Super-computer could throw light on 'mysterious' dark energy

January 11, 2008

Cosmologists have run a series of huge computer simulations of the Universe that could ultimately help solve the mystery of dark energy.

Results of the simulations, carried out by Durham University’s world-leading Institute for Computational Cosmology (ICC), tell researchers how to measure dark energy – a repulsive force that counteracts gravity.

The findings, published today in the Monthly Notices of the Royal Astronomical Society, will also provide vital input into the design of a proposed satellite mission called SPACE – the SPectroscopic All-sky Cosmic Explorer - that could unveil the nature of dark energy.

The discovery of dark energy in 1998 was completely unexpected and understanding its nature is one of the biggest problems in physics.

Scientists believe dark energy, which makes up 70 per cent of the Universe, is driving its accelerating expansion. If this expansion continues to accelerate experts say it could eventually lead to a Big Freeze as the Universe is pulled apart and becomes a vast cold expanse of dying stars and black holes.

The Durham research was funded by the Science and Technology Facilities Council and the European Commission

The simulations, which took 11 days to run on Durham’s unique Cosmology Machine (COSMA) computer, looked at tiny ripples in the distribution of matter in the Universe made by sound waves a few hundred thousand years after the Big Bang.

The ripples are delicate and some have been destroyed over the subsequent 13 billion years of the Universe, but the simulations showed they survived in certain conditions.

By changing the nature of dark energy in the simulations, the researchers discovered that the ripples appeared to change in length and could act as a “standard ruler” in the measurement of dark energy.

ICC Director 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.

“Astronomers are stuck with the one universe we live in. However, the simulations allow us to experiment with what might have happened if there had been more or less dark energy in the universe.”

In the next five to 10 years a number of experiments are planned to explore dark energy. The Durham simulation has demonstrated the feasibility of the SPACE satellite mission proposed to the European Space Agency’s (ESA) Cosmic Vision programme.

The project has been put forward by an international consortium of researchers including the Durham team.

SPACE, which is led by Bologna University, in Italy, is through to the next round of assessment by the ESA and if successful is planned to launch in 2017.

Co-principal investigator Professor Andrea Cimatti, of Bologna University, said: “Thanks to the ICC simulations it is possible to predict what SPACE would observe and to plan how to develop the mission parameters in order to obtain a three-dimensional map of the Universe and to compare it with the predictions of the simulations.

“Thanks to this comparison it will be possible to unveil the nature of dark energy and to understand how the structures in the Universe built up and evolved with cosmic time.”

Source: Durham University

4.1 /5 (27 votes)  

Filter


Move the slider to adjust rank threshold, so that you can hide some of the comments.


Display comments: newest first

TimESimmons
Jan 11, 2008

Rank: 1 / 5 (4)
Guess what's really driving the expansion of the universe.

http://www.presto...ndex.htm
Quantum_Conundrum
Jan 11, 2008

Rank: 5 / 5 (2)
Um. TimESimmons:

"Dark Matter" and "Dark Energy" are two completely different theoretical concepts.

Dark Matter is thought to consists of black holes and exotic particles which have gravity, but escape conventional forms of detection, thus theoretically explaining the so-called "missing mass" in galaxies and certain star clusters.

Dark Energy is the theoretical force which causes space-time expansion.
earls
Jan 11, 2008

Rank: 5 / 5 (2)
Tim, not to mention you have ZERO evidence. I've read your page three or four times now, I like your ideas, but...

Until you put a hoverboard in my hands, PURE SPECULATION of anti-grav matter means jack.

IMO, the results can be explained with current information without the invention of new terms and phrases.

As far as the article goes, simulations of bad information don't shed light on anything.
Quantum_Conundrum
Jan 11, 2008

Rank: 3.7 / 5 (3)
Earls said: "simulations of bad information.." etc.

Too true. A computer program can only do what it is programmed to do. In this case solve some differential equations (most likely approximately) and then blit them to the screen as an image. It doesn't "shed light on" anything. A person must solve a general algorithm, and consequently the general equations, before they can even begin to program a computer. Therefore the computer cannot tell you anything about a simulation that you could not have learned by solving the problem by hand.

Bad theory Bad evidence = bad model, regardless of how good the mathematics and computer simulations may be.


Right now, I consider "Dark Energy" to be about as scientific as the "Force" from Star Wars.

At best, one could view "Dark Energy" as a mere catch phrase for "All the stuff we don't know about physics."

In fact, most often you can substitute that phrase for "Dark Energy" and the sentence still holds true gramatically and contextually.
Quantum_Conundrum
Jan 11, 2008

Rank: 3.3 / 5 (3)
Also:

"The discovery of dark energy in 1998 was completely unexpected and understanding its nature is one of the biggest problems in physics."

This is a misleading statement which might lead an un-informed reader to think that scientists have ever actually "seen" dark energy in a lab or measured or tested it. They haven't.

The substance called "Dark Energy" could be almost anything, or it could be the product of several things which are otherwise unrelated, nobody knows. But that statment in quotes above makes it seem like someone already has a sample of it somewhere or something.

Dark Energy is undefined as of this time, though there are a number of differing models of what it might be or how it might interact with the rest of the universe. H owever, whatever Dark Energy is, as far as we know, it could be one or more forms of matter or energy, and not just one simple substance.

It could be.

DE = unknown energy/substance A

DE = B (an error in "law" of gravity!)

