[Conan the Librarian]

Actually, it’s not that dark. More like about sunrise or sunset on earth.

https://www.space.com/29600-pluto-time-nasa-new-horizons.html

[Telepathic Intruder]

At Pluto’s closest approach to the sun, it gets only 4% of 1% the sunlight that Earth does. That may provide enough light to see dimly by, but not enough to heat it at all.