The smallest major planets are (from smallest up): Mercury, Mars, Venus, Earth. The Scale of The Universe shows everything from the smallest to largest things in our universe. This means that Earth is actually approximately 2.6 times the diameter of the smallest planet, Mercury. Check out the Scale of The Universe right now! The biggest planets in size are (from largest down): Jupiter, Saturn, Uranus, Neptune. If you’re interested in planets, the good news is there’s plenty of variety to choose from in our own Solar System. Amazing to see The biggest planets in size are (from largest down): Jupiter, Saturn, Uranus, Neptune.

Fred Espenak.

The smallest planet in our solar system is Mercury and the largest planet is Jupiter. There are a couple of different ways to measure how “big” something is. Solar System Planet Sizes - Largest To Smallest; Solar Eclipse Astrophotography (Solar System) Star Formation in the Early Universe (Artist Adolf Schaller) Apollo 11 Moon Landing 20 July 1969 - "That's one small step for man, one giant leap for mankind" ALCHEssMIST Astronomy Blog Another size comparison puts Earth at 3.67 times the diameter of the Moon. Smallest Planet: Mercury Mercury is a tiny black dot as it transits the Sun in 2006. The smallest major planets are (from smallest up): Mercury, Mars, Venus, Earth. Our home planet Earth is the fifth largest of the eight planets and measures in at 12,756 km in diameter.