energy.
If all goes well, SPACE will launch in 2017.
Original Source: Durham University News Release
Filed under: Dark Energy
January 14th, 2008 at 9:23 pm
until the ripples are found, i will remain highly skeptical. even if they are, i will still need more evidence… but finding the ripples will be a good start.
January 14th, 2008 at 9:42 pm
I think that is the case in all new discoveries. Until there is tangible evidence it all remains thoeretical. What I find amazing is that there is the computing power to create these "senarios" and to compare them to the actual findings.
January 15th, 2008 at 3:51 am
Cound the astronomical Unicorns - white holes, be spewing out dark energy, making white holes currently impossible to detect?
January 15th, 2008 at 10:11 am
I don't see how dark matter would make 'white' holes undetectable. Being white, these holes would be easier to find than black holes, of which we've found plenty. We find black holes by the matter falling in…why would we not see matter falling out of a white hole? You say maybe 'cause it's dark matter (if that's the case these holes would not be 'white.') Well, then we would see the gushes of the outgoing dark matter influencing regular matter. In a dark universe, light or matter emitting objects would be the easiest to find.
January 15th, 2008 at 11:12 am
Until indisputable evidence to the contrary is found, I remain sceptical about the existence of some mysterious dark energy. I find Wiltshire's model to be much more probable. For example in "Cosmic clocks, cosmic variance and cosmic averages" (arXiv:gr-qc/0702082v3) David L. Wiltshire proposes that the universe be modeled as:"… a dramatically new interpretation of averaged cosmological quantities, in the context of standard general relativity. The Einstein equations are retained, as is the geodesic postulate (or theorem for those who regard it as such) that a test particle follows a timelike geodesic, and that it measures a proper time defined by the metric. What is abandoned is a simplifying assumption about averaging a cosmological spacetime geometry." He goes on to suggest that "…This new proposal, if it is correct, means that present epoch “dark energyâ€? is an historical accident resulting from a misidentification of gravitational energy, which is not local and cannot be fully described by the internal energy of a fluid–like quantity."
January 15th, 2008 at 1:24 pm
Maybe it's just osmosis. The universe is simply expanding into the nothingness beyond the edges, because it wasn't there before. A never-ending pressure regulation.
This reminds me of a Zen riddle.
January 15th, 2008 at 1:55 pm
I agree with Dark Gnats remark that says: "A never- ending pressure"
In my opinion this pressure is caused by the continious creation of "particles with no properties" that you may call Dark Matter.
January 15th, 2008 at 2:50 pm
"particles with no properties"
having no properties, semantically, is a property, and yes, even though i have no comprehension, i call it dark matter. why because people smarter than i, call it dark matter. it pays to listen to them when they speak.
January 15th, 2008 at 9:00 pm
I referenced dark energy, not matter, when speaking of the near legendary white holes. We are having enough difficulty detecting dark matter, I've heard of no dark energy detection to date, only inference. These comments alone show the difficulty of keeping dark matter totally separate from dark energy. Interesting.
January 16th, 2008 at 1:13 am
Dark, or invisible energy IS the overall E.M.F. First detected by Penzias & Wilson as the remnant of the big bang & later mapped by the COBE satalite as the Microwave Background Radiation.
There is no dark matter. Mystereious or other wise.
When the EMF is compressed, as in a singularity with turbulence it becomes regular matter & is no longer dark. ( This is not the time or place to explain how matter is formed from the over all EMF surfice it to say that only the singularity has the conditions to produce regular +ve matter )
We are being stretched as we expand into the Big Nothing ( A non-region of almost infinite vacuum) For our Universal expansion to be accelereating there has to be a constant force greater than the entire Universe. Therefore the force has to be external.
January 16th, 2008 at 5:15 am
[...] impact of regular matter And scientists have absolutely no idea what it is But a new supercomputer read more ->Chicago Tribune says:It was a dark and chilly night when the copy editor called He s an excellent [...]
January 16th, 2008 at 6:58 am
Consider a situation wherein the Mass Length as well as Time are truely infinite and much beyond our observable 'universe'. Suppose big-bang happened as a result of a tremendous 'pull' from a much bigger universe that we can observe today and say it got trigged from a surrounding place 50 billion light years away. We shall not be able to observe it because we are just 13.7 billion years old. Only when we are midway, we shall be able to see this wall which is gigantic in mass…it is making our observable universe expand. We are all thinking that there is something within our observable universe expanding it but the answer lies outside.
As far as dark matter goes it is very much within but dark energy is a pull from outside.
January 16th, 2008 at 10:56 am
Imagine a non-dimensional primordial source inflating dark energy, condensing dark matter, precipitating baryons and their aggregates, evolving organs of perception capable of comprehending this process as relativistic spacetime.
Pure undifferentiated coherence propagates as rapidly expanding perception evolving a complex venue supporting proliferating organs of comprehension.
Perception condensing as collective identification expresses first gravity, then the forces underlying ordinary matter and energy.
Primordial inflation is a deformation of space corresponding to the spiration of dark energy dampened only by condensing dark matter. Nucleosynthesis is a further condensation precipitating strong and weak forces which, at a certain density, propagate a fluctuating electromagnetic field as waves of radiation.
Nothing is known In the absence of perception.
January 16th, 2008 at 2:38 pm
We are probably inside a black hole. Now you know what it feels like - we cant find any white holes because we are one.
January 23rd, 2008 at 12:40 pm
i cant understand why matter and anti-matter are in same proportion
or
why dark energy is more in amount than dark matter i think tht source of dark energy may be stars like our sun some advanced tech is needed to detect this mystrious thing
is dark energy is observed or it remain just therotical concept in cosomology
February 6th, 2008 at 12:03 am
its said that dark matter was the first thing created right after the big bang in the bible it said god was created first. its also said that dark matter can take on most any form. God says can too. they say dark matter holds the univers together. God said he can do that to. Now put relegion aside but could dark matter be the god we've been looking for