Science
The Solar System Quiz
Planets, moons, and cosmic wonders — how well do you know our cosmic neighborhood?
Planets, moons, and cosmic wonders — how well do you know our cosmic neighborhood?
Our solar system spans 287 billion miles from the Sun to the outer edge of the Oort Cloud, containing 8 planets, over 200 moons, and countless asteroids and comets. This quiz draws from a pool of 10 questions covering planets, dwarf planets, moons, and orbital mechanics — with each attempt randomized so no two rounds are the same.
Each round presents 10 multiple-choice questions. Pick your answer, get instant feedback with a detailed explanation, and see your final score at the end. No signup or timer — just you and the cosmos.
Questions cover planetary sizes, ring compositions, moon counts, axial tilts, and famous storm systems like Jupiter's Great Red Spot. You'll also encounter dwarf planet reclassifications and surface temperatures — did you know Venus is hotter than Mercury despite being farther from the Sun?
There are 8 recognized planets in our solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Pluto was reclassified as a dwarf planet by the International Astronomical Union in 2006 after the discovery of similarly sized objects in the Kuiper Belt.
Venus is the hottest planet, with surface temperatures averaging 465 degrees Celsius (869 degrees Fahrenheit). Despite being farther from the Sun than Mercury, Venus traps heat through a runaway greenhouse effect caused by its dense carbon dioxide atmosphere.
Earth orbits the Sun at an average distance of about 93 million miles (150 million kilometers), a measurement known as one astronomical unit (AU). Light from the Sun takes approximately 8 minutes and 20 seconds to reach Earth at this distance.
Last updated: March 2026