Negative matter is a theorectical, and little known, form of matter whose mass is oppisite in sign of normal positive matter. Negative matter is NOT antimatter, which as far as known, has normal (positive) mass just like regular matter. Normal (positive) matter causes all matter including negative matter, to move towards it. Negative matter causes all matter including positive matter to move away from it. This is caused because negative matter has a oppisite gravitational field compared to normal positive matter. Negative matter can have it's own anti-matter too. So, if we take a ball of negative matter and put it behind a ship of normal positive matter with equal magnitude, then the negative matter would push the positive matter away from it while the positive matter would pull the negative matter towards it. This gives us an unlimited amount of unidirectional acceleration without the need for either a energy source or reaction mass! Now, at first glance, this system cannot exist because it violates the laws of conservation of linear momentum and energy. Amazingly enough, it doesn't.
When the two objects are at zero velocity, the total momentum of the system is zero. After the two objects have reached the velocity v, there combined momentum is still zero,

P++P-= (+M)v+ (-M)v=0

because the ball of negative matter has negative momentum.
If you add "-" and make sure the negative mass object and the positive mass object have the same magnitude, no law of physics is violated. But what if one of the objects had a higher or lower magnitude then the other? I read a paper by Robert L. Foward on this problem. It shows that STILL the drive would NOT VIOLATE the laws of conservation of energy and momentum. This is perhaps one of the strangest forms of matter one can think of, and amazingly it does have some "proof" to it. When one looks at large-scale 3-D "maps" of the universe, you can see that there are many voids or "bubbles" more then 100 million light-years across. Galaxies and clusters of galaxies mostly lie on the surface of the bubbles. And those galaxies that do exist in the voids are very unusual galaxies that are characterized by strong, high-excitation emission spectra. One explanation is that the universe was formed with a equal amount of positive and negative matter. These voids contain negative matter objects that are pushing away from each other while at the same time being pulled by the positive matter galaxies. This might be driving the expansion of the universe. Could dark matter, exotic matter, and all other "wierd" matter all be negative matter? And if we can synthesize it, we can either, one, create near-light starships, two, create negative anti-matter, destroy it, and use the negative energy to be used in a warp drive ! So, is negative matter exotic matter and dark matter all in one?

__________________
<span style='color:green'>&quot;We are the Borg. You will be assimilated. Your biological and technological distinctiveness will be add to our own. Resistance is futile.&quot;
Borg Hail</span>

Just to clear some terms up, Negative Matter cannot be Dark Matter, which is hypothesized for matter being gravitationally attracted to it. You probably mean Dark Energy which is thought to be pushing the universe apart.

__________________
Forming opinions as we speak

Ok, maybe negative matter is not dark matter. But in theory it could still exist. Right?

__________________
<span style='color:green'>&quot;We are the Borg. You will be assimilated. Your biological and technological distinctiveness will be add to our own. Resistance is futile.&quot;
Borg Hail</span>

But dark matter and dark energy are still as theorectical as negative matter. Is there really dark "energy" and dark "matter?"

__________________
<span style='color:green'>&quot;We are the Borg. You will be assimilated. Your biological and technological distinctiveness will be add to our own. Resistance is futile.&quot;
Borg Hail</span>

Dark Matter is a theoretical substance that is used to explain the orbital motions of stars on the outer edges of galaxies, and galaxies in clusters. Without the added gravitation of this invisible matter, our current gravity equations cannot explain the observed motions. Based on what we see through telescopes, the stars on the outside of galaxies, and the galaxies in clusters, should all fly apart at the speeds at which we see them traveling, but they stay together so something (Dark Matter?) must be adding extra gravity without being seen through the telescopes.

Dark Energy is a theoretical energy field permeating the entire universe that counteracts the force of gravity. Also, based on our current gravity equations, the amount of matter in the universe should be sufficient to slow the expansion to a stop, and reverse it. This, according to WMAP, is not the case. It appears the universe is in fact accelerating, and will continue to forever, therefore we need a new repulsive field (Dark Energy?) to countact the gravity of all the matter and explain the observations.

Personally, I think that Einstein gravity is accurate at short distances (several lightyears), but, just as you can safely use Newtonian Mechanics for slow speeds and low masses because the Einstein equations only significantly differ at high speeds and masses, there are other variables that were unknown at Einstein's time that change the equation at large distances (MOND?)