DE = A B

DE = A any number of other factors

DE = B any number of other factors

or

DE = A B any number of other factors

and so on.

gopher65
Jan 11, 2008

Rank: 3 / 5 (2)
Yeah. I find the results of the studies into the nature of Dark Energy interesting, and I'm sure everyone else does too, but I've been completely baffled by the media response to it. I like hearing about guesses as to the nature of DE, but I'd also like it made clear that they are in fact wild guesses with little, or in some cases absolutely no, evidence to support them. They're cool guesses, but still still guesses.

One of the things that this kind of cavalier treatment of these stories leads to is for common joes on the street to see a story labelled "ZZZZ's idea about DE proven wrong" and then say "AHHA, See, Science was wrong again!". When if fact it is nothing more than someone's wild pet conjecture being disproven.
OutoftheWood
Jan 12, 2008

Rank: not rated yet
Of course, no-one's going to take seriously the idea that the accelerated expansion of the universe is to caused by any energy as we know it. That is, just as virtually no physicist takes Bohmian mechanics seriously.

So Bohm found that in order to causally explain quantum wave diffraction in terms of hidden variables he needed to describe a distinct cause acting in addition to the forces, which he called the quantum potential. This cause needing to be described given that quantum objects are both particles or point objects with defined trjectories while in motion and also indefinitely extended waves which deflect the particle paths so as to cause diffraction pattern. While, unlike all the forces, the quantum potential would need to be nonlocal in that, unlike the four fundamental interactions, such a cause could not be described as acting as it surrounds objects in 3D space.

Then couple the Bohmian causal account with the evidence for the "proxy wave" - whereby the diametre of photon waves are measured to increase over astronomical distances, and it seems to me, you have the beginnings of a theory of 'dark energy' as a nonlocal "cosmic quantum effect".

And you can also think, well, what about the formation of cosmic voids as nonlocal quantum effects, and then... um... Galaxy and galaxy cluster formation?!!

What? Cosmic nonlocality?? Must be a cranky idea really, musn't it?
TimESimmons
Jan 14, 2008

Rank: 1 / 5 (1)
earls - Yes i know my evidence is circumstantial but the list is growing. One day my proof will come in.

http:\\www.preston.u-net...ndex.htm
Ragtime
Jan 16, 2008

Rank: 1 / 5 (2)
Sometimes a single new clever idea can save a lotta money spent in computer simulation, which were done in the hope, the old theories can reveal some new secrets.
Ragtime
Jan 16, 2008

Rank: 1 / 5 (2)
By Aether Wave Theory the Universe expands by increasing speed by the same way, like huge stars are collapsing. This makes their interior more dense, so that the view through such interior brings an illusion, the farther areas are even farther. The same effect can be observed at shorter distance scale (compare the MOND gravity theory).
Rank 4.1 /5 (27 votes)
Tags

Relevant PhysicsForums posts

More news stories

Explained: Sigma

It's a question that arises with virtually every major new finding in science or medicine: What makes a result reliable enough to be taken seriously? The answer has to do with statistical significance -- but ...

Physics / General Physics

created Feb 09, 2012 | popularity 5 / 5 (19) | comments 76

Quantum physicist explains $100K offer for proof scaled-up quantum computing is impossible

(PhysOrg.com) -- MIT researcher Scott Aaronson has certainly riled the physics community with his offer this past Friday, of $100,000 to anyone who can prove that scaled-up quantum computing is impossible. ...

Physics / Quantum Physics

created Feb 08, 2012 | popularity 4.2 / 5 (13) | comments 35 | with audio podcast weblog

Diamond light, brighter than the sun

It’s the size of five football pitches and generates light 10 billion times brighter than the sun. As the Diamond Light Source celebrates its tenth anniversary this year, Penny Bailey visits one of the ...

Physics / General Physics

created Feb 07, 2012 | popularity 4.3 / 5 (7) | comments 18 | with audio podcast

Physicists 'record' magnetic breakthrough

An international team of scientists has demonstrated a revolutionary new way of magnetic recording which will allow information to be processed hundreds of times faster than by current hard drive technology.

Physics / General Physics

created Feb 07, 2012 | popularity 4.5 / 5 (41) | comments 14 | with audio podcast

Hints of the Higgs - papers are submitted

Back in December 2011, the ATLAS and CMS experiments at CERN presented some exciting results that provided tantalising hints of the Higgs boson.

Physics / General Physics

created Feb 08, 2012 | popularity 4.1 / 5 (7) | comments 10


Injured boomers beware: Know when to see doctor

(AP) -- It happened to nurse Jane Byron years after an in-line skating fall, business owner Haralee Weintraub while doing "men's" push-ups, and avid cyclist Gene Wilberg while lifting a heavy box.

Google might launch Drive for cloud storage soon

(PhysOrg.com) -- Google's next big move, according to the Wall Street Journal, is a cloud storage service called Drive. Hardly first to the plate, Google is simply catching up to introducing its cloud reposi ...

Latin America mining boom clashes with conservation

Latin America is experiencing a mining boom as prices rise fuelled by a hike in global demand, but the region is also being hit by a wave of violent protests, strikes and rallies by environmentalists.

Love a click away in Indonesia's Twitter Republic

He was a geeky kid from Yogyakarta, she a glamorous city girl in Jakarta. In a country with one of the world's most vibrant social networking scenes they fell in love on Twitter.

Europeans protest controversial Internet pact

Tens of thousands of people marched in protests in more than a dozen European cities Saturday against a controversial anti-online piracy pact that critics say could curtail Internet freedom.

Walney offshore wind farm is world's biggest (for now)

(PhysOrg.com) -- The Walney wind farm on the Irish Sea--characterized by high tides, waves and windy weather--officially opened this week. The farm is treated in the press as a very big deal as the Walney ...