Can electromagnetic waves be affected by gravity?
Can electromagnetic waves change their properties in the presence of gravity?
If you explain what it is about the results from googling e.g. "electromagnetic waves affected by gravity" that you don't understand, it will be easier to help you.
I'm not sure what you mean by change their properties. Light's wavelength and direction is changed when it passes by or moves towards or moves away from a gravitational source.
Yes (and somewhat No apparently too)
If you follow Einstein's theory of general relativity then gravity has no direct effect on electromagnetic waves itself.
Gravity however affects space time itself warping it towards the gravity source. Thus any electromagnetic wave passing close enough to the gravity source will bend towards that source when observed from the outside.
From the point of the wave however, it follows a straight path and is not affected by gravity at all.
If you mix in quantum theory, it's getting even more weird, because suddenly parts that work well for general relativity no longer work within the quantum model. This is part of current research in physics to bring general relativity and quantum theory into alignment.
Yes. Einstein predicted one such effect known as gravitational lensing. This occurs when light from a distant star or galaxy passes near a galaxy or galaxy cluster on its way to our planet. The nearer galaxy actually bends the EM waves and causes a focusing effect enabling us here on earth to actually see the more distant galaxy. If you do a Google search on 'gravitational lensing' you'll get some very cool pictures of this effect and a more complete explanation of this.