Also, Negative Matter is also theorized as the necessary substance to maintain stable wormholes. The gravity from normal matter is supposed to cause a wormhole to instantly collapse, destroying anything passing through, but negative matter could be used to counter the collapse and allow safe passage through the wormhole. FYI...

__________________
...and we'll be saying a big hello to all intelligent life forms everywhere; and to everyone else out there, the secret is to bang the rocks together, guys...

Does dark matter only exist in the halos of galaxies?

__________________
<span style='color:green'>&quot;We are the Borg. You will be assimilated. Your biological and technological distinctiveness will be add to our own. Resistance is futile.&quot;
Borg Hail</span>

If dark matter exists [seems likely to me], it exists pretty much everywhere, but it is concentrated somewhat in galaxies. There is more dark matter than luminous matter, but the ratio of dark matter to luminous matter is higher in the halo of galaxies than toward the center, but the concentration of both luminous and dark matter is highest at the center of the galaxies.

There are several types of experiments currently trying to detect dark matter:
- Experiments underground trying to detect dark matter bumping into very cold matter. These should show different counts during the part of the year when Earth is going with the galactic orbit vs. against it.
- Experiments looking for dark matter anihilating itself near the galactic center [and other places]. This would be looking for a peak in the gamma ray spectrum in that direction.
- Observations of the gravitational effects of the Dark Matter in galaxies and galactic clusters, either through motion of luminous bodies, or weak gravitational lensing.

__________________
Forming opinions as we speak

I think what you are saying is that a form of matter can exist with the opposite gravatational effects of normal matter, a kind of repulsive matter. As far as I know this would violate the principles of general relativity. To make this theoretical matter more realistic, you will need to define its properties mathematically and determine how to adjust general relativity to accomodate this form of matter. Then you will need to determine some means of either detecting or producing it. I imagine that would be quite a difficult task. Since you are made of positive matter, any attempt you make to manipulate negative matter once you create it would fail. You would never be able to catch it in your lab or measure it with your postitive matter instruments. As far as the "holes" in the WMAP data, if there were matter there, negative or positive, no matter what it's gravatational influence it would still appear as matter not a void.

__________________
Quid hoc ad aeternitatum
The conversion of complex and abstract ideas into simple and concrete ones is the essential function of teacher of a body of knowledge.

B)
Hi, I've just signed in. I recognize a couple names here. I'm BettysFetish; it's just a name.
Since this is an "alternitive idea post" section, I'd like to propose that we think "outside the box". I've read this entire thread. I'd like to ask, has anyone heard of any results, so far, that claim we're on to anything to explain our expansion rate? I keep up, somewhat, with this and I've not heard of any developments yet.
I like to ask anyone interested to look with me from a different angle. I've always been interested in the exsisting conditions before the creation of matter. The void in question would have been opposite of anyplace we could imagine. There would be no requirement that any mass, whatsoever, would have to be displaced to make room for the energy/mass being formed. Any forces in this pre big bang epoch would be negitive or false. The formation of any positive energy/matter within this "vessel with no walls" would be "drawn towards" the outside by opposite attraction.
I'd like to propose that the void in question is still out there surrounding us and always beyond our horizon. It surely didn't vanish or disappear just because one or two particles managed to quantum tunnel out of confinment and tip the balence our way. The forces present there are still there pulling ever faster.
I wonder, could we be looking for something that is simply not here. With our current means for detection it seems a bit of a stretch that we've not had any luck or any hint at all where to look. As I sign out; after all is said and done, bla bla bla. Well- - I think it still applys here. Should my "shot in the dark idea" have any merit here then we're simply being pulled on from all directions and there is no dark matter out there to find. Which makes it a force, not a particle. Besides if it was a particle it seems that it's replusive effects would diminish with distance/expansion, not accelerate, as the suspect particles and their effects become farther and farther apart.
This would simply represent a gravitation attraction pulling us outward and with no matter in the way, not even a hydrogen molicule, our outward motion "would" forever increase.
L8R

__________________
After all is said and done, Gravity Rules&quot;.

Hi BettysFetish, welcome to the forum.
I've seen a couple posts in the last few months by people talking about the expansion coming from a pulling from the outside rather than being part of the equation of state for the inside of the universe.

Your proposal seems fairly simple compared to the others, but I'd like to caution you against assuming that a vacuum has some kind of sucking power. A vacuum is nothing.

