system
Given the following post, respond as if you're commenting on Reddit:
human
What percentage of the light produced by the sun hits Pluto?

I understand that this number varies; a range is an acceptable answer.

This question came up as I was viewing pictures from the New Horizons space probe. Pluto seemed decently lit which was surprising to me. I was expecting it to be a lot darker.
gpt
If you have a sphere whose centre is at the sun and whose surface is at the orbit of Pluto (roughly, it's an ellipse IRL), the answer to your question is the fraction of this sphere's surface area that is occupied by Pluto. That is the ratio of Pluto's radius to its orbital radius squared. This is about 0.04 trillionths.

The images you see rely on long exposure times and significant post-processing.