Isnt light to be considered dark substance since it cannot be shadowed by other substances =Dark matter?
473304
This is a very intriguing question which I plan on researching. I have a conception of light and its physical properties and also the tremendous mysteries of a 'Black Hole'Where current day Physics is just beginning to grasp.NOTHING escapes the gravity of a 'Black Hole',not even light!Through the efforts  of dilligent astronomers, one was actually 'seen' and filmed as it passed in front of a known group of stars...outlining the very hole itself.(like passing an object in front of a bright light source and observing the outline of the object...i.e. Solar eclipse...,) knowing of there existence and how to track them now ,has given a whole new meaning to the destructive forces of a 'Black Hole' as it swallows up Stars, that Dwarf our Sun in comparrison,and the Solar System it may support.This is Truly Dark Matter on the 'Anti' side...Anti-matter...a Black Hole is given birth by a Star,such as our Sun, that is dying.As this Star,once a source of Light that supported a probable solar system, goes through its Final death throws it eventually explodes, but it just doesnt explode! as its  surface layers are  blasted outwards, its  core is smashed inwards. The center of the star  collapses in on itself. Billions upon Billions of tons of Star stuff crushed smaller and smaller until the whole Star is squeezed to a microscopic point,and from the remains of the dying Star, ....a BLACK HOLE is born....in our Galaxy,the Milky Way, a Massive Star explodes and creates another black hole every 1000 years. There is a estimated 10 Million Black Holes roaming our Glaxy today, creating Havoc sucking matter in around them... NOTHING escapes! As we know, anything of SUBSTANCE has mass, microscopic as well as Galatic.Once realized that the incredible forces hatched by a black hole having the ability to bend light and distort the Space/Time continuum which in itself is invisible to the eye, is it a possibility that this very same process is taking place at a molecular level? If manipulated correctly, is 'Cloaking' a possibility? your Question is very intriguing indeed!
328994
Dark does not push light away, the light is what is moving. Using your example of "over the horizon", the sun (which produces light) moves to the other side of the earth (where we can't see it) then we see dark. But dark does not move, it is just the term we have come up with for what it looks like when there is no light present.
672804
its like we have developed the properties of particles and waves much before than we be knowing that actually everthing in the universe is having both properties.\n\nlight has a nature which can neither be defined as of wave and nor that of particle. hence, in old science terms light is both the particle and wave. \n\nif you are much intrested in this phenomenon then read about string theory which states that there are two things important\n1. the object\n2. the relation \n\nwe in neutoneon science have concentrated on 1st. but actually the nature can only be studied with the help of 2nd.
380500
It's the matter in galaxies that provides enough gravitational force to prevent them from being flung apart by their angular momentum.  It's called dark because we can't see it
567055
Dark matter has mass. The spirit leaves the body when a person dies.\n\nThe spirit does not have mass. This can be proved as follows: When we die and as our spirit leaves our body, our weight does not decrease, unless we wait long enough for bacterial decay.\n\nTherefore, spirits do not consist of dark matter.
230733
In cosmology, dark matter refers to hypothetical matter particles, of unknown composition, that do not emit or reflect enough electromagnetic radiation to be detected directly, but whose presence can be inferred from gravitational effects on visible matter such as stars and galaxies. The dark matter hypothesis aims to explain several anomalous astronomical observations, such as anomalies in the rotational speed of galaxies (the galaxy rotation problem). Estimates of the amount of matter present in galaxies, based on gravitational effects, consistently suggest that there is far more matter than is directly observable. The existence of dark matter would also resolve a number of inconsistencies in the Big Bang theory, and is crucial for structure formation.\n\nIf dark matter does exist, it has vastly more mass than the "visible" part of the universe. Only about 4% of the total mass in the universe (as inferred from gravitational effects) can be seen directly. About 23% is thought to be composed of dark matter. The remaining 73% is thought to consist of dark energy, an even stranger component, distributed diffusely in space, that probably cannot be thought of as ordinary particles. Determining the nature of this missing mass is one of the most important problems in modern cosmology and particle physics.
710893
light my son light.\ndarkness means 0% illumination.As light from a star  travels in all direction it covers all of the universe(and never gets destroyed in vaccum so keeps on travelling) And there are so many stars.\nonly a small part of the space is filled with light absorbing object and black holes.So almost 90% of space is occupied by light.\nso light is the king!!!!
