E-mail updates
Follow on Twitter
Subscribe to RSSA supercomputer simulation produces a virtual spiral galaxy that comes close to matching the look of our own Milky Way. Msnbc.com's Alan Boyle reports.
How long does it take to simulate the Milky Way? The answer is about nine months, if you're using a powerful supercomputer. That's how long it took for researchers at the University of California at Santa Cruz and the Institute for Theoretical Physics in Zurich to produce the first simulation of galaxy formation that approximates the look of our own Milky Way spiral.
"Previous efforts to form a massive disk galaxy like the Milky Way had failed, because the simulated galaxies ended up with huge central bulges compared to the size of the disk," Javiera Guedes said today in a news release about the project.
Guedes worked on the project during her time at UC-Santa Cruz, and is now a postdoctoral researcher at the Swiss Federal Institute of Technology. She's the first author of a paper accepted for publication in the Astrophysical Journal that describes the simulation, known as the Eris galaxy.
For 20 years, astronomers have been trying to come up with a simulated galaxy that comes close to the look of the Milky Way and other spiral galaxies — but fell short of the mark. Guedes and her colleagues were more successful in part because of the computer firepower at their disposal: 1.4 million processor-hours on NASA's Pleiades supercomputer, plus additional supporting simulations at UC-Santa Cruz and the Swiss National Supercomputing Center.
"We took some risk spending a huge amount of supercomputer time to simulate a single galaxy with extra-high resolution," said UC-Santa Cruz astronomer Piero Madau, one of the paper's co-authors.
The effort used a software platform known as Gasoline to trace the motions of more than 60 million particles, representing galactic gas as well as dark matter, over the course of more than 13 billion years.
Annotated animation of Eris galaxy from University of Zurich.
Madau said developing a realistic simulation of star formation was another key to Eris' success.
"Star formation in real galaxies occurs in a clustered fashion, and to reproduce that out of a cosmological simulation is hard," he said. "This is the first simulation that is able to resolve the high-density clouds of gas where star formation occurs, and the result is a Milky Way type of galaxy with a small bulge and a big disk."
The recipe for the Eris galaxy limited star formation to the high-density regions of the galactic disk, which resulted in a more realistic distribution of stars. Within the high-density regions, supernova explosions powered an outflow of gas from the inner part of the galaxy, keeping the central bulge from getting too big.
The point of the exercise wasn't merely to come up with a pretty animation. The virtual conditions for Eris' creation are consistent with the theory that galaxy-scale structures coalesced from cosmic webs that were dominated by cold dark matter. Gravity drew primordial clumps of dark matter together into bigger clumps, and the "ordinary" matter that makes up stars and galaxies fell into those dark-matter clumps — giving rise to visible galaxies embedded in halos of invisible dark matter.
Cosmologists contend that the universe consists of 4.6 percent ordinary matter, 23.3 percent dark matter and 72.1 percent dark energy. But the fact that astronomers found it difficult to produce galaxies like the Milky Way using that formula led some to question the prevailing cosmological model of the universe. The Eris galaxy simulation "shows that the cold dark matter scenario, where dark matter provides the scaffolding for galaxy formation, is able to generate realistic disk-dominated galaxies," Madau said.
The research team's effort may be a tour de force for supercomputing, but don't confuse the virtual Eris with the real-life Milky Way. Even though Eris is an incredibly high-resolution simulation, its 60 million particles of gas and dark matter pale in comparison with the Milky Way's hundreds of billions of stars.
Swiss researcher Lucio Mayer discusses the galaxy formation simulation with interviewer Michele De Lorenzi.
Extra credit: Eris is named after the Greek goddess of discord, in recognition of the decades of discordant debate that have surrounded the scenarios for forming spiral galaxies, according to a description of the project on the HPC-CH weblog. Guedes' website includes a quote from the Iliad: "The soldiers fought like wolves while Eris, the Lady of Sorrow, watched with pleasure." The simulated galaxy isn't the first astronomy-related object to bear that discordant name: Eris is also the name given to the dwarf planet that caused so much trouble for Pluto.
More about dark matter and cosmology:
- Has dark matter finally been seen?
- Dark-matter stars could solve cosmic mystery
- Gallery: Dark matter revealed!
