3mph

10/4/2011 6:09:02 PM

One of the most interesting thing about the deviation from homogeneity in the universe is that it's entropic. Just like perching on a high place requires sustaining lower entropy energy than what you'd get by falling, the smooth nature of the universe that was present at the big bang is low entropy. Everything started homogenous, and everything gets more heterogeneous as time goes on. Gravity is an entropic force. Eventually, matter will prefer to locate itself in dense local clusters, and possibly black holes.

As dark energy continues to tear the universe apart, all matter may find itself isolated to a black hole that comprises its local group or some small fraction of it.

Quote :

"why does puck_it think the universe is infinite again?"

I'm not puck_it, but until we prove spacetime has a curvature that will wrap it back around on itself (which we have not), then we can't know that it's not infinite. The big bang doesn't prohibit an infinite universe. However, the definition of a "universe" might, since we do have evidence to believe our sphere of influence will be limited, our own universe is finite. Although, that's just in one manner of speaking.

[Edited on October 4, 2011 at 6:19 PM. Reason : ]

10/4/2011 6:18:50 PM

lol im not gonna get all upset... i just dont know how to parse it any better, specifically after i cite research that says there is homogeneity.

regarding why i say the universe is infinite... currently they observable universe is ~13 Gly, radially, (26 Gly across)... but extrapolating the acceleration of exapansion and doing all sorts of nerdy calculations and such, there's conjecture (and this can never be proved in our life time, or even in the lifetime of the sun) that the universe has expanded out to something like 60 Gly across. 60 billion light years. thats friggen huge. but not infinite.

However, since the expansion is accelerating, there's no evidence to show it has ever slowed down, and time is generally accepted as being infinite... the bound of the universe is generally stated to be without bound at infinite time. unless we can show some sort of blue shift, to show it's decelerating, this will likely remain widely accepted.

there's also the possibility that there are multiple universes. perhaps infinitely many. picture our universe as an cone on a plane, who's to say there arent cones next to it, randomly dispersed. spreading to infinity, all the while changing the scale at which homogeneity is considered to appear. but the beauty of infinity, regardless of that scale, it's still a drop in the bucket.

10/4/2011 6:50:16 PM

I still don't understand.

Again, are you saying that spacetime wasn't created at the big bang?

like this thing

Quote :

"and time is generally accepted as being infinite"

are you saying that time extends backward infinitely? Because I've always thought/learned/heard that time began at the big bang.

[Edited on October 4, 2011 at 9:17 PM. Reason : .]

10/4/2011 9:17:27 PM

I really don't understand this homogeneity thing...

I'll have to look it up.

The universe has a structure a stringiness, but I seem to be hearing that our perception of that stringiness has something to do with our observation point?

Like I said, I'm hearing, in this thread, that the universe is homogenous but I see stringy galaxies.

Are people here saying that the dark energy and dark matter is homogenous?

[Edited on October 4, 2011 at 9:26 PM. Reason : .]

10/4/2011 9:25:58 PM

Homogeneous would be defined as uniform density... so, if you take pennies randomly scattered on the floor with a square grid, you might end up with 6 in a square, 16 in another, none in another.... if you drew your squares bigger, you'd get closer and closer to having an equal number in all. Keep going out further and further, you can make larger squares, and eventually end up with the same number in all.

10/4/2011 9:41:24 PM

So is the distribution of other galaxies equal within all spheres of our point of view. Why I ask is that if the universe started from a singularity that exploded during the big bang, should not all the superclusters appear to be moving away from a common point? I do not understand how a supercluster could drift back to the coordinates to where the initial singularity existed. Also would not this mean that their should be a decreased distribution of matter within the direction that our own supercluster is accelerating into? As how can there be an equal amount of matter in all directions of our observable universe?



[Edited on October 4, 2011 at 9:49 PM. Reason : l]

10/4/2011 9:47:08 PM

^^

now I'm going to start getting mad at you because you are literally just fucking defining the word

you need to explain what you mean much better if you're going to be convincing

and I'm fucking ready to be convinced

...

better yet, you're just defining a smoothing function, really... or something.