801467
No, not really.\n\nEven high school labs now do light experiments that show photons are quanta.  One simple experiment, is with the photometer that emits electrons when struck by light.  The electrons are like billiard balls and the photons are the cue balls striking them to send them on their merry way.\n\nIf light were simply a ray (a force field), the amount of electrons emitted would be proportional to the strength of the light beam.  But they aren't and the number of electrons actually follow a step-function where at a given threshold of light, the electrons suddenly burst forth after none up until that threshold.\n\nThe photon concept, as bundles of energy, is the result of what I would call good physics.  Good physics is physics that starts with the physical phenomenon and then derives equations to explain it.  Bad physics, like string theory, starts with the math and then tries to explain a physical phenomenon, like strings.\n\nAs to your last assertion, think about it...would even physicists, who are renowned for their weird jargon, call something a "matter," which is a synonym for "mass" if it were not a mass?  No, dark matter is a mass...more correctly a mass-energy (due to E = mc^2).  DM accounts for about 96% of all the mass-energy in our known universe.  \n\nUntil just recently, DM has not been observed, which is why they called it dark.  But a recent observation of two galaxies colliding has seen the effects of the dark masses surrounding those two galaxies also colliding.  So, there is now observable evidence that the dark matter exists...the theory has been validated. [See source.]
100574
There's more than one: light, a hole, darkness, and shadows to name a few.  Also a hallucination.\n\n*Yankeesrock26ws, air actually does have mass, it's just that it's effectively constant on Earth so we tend not to notice it.\n\nhandsome_stranger wrote:\n>>>actually light can be changed to mass so i think it is not a good >>>answer\nBut then it's not light anymore.
752622
Dark matter is matter (the substances which make up physical objects) that does not emit or reflect enough electromagnetic radiation to be directly dected, but its prescence can be assumed by gravitation effects from surrounding physical objects. The composition of dark matter is currently unknown, but current evidence suggests that it is primarily made up of new elementary particles which are collectively being called nonbaryonic dark matter.\nDark matter is though to make up 25% of the universe. \n\nDark energy is a hypothetical form of energy that flows throughout space containing larges amounts of negative pressure and is used to account for the significant amount of missing mass in the known universe. Very little is known about dark energy but it is thought to make up 70% of the universe.
1165536
There is no such thing as "dark light", there is only light or the absence of light. The dark sky is simply the absence of light. Dark isn't a real thing, it is just a lack of a real thing, the real thing being light.\n\nNote that the sky is not totally dark, juts too dark for your eyes to see. There is some dim light everywhere, from distant stars or the cosmic microwave background or whatever, but it is all "light".
447237
Dark matter provides the gravitational force that prevents galaxies being ripped apart by their angular momentum.  We have no way of detecting it, except from the bending of light around it.
1021193
No idea what you mean by your comment.....\n\nIn cosmology, dark matter refers to matter  of yet unknown composition, that does not emit or reflect enough light to be detected directly. But its presence may be inferred from gravitational effects on visible matter such as stars and galaxies. \n\nEvidence suggest that there is much more dark matter than visible matter. As it is non-interacting with light it must be of non-baryonic origin. It also must be stable, because it exists since the Big Bang, 14 billion years ago. The only candidate among the elementary particles we know already are the neutrinos. However there are theories like Supersymmetry that predict other particles, that would fit the known data.
524044
Light is not actually a physical substance.  It is made up of photons.  Photons are electromagnetic energy.  They contain no mass, no electrical charge, and last indefinitely.  \n\nLight needs to reflect off of something else to be visible.  Everything we see around us is reflecting light.  When we see something, we are actually seeing light.  In fact, light is all our eyes can actually see.  We are never actually seeing the object -- just the light reflected from it.\n\nIn space, there is a void.  No atmosphere.  No particles to reflect the rays as they spill through space.  That is why in space you can't see the rays of light pass by.  They have no mass of their own, and they have no concentration of particles in their path to reflect their energy.  \n\nYou might consider some of the links below:
1107021
Yes. Darkness is an absence of light. To make it "darker" you subtract light. You cannot add darkness.
394958
Sorry, but we've ruled out the majority of dark matter being massive concentrations of mass (small black holes etc).  Things like that can be detected in gravitational lens searches, and the numbers of lensing events that we have detected pretty much rules out any type of "massive compact" dark matter being the bulk of what is out there.  This leaves us looking for even more exotic stuff - there is likely a nobel out there for someone who figures it out.\n\nAs for directly answering the question... I'm really at a loss to even begin to understand what is being said there.
1052554
Well, not speculating on whether dark matter is present or not, we know, from observation that there is something capable of altering the rotation curves of galaxies, causing gravitational lensing, affecting the flow of interstellar gases (including one case, VIRGOHI21, where a bunch of diffuse hydrogen in a region of no stars whatsoever is behaving as though it had a rather substantial mass despite the complete absence of any stars), and altering the large-scale structure of the universe, in precisely the same way that gravity does, and say, electromagnetic forces do not. We know that this mysterious gravity-like force is being exerted by objects that do not emit or absorb light, because we would be able to see it if it was. The simplest explanation for this phenomena is that it is in fact gravity, and that this gravity is being caused by the presence of large amounts of matter that we cannot see - i.e. dark matter. I suggest that you look at the wikipedia articles on this subject for more details.