Dark Matter and Dark Energy ?

I have a few questions on Dark Matter and Dark energy.
Is Dark matter a name just given to matter that does not emit light or reflect light or is Dark matter a special kind if substance unlike normal matter ?
Is Dark matter made up of atoms ? Does it follow different laws of Physics and Chemistry ?
Does Dark Matter exert the force of Dark energy or are they completely different entities ?

Bear in mind that I don't actually believe dark matter exists but as I understand it dark matter is a form of matter that we havn't yet discovered, this makes it difficult to answer some of your questions. For example we dont know whether it follows traditional physics as we dont actually know what it is.

The dark matter of the theory doesn't reflect light, yet its not just any substance that doesnt reflect light, its this specific type of matter.

Also most people believe that dark matter definately won't be atoms but a currently known or unknown subatomic particle.

GFAD you are TOTALLY wrong!

Dark Matter IS just any matter that does not EMIT light in the VISIBLE spectrum.

That means that something that emits radio-waves, or infra-red light IS considered Dark Matter. Something can even reflect light, but if it doesn't emit visible light, it's still Dark Matter. It's matter that's dark.

HOWEVER - there's a lot of different kinds of Dark Matter.

There's MACHOs - Massive Astronomical Compact Halo Objects
and there's WIMPs - Weakly Interacting Massive Particles

A MACHO is something like the Earth, like a Gas Giant, space dust, or Black Holes (notice how each of these are very different, but all are "dark").

A WIMP is something like an electron, a cosmic ray, or a neutrino.


Now, does Dark Matter follow ordinary laws of physics? Technically, yes - but much of the Dark Matter follows physics at the edge of our understanding.

For example, a Black Hole is dark matter (once again, I stress that it is dark because it does not emit visible light), but it's totally wierd because it exists with infinite density, and with non-existant space. This makes it act very peculiar when other objects move close to this singularity.

Now, the MACHOs, being normal matter like you and me, just sometimes under odd circumstances, aren't that exciting. What's really exciting are the WIMPs!

Why? Because WIMPs, like the name implies, don't interact with matter (whether dark or otherwise) very frequently. In fact, try this experiment. Put your finger into the air.

1
2
3
4
5

Now lower it. About 6 BILLION neutrinos just passed through your finger at nearly the speed of light. You didn't feel a thing. In fact, it's likely that not a single neutrino interacted with any of your atoms (which you had trillions and trillions of in that finger).

This is because Neutrinos are TINY. Miniscule. Remote. Almost non-existant. I mean, you may think that a neutron's almost not there, that the electron is - for all intents and purposes NOT there - but that's NOTHING compared to the absolute zeroness of the neutrino.

Imagine an atom like this - you have a full-scale Baseball stadium. There's a football helmet in the center of the field. That helmet is the nucleus of the atom. All the mass that makes it up is located essentially there. Then, way out at the furthest bleachers, is a tiny ball-bearing. That ball-bearing is an electron. The rest of the space in the stadium is purely empty.

Except, that is, for the occassional neutrino, cosmic ray, or photon that passes through. Now, since the photon is acting like a wave, it's got some width to it, and so there's a pretty good chance that it will hit that electron. The photon's like a Zamboni travelling into a hockey rink with a full team of players in it - if no one's paying attention, someone will hit it.

The neutrino, however, is like a speck of dust. The chances of it hitting anything are remote to say the least.

As such, it rarely ever interacts with the centers of mass in the atom (the electron - which is almost nothing itself - or the neutrons and protons in the nucleus).

That's the problem with WIMPs - they're hard to even know that they were there.


And that's the summary of Dark Matter. For the most part, it's ordinary matter following ordinary rules of physics... it's just that usually the matter's in a situation that's unordinary, like under intense gravity, or is just so tiny it almost doesn't exist.


Dark Energy... that's a whole different ball-game altogether.

Im not expert on the subject what so ever, all i know is what ive seen on a BBC documentry about dark matter and energy. I do admit that it does sound quiet silly but there is scientific proof that both do exist, even though we can not sense it, or measure it with equipment. Here is a nifty little piechart showing the ratio of matter to dark matter and energy. If this theory does follow through, it will be a very intresting aspect of physics and astronomy. If it fails im sure it will be laughed at quiet alot in a few hundred years.

Yarium, you gave a very full an informed reply but that doesnt make all the information in it correct.

Originally posted by Yarium
Dark Matter IS just any matter that does not EMIT light in the VISIBLE spectrum.

What, so I am made of dark matter? The screen I'm looking at isn't but the coffee cup im holding is? I don't think thats what any cosmologist would define as dark matter.

Originally posted by Yarium
HOWEVER - there's a lot of different kinds of Dark Matter.

