Astronomy Quiz – 8 Questions (& Answers)

Welcome to this short quiz! It contains 8 questions about space.

Read the questions with a friend to see who knows more about space. Or read them alone to procrastinate from whatever led you to this page in the first place. Whatever the reason: Good luck with the quiz!

When you have an answer, click the question to see if you got it right.


Question 1: Is the Universe infinite?

Yes, it appears so.

However, the observable universe is finite. The size of the observable universe is determined by the horizon.


Question 2: How many stars are there in our galaxy, the Milky Way?

There are roughly 200 billion stars in the Milky Way. Our Sun is one of them.


Question 3: Is the Moon a planet?

No, the Moon is not a planet.

The Moon is a satellite orbiting Earth and it’s believed to be made from the debris expelled by an impact between a young version of Earth and a smaller planet (named Theia) when the Solar System was very young.


Question 4: Can a planet have two suns?

Yes, a planet can have more than one sun.

Many stars actually live in pairs already, so if a planet orbits one of those stars, it has two suns.


Question 5: What were there before the Big Bang?

Nothing meaningful.

You need time in order to measure “before”, and since time was created in the Big Bang, the question does not have a meaningful answer. It’s similar to asking what’s North of the North pole.


Question 6: Which is bigger, the Sun or the Moon?

The Sun is 400 times bigger than the moon.

Fortunately, it is also 400 times further away, which means we can have solar eclipses when the Moon exactly covers the surface of the Sun (at least that is what is looks like to us here on Earth). It doesn’t have to be like this – the size and distance do not have to be equal. So consider us lucky!


Question 7: Which galaxy do we normally consider to be our closest neighbor?

Andromeda (M31) is usually considered to be our closest galaxy neighbor at a distance of 2.5 million light-years.

However, there are numerous smaller satellite galaxies around the Milky Way. We usually consider Andromeda our nearest neighbor because it’s very large – it’s even bigger than our own galaxy.


Question 8: Does sound travel faster or slower in space compared to on Earth?

Slower. In fact, it does not travel at all.

Space is basically empty, and sound waves need particles in order to propagate. Empty space has no particles for sound waves to propagate via, so sound can not exist in the space between stars and planets.

When the universe was very young, it was also much denser and hence could (and did!) host sound waves.


I finished and won bragging rights to @astronomicca’s space quiz!

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