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Scientists Complete Universe Millennium Simulation
james tech writes "The Virgo Consortium recently completed its massive "Millennium Simulation", tracing the universe's evolution from its early origins to present day. To simplify the computations, they considered only dark matter which composes most of the universe. Using a 512-node cluster with IBM processors, the group produced over 20 terabytes of data with some of the most breathtaking images of the universe never seen. A visible matter simulation is underway, at a lower resolution."
"It doesn't matter how beautiful your theory is, it doesn't matter how smart you are -- if it doesn't agree with experiment, it's wrong." -- R.P. Feynman
I feel that this quote is appropriate, as I believe this type of simulation possibly cannot contain every essential physics that governs the evolution of the Universe. Some oversimplification must be present and some tweaks (e.g. dark matter) may go into the modeling to match whatever we see it today.
This isn't the end of the study of cosmology. That's all I'm trying to say.
I support basic research and modelling, but this seems all too artificial to have any useful predictive benefits. It's like trying to draw Michaelangelo's "The Adoration of the Magi" with only a green crayon, it might look something like what you're trying to simulate, but in all essential aspects it's completely and obviously fake. If they lack the computing power, why aren't they waiting a few years when they can afford to improve upon their resolution, produce something useful?
Sorry, but this reminds me all too much of other unhelpful models that are done "just because we can" rather than because it has some sort of utility, for example early climate change models which were incredibly unhelpful in the long term by making people rightly sceptical, when doomsday predictions didn't materialise. The fact is, this generates pretty pictures, maybe a nice paper in some backwater of journal land, and not much else beyond froth. It shouldn't really be called science, like someone making a work of art out of say, pictures of cells, isn't considered science.
Inevitably, I will be modded down for having a negative view.
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That this whole universe as we see it is not an experiment in somebody's supercomputer?
Coca-Cola, sometimes War.
Why did they stop at 13.6Gyr? Why not run this simulation into the future? Looking at the pictures, it doens't look like a stable situation has been reached yet.
I cannot access the article at this moment but I am very suspicious of how accurate / scientific this simulation is. It surely is an amazing artistic work but heck, we don't even know the mass density of the universe (related to its curvature). Yet that sounds like a required data to make a simulation. This simulation should be ruled by the equations of general relativity which is still drafty. Most equations lead to cahotic behavior... we have trouble simulating three bodies because of the unstability of the system...
\u262D = \u5350
So its "pretty obvious"?
I guess thats in the same class as "its KNOWN the earth is flat"...
So please give me a proof, or at least a good theory, why there cant be particles that dont interact with the strong or electromagnetic forces and have large mass?
We SEE the results of their gravitation (and not just with the galactic rotation, but you cannot really do cosmology ignoring them), so who are you to claim them a "hack to make maths work"?
(btw: maths work really most of the time. The trick is that the result should represent reality)
HI O WISE PRINCE. WHT TOOK U SO DAM LONG?
"Just a theory" is a phrase that should never be used in the context of Scientific discussions. It shows a misunderstanding of what the word theory means in Science. A Theory, put simply, is an explaination for observed phenominon which can be experimentally disproven, and is capable of being used to make predictions. Mathmatical theory applies to the real world only insofar as it correctly explains real-world phenomina, and predicts the actions of the real universe. Current theories on the creation of the Universe are anything but simplistic, and are accurate according to the data we've collected so far. When more data comes along that proves the theory false or inadequate, the theory will have to change, creating a stronger theory. The idea that it's somehow worthless because it's incomplete is ridiculous.
Whether we know WHY visible matter moves the way it does is not at issue; the issue is that we do know HOW visible matter moves, and in fact we understand it very well and can predict it with great accuracy and consistency. Of course the universe doesn't recognize our "simplistic definitions"--our definitions recognize the universe. There's quite a difference.
There's nothing arbitrary about it. Science is a description of how the world around us behaves; inventing fanciful and largely frivolous reasons to explain WHY is best left to philosophers and theologians.
I suspect your science education has been thoroughly inadequate. Please rectify this tragic oversight before having further opinions on scientific matters.
Bah.