The galaxies exist in a stringy pattern, that's well know.

You're saying that's homogeneous, when all the galaxies in the WHOLE FUCKING UNIVERSE, exist in this stringy pattern, with VAST VOIDS between them?

...

are you saying this pic that Smath74 put up, which is totally fucking correct and awesome, is somehow incorrect from a certain point a view? Are you saying that's the case by "making the squares bigger"? Seriously?



[Edited on October 4, 2011 at 10:05 PM. Reason : ...]

10/4/2011 9:59:34 PM

I think the exact number where homogeneity exists is a resulution of something like 300 million light years. That image has 100 million light years drawn on ... I cited a paper earlier in the thread....

I don't quite know what more you want? I defined it, there's some numbers...

All I can do is define the process, other wise I'd write a paper if i could execute it.

[Edited on October 4, 2011 at 10:59 PM. Reason : .]

Don't be mislead by that image either, it's quite a bitch to read, because your mind wants to flatten it... its a sphere

[Edited on October 4, 2011 at 11:03 PM. Reason : .]

10/4/2011 10:55:58 PM

ahahahha

I'm not reading your stupid paper... you know why?

It's from fucking 1986.

COBE wasn't even launched until 1989

you need to go read a fucking book

10/4/2011 11:22:25 PM

I make everything up

[Edited on October 5, 2011 at 12:50 AM. Reason : troll troll troll]

10/5/2011 12:37:26 AM

If I remember correctly, nastoute actually has claimed to have a physics degree and flamed me in threads about astrophysics before.

I'm going pretty far back here, but I think that even in his flaming he noted that he was a physics grad and a valedictorian (granted, half of every graduating physics class are "valedictorians"). I remember looking up his research and seeing stuff about turbulence and sonic waves from ejected clumps of matter in supernovas.

[Edited on October 5, 2011 at 1:34 PM. Reason : ]

10/5/2011 1:33:23 PM

very far from any "valedictorian" and that's really kind of sad and creepy

why do you think I'm trolling? I'm asking specific questions and I get none answered.

and then I realize that this dude probably knows NOTHING

it's just that, if you're going to talk about the cosmic microwave background, you should know, like, the super basics about it...

...

The really funny thing is that the paper he put up seems to be essentially correct but I think puck_it is misunderstanding what it says.

The CMB is very isotropic, negating local effects, but has significant small, local, anisotropy. This anisotropy, I've always understood, is the fingerprints of nucleation for the large scale structures we see today.

[Edited on October 5, 2011 at 2:34 PM. Reason : ...]

10/5/2011 2:19:14 PM

Quote :

"very far from any "valedictorian" and that's really kind of sad and creepy"

To be clear: you are offering a contradiction - what I remember is not correct. Am I reading this right?

Quote :

"and then I realize that this dude probably knows NOTHING"

Again, to be clear: this statement is in reference to puck_it?

10/5/2011 2:53:24 PM

However in later surveys, isotropy and homogeneity (not specifically mass distribution, but of governing physical laws) were found to exist at resolution of about 100 Mparsec... 300 Gly. The voids and "stringyness" were found to be repeating and and thus regarded as homogeneously distributed

[Edited on October 5, 2011 at 3:07 PM. Reason : shrug]

10/5/2011 2:57:11 PM

guys, what's important here is to know that the universe takes off

10/5/2011 3:07:46 PM

This is true. I dont even know how we ended up on this shit after talking about neutrinos and shit.

Anyone see any updates of an oh shit error found.

10/5/2011 3:10:48 PM

Speaking of universes,


Are each of our minds separate universes?


How I view the world, and how someone else views the world are two different things. What's true in my universe, might not be true in someone else's universe.

10/5/2011 3:12:28 PM

Quote :

"How I view the world, and how someone else views the world are two different things. What's true in my universe, might not be true in someone else's universe."

