system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do asphalt roads go from dark black when fresh to the dull grey?

I was driving on road that is being renovated and this question popped into my head. Asphalt is black like coal when fresh and I want to know how/why it goes grey.
gpt
It’s called *photobleaching*. 

Here’s why some things are black: their chemical structure absorbs energy from the suns rays. That energy has to go somewhere. Sometimes, that energy gets turned into heat. But sometimes that energy is enough to break apart a chemical bond. The broken bond forms a slightly different chemical that is a different color — so over time, some of the asphalt chemically bleaches to turn gray.