New universe simulation supports Big Bang and theories of universal evolution

originally posted by: Indigent
a reply to: muzzleflash

could you elaborate what you mean with that? do you know that has 0 relation to anything right? big bang = all was in a infinitesimal point and expanded from it. simulation = all in simulation was... (the same)

Where does they are creating energy when they defined it existed from time 0. do you know big bang don't cover anything before 0 or 0, it just explain the expansion after 0 right?

You claimed I didn't believe in Photons.

What are you even trying to argue?
That a computer simulation creates a real universe like this one?
Prove it?

a reply to: muzzleflash

you use wikipedia and yahoo, made me laugh

i am not on Your frequency!

expanding universe is theory!
quasars and colliding galaxies prove it is not working theory, just accepted and forced... lie.

a reply to: muzzleflash

That a computer simulation creates a real universe like this one?

From a logical point of view, if the simulation was 100% accurate, the simulated universe would be just as "real" as our universe. The fact it exists on a computer doesn't make it less real than ours, for all we know we may be in a computer simulation. But like I mentioned before, it's impossible for us to create a 100% accurate simulation of the universe because it would require all the energy in the universe.

a reply to: muzzleflash

all i'm saying is you define what is real in therm that are inadequate, for example leaving photons out of it. You seem to believe energy cannot be created by laws of physics and use wiki to prove it, when in a simulation this is also true as the energy of the system does not change in the simulation it was defined at the beginning, much like our universe, does any law of physics explain how the energy originated?

And most importantly a simulation could very well recreate a working universe, the universe follow patterns like collisions, gravity and so on we put into equations and this very same equations can be used in a simulation to rule it. Your definition of what is real is what fails you.

a reply to: Indigent

does any law of physics explain how the energy originated?

Science doesn't attempt to deal with anything that occurred before or led up to the big bang precisely because they don't want to have to explain how energy can originate from nothing. They say that at time 0 there was already an infinitely small point of energy, and then when time began flowing, the energy was diluted as the universe expands. So from time 0 until now there was always the same amount of energy. Personally I don't buy into that ridiculous theory for one nanosecond. For a start we live in what appears to be an infinitely flat universe, such a universe can not arise from a big bang which created a finite and closed space-time.

And if that's the case then it's not correct to say time and space didn't exist anywhere before our own big bang, and there very well may have been an infinite number of big bangs before ours. We obviously need a way to explain where the energy of our universe came from and what caused the big bang. The most likely answer, which is the answer proposed by many respected physicists, is that our universe is the result of a random quantum fluctuation which created an equal amount of negative and positive energy. Look up "a universe from nothing" by physicist Lawrence M. Krauss and also the theory of a "zero-energy universe".

I'm curious about what the difference would be if the simulation were re-programmed to simulate a universe with 2 spacial dimensions or 4 spacial dimensions instead of 3.

a reply to: Astyanax

All simulations (models) work perfectly with past data.....otherwise it's useless. Using the simulation as a tool only comes to the fore once you run it forward as it predicts how things will be. If the events it predicts come true then the simulation is solid.

This is how models/simulations are developed they are tweaked and tweaked to get ever more accurate. What you usually have as well is multiple models/simulations written by different people. As time goes by if these models are tweaked and converge then you can make assessments about where they are converging. Some people don't get that though......

a reply to: Junkheap

I cant resist and have to say that we live in 4 dimensions, you cannot define anything with 3 that gives you a position but you need time too

originally posted by: DietJoke
a reply to: muzzleflash

We trust 3d simulation for many important things like simulating aerodynamics instead of using a wind tunnel.

But ultimately it is but an abstraction. To rely totally on simulation is to miss the point of science, which is about testing it for oneself.

Yes true but simulation is one of the processes of the scientific method. Once you can simulate, or build a model that gives a fair representation, you can see the parts that dont match up perfectly. Then you can start to fill in the details and make it even more complex and realistic.

This is barely a fair representaion but it does show that the formulas are sound enough to make a more realistic model.

If you want to include other processes like genesis of life, we will have to gather much more info and then be able to input that data into a similar modeling program. One day soon, i expect to see such a model.

originally posted by: Indigent
a reply to: Junkheap

I cant resist and have to say that we live in 4 dimensions, you cannot define anything with 3 that gives you a position but you need time too

Time is not really a forth dimension. It is a function/property of space. Without space there is no time.

originally posted by: Woodcarver

originally posted by: Indigent
a reply to: Junkheap

I cant resist and have to say that we live in 4 dimensions, you cannot define anything with 3 that gives you a position but you need time too

Time is not really a forth dimension. It is a function/property of space. Without space there is no time.

maybe the other way around, no time no space

originally posted by: Astyanax

According to Dr Mark Vogelsberger of Massachusetts Institute of Technology (MIT), who led the research, the simulations back many of the current theories of cosmology. 'Many of the simulated galaxies agree very well with the galaxies in the real Universe. It tells us that the basic understanding of how the Universe works must be correct and complete,' he said.