There's MACHOs - Massive Astronomical Compact Halo Objects
and there's WIMPs - Weakly Interacting Massive Particles

As far as physics is concerned dark matter is currently of unknown composition, what you are repeating are simply theories for what dark matter could be composed of even if it exists at all, which an increasing number of cosmologists are considering.

Anyway thats my understanding of it.

wimps and machos are still yet to be proven, am i correct? Jeff E Bayles said that we are in a time pulse, the differing time pulse explain the nutrino effect. dark energy is sort of low on time pulse, and has little to no mass or charge. well what i think is that there is a dark energy halo around our galaxy, and that its time volume effects our galaxies light matter. resulting in what our physists might call a multi-mathematicle state, where each seperate volume of time effects the field energy of another, which i believe explains a lot of the qauntum weirdness we see in string theory. he also said that there is a infinite energy potential through a non-local energy space via a A-vector in between it and our reletavistic space-time. well i think that the closer the negative and positive energy levels come together the greater the non-local energy potential, via time pulse, and the infinite energy potential is what we define as zero-point energy. which brings me to a rather bizarr dream i had, a ET, possibly of the verdant (grey) race was smoking a ciggarrette inside a maze. then a vortex appeared from the maze, and he was sucked in, as he was falling into the vortex i heard him yell to me, "i am already 90 years old!". wierd isnt it?

Thanks for clearing that up Yarium, I think a lot of people get confused about it, I know I was for awhile.

You have alot of questions about Dark energy and Dark Matter siddharthsma, but dont feel bad your in great company.

The names 'dark matter' and 'dark energy,' serve mainly as expressions of our ignorance of the subject.

Current models of the univesre appear to show that some 95% of the universe is invisible to us!. We can not sense it, or measure in any way so if its out there we really dont have any clue what it is.

So really even the best minds on the planet can only offer you theories to answer your questions. Scientist dont even really understand what gravity is yet, we think we know what it does pretty well but thats not the same thing. Theres still alot we dont know.

Originally posted by gfad

Originally posted by Yarium
Dark Matter IS just any matter that does not EMIT light in the VISIBLE spectrum.

What, so I am made of dark matter? The screen I'm looking at isn't but the coffee cup im holding is? I don't think thats what any cosmologist would define as dark matter.

Actually, YOU ARE made of Dark Matter! That's usually what I say on this subject "You are made of dark matter". If someone took an measurement of the mass of our solar system, they would see that only a portion of the mass is taken up by the Sun. Where's the rest of the mass? Unfortunately, their telescopes might not be powerful enough to see the light being reflected off of Jupiter, or Earth, or you. Thus, the "missing mass" could be almost anything! It could be one super-planet, instead of 4 Gas Giants and 5 rocky worldlets. The matter is "dark" - it's not giving off any visible light - and so would be considered "dark matter".

Originally post by gfad

Originally posted by Yarium
HOWEVER - there's a lot of different kinds of Dark Matter.

There's MACHOs - Massive Astronomical Compact Halo Objects
and there's WIMPs - Weakly Interacting Massive Particles

As far as physics is concerned dark matter is currently of unknown composition, what you are repeating are simply theories for what dark matter could be composed of even if it exists at all, which an increasing number of cosmologists are considering.

Anyway thats my understanding of it.

Repeat it with me, Wikipedia is good, Wikipedia is my friend:
en.wikipedia.org...

Take a look at "composition". It mentions some of the new classifications, such as "hot" dark matter (neutrinos), "cold" dark matter (MACHOs - and yes, they are proven to exist. A MACHO is any large, but dark, object - such as a planet, dust clouds, nebulae, asteroids, etc - though MACHOs make up only the tiniest portion of Dark Matter).

The reason why Dark Matter is always considered "unknown" is because it could be one of so many things. Look back to my example of someone looking at our sun. The missing mass around it is unknown, so it technically could be made of anything. But, being here, we know where most of that mass is - it's in Jupiter for the most part, and the rest of the planets for the lesser parts. That's why it's unknown.

Now, you say that's your understanding of it, and that's fine. Dark Matter, by its nature, is something that has lots of venues in it to be explored - and so we'll constantly be adding to it. However, what we have found so far in MACHOs and WIMPs is correct... but there's still more missing parts still to be filled.

baryonic matter include brown dwarfs or perhaps small, dense chunks of heavy elements; such objects are known as massive compact halo objects, or "MACHOs".
en.wikipedia.org...

Heavy Elements are things like iron, carbon, etc... all the things that make up us.

