system
Given the following post, respond as if you're commenting on Reddit:
human
[ELI5] In the dark, why can we see an object when using the peripheral vision, but looking direcly at it we can barely see it?
gpt
There are two types of light receptor in the eye: rods and cones. Cones are colour sensitive but aren't good in low light conditions, and they're concentrated around the centre of your field of view in order to give you good colour vision during the day. The peripheries of your eye have mostly rods in them, which are much more sensitive to light, so in low-light conditions you'll see better at the edges of your vision than directly ahead.