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Space Science

Astrophysicists Build Realistic Virtual Universe 129

sciencehabit writes "In the most detailed effort yet, astrophysicists and cosmologists have modeled the evolution of the universe right down to the formation of individual galaxies. The results of the mammoth computer simulation neatly match multiple astronomical observations, ranging from the distribution of galaxies in massive galaxy clusters to the amounts of neutral hydrogen gas in galaxies large and small (abstract). The findings once again neatly confirm cosmologists' standard theory of the basic ingredients of the universe and how it evolved—a result that may disappoint researchers hoping for new puzzles to solve."
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Astrophysicists Build Realistic Virtual Universe

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  • I wanted to get a dollhouse for the kiddies, but a universe is even better.
  • Where the extra matter went and how the universe expanded faster than the speed of light, temporarily?

    Because something tells me TFA is missing that bit or exaggerating in their last line about puzzles.

    • by flyneye ( 84093 )

      I have problems with the reality of this universe, how much damn improvement could a computer sim offer?

    • TFA mentioned that they included Dark Matter in the model . . . which is quite bold, considering that we are still quite clueless as to what exactly that actually is . . . except that we need Dark Matter to keep our other equations from breaking . . .

      • by geekoid ( 135745 )

        Dark Matter is a real and observed phenomenon.

        " Dark Matter to keep our other equations from breaking"
        Now you're just being ignorant..or stupid. You pick.

  • I hope they have a pretty accurate trading model with a good economic base. Need to buy and sell across multiple systems to save up for that bad-ass ship.

    • As a matter of fact they do. Their highly accurate model is based on the premise that "You, your ship, and everything in it die/decay/degrade beyond functionality before you get 10% of the way to the nearest star". If any sentient life happens to be orbitting that star then in a few thousand years when your remains arrive they may end up as part of a museum exhibit or Black-Ops coverup.

      Without FTL the only things we could possibly trade in are knowledge and culture. And with FTL... well if Einstein was r

      • by Sique ( 173459 )
        Even without FTL, it's possible to arrive at another stellar system within your life time, if you are able to constantly accelerate (and decelerate after half the distance). Thanks to time dilation, for you, about 5 years pass, until you arrive at the next stellar system (the exact number depends on your actual acceleration). The main problem: If you go back. on Earth, millions of years have passed on Earth until you arrive.
        • First you need political will. Sadly, that exists nowhere on this Earth.
        • Well, yes and no.

          Depending on how far "the next stellar system" is from start, and your acceleration, of course.

          For 1G and 5 years, you'll go about 11 light years.

          Beyond that distance, you'll add extra distance very quickly - 22 light years will take you 6.2 years. 100 light years will take 9 years.

          And you can manage 11+ BILLION or so light years in only 45 years.

          While this does theoretically allow traveel interstellar distances within a lifetime, for practical purposes (we don't really want to burn a

          • An excellent breakdown - just don't forget you also need fuel, though I suppose a ramscoop plus mass-energy converter would let you sustain accelerations once you got up to speed. The fuel for that initial acceleration and deceleration is still going to be pretty mind-boggling though.

            I agree it's plausible for colonization or exploration purposes, but for trade? Trade needs to be cost-effective, and those shipping costs are going to be killer...

            • I agree it's plausible for colonization or exploration purposes, but for trade? Trade needs to be cost-effective, and those shipping costs are going to be killer...

              No, it's not worthwhile for trade, really. especially since no material good could possibly be worth shipping across interstellar distances. Trade, as such, would be trade in IDEAS, not things. And you can do that with a com laser.

              As a completely off-topic aside: Is that dove EVER going to get laid? He's been chasing a dove hen around my b

              • by geekoid ( 135745 )

                no known material good could possibly be worth shipping across interstellar distances.

                See: Dune for an example.

                • I imagine that without FTL it would be cheaper to synthesize spice than ship it a few lightyears. Billions or trillions of dollars per pound? That's getting into the range where you could potentially fine-tune your best attempt at chemical synthesis by using little laser "tractor beams" to add/remove individual atoms, and still have a huge profit margin.

                  Now maybe if it was some new element with "miraculous" properties - like say element 543 that's the critical component of an alien antigravity drive... B

        • CrimsonAvenger did a great breakdown of time versus acceleration, so I'll just throw out a second factor: we can't actually pull off that kind of acceleration with any current (even speculative) fuel technology. Consider the size of the rockets used for orbital launches, just to accelerate a few thousand g at a few G for several minutes. Now increase that a few thousandfold to keep it up for a year. Except... it's even worse than that - far, far worse, because the fuel required for sustained acceleration

  • by RichMan ( 8097 ) on Wednesday May 07, 2014 @07:15PM (#46944511)

    the big question is are entities in the simulation able to detect it is a simulation.

  • by jclaer ( 306442 ) on Wednesday May 07, 2014 @07:35PM (#46944617)

    Choosing parameters that best simulate a model does not mean that model is correct.

    • by Anonymous Coward

      Finally I'll be able to make an apple pie from scratch!

