i read from people saying that light has very little mass so minute that gravity cant affect it
Einstein already answered that question
But i guess it is an electromagnetic wave having no mass. but yes, light does have a dual nature..so obviously it would have mass.
Light has relativistic mass (mass by virtue of its energy), in the same way we gain mass when we're moving (ie, very little). Photons have no rest mass though, so if you could stop a photon it would cease to exist. Is light a matter? I don't know what you mean by that. Light can be considered a stream of photons (small packets of energy) or as a wave which requires nothing to carry it (as opposed to, say, sound, which can only travel through something with matter in it. It can travel in air, water, etc, but not in a vacuum). As light can act as both we say it has a quantum duality. As light is so small and quick we don't have any way of observing its appearance without coming up against limits imposed by Heisenburg's Uncertainty Principle. That is a physical law stating how much you can know about a particle, you're welcome to read up on it, but basically that's what it suggests. Gravity does affect light. That's actually what we use to detect black holes. It's only largely deflected by stars and black holes though.
It does NOT have rest mass. This applies to all the photons along the entire electro-magnetic spectrum, including visible light. In fact, as it travels at light speed (duh) it cannot have rest mass. That can be easily shown. [See source.] But it does have momentum, P = Mc = hf/c; where M = m/sqrt(1 - (v/c)^2) is relativistic inertia, h is Planck's Constant, and f is the photonic frequency. [See source.] This means light wants to follow the curvature of space-time. Out away from mass, energy, or pressure sources, the curvature of our universe is pretty flat. It does not curve. It's called Euclidean Space and R^2 = X^2 + Y^2, the Pythagorean Equation, holds true. This is why anything with momentum tends to go in a straight path unless acted on by an external force. It's just following the non curve of normal space. But close in to mass, energy, and/or pressure, space-time bends according to the general theory of relativity. In fact, in the extreme, space and time can contract so much they form black holes which act as sort of gravity wells. Having momentum, the photons follow the extreme curves and fall into these black holes, never to return to ordinary space-time. Which is why those holes are black. And this is why photons appear to be attracted by gravity despite not having rest mass. They are simply following the curvature of space-time into the sources of those curves.
Light does not have mass - at least in the conventional meaning of mass. Gravity foes not affect light directly. It does distort (bend) space, and light travels through this curved space, and so it follows a bent course, but it is not the interaction of gravity and the mass of the light, but of gravity and space itself that causes the light to 'bend'.