__________________
Forming opinions as we speak

antoniseb, hey!
I've got some time finally; I work with the mentally handicapped, it keeps me busy. Perhaps you've seen a post or two of mine somewhere else?? Or do you mean some important theory that I may have missed?
I used the word "sucking" a bit ambiguiously in my last post. Your right, thats not descriptive of the conditions in question. I think when greater minds than my own use the word "vacuum", it is in a concepual sense. In a universe of our polarity (matter vs. anti-matter; thats important later) there can be no precise knowledge of "what was nothing." We commonly think of a vacuum state, but in our world, "Any" vacuum requires some kind of containment vessel to maintain a negitive pressure. So we have two points to "re-conceptualize." One, how could a true vacume be created with no confined area, and two, in order to visualize even this requires the presense of matter. The epoch in question here must have been , quite frankly, literally, and without question, "Nothing." WoW!!! Thats deep.
Do you agree with quantum theorys? I think that in this "place of no time" there were surely virtual particles "and" anti-particles constantly being created and annililated. These however are massless and "In this world, non exsistant."
This place with no time will therefore be the negitive of everything we could possibly imagine. What happens here if even one particle is created from some quantum flucuation? What could be the result of even one particle suddenly being in a place it simply does not belong?
Here is where this theory gets problematic. Where do you think this should lead, to what result?
Nothing, inherently, is an unstable system. If anything happens in nothingland, then the intire system is thrown out of balance.
If a particle with a proton in the middle and an electron orbiting it appears here, where should the nothing go? Well,- - nowhere of course, theres nothing here but negitive virtual energy. This, I beleive, provides an opposite "or negitive" energy medium. Since opposite forces attract, the mass about to created would be "drawn" out, allowing for expotential growth of energy/mass.
I'd like to go on but I'm tired. What opinion might you have to offer on this to date? I'd like help with this from those of you who might not laugh at Newton.
There "is" an answer to why the universe's expansion accelerates. I just don't see, as yet, any firm sign that it's a "repulsive particle force" from within.
As we look deeper and deeper into the universe, we see farther and farther back in time, agreed? And we wonder why the galaxys are moving faster and faster? Well think about that a second - - - - in the very, very beginning, things were moving well beyond "c" for a while. And before that, there was nothing, right?? So what should we expect to see if we look far enough back(or out there)? Nothing, of course. And that nothing is receeding from the point of origin at greater than "c".
L8R

__________________
After all is said and done, Gravity Rules&quot;.

I was referring to posts by guests on this forum. Usually the people suggesting such theories seem a little less scientifically based than you do. None-the-less, the science of vacuum energy is still mostly theory. In our universe there does seem to be pairs of virtual particles appearing and disappearing all the time from vacuum.

I disagree about the need for a container to support a vacuum. There is no negative pressure associated with a vacuum. Note please that the space between clusters of galaxies is not a perfect vacuum, but by earthly standards, it's pretty close.

__________________
Forming opinions as we speak

:P Hey, hope everyone is well.
I'd like to pursue this vacuum thing a bit further. Antoniseb, tell me something if you know, I'm not sure, how is a vacuum measured here on earth? I mean a negitive presure is less that a predetermined value from some surrounding vicinity isn't it? There is measureable differences in meteorological terms but to get extream values we need some closed, airtight, vessel. Would you agree with me to this point? I've read that we can only produce, here on earth, extreams that are only close to actual unoccupied space; a few particles per inch. If you were to build a container in space to begin with, could we close it off and withdrawl any more from within? Even this could not be "absolutly nothing". Yet there was less than that pre-big bang. Can you agree still?
I still feel that "vacuum" is still the wrong term. In it's content, it does not convey the esscence of "nothing". And "nothing" is a term that cannot be fully complyed with. I.E., What are you doing; nothing? You must be alive, so something is happening. Or, It vanished, theres "nothing" there. Well you specify a place, there at least, should be air particles there where the something was.
"Nothing", absolutly, undeniablely, literally and unquestionably nothing is not possible on earth or in the heavens.
TAG, - your it.
L8R
-----"After all is said and done, Gravity Rules"-----

__________________
After all is said and done, Gravity Rules&quot;.

For easily created partial vacuums, we measure pressure. There are several units for pressure, such as atmospheres, inches of mercury, pascals, etc. For extreme partial vacuums, we estimate atoms or molecules per cubic centimeter. For a complete vacuum, there is literally nothing to measure.

At some level, we can talk about quantum phenomena related to things much smaller than protons and neutrons, but while these explain a lot of things we see, we haven't really observed then directly.

__________________
Forming opinions as we speak