By a certain definition of a "universe", any two things that have the ability to interact are in the same universe. So:

- apply principle
- both of your minds are in the same, larger universe
- profit?

10/5/2011 3:15:57 PM

WE'RE ALL A HOLOGRAM

10/5/2011 3:20:02 PM

Nm... lets keeps this conversation scientific.

[Edited on October 5, 2011 at 3:27 PM. Reason : .]

10/5/2011 3:23:46 PM

indeed, we are all holograms

10/5/2011 8:35:05 PM

fucking magnets!

10/5/2011 9:10:45 PM

I don't want to talk to a scientist

y'all mother fuckers lying and getting me pissed

10/5/2011 9:34:02 PM

Its just a simulation, don't get so worked up

10/6/2011 12:59:25 AM

honestly...

both quantum and general relativity make me wonder what the holy fuck anyone must have been smoking to make a simulation of our world the way they did.

Ok, so there's this thing called Lorentz Invariance. And basically it makes the universe look the same to everyone going any speed as long as it's not bigger than c. You can go 0.9c or 0.99c or 0.99999999999999999999c, and the laws of physics behave the same.

Let me put it this way: if you had to simulate physics on a computer (given the above requirement), everything goes to hell. There are theories that reduce the universe to what could be simulated on a computer, look up "loop quantum gravity". Yeah, every one of them are wrong b/c they violate the Lorentz Invariance.

---
If you thought that was difficult to simulate on a computer (more generally, a formal system), you might piss yourself reading about quantum. Some of the prevailing theories for quantum have a particle travel every possible goddam path before it ever gets where it's going. They're narrowed down by some integrals or some shit like that. Fucking scientists, amirite?

Look guys, quantum physics says that we do everything before we can do anything. How bout you go simulate that shit? The idea that we're in a simulation is stunningly not consistent with physics.

I think that existence itself if pretty baffling. But in terms of shit we've discovered (shit that wasn't totally obvious to begin with) that discovery by physics has got to be the most wack things we've ever discovered.

Dark energy might be a close 2nd.

10/6/2011 1:18:23 AM

But guize, I have a cray.

But yes, I've never subscribed to the hologram or simulation theories.

Things are a marvel... I often sit around and look at shit that we made and think about how mind blowing it is... we're just a bunch of atoms. Somehow we combined into this. And complicated atoms came from stars blowing up. Pretty fucking wild.

[Edited on October 6, 2011 at 1:51 AM. Reason : .]

10/6/2011 1:43:04 AM

Quote :

"But in terms of shit we've discovered (shit that wasn't totally obvious to begin with) that discovery by physics has got to be the most wack things we've ever discovered. Dark energy might be a close 2nd."

you mean conjectured, not discovered. we haven't discovered DM or DE yet. It's just that our calculations don't work unless we say it exists. Same kind of argument generally applies for QM, but then again, I don't know how we would go proving QM anyway. Beyond basic newtonian physics, shit really isn't provable to us yet. That we could even experimentally verify Einstein's ideas was difficult.

10/7/2011 7:39:08 PM

dark matter and dark energy are observations.

10/7/2011 8:29:34 PM

not exactly. they are postulations based on the inability of expected calculations to line up with actual observations. As such, they would best be described as a rationalization and naming for such a failure of our current understanding. I mean, even the name of them is indicative of a virtual fudge factor: dark matter. dark energy. It's almost the scientific equivalent of "God did it." The very names evoke an almost mystical and mysterious nature to the supposed phenomena, especially when we can't directly observe them.

10/7/2011 8:52:04 PM

I think this video explains dark matter pretty well. It even mentions CERN!!!

http://www.phdcomics.com/comics/archive.php?comicid=1430

10/9/2011 9:13:55 AM

going from this

Quote :

"the inability of expected calculations to line up with actual observations"

to this

Quote :

"they are postulations"

is missing a step. What is postulated? It's not postulated that the evidence disagrees with the expectation. That was observed.

10/9/2011 1:43:26 PM

Heavens NO, Hell yeeeaaahh.

