What is the smallest planet in outer space?
The smallest planet in regards to both mass and volume is Mercury — at 4,879 km across and 3.3010 x 1023 kg, this tiny world is nearly 20 times less massive than Earth, and its diameter is about 2½ times smaller. In fact, Mercury is closer in size to our Moon than to Earth.
Join Alexa Answers
Help make Alexa smarter and share your knowledge with the worldLEARN MORE