- Dark matter mapped in 3-D detail
In addition to Madau and Guedes, co-authors of the paper include Simone Callegari and Lucio Mayer of the Institute for Theoretical Physics in Zurich. This research was funded by NASA, the U.S. National Science Foundation, the Swiss National Science Foundation and an ARCS Foundation fellowship to Guedes.
Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter or adding me to your Google+ circle. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for other worlds.
Leave a Comment:
"The effort used a software platform known as Gasoline to trace the motions of more than 60 million particles, representing galactic gas as well as dark matter, over the course of more than 13 billion years."
Those particles are doing lots of different things, so naturally there is a lot of number crunching going on.
A beautiful simulation. Much work remains, as there are far more varieties of galaxies than 'simple' spiral galaxies such as our own. It is interesting that the 'dark matter' is a required scaffold for the simulation, and the connecting link on dark matter was quite interesting. Thanks, Alan!
What they ended up with looks a lot like an Sa class galaxy such as Messier 63, the Sunflower Galaxy. Our Milky Way is classified as an SBc barred spiral. The simulation has a small short bar through part of it's evolution, but not by the end.
Hopefully they'll get more time with the supercomputer to see if they can at least simulate the evolution of a few other galaxy classes.
One of the things they have not done yet is to start smashing galaxies into each other. Our galaxy has had a few mergers, so our current structure would probably not be able to be derived from a single galaxy simulation.
Eight months on their supercomputer, and 570 years (6840 months) on a pc? That means that back-of-the-envelope this supercomputer is 855 times faster than a pc...? In reality I would expect anything that takes 8 months on a decent supercomputer to take much more than 855 times longer an a pc because of memory/disk limitations and related bottlenecks on the pc. Something is not right here. The main computer used is Monte Rosa which is a Cray XT-5 with 22034 2.4GHz Opteron Cores and an optical interconnect. I don't see how this would only be 1000 times faster than a pc. Perhaps they didn't have the whole machine at their disposal.
There were 22034 instances of "ANGRY BIRDS" running at the same time as the simulation.
Yet another monumental waste of time and money to promote the archaic notion of a gravity based cosmos. I will admit to the amazing science and skill involved in creating the model, but in the end you have a pretty toy that has a questionable connection to reality. This process of science by computer model tempts us to believe in the fairy tales that pervade our understanding of the universe. Dark energy-72%? Dark matter-23%? Let's just say we are 95% unsure of what is out there. I believe it is time to embrace the possibility that electro-magnetism is the primary force that has shaped our world.
I disagree, Nothing is a waste of time if it eliminates possible aspects of knowledge that are not correct. You are not born with the ability to run you have to first learn how to crawl and then walk.
Besides how many new technologies were developed from research that was focusing on achieving another result but instead opened the door to other advancements that wouldnt have been discovered if that waste of time project hadnt been performed?
How can you say that electromagnetism is the primary force that shaped our world and admit that we don't know what 95% of the matter out there is? What if that 95% doesn't have electric charge and therefore doesn't interact electromagnetically?
The 95% unknown is part of the gravity based model (myth). Dark matter and dark energy were made up and thrown in because the math didn't come out right. We actually have a very good idea that 99.99% of all known matter is in the plasma state. Plasma is an excellent conductor of electricity.
czeke, they're called publications, generate some or can it!
Pirate C, your point is well taken. Certainly many new products and techniques have been the result of looking for something else. Perhaps here advancements were made in the computer sciences and I am happy for the researchers if this is true. As to the astronomy, I think it is a step backward, getting closer to the earth is flat every day. Your analogy of learning to run is a nice segue to my point. I think we are somewhere between crawling and walking, going in the wrong direction.
You have that idea. That position has had zero traction with the science of astrophysics.
Michael(Astronomy.FM), I believe that stars are in the plasma state. IF this is true, I would guess that in any star system, the mass of the star compared to the combined mass of all its planets and their moons would tilt heavily in favor of the star. If stars are not in the plasma state, what are they?
That's true. The difference is that we know there is much more mass in the Universe outside of stars than in.
Czeke I agree with you in the aspect that Nasa ended the space shuttle, Russia is now having issues with its launch platform so where does that leave us.
I dont think we are sliding backwords in terms of Astronomy, it is slowing down possibly due to the economy. But in truth the our science and knowledge is still in its infancy and it has a lot to grow but in the last 20 years we have made great strides.
