[img]http://i41.tinypic.com/mlgpcn.jpg[/img]
Yes, another science thread. Today we will learn the difference between [i]dark matter[/i] and [i]dark energy[/i]. They have very similar names, but are entirely different, and not to be confused.
[b]Why should I care?[/b]
Because one of the subjects at hand is more plentiful than normal matter in the universe and the other will destroy the universe, that's why.
[b]DARK MATTER[/b]
Once upon a time, an astrophysicist named Fritz Zwicky was observing the coma cluster. He decided to apply all the mathematical divinations to see how much matter existed in the system. Now, you would think that the result would not tell you that there was 400 times the amount of matter than could be seen or otherwise detected, but that's exactly what happened. 400 times more matter than we see? This cluster includes over 1000 thousand galaxies, but produced the gravity of 400000. [i]What??[/i]
So he invented Dark Matter, which is quite simply matter than cannot be seen.
Today, we have found no mathematical models to disprove the existence of Dark Matter (the one's that did are either highly speculative or have been thrown out the window). In fact, we've only found more and more evidence, like the ever-compelling Bullet Cluster.
[img]http://scienceblogs.com/startswithabang/upload/2009/03/bullet_cluster1.jpg[/img]
Okay, so what's happening here? We got some colliding galaxy clusters going on here. What's interesting is that as they sweep across each other, the galaxies are being displaced, but the gravitational disruptions (light bending) are not. The gas trails do not even begin to account for the gravity here. Oddly enough, if you asked an astrophysicist how you could indisputably confirm the existence of Dark Matter, he would tell you the very same scenario as what is happening here. Weird, huh?
[b]TL;DR[/b] Dark Matter is all the universe's shit that we don't see, accounts for 63% of all matter in the universe.
[b]DARK ENERGY[/b]
So now we know exactly what dark matter is, but what is dark energy? Lemme say now that it has nearly nothing to do with the latter. 'Dark' simply refers to the mysterious nature of the subjects.
SO
Dark energy, or a cosmological constant just like it, was first proposed by ol' Steinie, or Albert Einstein, if you prefer formality. He created it to counteract gravity and it's pull, and create a stable universe. This means that he didn't like gravity pulling the universe back together, so he created dark energy to pull it apart, and create a static universe. Further calculations revealed this to be impossible. A single fluctuation would send the universe on a crash-course with itself, or even more terrifyingly, runaway expansion. He later referred to it as his 'greatest blunder'. Little did he know he was right.
Edwin Hubble was the first to notice this. He had been working on finding out how fast the universe was collapsing in on itself, since that was what was happening and they could not possibly be wrong, right? Well when he got the numbers and punched them in, waiting ever so patiently for the positive number that would tell them how fast the universe was caving in, a most peculiar thing happened.
He got a negative number.
[i]What does this mean?[/i] The universe is expanding, and it's not slowing down. In fact, it's expanding [i]faster.[/i] How could this be? The initial shockwave from the Big Bang should have worn out billions of years ago, nor should it accelerate!
Dark energy was back in business.
[b]what does this mean?[/b]
It means the universe is screwed. If it collapsed back in on itself, we'd have another universal singularity, and possibly another Big Bang. This is not the case.
The universe will continue to expand forever. And ever. And ever.
The fuel for stars will run out, the last red dwarves will die out, there will be no light. The universe will go completely dark. A Black wasteland composed of sluggishly spinning husks of stars and heavy gases that make up the sorry excuses for galaxies.
Eventually, the only interesting thing happening will be black holes. They'll have free reign, and eventually [i]they will absorb all stray matter in the universe.[/i] Even these physical impossibilities are not infinite, however. Hawking radiation will slowly chip away at them, until they vaporize. Even the biggest, most gargantuan black holes will die, and all they will have to show is scattered radiation.
This radiation will settle too as the universe expands faster and faster, until they form a uniform sheet over the whole universe, equally spread out and distributed.
Heat Death.
Now before you get all :emo: on me, there is hope. There are chances that maybe the universe will find a way to regenerate. Quantum fluctuations are one such way, but we're not here to discuss those.
[b]TL;DR[/b] Dark Energy is the name tagged to whatever is responsible for the force that is accelerating the rate of expansion for the universe. It accounts for 72% of all matter and energy in the universe.
That's all folks! Make good use of this knowledge! Outsmart your friends, correct your teachers, or just pride yourself in being slightly smarter. Maybe I'll make more threads someday.
