Pluto was once known as the smallest planet in our solar system. Now it's called a plutoid or dwarf planet. The three known plutoids are pluto, Eris, and Makemake. The temperature in pluto is extremely cold; it's temperature is 375 to 400 degrees below zero. Not much is known about pluto because it is so far away from Earth.
If you look closer at the picture on the left, you will notice a heart on the bottom right of pluto.