-
Asked by 232grak26 to Daniel, Hannah, Maggie, Ry, Scott on 14 Nov 2017.
-
Maggie Lieu answered on 14 Nov 2017:
If the gravity is strong enough, then it can bend light. It works in the same way that we are pulled to earths gravity. This is called gravitational lensing and makes pretty arcs on the sky like this:
-
-
Ry Cutter answered on 14 Nov 2017:
Great picture Maggie. It’s the smiley face gravitational lens event!
Gravity does bend light!
If we imagine space time like a big trampoline and stars like bowling balls. If we put a bowling ball on the trampoline it dips. These dips happen in space time; the bigger the dip, the stronger gravity is at that point! Imagine rolling a tennis ball along a flat trampoline, the tennis ball will go straight. If we roll a tennis ball on a dipping trampoline, the tennis ball is going to bend in a different direction! Light is like the tennis ball, it will go straight on the flat spacetime and bend on the curved spacetime… bend when there’s gravity!
If the gravity is strong enough the light will go in a complete circle, the light can’t escape! We call those black holes, and are some of the most fascinating things in the universe!
Brilliant Question,
Ryan -
Scott Melville answered on 14 Nov 2017:
Awesome – we have a great lensing picture and a solid trampoline analogy 🙂
I’ll add a couple of things which might or might be helpful (if they sound confusing, then just ignore them 😉 ).
Imagine that you were watching an ant crawl along an orange. The ant is convinced that it’s going in a straight line, it just keeps walking forward. But from your point of view, the ant is clearly walking along an arc – its path looks bent to you. Something very similar happens with light – it ‘thinks’ that it’s going in a straight line, but when it gets near the Sun it’s like an ant on an orange – from far away it looks to us as if it’s tracing a curve. (I guess what I’m saying is, ‘bent’ and ‘not bent’ are matters of opinion – don’t be too hard on the light, it’s actually trying its best to go straight!)
The other thing is that light doesn’t have any mass, so you might worry about why gravity affects it at all. Well, we’ve all heard of Einstein’s E=mc^2 – what this means is that energy and mass are actually interchangeable, from a gravity point of view. So if light has some energy, then it’ll be affected by gravity AS IF it had mass 🙂 -
Hannah Middleton answered on 15 Nov 2017:
Yes it can, just like the other’s say it’s called gravitational lensing: gravity is acting like a lens and warping the images we see. There’s a nice animation here of how it works
Comments