Some of my friends were talking of dark matter. They told me of how now it can be used as a major energy source, but it was very unstable. If anything disrupts it then then it will cause a devastational explostion.... Is this true? And can someone explain dark matter to me? I never really understood what it was.... Thnx

I don't know what dark matter is, but here are some of the hypothetical candidates that have been put forward over the years, unsorted as to likelihood;

Neutrinos
Gravitinos
Axions
Photinos
Wimps
Machos
monopoles
cosmic string
domain walls
textures
adjacent branes
mirror matter
Black holes
Dyson Spheres

I think some of these could undoubtedly be used for energy production, if they existed;
but they are all speculative, and many are no longer considered possible.
__________________
SF worldbuilding at
http://www.orionsarm.com/main.html

<i>Some of my friends were talking of dark matter. They told me of how now it can be used as a major energy source, but it was very unstable. If anything disrupts it then then it will cause a devastational explostion....</i>

I think your friends may have been talking about antimatter rather than dark matter. When a matter particle meets an antimatter particle, they anihilate each to produce energy in the form of light. This is a very efficient way to produce energy. The problem is: you need to make the antimatter first, and that requires more energy than you get back when it annihilates. Storage of antimatter can also be problematic, because it cannot touch ordinary matter without exploding.

so has this "anti-matter" been discovered?

Originally posted by w00t
so has this "anti-matter" been discovered?

Sure has. It's just particles with opposite charge or spin to their counterparts. For example the positron is an electron with a positive charge.

Dyson Spheres? are your serious??? :bugeye:

Scientist's have actually produced an anti-hydrogen atom consisting of a positron orbiting a an anti-proton.

Originally posted by WellCookedFetus
Dyson Spheres? are your serious??? :bugeye:

No, but I was trying to be exhaustive;
they have been suggested as a possible explanation for missing mass, but it is dammned difficult to make a Dyson sphere invisible, as they radiate too much infrared.

To make a DS invisible it would need to be a light-day or so in diameter, iirc, to radiate at the same temperature as the CMBR.
__________________
SF worldbuilding at
http://www.orionsarm.com/main.html

A light-day in radius: you have to be a pretty insane species to build it. Also just try to imagine how many would be needed to hide a significant amount of the universe’s mass :eek: well it is a possibility.

Antimatter was first theorised by Dirac, back in about 1930. It is now observed all the time in particle accelerators and in certain types of radioactive decay.

The total amount of antimatter which has been made by human beings in the last 70 years amounts to much less than 1 kg.

it amount to a few atoms worth, with modern production techniques it would take a billion years for us to make a kg of anti-hydrogen.

Fydus, i'm not a scientist. it seems to me from what i have seen other people say on other forums, dark matter and dark energy are kind of invisible stuff to make up the balance of matter that current theories kinda suggest should be in the universe. I think it is meant to be very dense and very small, and maybe can kind of coexist with matter in the sense of pass through it. I ahvent sen anything about it as an energy source, but would imagine ifd it did exist it could be one one day if it could be worked out how. Therera re quite a few reports suggesting it does exist through observed things that suggest it.

Isn't dark matter unidentified matter / non-barlymoric and more mythical than proven

joey. i go on another science forum and have read lots of articles people have posted that point to evidence that they say supports the notion it actually exists. I gues it is not widely accepted conventional theory however as yet, i am not a scientist.

Originally posted by ele
joey. i go on another science forum and have read lots of articles people have posted that point to evidence that they say supports the notion it actually exists. I gues it is not widely accepted conventional theory however as yet, i am not a scientist.
No, it's widely accepted that dark matter must exist in some form or other and we certainly observe it's effects. It is known that a fair proprtion of the dark mass must be made out of non-baryonic matrial, but what exactly is unknown and the subject of much speculation.

Joey i checked it out and it is pretty much accepted evidently that dark matter exists, and the rest f my post is prety much okay too.

Supposedly two types- WIMPS and neutrinos and stufff which are the small dense coexisting going through stuff ones and maybe big ones like in blackholes etc.

they said the stuff that made us know it was there was evidence such as "gravitational lensing". i cant expolain that as i didnt read the threads about it as it didnt interest me as much as dark matter stuff.

