Science
Astronomy Beyond the Solar System Quiz
Black holes, galaxies, and the edge of the universe — deep space knowledge.
Black holes, galaxies, and the edge of the universe — deep space knowledge.
The observable universe stretches roughly 93 billion light-years across and contains an estimated two trillion galaxies. This quiz draws from a pool of 50 questions covering star lifecycles, black holes, galaxy types, exoplanets, dark matter, and the cosmic microwave background — 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 span everything from the life and death of stars — main sequence, red giants, white dwarfs, supernovae — to the mysteries of dark energy driving the universe's accelerating expansion. You'll explore how the James Webb Space Telescope peers into the early universe, how astronomers detect exoplanets light-years away, and what happens at the event horizon of a black hole.
The observable universe has a diameter of roughly 93 billion light-years. Because the universe has been expanding since the Big Bang approximately 13.8 billion years ago, the most distant objects we can detect are now far more than 13.8 billion light-years away due to the stretching of space itself.
A black hole is a region of spacetime where gravity is so extreme that nothing — not even light — can escape once it crosses the event horizon. Stellar black holes form when massive stars exhaust their fuel and collapse, while supermassive black holes, millions to billions of times the Sun's mass, sit at the centers of most galaxies.
Current estimates suggest there are roughly two trillion (2,000,000,000,000) galaxies in the observable universe. This figure, based on Hubble Space Telescope deep field observations and mathematical modeling, is far higher than the earlier estimate of around 200 billion galaxies.
Last updated: March 2026