I generally find that joke is found to be funny in direct proportion to the audience's scientific illiteracy. "Har har, look at those silly scientists, spouting their nonsense. I'll just sit here and laugh at them while I enjoy all the lovely modern technology their work has made possible."
While mildly amusing, it betrays a deep failure of understanding the value of analytical simplification. Just because something sounds silly to the uninformed does not mean it has no value.
As pitiful as the current public understanding of science is (as evidenced by such things as the rampant belief in nonsense like 'creationism'), it'd be nice if the problem not further exacerbated.
From that Thunderbolts website:
"So the Deep Impact mission could prove to be an acid test. The electric theorists have made their position clear, and there won't be much wiggle room for the conventional "dirty snowball" hypothesis. If water is not observed to explode from the surface at the projectile's impact, a domino effect will be set loose. An absence of water would mean there is no mainstream model left, only the electric model would remain. A single event could thus alter the mindset of all who work in the theoretical sciences: it would mark the end of the imagined "electrically neutral" universe lurking behind every statement we heard from David Morrison"
Oh dear. Looks like convential science wins again eh !
The fact is, this generates pretty pictures, maybe a nice paper in some backwater of journal land.
Well, if you considert "Nature" a backwater journal, then i dont know.... where should i publish? This paper went through a peer-review process, so its not just pretty pictures.
Although, I am partial to agree that simualtions are approximations, how long should we wait then before we attain "suitable" computing power? Everything starts somewhere.
Not most of the science professors I've taken classes from. Then again, some of them were pretty humor impaired. :D
Suffice it to say it sounds funnier the less you actually understand the subject matter. It has a very shallow perception of the subject; someone who actually knows the material is more likely to think "wait, that's not how it works..."
Have you ever seen technology-oriented jokes of the variety that poke fun at how difficult simple electronic devices are to use? The whole "haha, the power went out a month ago and the VCR still flashes 12:00, isn't that funny" variety of stuff. People who are clueless about technology usually find such humor funny; people who actually know their stuff are more likely to scratch their heads and say "but that's stupid." The same thing is going on with that joke.
Dark matter is "observed" indirectly through gravitational effects. It is not that the scientists doubt its existence, it is just that they cannot observe it directly, hence the name "dark".
A crude example would be if you were looking out your window at a lake. You might see waves caused by fish swimming below, but you would not be able to describe the fish, because you only saw the wave.
Remember, You are unique...just like everyone else.
Actually, I think only a scientist would find that joke funny. A nonscientist is just going to give you dumb stares.
It's an exaggeration for comic effect. Every good scientist recognizes in it some silly oversimplification he or she has made at some point in the past, because that's the way science gets done. The nonscientist doesn't get it precisely because he doesn't know how science gets done.
Public misunderstanding of science has little to do with the jokes of scientists poking fun at themselves. In fact, one of the best ways to convince the general public that science is simply wrong is to be humorless about it. Lighten up.
Stupid properties of dark matter: The interaction with regular matter must be asymetric. Why? Because they model it as a sphere of dark matter enclosing a disk shaped galaxy to get the expected rotation curve. If dark matter interacted with itself and visible matter in the same way visible matter interacts with itself, they should have the same distribution. I think they just observed that a big sphere of stuff would make their flawed model match reality and said "oh there must be this goofy thing here". Remember, there are NO direct observations of dark matter (or energy).
This argument has several flaws. There is direct evidence for dark matter in the cosmic microwave background data, which is why dark matter is now the preferred theory for explaining galactic rotation rates.
It's not actually the theory that all of the "normal matter" in our galaxy is visible in a disk, and all of the "dark matter" is distributed in a sphere - a significant percentage of the dark matter in our galaxy is thought to be normal matter that just didn't clump enough to form (many) stars - that is, disperse hydrogen gas.
For the remaining "exotic dark matter", the one thing we know about it (from the CMB data) is that it interacts weakly with normal matter. There's no reason to assume that whatever caused most "normal" matter to clump and eventually become stars would cause "exotic" matter to have a similar distribution. A disk makes sense for matter that tends to form clumps as a result of collisions, and a sphere makes perfect sense for matter that doesn't. It's not all that unintuitive or surprising, given the data now in hand.
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