In physics and cosmology, dark matter is matter that does not interact with the electromagnetic force, but whose presence can be inferred from gravitational effects on visible matter. According to present observations of structures larger than galaxies, as well as Big Bang cosmology, dark matter accounts for the vast majority of mass in the observable universe. The observed phenomena which imply the presence of dark matter include the rotational speeds of galaxies, orbital velocities of galaxies in clusters, gravitational lensing of background objects by galaxy clusters such as the Bullet cluster, and the temperature distribution of hot gas in galaxies and clusters of galaxies. Dark matter also plays a central role in structure formation and galaxy evolution, and has measurable effects on the anisotropy of the cosmic microwave background. All these lines of evidence suggest that galaxies, clusters of galaxies, and the universe as a whole contain far more matter than that which interacts with electromagnetic radiation: the remainder is called the "dark matter component."
The dark matter component has vastly more mass than the "visible" component of the universe.[1] At present, the density of ordinary baryons and radiation in the universe is estimated to be equivalent to about one hydrogen atom per cubic meter of space. Only about 4% of the total energy density in the universe (as inferred from gravitational effects) can be seen directly. About 22% is thought to be composed of dark matter. The remaining 74% is thought to consist of dark energy, an even stranger component, distributed diffusely in space.[2] Some hard-to-detect baryonic matter makes a contribution to dark matter but constitutes only a small portion.[3][4] Determining the nature of this missing mass is one of the most important problems in modern cosmology and particle physics. It has been noted that the names "dark matter" and "dark energy" serve mainly as expressions of human ignorance, much as the marking of early maps with "terra incognita."[2]
more
So this inspire me 2 conceptions:
1. the existence of aliens
Maybe they live millions of light years far away, but if they have high technology, they could come to use in a shorter time, or even instantly. They are able to find an energy in the dark energies which let them move faster than light, the fastest visible energy we know till now...
Each species have different structure of eyes: some can see the light, some can see the ultra-violet, some can see the ultra-red, some can see the X ray, etc... With the same analogyn aliens could see dark matter and dark ray that humain cannot see, so it's impossible to catch them to do experiment !?
2. the existence of ghosts
There are a lot of evidences and prooves shown to the public. But still ppl deny their existence. Because none can see, can hear, can smell, can touch, can taste so logically they dont exist, using the definition of the existence. But using your 6th sense, it's the perception of thing changed: sometime in the dark, u have the feeling that someone is watching over u, u feel the existence of another being...
U cant see ghost because it's made by dark matter. I've also heard that at the moment u die, your weight is less than before...