My main hope is the James Web telescope doesnt get canceled if that happens then yes we will be sliding backward.
HairyMan-3010060, Really? I thought the free exchange of comment was the idea here. I was not aware one needed to be published to participate. I will get to work on that!
I don't understand why I can't lose weight. I eat fewer calories than I burn but have hit a wall and don't seem to lose anymore weight. I'm going to tell my doctor it must be dark matter. Seems to work for science so I'll throw it out there and see if it sticks.
Deleted. See page 2.
Google "James Webb petition"to put your names on the list to hopefully get some funding back!
I look forward when they can start modleling at planetary scale. I would be interested to see how many Earth-like worlds develop.
If you mean Earth-like in composition and size, a galactic-scale simulation wouldn't be necessary. Most of that has to do with the composition of the accretion disk that formed the star (and system), and how many planets populate the system. It is already known that multiple planets and earth-mass planets are not uncommon. By far the most important factor in terms of composition is what generation the star is. A much more difficult question is if Earth-like planets form in binary star systems, and if their orbits are stable enough to maintain liquid-water temperature. This is important because binary systems are quite common.
Excellent work - another step in combining technology and physics to expand our understanding of galactic creation. Hope to see this continue to evolve on a universal scale.
Hopefully someday we'll be able to map where the aliens are living, and what they had for breakfast millions of years ago
Truth is,man cannot create,nor recreate anything.Man can pat himself on the back and say,(look what I've done)but all in vain.
That has got to be the most unintelligent comment I have read to date.
and that's saying something, eh pirate?
How do you even get yourself out of bed with that attitude, Virge?
Uhm, trouble is, he's right. What isn't there already cannot be put there. Simple as that. Not a philosophical argument, rather a physical one.
Uh, I made a bowl of cereal this morning. The cereal and milk were separate entities but because I am man, I can combine those entities and CREATE my breakfast. Virgil, Jack you guys should give it a try.
Backwards?
The ancient Mayans from what I understand said the center of our galaxy was the womb of the universe. So? Is it possible that the matter actually came out of the womb and not attracted by some weak gravitational force?
So the singularity came first? Makes sense, so what caused the singularity?
Is it possible that the universe isn't the base platform kinda like the earth isn't flat. Or how color is refracted light.
If we keep on finding lower levels to the atom isn't it safe to say that it should also work in bigger levels. -3, -2, -1 0 1, 2 ,3
Is the universe a circle or a sphere or some other shape altogether.
Well if it's been expanding from one point, more or less uniformly in all directions for a long time, then it figures to be spherical
If we are talking about "normal" three dimensional space that is one, but not the only possibility. The important debate is if the density parameter Omega is greater than, less than, or equal to 1.
"...rest easy baby, and recognize it all as light and rainbows, smashed to smithereens, and be happy."
I don't speak math, so I like to think of it as round. But with something so big, I guess any shape is fine
I like to think of the universe as a toy plasma ball with many external layers not one uniform exterior. Conceptually!
It just makes so much more sense to me.
It does seem as if theories are chosen and not that creative. Conforming theories. Micromanagement?
I have my own theories based on what I understand and HISTORY. I am no ""Scientist, but really aren't we all?
I will keep an open mind :)
Maybe we are a bit of fireworks for the amusement of some creatures we cannot imagine?
The Wilkinson Microwave Anisotropy Probe (WMAP) has confirmed that the universe is flat with only a 0.5% margin of error. Within the Friedmann-Lemaître-Robertson-Walker (FLRW) model, the presently most popular shape of the Universe found to fit observational data according to cosmologists is the infinite flat model.
czeke,
Don't get me started. If you think about it the science community has been talking about the possibility of Terra forming Mars for decades. Then also think about if and when we are able to recreate or manipulate life biologically would you want to take the chance doing it on your home world?
Tell you one thing I don't believe in Random. Maybe Random works in a scattered brain but I don't see it as even a possibility.
So it's like a big pancake?
Buddha,
If I where to go outside and look around it would be hard to convince me that the earth isn't flat. Using my current observation.
Perception.
@MDB123
There are two truly random "things" in the universe:
So to say you do not believe in Random, does that mean you do not believe in the weak force?
BTW... The drunkards walk thing is a science joke :D
Is that like saying "we are all created equal"? Is that your argument for randomness?