    • by DMUTPeregrine ( 612791 ) on Wednesday May 07, 2014 @09:01PM (#46945211) Journal
      If there are no parameters for a model that allow the model to simulate reality, then the model must be incorrect.
      If there are parameters for a model that allow the model to simulate reality, then the model may be correct, but may still be incorrect.

      This work moves us from the first state to the second, at least when it comes to simulating rather large scale structure.
      • Yep, it took almost a century, several geniuses, the invention of telescopes and calculus, and years of painstaking observations, to refine the heliocentric model to a point where it outperformed the predictions of the ancient geocentric model. Now that we have space craft we can (finally?) determine which model is correct [youtube.com] by observing the sun-earth system from an external viewpoint.

        By definition there is no point in space outside the Universe, and we still can't even observe our home galaxy from the outs
    • by Tablizer ( 95088 )

      Choosing parameters that best simulate a model does not mean that model is correct.

      You mean my RC plane is not really governed by regression equations? Shit, there goes my Nobel!

      • Observations use regression techniques, physical simulations do not. Two Nobel's in one day, that's gotta hurt!
    • When the parameters match observed conditions it does.

      • Science says you should be able to make predictions, so that the theory is valid. Matching observations in a model based on theories built to explain those same observations is circular reasoning.

        This does not mean they are not on the right path, of course.

        • The observations their model makes are different from the observations used to construct the model.

        • What precisely do you believe is the difference between a model and a theory? A theory is itself a mathematical model, a simulation simply computes the answer to the equations in those theories in order to "visualise" and explore a particular physical system at a particular scale. For the majority of the questions involving the real world calculating the answer requires an electronic number cruncher.

          This does not mean they are not on the right path, of course

          Indeed, when talking about the accuracy of any scientific theory (model) it should be noted that imperfect ce

      • Parameters are inputs, physical constants such as the gravitational constant. The model OUTPUTS are what you compare to observations
    • by Sique ( 173459 )
      This is a valid statement for any theory, not just a theory expressed in a simulation. Just because the theory works for some chosen values, it doesn't mean the theory is correct. Basicly yours is a null-statement, it doesn't yield any relevant information.
    • Their parameters aren't simply chosen, though: most of them come from a disparate range of experimental observations, and the remainder are constrained to reasonable values. Getting experiment out with experiment in, particularly when it's a range of different experiment types in each case, is strong evidence that a model is accurate.

      "The free parameters of our model are set to physically plausible values and have been adjusted within the allowed range to roughly reproduce the relation between mean stellar

    • I think it would be quite fun to make a complete simulation of the events in Genesis. That'll make sure they were true!
    • by geekoid ( 135745 )

      Do you just not understand what models are, how the work, and how to validate them? Is that why you just throw out that meaningless sentence?

    • No, but if you can't find parameters that make a model behave similarly to reality, that's evidence that the model is incorrect. This is science: all we can do is try to find evidence that shows that models are incorrect and try to make new models.

      The success of the simulation shows that the theories are consistent and may be complete (in the sense that other theories are not required) to the limits of the simulation, observation, and agreement. This is evidence that the theories aren't incorrect and

    • Actually that was a rounding error, the correct value is 947.2837289373726376152839

    • “When you entered the door of my office, you entered my electronically synthesized Universe,” he explained. “If you had left by the door you would have been back in the real one. The artificial one works from here.”
  • Funny (Score:3, Insightful)

    by Anonymous Coward on Wednesday May 07, 2014 @08:44PM (#46945089)

    I love the part about "new questions to answer". As if "Where did the super dense mass the universe came from, come from, wouldn't be a good question to answer...

  • Confirmation bias.
  • are a feature of some other species' universe-simulation: high

  • So when are they releasing it as a game?

  • The simulation is uncanny! I noticed that there is only 1 planet with life on it!

  • by Anonymous Coward

    Hint to /. editors and submitters: when talking about physics and astronomy papers, it's really helpfu to remember the existence of the arxiv, where the actual professionals go to find the papers.


    (Also, hint to commenters on cosmology articles: saying things like "simulations are pointless because they're confirmation bias" and "but they don't understand dark matter LOLOLOLOLOL" just make you look woefully ill-educated in the area, even to the level that a cursory skim of Wi

    • by gl4ss ( 559668 )

      you could have saved us a lot of time then by pointing out how it is not pointless, unless your point is "it gives me funding".

      basically, how is this on any fundamental level any more useful than the galaxies screen saver is?

      • by geekoid ( 135745 )

        Fundamental understanding of things is what we use to create new thing, even thing we had no idea we could create when the fundamental research is done.

        A good model will show us thing we didn't know would happen. Thing we can later confirm.

  • by argStyopa ( 232550 ) on Thursday May 08, 2014 @08:14AM (#46947957) Journal

    Probably a better one is "Simulation from the Big Bang results in output that looks like our universe at the galactic scale"

    To suggest that this equals "Astrophysicists Build Realistic Virtual Universe" more than a touch hyperbolic.

  • Have they solved the problem with quantum theory and the big bang being mutually exclusive (other than saying the laws of physics changed somehow)? If not, there is still a really big problem to solve.

  • But it runs thousands of times faster than ours. Eventually they evolve intellignece, discover our universe, and break into it.

Nothing ever becomes real until it is experienced. - John Keats