Why is light affected by gravity if it has no mass?
In: 3548
A 20lb rock is twice as heavy as a 10lb rock.
Both fall at the same rate.
So… What would a 0lb rock do?
There’s no rule that says “gravity only impacts things with mass”.
It might be a bit confusing if you think of gravity as a force, like a hand pushing down. While you can often think of it this way, gravity is more of a natural motion – a thing falling under gravity experiences no force at all yet it still moves inward. Thinking of gravity as if it’s a force can lead to confusion.
——————-
If you want a bit of a deeper dive, gravity’s relationship with light is actually quite fascinating. While light always locally moves at light speed, because this motion depends on local time, light can ‘slow down’ in regions where time itself is slowed down.
If you remember physics class, you might recall than light (and all waves) curves into a region where it’s slow. This is how lenses work.
Since gravity slows time, light curves towards the center of the gravity.
Latest Answers