Why would you talk in tongues? When you know I am not part of the category that would understand? Does it make you feel better? Superior?
When Einstein was asked "what is pi" He said "what do I care that is what charts are for".
I am rough around the edges I am not attacking you. :)~
@MDB123
Being a Buddhist, I do in fact think all beings are created equal.
Sorry, did not think I was speaking in tongues and I do not know you from a "hole in the wall"; I have no idea what you would understand or not understand, this is a science section after all and I speak scientifically when it is called for.
From a science perspective, the only random thing in the universe is the weak nuclear force (the force that causes atoms to decay).
My point is, you can not say you do not believe in Random or Rrandomness for there are truly random events going on all around you, including the atoms in your body. (also a lot of quantum "weirdness" too, but that is another topic...)
@Doug-950479
No, not in the same way as the Milky Way is, the Milky Way is round, wide by relatively thin.
What they are trying to really say, is they detect no curve, if it was curved, positive or negative, it would fold up into itself. Meaning... if you were to keep traveling in one direction, you would eventually end up in the same spot, and they have not found any support for this.
Buddha,
I have no doubt you are a good dude! :)
Random to me is without explanation. If you truly believe all things to be equal than it is a matter of explaining the unexplained.
Random is an illogical term. It is simply not yet understood.
We as a whole barely understand our own planet. I just hope I am alive long enough to enjoy the brilliant minds of our time.
@MDB123
Namaste, thank you :)
OK, I will agree with that, but remember, there are many words that are uses in science that have different meanings in everyday use, chaos or theory for example. So... What they mean by "random" is that they have absolutely no idea what causes an atom to decay, it is "random", spontaneous. You could stare at an atom at it could decay now or a trillion years from now, there seems to be no cause for it. It is only when you take a "chunk" of the stuff and and average out the number of decays over a specific amount of time (and develop the half life) can you give probabilities of when it will decay; this is how they do carbon dating.
This decay, also known as alpha radiation (basically a form of helium) is really weird in how it happens. "Randomly" an alpha particle "breaks off" from the atom, but it is imposable to pass through the electron cloud, the alpha particle does what is know as quantum tunneling, it literally disappears from inside the cloud and pops back into existence outside the cloud; yes, there is very much we do know know about the universe.
Lets just agree that the common use of random and the scientific use are not quite the same.
Quantum physics is a calling I never followed. Quantum entanglement especially intrigues me. I think it has the potential to change modern perception.
Maybe a different lifetime (if possible) and a better economy.
Maybe gravity isn't gravity at all.
Thank You for humouring me :)
Maybe ""black holes aren't the infinite toilet bowl but are the volcano of their galaxy!
Maybe instead of always conting down we need to be the speck of dust and count up.
Maybe humanities biggest mistake was comprehending left to right instead of continuing right to left.
Maybe black holes are both the toilet bowl and the volcano.
Maybe black holes connect to a source and share and recycle matter ( energy).
Maybe I ate to many lead tainted corn flakes :)~
@MDB123,
When you say, "Volcano", do you mean spitting matter out instead of sucking matter in? If so, you are walking about White Holes, they have not found any as yet, but like Black Holes used to be, meaning, mathimatical possibilities until they found them, White Holes too are mathematical possibilities.
They have Event Horizons too, but unlike a Black Hole, these horizons are the point of "non-enter" (the Black Hole's are a point of no return) and they spit matter out.
White hole? Thanks! Learn something new everyday!
So what is the possibility of these black holes and white holes connecting to the same infinite density? Maybe using quantum tunneling?
Maybe holes are the tool and the white or black is the current state.
I guess what I am saying is maybe the universe is like a ""complex atom, but we are so so very small we can see the individual parts and then manipulate the parts of the parts.
@MDB123
The theory of white holes and black holes being connected, one feeding in, the other belching out has been around for decades; that they are either very like, or actually ARE wormholes. This idea has generally fallen out of favor as new evidence suggest White holes are very unstable but black holes "live" for eons.
There are also some ideas that a white hole is the "big bang" moment, gushing out matter from a black hole existing in an other universe.
In another universe? Like cell replication?
Now that makes so much more sense to me.
Could it be a perpetual state within a perpetual state infinitely? I guess it couldn't be perpetual if it grows.
Alpha and Omega?
Maybe DNA is the infinite density, I mean it as an analogy or maybe literally?