--BHG

10/9/2011 1:50:06 PM

the postulation was that what made the expected calcs not work out was this magic matter and energy that can't be seen or measured. I mean, I know there are all kinds of smart people postulating these things, but you have to admit that a magical answer in science is, well, odd. Now, one day we'll figure it out and have a much better answer, whether it agrees with the DM and DE or not, but my gut reaction to these things, as an engineer, is skepticism.

10/9/2011 9:12:14 PM

Quote :

"Now, one day we'll figure it out and have a much better answer, whether it agrees with the DM and DE or not, but my gut reaction to these things, as an engineer, is skepticism."

If it disagrees with dark energy then it's an incomplete physical theory at best, and wrong at worst. That's physics - constructing theories to be consistent with the observed evidence. We're gathering more evidence all the time, and it's a important moment for physics when experimentalists obtain measurements that disagree with the accepted theories.

10/9/2011 9:18:46 PM

^^

did you even watch the video Nerdchick posted?

Dark matter has actually been observed too.

And i’m not sure what you even mean by "but my gut reaction to these things, as an engineer, is skepticism.” Is your skepticism that these don’t exist, that they are just matter we can’t measure yet? What exactly are you skeptical about?

10/10/2011 2:05:24 AM

Aaronburro's problem is that he thinks skepticism means ignoring data that doesn't fit his preconceived conclusion of "the official story doesn't have it right." Conspiracy theorists think they're being skeptical.

10/10/2011 9:21:11 AM

"selectively" skeptical

And just for the record, the "observation" is present if you assume either general relativity gravity or Newtonian, simple 1/r^2, gravity. Either way, the fact that they are accelerating away is a major major problem.

I recognize that it wouldn't be an "observation" if you didn't have the original model of gravity. But the idea that you would formulate a universally correct model of gravity without even knowing about dark energy is laughable.

10/10/2011 10:29:55 AM

Quote :

"If it disagrees with dark energy then it's an incomplete physical theory at best, and wrong at worst."

not if it's actually right. in other words, if we figure out something that explains away the current problems that led us to the postulation of DE and fits observations, then it wouldn't matter that it disagrees w/ DE.

Quote :

"Is your skepticism that these don’t exist, that they are just matter we can’t measure yet?"

It's more of the "we can't exactly measure it yet" aspect. That's the "magical" aspect of which I am speaking. The whole "we can't see it, touch it, smell it, photograph it, hear it, but trust us, it's there" aspect. I do recognize, IIRC, that there are some observations that suggest its existence, such as light bending through areas that we don't expect it to do so. But the other postulations of "shit is expanding in a way that we don't understand, so it MUST be DE/DM" would be laughable if it weren't for the credentials of the people saying it.

10/10/2011 12:50:49 PM

Quote :

"not if it's actually right. in other words, if we figure out something that explains away the current problems that led us to the postulation of DE and fits observations, then it wouldn't matter that it disagrees w/ DE."

We are absurdly far from that! Have you ever studied general relativity? GR is a srsly baller theory. It's the kind they made new mathematical notation just for. The cosmological constant was added for a irrelevant and wrong reason. GR did not predict this.

What level of physical theory would predict dark energy. Lord all mighty I have no idea! Don't hold your breath b/c it's probably not coming in our lifetimes. GR is baller, but quantum gravity will kick it's butt any day.

Quote :

"such as light bending through areas that we don't expect it to do so"

Given that we're calling this "dark matter"...

a) there's matter
b) it's dark

What are we missing? There's no magic. There's a big hunk of something that we've clearly identified and we don't know what it is. You're somehow taking the concept of dark matter to imply more than what it does.

10/10/2011 1:00:48 PM

Anything to undermine scientific inquiry as a legitimate path to truth. "See how it doesn't have all the answers regarding a Unified Theory of Everything? How can you trust it?"