In particular, it backs the theory that dark matter is the scaffold on which the visible Universe is hanging. "If you don't include dark matter (in the simulation) it will not look like the real Universe," Dr Vogelsberger told BBC News. Source

Emphasis on "basic", for sure.
They didn't even begin the simulation from the actual moment of the Big Bang. They started it 12 million years after and didn't let it run passed our present epoch to see what would happen. Or maybe they did and the simulation crashed...
In other words this simulation only confirmed what we've measured/observed, not necessarily our understanding of how the whole thing works. Nor does it get us any closer to what it is.

Originally posted by: Junkheap
I'm curious about what the difference would be if the simulation were re-programmed to simulate a universe with 2 spacial dimensions or 4 spacial dimensions instead of 3.

Making toy universes is something mathematical physics do all the time. 2D universes are popular because they're simple and can be used to model a variety of phenomenona very effectively. Contrary to what the mumbo-jumbo crowd here are saying, these simulations are perfectly valid. They do not assume what they set out to prove and their utility has been demonstrated any number of times.

Time is a fourth dimension in many of these models, but universes with four or more spatial dimensions are also frequently modelled. Google; you'll find plenty about this stuff.

Originally posted by: yorkshirelad

All simulations (models) work perfectly with past data.....otherwise it's useless. Using the simulation as a tool only comes to the fore once you run it forward as it predicts how things will be.

That's right. In this case they fed in the initial data for T=0, ran the simulation forward 13.8bn years, and got a close facsimile of the Universe as it exists today.

If people would only look at the link before rushing to share their opinions, these obvious things would not have to be tediously explained.

a reply to: PhotonEffect

Twelve million years out of 13bn is pretty much T=0. We don't know enough about conditions soon after the Big Bang to go back all the way to zero.

originally posted by: Indigent
a reply to: muzzleflash
does any law of physics explain how the energy originated?

Yes, Heisenberg's Uncertainty Principle. One of its outcomes is that empty space always has some energy (dubbed "vacuum energy", or "zero-point energy"). Vacuum is usually at its lowest energy state, but due to some quantum processes, it can be at higher energy state (dubbed "false vacuum").

en.wikipedia.org...

ChaoticOrder wrote: "Science doesn't attempt to deal with anything that occurred before or led up to the big bang"
That's not true, theoretical physics is eager to contemplate on the before-the-big-bang physics: en.wikipedia.org...

originally posted by: Astyanax
That's right. In this case they fed in the initial data for T=0, ran the simulation forward 13.8bn years, and got a close facsimile of the Universe as it exists today.

I'm not quite sure what to make of the note of caution from the end of the source though:

Cosmologist Dr Robin Catchpole of the Institute of Astronomy in Cambridge, added a note of caution, however.

Although he hailed the simulation as "spectacular", he added, "one must not be taken in by the sheer visual beauty of the thing. You get things that look like galaxies without them being much to do with the physics of how galaxies emerged".

The article shows all the simulated galaxy shapes and points out how much they look like real galaxies, but then Catchpole says the things that look like galaxies don't have much to do with the physics of how galaxies emerged, so it seems to be a mixed message.

In any case I agree with him that it does look "spectacular".

originally posted by: wildespace
theoretical physics is eager to contemplate on the before-the-big-bang physics: en.wikipedia.org...

At least when those guys say it's difficult to test their hypotheses, I can understand why it would be difficult to create a new universe. So it would appear the hypotheses are likely to remain untestable for now.

String theory or perhaps more accurately "string hypothesis" seems to invoke similar reasons for having no experimental confirmation (saying they need big bang conditions to test it), but it seems to me that we should be able to create some observations to support string theory (if it's correct) without creating new universes.

a reply to: Arbitrageur

I wish Catchpole had been quoted at greater length. He probably had more to say; he's a popular speaker and media pundit, if not on the American superstar (Carl Sagan et al.) level.

I think the point is that they could get the model to produce a result like the real thing — instead of crashing at some point because of some unanticipated flaw. Can't comment on Catchpole without knowing exactly what he meant.

so...
scientists are happy because they have develop a computer program that computes something that looks like reality...
how is it a proof to anything ??

LOL

I have a computer simulation here.
It is about a room with people.
Computer tells me that if there are 3 people in the room and 5 people go out, 2 more have to go in for the room to be empty
I agree on that simulation !

a reply to: KrzYma

Whatever your point is, you're not making it. Try again. I want to know what you mean.