The lower the layer the slower the time?
Scratch DNA I guess Stem Cell would be a better analogy.
Buddha,
Have you ever read the MASTER KEY SYSTEM?
You can google it, it is free.
I will be honest I didn't finish it because it freaked me out. I am a strong believer that fear keeps you alive. Sure a life of fear isn't living that is where the balance comes in. Created equal!
MDB124,
No, never heard of it, I will check it out; THX
Yet another example of the waste of NASA. 1.5 million years of super computing to show a simulation of a no brainer. Look at a telescope and you see Billions of years back into the cosmos to Galaxy formations of all types. NASA the Trillion dollar swallower of public funds for no real dollar exchange. Fired NASA. Put the Puter to work creating jobs instead of dumb a__es.
dumb a_— post that is a word hash of falsehoods and half-lies, finished off with an idiotic summary.
@Real Life: Maybe what papa tiger is saying is that you have to be an Alien (as in E.T.) to work at NASA. That, or he believes that computers program themselves.
NASA's annual budgets throughout its 49-year history total $618bn.
Russian and ESA budgets are comparable to NASA's, so a rough, yet conservative calculation of the total historical expenditure of the three largest space agencies is less than two trillion dollars.
NASA's budget for 2007 was $17bn. For comparison, the US Department of Defence's 2007 budget and the cost of the current conflict in Iraq both exceed $450bn, a sum large enough to fund NASA at its current budget for the next 26 years.
Furthermore, it is estimated that every dollar spent by NASA returns at least $2 in direct and indirect benefits to the economy.
Wasteful and expensive? Subject to opinion, but certainly much less so than other departments and agencies. Damaging to the economy and knowledge? Absolutely not.
Good luck Henry, hope you can hire a couple million people to start up your business.
We can't even begin to sort this out at this stage in our development. What was present before the singularity? Can we actually understand 'nothing'? Can nothing actually be a quantifiable 'something? Where did it come from, and what was there before it? We do not understand enough about the universe to ask the proper questions. Yet. But this could be a step toward that goal. But, assuming and creating theories is dangerous, because fashionable theories become accepted, and then we crow and invent new things to explain why existing theiories do not work rather than begin with another possible model. At some point we are going to have to accfept that we do not understand before we will be truly able to.
Real life, that is what I gathered from it as well. What's really hard to wrap your mind around is the fact that time is also created when these branes or strings collide. So its tempting for me to say these colliding branes might have just been there forever but of course time doesn't exist til they collide.
If anybody with a better understanding can help me understand this that would be awesome.
Remember... the scientific definition (meaning not the common definition) of time is entropy, meaning change, nothing more. No universe, no change, so "time" started with the universe because the universe stated to change the instant of the big bang. In theory, it is possible to have a closed system, allow the entropy to reach maximum and then time ceases to exist in the system, although you could not "look" at it because the act of looking would increase the entropy and therefore it would not have been at maximum.
Yes, noodle baking stuff indeed, LOL
Buddha, in such a closed system, in the absence of time, would particles still have well defined velocities?
@HairyMan-3010060
No, as a velocity would mean change would it not? In such a system, when the maximum entropy has been reached, the atoms would literaly stop, AKA, Heat death; it would reach 0 Kelvin.
Very cool stuff Buddha.
@HairyMan: Correct. Zero Kelvin is as cool as it can possibly get.
Buddha-Dude:
You are wrong on two counts.
1. Heat Death does not imply 0 Kelvin. It only requires that all temperature differences or other thermodynamic process can no longer be exploited to perform work.
2. As the universe cools (current temperature on average between 2 and 3 K), it asymptotically approaches 0 Kelvin, and will only reach 0 Kelvin in infinite time (ie never). It just gets minutely closer and closer.
@Brett
You are correct, my Fo Par. It has been a few years since I studied entropy, just went back to my books and checked; D'oh! Sorry about that.
Now... My question about entropy is (saw this in my book so asking for a deeper defination), when the universe expands to the point where each atom is esentialy a closed system, meaning each atom is so far away from each other that it is impossable to interact with each other in any way, would said atom not leak all heat and energy away to the point where it reaches 0 K?
Interesting question(s).
1. Due to gravity, there will still be clumps of atoms all over the place. There will be "free" atoms - almost all hydrogen, but still many clumps - dead stars, planets, etc... Without significant energy there will be nothing to blow things apart supernova style.