[edit on 1-6-2006 by Yarium]

Originally posted by Yarium
Actually, YOU ARE made of Dark Matter! That's usually what I say on this subject "You are made of dark matter". If someone took an measurement of the mass of our solar system, they would see that only a portion of the mass is taken up by the Sun. Where's the rest of the mass? Unfortunately, their telescopes might not be powerful enough to see the light being reflected off of Jupiter, or Earth, or you. Thus, the "missing mass" could be almost anything! It could be one super-planet, instead of 4 Gas Giants and 5 rocky worldlets. The matter is "dark" - it's not giving off any visible light - and so would be considered "dark matter".

I'm sorry but I still don't think your explanation is right. Dark matter isn't just any old atoms lying around that don't emit light! Dark matter is a theory (yes a theory ie. MAY NOT EXIST) to solve the galaxy rotation problem. This problem arises because galaxies spin so fast that they should rip themselves apart yet some physicists think that there may be some other form of matter in the galaxy that we cant see that adds mass so its not ripped apart. This is dark matter. This mysterious, THEORETICAL substance or mix of substances that adds required mass to a spinning object. It's almost just a fudge factor ... an easy way to solve a problem that isn't covered by traditional science, try looking up Einsteins cosmological constant for the mother of all fudge factors. It's not just anything we can't see.

They would spin themselves apart unless there was some other matter there - but READ WIKIPEDIA!

Read the article I gave you to read! It states right there,

Originally from Wikipedia
"In cosmology, dark matter refers to matter particles, of unknown composition, that do not emit or reflect enough electromagnetic radiation to be detected directly, but whose presence may be inferred from gravitational effects on visible matter such as stars and galaxies."
en.wikipedia.org...

That other matter there is a mix of both normal matter AND "other" matter.

There's Hot Dark Matter, Cold Dark Matter, Warm Dark Matter, and Baryonic Cold Dark Matter (which is us and other MACHOs).

Yarim I think you're a bit confused, we're not made of dark matter, the missing mass problem arises from the fact that the critical density of matter and antimatter dont make up enough mass to yield a flat universe (which inflation predicts and we observe) We know the mass of our solar system and the planets that are in it dark matter is not part of it.

Also just because something doesn't emit light in the visible spectrum doesn't mean its dark matter at all, it just means its transparent to humans. Dark matter probably doesn't even interact with electromagnetism, strong, and weak forces only gravity.

Gravity is really the only proof we have that dark matter exists.

[edit on 2-6-2006 by Distortion]

Yarium, "read the article i gave you to read" certainly sound patronising from someone whos explanation doesnt match up with whats in the article! I checked wikipedia before I made my first post, before you even referred to it and it confirmed just what I thought and what I've posted above.

Even the paragraph you quoted gives a totally different definition of dark matter to the one you gave. It includes one word which makes a world of difference ... reflect. Dark matter doesnt emit or REFLECT light, this rules out your "we are all made of dark matter" statement.

Key word, "enough". It doesn't emit or reflect "enough" light to be detected. I'm sorry if I sounded patronising, I apologize, it's just that this topic comes up a lot and I always need to answer it.

Anyways, back on topic, like I said, there's many different kinds of Dark Matter - it's a catch-all phrase. For example, I could tell you I have a clock. Is it mechanical? Electrical? Is it standard time, military time? What time-zone is it in? Is it on my wrist? Is it on the wall? Is it on a stand? Does it weigh 2lbs or 10? There's a lot that you don't know when I tell you something is a clock - but since I labelled it as a "clock" there are a few things that you can summise.

By the same token, I could tell you that I have an object in my house. Even if you knew how large my house is, you don't know the size of the rooms in it, and an object in a house can cover a LOT of objects! Let's coin it "House-Matter". You can't detect it because you can't see through walls. It's invisible matter, as far as you're concerned. Who knows what House-Matter could do! Is it alive? Does it produce an Electromagnetic field? Does it react the same to anti-matter? You don't know, because you don't know what that House-Matter exactly is.

But then you could break down House-Matter. You could be pretty confident that some of the House-Matter is made up of carpet and tiles. Perhaps it's only a tiny amount of the House-Matter, but it's there. Since I'm typing this to you, you're very confident that I'm typing it to you from a computer, but you're not entirely certain since it could be a PC, a Lap-top, a Blackberry, or a Cell-Phone.

You would assume that I have a kitchen, with pots and pans, though you wouldn't know what kinds of pots and pans, what size they were, or what colour, nor the exact amount since some people keep more pots and pans than others.

It's likely that I have a bed... or 2... or more. They could be small sizes, or King sizes. Or a mixture of. One might be for guests, who may or may not be present at the current time. Such guests might be relatives, or powerful figures of State. They might have 1 pillow, or many - fleece, or feathers, or cotton.


