Astronomy Facts
1 / 15Test your knowledge of the stars, planets, and cosmos!
15 quick questionsNo sign-upFree to playTap an answer below to begin ↓
Which planet is known as the 'Red Planet'?
About Astronomy Facts
Test your knowledge of the stars, planets, and cosmos! Astronomy Facts packs 15 multiple-choice questions with a mix of 5 easy, 5 medium, 5 hard questions into a relaxed session of roughly 7 minutes — no sign-up, no timer pressure. An explanation appears after every answer, and finishing once a day keeps your streak alive.
A few sample questions
1. Which planet is known as the 'Red Planet'?
Answer: Mars
Mars is called the Red Planet because of the iron oxide (rust) on its surface, which gives it a reddish appearance when viewed from Earth.
2. What is the closest star to Earth?
Answer: The Sun
The Sun is the closest star to Earth, at an average distance of about 93 million miles (150 million kilometers). The next closest star system is Alpha Centauri, about 4.37 light-years away.
3. How many planets are in our solar system?
Answer: 8
There are 8 planets in our solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. Pluto was reclassified as a dwarf planet in 2006.
4. What is the name of our galaxy?
Answer: The Milky Way
Our solar system is located in the Milky Way galaxy, a barred spiral galaxy estimated to contain 100-400 billion stars and spanning about 100,000 light-years in diameter.
5. Which planet is the largest in our solar system?
Answer: Jupiter
Jupiter is the largest planet in our solar system, with a diameter of about 86,881 miles — more than 11 times that of Earth. It is so large that all other planets could fit inside it.
Things you'll learn along the way
- A solar eclipse occurs when the Moon passes between the Sun and Earth, casting a shadow on Earth. During a total solar eclipse, the Moon completely blocks the Sun's face.
- Saturn has the most extensive and spectacular ring system in our solar system. The rings are made primarily of ice particles, with smaller amounts of rocky debris and dust.
- A light-year is a unit of distance, not time. It is the distance that light travels in one year, approximately 5.88 trillion miles (9.46 trillion kilometers).
Frequently asked questions
Can I print Astronomy Facts?
Yes — use the Print button at the top of the page for a clean question sheet, or "Print with Answers" to make an answer key. Printed sheets work well for group play at home, in a classroom, or at a senior center.
Will I lose my progress if I close the page?
Your overall progress — XP, streaks, and badges — is saved in your browser automatically. A quiz that's underway restarts if you leave mid-game, but at about 7 minutes, Astronomy Facts fits comfortably in one sitting.
How many questions are in Astronomy Facts?
Astronomy Facts has 15 multiple-choice questions. Each one has four answer options and an explanation that appears after you answer, so you learn something even when you miss.
Is Astronomy Facts free to play?
Yes. The entire SeniorBrainGames catalog — including Astronomy Facts — is free, with no sign-up required, no time limits, and no ads on top of the game. It also works offline once the page has loaded once.
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