2. Even if all of the atoms in the universe were closed systems, they would continue to leak energy yes, but never reach perfect absolute zero. There is an easy way to visualize this - in order to get atom A to a perfect absolute zero, you would need something below absolute zero for it to leak energy to.
There is a major thing that we are overlooking in this discussion which is mass-energy equivalence. E=mc^2, tells us that mass and energy are essentially the same thing. The universe is a closed system (we think). Thus the amount of mass-energy is constant. At the time of the big bang it was almost all "energy". Now we are in an era of mass-energy change... "mass" changing to "energy", "energy" changing to "mass". (To make things very simple.) In an open universe, there will be very very little energy, forever tapering off towards, but never reaching zero energy.
*Please note that for simplicity (and a bit of laziness) I am kindof abusing the term mass here. We must rememer that mass is a property of matter, but is not matter in itself.
That sounds depressing, I truly hope the our future is the scenario where everything returns to a singular point and then another big bang happens. Anybody know which model is more probable?
@HairyMan - you are hoping for a Big Bounce.
To know what will happen to the universe, or even what is more probable we need to sort out dark matter / dark energy, or just rely on observation and hope we are right.
The fate of the universe depends on a parameter commonly referred to as Omega - the average density of the universe divided by a critical value of that density. This leads to three possibilities: Omega > 1 means that we have a "closed" universe and someday it will be big crunch time and possibly big bounce time neglecting dark energy. However some believe that with sufficient dark energy the universe could keep expanding forever leading to heat death, aka The Big Freeze, or The Big Rip (See more below). If Omega = 1 we have a "flat" universe and it will continue to expand forever, but slowing down more and more, approaching zero expansion but never getting there. This will result in (again) heat death or The Big Rip. If Omega < 1 the universe is "open" and (yet again) we have heat death or The Big Rip.
The Big Rip is the possibility that with sufficient dark energy, the rate of expansion will increase and dark energy will overpower all other forces. I'm not going to get into this, but you can look it up. Very basically, all matter will be torn apart by the ever accelerating expansion of the universe.
So what do we know (observationally)? The universe is currently expanding. It is also accelerating (unless there is something VERY VERY wrong with our observations). So if I had to make a judgement call right now I would say that the universe will continue to expand forever and most likely result in heat death. The Big Rip is too difficult to experimentally make a call on at present day, whereas heat death (in the absence of The Big Rip or some other Big Something that someone has yet to dream up) is a virtual guarantee (provided the current expansion continues forever). But who am I to make that call!
Another thing to consider in the cases where The Big Freeze or The Big Rip are the outcome (or in a closed universe with a very very very slightly > 1 Omega, is if the proton decays. Again that is way beyond the scope of the discussion here. But again I can't stop from going on a little bit. If the proton does decay (say with a half life of 10^100 or so years) there's not going to be much going on sooner than later. If however the proton does not decay Things will also get dark and cold, but later more than sooner.
Yet another possibility is the multiverse theory, where our universe is not the only one. In this case, the superverse may never end, as there are possibly infinite "universes" or just verses all doing their own thing in their own time all over the place. Interestingy some are just now claiming "observational evidence" of this: Most however contend that knowing if we are or aren't part of the multiverse is by definition not knowable.
Either way the current age of the universe is 13.75 ± 0.11 billion years. Given the predicted timeframe for stars to form "normally" we are very approximately 1/1000 of the way to when things will start to get "weird", unless dark energy or dark matter interfere first.
Finally, there are even more bizzare theories out there. Basically if you want a certain end / non-end to the universe, there's a theory for that.
You'll never find an answer in the Cosmos for problems here on Earth. So stick to your ground grubling dreamer of traveling to far away Worlds. Black Matter would wear out your ship.
Watch out when the Black Hole starts to spew out Gamma Rays. It's in a quiet stage right now. When the orbits decay of the near stars to it BOOM !
The whole problem is expanded upon, or retracted upon, or own limited understanding of all things. If it all started "someplace" (where?) from a big bang (of what, and why?) and then is expanding (to where, from where?)...what is where it isn't? You know, what is at the edge of the Universe? Where does "space" end? If it does end, what is past the end of space? If it ends, something has to be beyond the end. If it doesn't end, how can it not end? We all tend to think "inside the box". If that is the case of "space"...what is outside the box? We have seen, supposedly, not only distant stars inside our own Galaxy, but distant Galaxies that contain yet more stars. Always moving, having some purpose. Going where? From what? If you are going somewhere, you came from somewhere. And most importantly, why? We will never have all the answers. But we will have many more questions.