The evidence (observations) for dark matter primariliy consists of the unusual motion of groups of galaxies (as described by Fritz Zwicky, and the flat velocity rotation curves at the outside of spiral galaxies as described by Vera Rubin.

The unusual motions of stars in these cases were explained by the existance of massive amount of dark (non visible) matter - and was based upon the Newton theory of gravity (which was only verified for distances in our solar system).

However, my re-eximation of the observational data published by others showed that if one generalizes gravity for large distances by adding a term that increases linearly with distance, the observations can be easily explained without requiring dark matter.

This generalization is further supported because it claifies the true meaning of the Hubble constant as being dependent upon travel distance of light (tired light proposed by Fred Zwicky) rather than the assumed star velocity and Doppler shift. Many other mysteries are also clarified, and the expansion of the universe is also questioned.

This is not speculation and is supported by details, equations, and references on pages on my web site at:

http://inventing-solutions.com

Originally posted by James R
Storage of antimatter can also be problematic, because it cannot touch ordinary matter without exploding.

I seen some guys in TV that made antimatter in a lab. They stored it in some container that was (obviously) a vacuum inside and it suspended the particles in the middle so it did not touch the wall of the container. I wish I remember exacatly how they did that.

Thanks advisor7. i have gotten to the stage myself of wondering re the supposed evidence for dark mattera s i have read of alternate theories to explaint he same observed phenomena, Plus other phenomena also.

I have been thinking of posting a thread here about it and I think i'll post a link to your ideas on my thread ont he other forum about this stuff. Hope you diont mind?

It would help distribute my suggestions.

Thanks,

Sol

"I wish I remember exacatly how they did that."

They do it with strong magnetic fields that 'trap' the particle inside a certain region as to not let it touch the edge of the container

Thanks much!

Originally posted by advisor7
The evidence (observations) for dark matter primariliy consists of the unusual motion of groups of galaxies (as described by Fritz Zwicky, and the flat velocity rotation curves at the outside of spiral galaxies as described by Vera Rubin.

The unusual motions of stars in these cases were explained by the existance of massive amount of dark (non visible) matter - and was based upon the Newton theory of gravity (which was only verified for distances in our solar system).

However, my re-eximation of the observational data published by others showed that if one generalizes gravity for large distances by adding a term that increases linearly with distance, the observations can be easily explained without requiring dark matter.

This generalization is further supported because it claifies the true meaning of the Hubble constant as being dependent upon travel distance of light (tired light proposed by Fred Zwicky) rather than the assumed star velocity and Doppler shift. Many other mysteries are also clarified, and the expansion of the universe is also questioned.

This is not speculation and is supported by details, equations, and references on pages on my web site at:

http://inventing-solutions.com

there is a good article on this in This month's Discover Mag.

antimatter has a very good weight/thrust ratio for interplanetary / interstellar spacetravel, however as mentioned in the last 70 years we have produced less than 1 kg of the stuff, because it is insanely expensive, up to now you need really large amount of energy and huge expensive particle accellerators etc to get 1 in a million or something collisions to manifest itselve as antimatter.

However,

Particle accellerators and synchronotrons were build for scientific research in general, they could be optimized to be build for the dedicated production of antimatter with better hit ratios, improvements in superconducting materials will lead to cheaper magnets and better beamfocus.

Antimatter production will really get into gear when we make a breakthrough with nuclear fusion first. This will ultimately provide dirt cheap energy and it really wouldn't matter how much energy it costs to synthesize some antimatter...

Trust me we won't being do much better then 1g ever 1million years with any technology even remotely based of the conventional in anti-matter production.

I saw the article in the recent Discover magazine, and they still are concerned with the mystery of Pioneer 10/11 motion, and dark matter and gravity.

When they get around to reading my new model of gravity and the cosmos at my web site http://inventing-solutions.com the will get answers to the questions.

I hope others will link to my site and also suggest that Discover look
at the site.

It will help those struggling with the wrong understanding of the universe and can make their work more productive.

Pioneer 10/11 motion was answered by heat radiation from the RTG reflecting of the side of the radio dish and providing a (very VERY) slight acceleration.

Not much is known about dark matter but it may hide in small mass of subatomic particles neutrinos about 25-30% of matter in the universe is dark.