10/10/2011 1:55:07 PM

Quote :

"What are we missing? There's no magic. There's a big hunk of something that we've clearly identified and we don't know what it is. "

really? we've driven out there and touched it? we've put a chunk of it in our hands and walked around with it? Same goes for DE. We've now got a battery running off of it? Look, if we called this stuff by another name, say "hand of God", it'd be laughed at. it's only because we've really got no better explanation that we even entertain the notion. That's not to say that there's zero evidence for its existence or for the theories about it.

Quote :

"The cosmological constant was added for a irrelevant and wrong reason."

Exactly. They created a fudge factor and attributed it to X and then found out it was really due to Y. The same may one day happen for DM and DE.

Quote :

"Given that we're calling this "dark matter"... a) there's matter b) it's dark"

Let me try it this way:

a) there's God
b) he lives in the sky and is invisible.

see?

10/11/2011 9:54:51 PM

A)The multitude of scientific modeling that is consistent with reality and suggests the existence of what we currently call dark matter and dark energy compared to the arbitrary suggestion that a deity exists and it's a particular deity of the 10,000 humans have made up over the history of our world?

B)The observational evidence that is consistent with what we currently call dark matter compared to absolutely no even indirect observational evidence that something "invisible" lives in the "sky".

Here you go again equivocating religious faith with inductive reasoning. There is nothing about reality that suggests "God" is real. There are mountains of evidence to suggest the thing we currently call Dark Matter is real. That we don't yet fully understand it does not mean that we're just making it up.

And what point are you trying to make, exactly? That belief in God is as unfounded as you think the belief in Dark Matter is? You're half right.

Your consistent failing is your insistence that scientists are convinced that they have discovered the absolute truth of reality. You ignore rational people constantly telling you that scientists are the only ones admitting that they don't have the truth. We admit that DM and DE are our current best guesses that fit our current understanding of cosmology and are subject to change given more information. This isn't a failing of the science rather it is its strength and it is not a suggestion that we should ignore what is currently our best estimate of reality.

[Edited on October 12, 2011 at 12:03 AM. Reason : .]

10/11/2011 11:59:32 PM

Quote :

"Exactly. They created a fudge factor and attributed it to X and then found out it was really due to Y. The same may one day happen for DM and DE. "

But the same would never happen for religions and their deities.

That's the point.

You have just proven for us all, burro, that science != religion.

Thanks buddy.

10/12/2011 12:18:02 AM

Quote :

"really? we've driven out there and touched it? we've put a chunk of it in our hands and walked around with it? Same goes for DE. We've now got a battery running off of it? Look, if we called this stuff by another name, say "hand of God", it'd be laughed at. it's only because we've really got no better explanation that we even entertain the notion. That's not to say that there's zero evidence for its existence or for the theories about it."

It's not clear what you're arguing.

Your writing here is indicating that you are doubting the strength of evidence for the fact that something with the properties of dark matter exists. If that's the case, you may simply state that you won't be satisfied until we get bigger telescopes, more detailed simulations, and more examples that evidence dark matter all over the sky.

10/12/2011 8:30:42 AM

He's just trying to justify believing in something that has even less evidentiary support by asserting that no amount of evidentiary support is capable of justifying scientific belief. Science can't answer any question fully so you might as well believe in magic.

10/12/2011 8:59:05 AM

Too much SB-esque banter in here to sift through.

Is this confirmed or no?

10/12/2011 10:46:55 AM

Not yet.

10/12/2011 11:10:50 AM

Quote :

"Too much SB-esque banter in here to sift through. Is this confirmed or no?"

And I'm taking "this" to be FTL neutrinos?

It's not confirmed by outside labs, but the entire point is that the people who did this were some of the only people with sufficient capabilities to pull it off. There's a bit of a predictable patten, in that the newest discoveries in science tend to be more challenging to verify.

It takes some very clever trickery to use the same apparatuses to discover something that no one else had previously seen.

10/12/2011 11:24:57 AM

I suppose what I meant to say was:

What's the status on the verification of this claim by the scientific community as a whole?


Or something of that nature

10/12/2011 11:33:17 AM