How does the gravity of an object affect light?

Question

Light doesn’t have mass; therefore, it is not affected by gravity.

Less energetic light will not be able to escape from a compact massive object, such as a neutron star, but more energetic light will be able to.

Light coming from a compact massive object, such as a neutron star, will be blueshifted.

Visible light coming from a compact massive object, such as a neutron star, will be redshifted, but higher frequencies such as X-rays and gamma rays will not be affected.

Light coming from a compact massive object, such as a neutron star, will be redshifted.

Answer 1

Light does not have mass but all wavelengths are effected by gravity since gravity distorts the space around a massive object. Thus the correct answer is: "Light coming from a compact massive object such as a neutron star will be redshifted."

Answer 2

Light coming from a compact massive object, such as a neutron star, will be redshifted

Answer 3

Less energetic light will not be able to escape from a compact massive object, such as a neutron star, but more energetic light will be able to.

Answer 4

Your very first statement is categoriacally wrong. Light is affected by gravity and in turn causes gravity. It was this realisation that led Einsteing to general relativity (he realised it through an easy thought experiment).

Whats more, special relativity led him to realise that because mass is frame dependent (moving observers will not agree on the mass of an object), doing sums on gravity as if it just depended on mass was going to be a problem.

To get technical, gravity depends on stree-energy - which is a measure of relaticistically treated mass and the mass equivalence of energy in a region of space.

Gravity does two things to light. First, it curves the path of passing light. Second, it red shifts light coming from a massive object.

Energy has no affect on whether light can escape a massive object because energy is a surrogate for mass and you know that escape velocity does not depend on mass.

A massive object can never blue shift light coming from it. But it will also affect light of ALL frequencies.

I think you need to go back to the books.

Answer 5

E=mc^2 is Einstein's basic building block for the rest of his theory, most of what has been proven.

It suggests that light has the potential of having mass, but I do not know if that is the reason that light bends around a massive object.

It was, however, proven that light bends around the sun in the exact manner predicted by Einstein. I believe experiments carried out during solar eclipses proved this fact.

Apparently someone using Einstein theory postulated that if you had an infinitely powerful telescope and you looked out into space, that you'd see the back of your head.

Now I had not heard of the blue shift. This is slightly different than bending of light. Normally a shift is associated with the speed of an object relative to your position. How could they tell if it was due to the relative motion or due to gravity? I would have thought that if an astronomer had seen a blueshift they would automatically correlate that to motion of the star.

Answer 6

I'm surprised that you didn't mention anything about gravitational lensing. The gravity of certain galaxies do something to distort light, from more distant galaxies.

Answer 7

It's called Gravitational Lensing.

Light conforms to the shape of space, and the shape of space is altered by large bodies.