There is a massive mystery in the universe, Dark Energy and Dark Matter. Nobody knows what these evil things could be or that they are proof that the universe’s laws we have made up are total rubbish. The dark stuff does sound a bit hellish but that’s just a name and a bit inappropriate as really it’s just not visible i.e.it’s invisible.
Dark energy is the name given to an unexplained force that is drawing galaxies away from each other, against the pull of gravity, at an accelerated rate. Dark energy is a bit like anti-gravity, where gravity pulls things together dark energy tugs them apart.
How can astronomers be so certain of something they have never seen? The answer comes from observations of how stars and galaxies move, studies that have been going on for more than 50 years. Within spiral galaxies, individual stars and clouds of gas are orbiting faster than they should if they were only being affected by the gravity of the galaxys visible matter. The same is true for clusters of galaxies, the motions of individual galaxies cant be explained by the gravity of what astronomers can see.
To explain these observations, astronomers have deduced that galaxies are surrounded by vast halos of a different, unseen kind of matter.
If you could see dark matter, say astronomers, most galaxies, including our own Milky Way, would appear 10 times larger than they do in telescopes. All the known stars, galaxies, planets, and clouds of gas and dust are just a small fraction of whats out there.
The first person to come up with a theory on dark matter was a Swiss astrophysicist in 1933. Fred Zwicky was studying the Coma cluster of galaxies, a group of individual galaxies smothered in a big hot gas cloud, when he discovered evidence of unseen mass.
It was determined that the entire sum of matter in the universe, the physical universe of stars and planets and the like, was only 0.4 percent of the total mass of the universe. A further 3.6 percent was made up of interstellar gas. Dark matter was determined to fill 23 percent of the total mass of the universe, leaving the mysterious dark energy to fill the remaining 73 percent.
This estimate proved very accurate and WMAP provided proof of dark matter and dark energys existence. WMAP’s complete look at the universe found that dark matter makes up 23.3% (to within 1.3%) of the universe and dark energy makes up 72.1% of the universe (to within 1.5%).
The very origin of the term dark matter leads many to consider it simply a label for the unknown. Is there only one type of matter that is “dark matter”, or are their many forms of matter that are unobservable to humans, or an infinite amount? Scientists and astronomers continue to use the label with the understanding that they are not one hundred percent sure of what the label itself actually means.
Some people think it is just ordinary matter that is too cold or sparse to be seen optically whereas other people think it is some type of as yet undefined exotic matter. If it is just too cold to be seen then there’s just no point talking about it until we can get something to sense it. But if it is exotic matter then what could it be?
A theory that has been around a long time is that dark matter is made out of WIMPS. A good name but it does not reflect the character of this type of WIMP. A WIMP is a Weakly Interacting Massive Particle. These particles are not weak as the name suggests but very strong and pass through matter. At the moment a million of these particles could be passing through your finger.
WIMPS make up about 90% of dark matter so the big brains think. The other 10% could be made of MACHO’s & neutrinos.
Massive astrophysical compact halo object, wow!, or MACHO, is a general name for any kind of astronomical body such as neutron stars or brown dwarfs that might explain the presence of dark matter in galaxy halos. A MACHO is a body composed of normal baryonic matter, which emits little or no radiation and drifts through interstellar space not part of any solar system, minding it's own business.
Another theory involving undetected particles is that dark matter is made of subatomic particles called Axions. Axions are many times lighter than electrons and have no electric charge. One of the main differences between WIMPs and axions is their mass. Therefore, the difference between the two theories (WIMPs or axions) is that dark matter is either made of a large number of light particles (axions) or a smaller number of heavier particles (WIMPs).
One theory suggests that if two lingering particles of dark matter collide, they should annihilate to create an ordinary particle and an antiparticle, such as an electron and a positron, which can be observed. Those particles should emerge with an energy determined by the mass of the dark energy particles, leading to a sharp peak in the energy spectrum of electrons and positrons from space.
so many ideas and theories exist. Perhaps space is curved, and can be (and has been) compared to a fabric, this could ask the question that space itself could be made of dark matter. That could bring on all sorts of discoveries.
Perhaps scientists dont entirely understand the way gravity works, perhaps Isaac Newtons famous law of gravitation needs some revising. Einstein revolutionised science and I don’t think that he is the final word, there could be a revolution on the way as dark matter and dark energy challenge the way we think. For more try here.
What if Dark Matter is just a by product of a Black Hole? Black holes take in matter, so where does it all go? Perhaps black holes eject stuff that we don’t know about yet. It would have to be a completely different type of matter but who knows?
there is a race to find what dark matter actually is. The FERMI gamma ray telescope is studying lots of things and one of them is dark matter. PAMELA space observatory is also on the hunt. The Cryogenic Dark Matter Search (CDMS) is a bit different being underground but is looking for the same thing.
As early as this October, the Large Hadron Collider near Geneva, Switzerland, could provide the much-awaited breakthrough by creating dark-matter right here on Earth. Scientists could then learn about the properties of these particles, starting with their masses for instance, and see whether they can produce the effects hinted at by Fermi and PAMELA.
There is a theory of supersymmetry that suggests that all known particles have, as yet undetected, superpartners. If they exist, the LHC should find them and very soon.
Well, it looks like dark matter and dark energy may not remain dark for very much longer and may create a new age of physics. It may release some laws that may explain a lot of other things and also help us to get around the universe. Let’s hope so.