Question

which outer planet is most like earth?

Answer 1

Venus and Mars are the most like Earth but in different ways.
In terms of size, average density, mass, and surface gravity, Venus is very similar to Earth.

Answer 2

Kepler 452 b which is 1400 light years from earth. this planet was discovered by Kepler telescope and announced by NASA on 23rd of July 2015.

this exoplanet is quite same like earth Sun system. it has habitable temperature which can support life.

Kepler-452b has a probable mass five times that of Earth, and its surface gravity is twice Earth's.

Kepler revolves around the sun like stars which is 6 billion years old.
the star is 1.4 billion years older than sun.

hope it helps !