In the end, you simply don't know EXACTLY what House-Matter is.

The same is true of Dark-Matter. We know what SOME of it is, but not all of it. We can't tell exactly what it is for the simple reason that we cannot see it. You may feel free to ask your local physicist at a university or college in your area.

SOME of the Dark Matter is taken up by planets and asteroids and dust... but it's only the tiniest amount of the total "stuff" that makes up Dark Matter. A good portion, we figure, is in neutrinos - but it's been found that there's still missing stuff. If it's dark, then it's Dark Matter.

Whilst to people here on earth we are not Dark Matter, to someone looking at us from far away, who can detect us only by gravity, we are INVISIBLE matter.

That's why Dark Matter is Dark and is such a catch-all term.

Dark matter is probably not composed of mainly neutrinos because since we know the amount of dark matter of the universe 23-24% of total mass we can calculate the amount of neutrinos needed to accompany a 1 cubic meter space to result in 24% of critical mass density. When we plug the numbers in (I have them somewhere ill put them up later) we find that the amount of neutrinos is something like 1x10^30 or something outrageous. If this were true we would be finding neutrinos all the time.

I just saw theres going to be a show on the Discovery Science Channel all about Dark Matter and Dark energy. Its intitled " Most of the Universe is Missing" and is on June 13 I believe.

Looks like it could be interesting for people interested in this subject.

My conjecture at this moment is this. Our universe expanded into the dark matter at the big bang.

Imagine our universe is an egg and the shell of the egg is the outer edge of our universe. That shell is dark matter and it is also the invisible matter that is causeing our universe to continue to expand.

The initial bang set in motion the expansion and left the gasses (that formed the galaxies spread out and left behind (egg yolk?)the expanding outer shell.

That outer shell is still expanding due to the initial big bang and the energy and heat created by the forming galaxies continues to push it outward like a hot air ballon BUT at the same time the dark matter egg shell has mass and strong gravity that is also pulling the galaxies and gases that were left behind along with it on the ride as the outer shell expands.

The outer most edge of our universe is the missing darkmatter and while it expands it also is dragging the galaxies apart like we all live inside an expanding ballon.

Did I mention that I stayed at a holiday Inn express last night?

X

I believe this is the one they're going to be showing on the discovery channel. Was quite interesting.

video.google.com...

reply to post by Yarium
I have been scanning comments on dark energy finding very interesting points of view. After thirty-five years of research into physical theory I believe I may have something to contribute to the discussion. I hope you find it so.
I contend matter, dark matter, and dark energy, are one and the same thing, mere effects of what is being termed dark energy. The idea of dark energy goes back to the early part of the last century, and certain conclusions about energy during that time precluded any possibility of understanding what form it might take or how it presents itself. Two of those conclusions came from two tests during that time and they were critical.
The first of these tests was Young's two-slit experiment in 1801 which concluded that energy was daul in nature, that energy was both particle and wave. This would lead to the quantum theory and from that it was concluded cause and effect ended with the wave function and the inquiry has been stuck since that fateful time. For compelling reasons I suggest there is cause and effect at the atomic level and can be revealed.
The second critical error came in 1881 with the Michaelson/Morley interferometer test which was of unique design to determine if there was in fact a carrier for the propagation of light pervading space, or aether as they termed it, and the conclusion was there isn't. Einstein was keenly interested in this test becuase he was developing his special theory of relativity and from that came the general theory. Had a different conclusion being drawn it would affect the outcome of his theory of gravity because an operator would have been included to account for it. The true nature and form of the aether would have precluded the possibility of a big bang emerging out of the theory. Now even as dark energy has been pretty much confirmed it is not known what to make of it. I suggest that it is real, it exists, and it is possible to know and understand the true nature and form it possesses.
While all of this may seem audacious to some or many, I assure you a final description of energy is available and can be subsantiated. All of the mystery and paradox riddled throughtout theory can find exposure. Things like inertia, gravity, light speed, ad infinitum, all have solutions simply by understanding the true nature of space. Isn't it strange that cause and effect ends with the wave function but is behind all manifest energy? Isn't it kind of strange science knows space determines the path falling matter takes but the cause is a mystery? What is it about space empty space that can affect galaxies? If space can do that surely it can have an effect on a "particle"?
I would be glad to engage on the subject in a more meaningful way should anyone be inclined to do so. I just thought I would throw my hat into the ring.

anonymous

reply to post by Yarium

It is wrong to believe we, as humans, do not emit light. If we did not emit light we would not be visible. Light is emitted from us by the light, or various frequencies of radiation striking the atoms, with a visible light frequency emitted from the atoms. The various light frequencies re-emitted produce the demarcation points to produce the form we possess.

anonymous