Can light be affected by gravity?

Answer 1

Yes, light is affected by gravity. For example, if you take light at the base of a building and make it go to the top of the building, the light at the top will be slightly redder than that at the bottom. This redshift is due to the gravitational filed of the earth. This effect has been measured, although it is small. Also, light will bend slightly around a massive object. For example, light that just grazes the limb of the sun will be bent by about 1.7 seconds of arc. This is a very small amount of bending!

To get more dramatic effects on light, you have to look at much more dense objects than the sun. It is possible for light to orbit a black hole in a circular orbit, but that orbit is unstable. The gravitational lenses that a previous poster commented on are usually from light going past a very massive galaxy rather than a black hole. These are currently being used to help investigate dark matter and dark energy.

There are differences between the way light is affected by gravity and how ordinary matter is affected, but the differences are subtle and based in the fact that light goes at the 'speed of light', which is a special speed in relativity.

Answer 2

Light can be affected by gravity. One example: any black hole. The reason it is called a black hole is that the gravity of a black hole is some strong, that not even light can escape it. The black hole is surrounded by what is called an event horizon. This is an imaginary boundry around the black hole that denotes the point where its' gravity would catch you and suck you in. This event horizon is like a globby sphere. Light can get closer is some points than others. Once light enters the event horizon, it cannot escape and it is pulled into the black hole.

Answer 3

Yes. Light cannot escape a black hole. Even smaller mass objects like a planet or moon has some effect in bending light due to their gravitational pull. Current theories state that time is also affected by gravity.

Answer 4

According to Einstein's General Relativity Theory,light will be affected in the same way matter is affected by gravity. This is because under this theory, we should think of gravity not in terms of vector like forces, but as a consequence of the "shape" of the universe.

From Newton's point of view, gravity was a linearly directed force with which all objects with mass pulled on all other objects with mass. His analysis showed that the strength of the force was proportional to the product of the 2 masses attracting one another, and inversely proportional to the square of the distance between them. Thus an apple and the earth would pull toward each other, and the apple "falls" from the tree. Since light (whether perceived as a ray or a photon) has no mass, Newton's equation predicts that it will not be attracted by gravity towards anything, no matter how massive.

In order to construct a theoretical framework that would be consistent to all observers and that did not rely on some independent fixed reference frame, Einstein had to discard this perception of how gravity works and devise a new understanding. According to this theory, all object with mass alter the curvature of spacetime, the 4 dimensional fabric of the universe. Objects moving through spacetime then simply follow the curves that have been created.

Since human brains are not good at picturing things in 4 dimensions we usually resort to an analogy in 3 dimensions. Imagine spacetime as a sheet of rubber, stretched flat when there is no matter present. If we place a massive object like a star in this "space" it pushes down into the rubber sheet creating a dimple or pit in the rubber. an asteroid flying by the star would not travel in a straight line as it rolled along the sheet, it would curve as it went through the dip, coming out in a new direction. If an object were going just the right speed, it might get stuck in the dimple and travel around the star in an orbit like a ball around a roulette wheel. So far the predictions of this theory are the same as Newton's, but now comes a big difference- if light traveled along this rubber sheet of spacetime, it would follow the curve too, since the curvature of space is already created by the star. In fact if the pit is deep enough and the walls very steep, the light might fall into the pit and never escape. (what we call a black hole) Newton didn't notice this bending of light because it takes very massive objects to get something as fast as light to curve enough that you can notice. This is the same reason we still learn and use Newton's equation - it works well most of the time. But experiments have shown that in fact Newton was wrong and light IS attracted towards object with mass, as Einstein's theory predicted.

Answer 5

Yes it can. When light from a distant star passes a massive star on its way to the Earth, the light is actually BENT by gravity. This was predicted by general relativity and has been experimentally verified.

The Sources field shows a particularly interesting photograph of this effect -- a quasar's light being split into a "cloverleaf" pattern as it passes a massive galaxy between us and the quasar.

"The Universe is not only stranger than you imagine, it is stranger than you CAN imagine."

Answer 6

Certainly. Observation of the shift in star positions caused by the sun's gravity, as measured during a solar eclipse, was an important step in validating Einstein's theory of general relativity.

Answer 7

Yes. A black hole is an area with gravity so strong that not even light can escape it.

Answer 8

Yes. In fact, gravitational lenses are a common phenomenon. Light passing through an extremely powerful gravitational field (near a neutron star or black hole) is refracted and bent so that images of things beyond appear as multiple images arranged symmetrically.

Answer 9

Yes it can. Light is "bent" by anything that is massive. Even the Earth bends light slightly.

Answer 10

Absolutely.