<|im_start|>system
You are a helpful AI assistant.<|im_end|>
<|im_start|>user
Why is light affected by gravity even if it doesn't have mass?<|im_end|>
<|im_start|>assistant
According to Einstein, gravity affects the curvature of space and time.  Light's path traveling through this space is therefore affected even though it does not have mass.<|im_end|>
<|im_start|>user
Can you concisely explain General Relativity?<|im_end|>
<|im_start|>assistant
General Relativity, formulated by Albert Einstein in 1915, is a theory of gravity that describes how massive objects like stars and planets influence the fabric of spacetime, causing it to curve. This curvature of spacetime dictates how objects move and how they interact gravitationally. In simpler terms, objects with mass cause spacetime to bend, and this bending affects the motion of objects, including light, even if they don't have mass.<|im_end|>