It really does always boil down to "Why?" .. Why does the universe exist at all? .. Why not have an infinite void of infinite nothingness instead?
The universe itself, must be a living entity. I wonder if anyone has ever thought of the possibility that our reality is really just a function of being inside of a massive black whole.
Space is not a big empty place where the universe whizzes around. It is a thing. It fuels matter as it becomes matter. The conversion of this space stuff to matter is what give atoms their endless energy. Where matter is absorbing space the pressure of space is lower, where matter is less concentrated the pressure of space is greater. Space flowing into matter is gravity. The greater the mass the greater the flow the greater the gravitational effect. And space is expanding or increasing simultaneously. It is this balance of expansion and absorption that allow matter to accrete without everything becomming a black hole.
Sounds like this should be able to go on forever
I'm sure this is an accomplishment, but I've seen artistic representations of what they (the artists) imagined the Milky Way looks like since I was a kid (I'm 53 now) From what I can tell, what they came up with using a super computer, is not all that much different from the artist drawings of my youth.
I'm sure there are practical science uses for what they are doing and I fully support that, but what they came up with in visual terms is not so much different than what many have imagined for a long time now by viewing other galaxies through telescopes.
I imagine early astronomers used similar logic to determine the earth was round and not flat long before anyone ever went around the world.
Real Life, I concur. As I said, I'm sure there are practical science applications for what they are doing, and I fully support that. But, I'm also sure my ability to understand those applications are way over my head.
It looks very similar to the formation of a hurricane. From a tropical depression, tropical storm etc. Without pressure differentials in the vacuum of space, what is the gravitational spark that sets the process in motion?
Ya Fletch, what sets something on the scale of a galaxy in motion? The simulation shows a spinning center but galaxies are all about star formation. It seems black holes are required first or are made very early in galaxy formation for this clumping and star formation.
Black holes are not required for galaxies to form, there are many types of galaxies not all of them have black holes at their center.
Better back up what you say.
Click on my "User Name," then click on "Primer For The Universe."
They tweaked the code (limited star formation to the rim amoung others) so that the results looked similar to the Milky Way. This is an instance of knowing the result and then playing around with the boundary conditions and code to get the result you want to compare with, a self fulfilling simulation.
Depends.
Do you live on the coast of a large body of water?
Are there sailboats or a bridge that extends to the horizon on that water?
Do you have reasonably decent eyesight?
If the answers to all of these questions are yes, you sir can see observationally that the earth is in fact round.
If that isn't enough, you can get your own weather balloon to send a video camera to the edge of the atmosphere and see earth's curvature second hand.
Still not enough? Observe a lunar eclipse. They happen about once a year. You can see the curvature of the earth's shadow on the moon's surface.
Want still more proof? Go stand on the beach of an ocean. Ask yourself why you can't see the beach on the opposite side of the ocean or any islands in between.
@Tripto: I don't think that's his point. I think he's saying that when you're very small compared with the radius of curvature, things look reasonably flat; you have to make just the right kinds of observations (like the ones you suggest) to find out otherwise. Similarly, from our vantage point, the universe looks flat (flat in three dimensions, not flat in two). It takes very sophisticated measurements to disprove flatness, and so far all measurements of the universe are consistent with the universe being flat.
And it goes without saying that just because the Earth turned out not to be flat, that doesn't mean the universe will also turn out not to be flat.
There were 22034 instances of "ANGRY BIRDS" running at the same time as the simulation. That's why it took so long....
czeke - you say 99.99% of matter in the universe is plasma? Plasma is hot - and radiates a lot of energy (in other words plasma is very bright). If this is true, why can't we see it all?
If electromagnetism is the dominant force in the universe as you say, then why is it gravity that allows stars to form in the first place, and also the force that ends them - in supernova, or as a black hole, when the inward gravitational attraction of the star's mass overcomes the outward force of radiation pressure?
Yes, the free exchange of comment is the idea here, but it needs to be backed up. Otherwise you will just confuse others with false "facts".