100k dark matter particles pass through you every second or something like that
[QUOTE=ramblingoxen;21531630]100k dark matter particles pass through you every second or something like that[/QUOTE]
Yeah, that's why i feel really dark sometimes.
insert racist comment here
[QUOTE=ramblingoxen;21531630]100k neutrinos pass through you every second or something like that[/QUOTE]
I believe this is actually correct.
The two are at complete opposites of how they interact with matter.
If we can grab some of that Dark Energy we might get speed that is higher then Lightspeed.
Or not cause we all know im a dunce.
[QUOTE=SinjinOmega;21531735]im a dunce.[/QUOTE]
Exactly.
[QUOTE=ramblingoxen;21531630]100k dark matter particles pass through you every second or something like that[/QUOTE]
Pretty sure those are neutrinos, which are not dark matter.
Those are neutrinos that pass through you, but no harm they don't do much.
Just punch molecular holes through you is all.
:science: :iia:
Not just Neutrinos, but W.I.M.P.s in general, or Weakly Interacting Massive Particles. Tiny particles that interact with baryonic (or 'normal') matter through weak nuclear force and gravity.
[QUOTE=Raxas;21531620] until they form a uniform sheet over the whole [b]galaxy,[/b] equally spread out and distributed.
Heat Death.
[/QUOTE]
:psyduck:
^
Oh shit thanks for that, I fixed it.
Well, we can not escape heat death. But we can ensure that we will exist. Just because this universe will die, does not mean it is the only one.
Just need to find a way to travel between alternate realities without killing our selves. Hopefully we can get to one that has a equal push and pull on all matter.
Also, the universe is everything in this reality. So it is hard for it to expand when it is made of nothing.
If dark matter also vibrates, then it'll be a big step forward for my "Everything is waves" idea.
If it doesn't, then it disproves it.
Eighter is good, I just want an answer.
[QUOTE=Raxas;21533062]^
Oh shit thanks for that, I fixed it.[/QUOTE]
So I guess the radiation will keep spreading as the universe keeps expanding?
Yep.
[QUOTE=Herr Sven;21533151]If dark matter also vibrates, then it'll be a big step forward for my "Everything is waves" idea.
If it doesn't, then it disproves it.
Eighter is good, I just want an answer.[/QUOTE]
Wave is just a model, they don't really exist.
[QUOTE=Shadowspike;21532872]:science: :iia:[/QUOTE]
get out troll
It's kind of comforting, actually.
Realizing that no matter what we do, even if we become the rulers of the Universe itself, Everything (capitalized, since I mean Everything) will die, and there's absolutely nothing we can do to stop it.
Is simple dust that does not emit light of it's own classified as dark matter?
[img]http://dgsphysics.files.wordpress.com/2009/06/225px-dark_matter.jpg[/img]
Dark matter?
TL;DR Dark Matter is all the universe's shit that we don't see, accounts for 63% of all matter in the universe.
TL;DR Dark Energy is a force that is accelerating the rate of expansion for the universe. It accounts for 72% of all matter and energy in the universe.
[b]63% of all matter[/b]
[b]72% of all matter[/b]
How can this be?
[QUOTE=British.;21541231]TL;DR Dark Matter is all the universe's shit that we don't see, accounts for 63% of all matter in the universe.
TL;DR Dark Energy is a force that is accelerating the rate of expansion for the universe. It accounts for 72% of all matter and energy in the universe.
[B]63% of all matter[/B]
[B]72% of all matter[/B]
How can this be?[/QUOTE]
They arent proven to exist yet
If we do a polar inversion on the universe dark energy will pull instead of push and everything will stop accelerating away.
[QUOTE=British.;21541231]TL;DR Dark Matter is all the universe's shit that we don't see, accounts for 63% of all matter in the universe.
TL;DR Dark Energy is a force that is accelerating the rate of expansion for the universe. It accounts for 72% of all matter and energy in the universe.
[b]63% of all matter[/b]
[b]72% of all matter[/b]
How can this be?[/QUOTE]
He kinda screwed it up a bit, but Dark Energy accounts for about 73% of all Mass/Energy in the universe (Mass == Energy). Of the remaining 26%, Dark Matter accounts for 23% and plain old normal matter accounts for 4.6%.
It's pretty much the old fantasy setting of Order versus Chaos applied to real science. Chaos was doing pretty good at the beginning, but then something suddenly went boom and now Order is making the universe smooth and gray and dull.
Obviously neither can ever be let to win, but what are we gonna do?
That aside, the universe expanding thing won't affect us in the slightest way. By then that it would matter, we would be either long dead as a species, or would have found our way into another universe.
[QUOTE=Ishmael12;21531684]I believe this is actually correct.[/QUOTE]
Actually it's 60 TRILLION neutrinos.
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