Does light travel in a straight line or does it spread out?

thats a difficult question to answer but simply put in open space a particle that has mass cannot achieve light speed because as a particle gains momentum that energy causes the particle to become more massive thus requiring more energy to accelerate this is what E=mc2 means, that energy and mass are one and the same, photons are a massless particle and therefor cannot move slower then light speed, based on that you can assume that the photon of light moving at light speed is actually at its lowest possible energy level in regards to momentum and therefor has no energy available to change its direction unless it bounces from another object. another particle that travels in a straight line is radio signals and thats why tall buildings sometimes can block the signal.

Light travels in a straight line.

No. Light is a particle that acts like a wave and therefore is never in a straight line

In a straight line. At the speed of light.

No it travels as a wave. Improvement: No actually, it DOES travel in a straight line :)

if light did not travel in a straight line there would be no shadows as the photons would simply move around the obstruction and strike the ground.

nothing they travel in straight line

light travels in a straight line because it can only be bend by reflective objects.

one of the properties of light is that light travel at straight line

the light travels in a straight line becauise it is going straight on to you object what you are looking at.

There are more things for the light waves to bounce off of in water, so light can not travel in a straight line or as far.

Light will travel in a straight line when there is nothing to refract, reflect, or diffuse it from it's course.

travels through a uniform medium

It travels in straight line unless obstructed by a change in medium or other obsticle. And the speed of light is 3.8X10^8 meters per second (in a vacuum)

While light will travel in essentially a straight line, it is affected by gravity. A strong enough gravitational pull can bend light and actually change its direction.

Normal. It takes a lot of mass to bend light.

Light travels in a straight line under most conditions.

Normally light travels in a straight line. However, it has been demonstrated that gravity can bend the path of light.

If light does not travel in a straight line, vision would not be accurate since objects will appear to be in different places. The reflected light that hits the eyes will bring images from different areas.

It does not, it is bent by very strong gravitational fields

Light travels in astraight line as it has the property known as the rectilinear prpogation of light.

I can't really think of any "evidence" of this that isn't trivially obvious. Take an object. Put something in between you and the object. Can you still see it? Then light must travel in a straight line. However... in fact, light does not travel in a straight line, it travels along a geodesic path, which ordinarily happens to be very, very close to a straight line. Near very massive objects, though, geodesics are not even close to straight lines.

Yes, according to the rectilinear propagation of light, light does travel in a straight line. The only two things that can possibly alter that are near-relativistic speeds, and intense gravity. The latter was proven during a total solar eclipse in 1919.

Energy does always travel in a straight line. It is true that close to a massive object the energy may 'appear' to bend, but this is simply because mass bends space, a straight line through curved space is still a straight line. So the reason that energy travels in a straight line is because a straight line is actually defined as the path taken by a beam of light!

Light ray and gamma ray both travel in a straight line.