Re: what is the coldest planet in the universe?

Nikki,

Nobody knows what the coldest planet in the universe is, because
we only know about a few planets so far: those in our solar system, plus
a few around other stars. So your question is sort of like me asking you
"who is the tallest person in your school?" but only letting you count
the people in your class.

The coldest planet in our solar system is Pluto. It's the coldest because it's
the furthest from the Sun and because it has very little internal heat
(for example, like the decay of radioactive elements which occurs in the center
of the Earth.) You can find out more about Pluto in almost any book on astronomy
or the solar system.

Pauline