Our night sky is pricked with the light from millions of incredibly bright stars -- and yet, those twinkling beams are just a tiny insight into the brilliance and immensity of our universe. How much do you know about simple astronomy facts?

Space is mostly an empty vacuum, but it's not entirely empty. There's matter in every part of space, even if it just a few scattered atoms.

The Galactic Center is what's called the rotational center of the Milky Way galaxy. It's the brightest and densest part of the Milky Way and is probably the location of a supermassive black hole. The Galactic Center is a favorite subject of night sky photographers because its brightness and colors are evident using modern cameras.

We humans still can only detect about 5% of the matter in the universe. The rest is invisible matter (dark matter) and weird energy (dark energy) that even Stephen Hawking can't explain in a one-sentence quiz description.

False, the American Moon landings were a conspiracy concocted the U.S. government. We're kidding, of course -- yes, the Moon is (so far) the only celestial body that humans have touched.

Gaze into the heavens on dark night and the number of stars seems incalculable. The reality is less impressive. You can see several thousand stars from your perspective and that's about it. Don't believe me? Go ahead and start counting and get back to me on that.

The Sun is about 93 million miles from Earth and the speed of light is about 186,000 MPH. The light you see from the Sun is always about 8 minutes old. The light from distant stars? Millions of years old, meaning those twinkles in the sky are a time machine of sorts.

It's true, the Moon really does look larger when it's close to the horizon. But it's not some weird atmospheric disturbance that causes this effect -- it's a mild illusion caused by the relative contrast in the size of objects (trees, buildings) on the ground compared with Moon's immensity.

Nebulae are clouds of interstellar dust and gas, and they mark areas where stars have died (or are being created). They take on beautiful and unique shapes -- with a powerful telescope, they are breathtaking to behold.

The Moon has no atmosphere, and thus, no wind. It's entirely possible that the footsteps taken by Armstrong and Buzz Aldrin are still there, and will be there forever, or until aliens land and rudely sweep them out of the way.

When Neil Armstrong first walked on the moon, he said, "That's one small step for man, one giant leap for mankind." Are his footprints still on the moon?

The Moon is smaller than Earth, but it is by no means miniscule. Its diameter is about 25% of Earth's. Translated: if the Moon ever crashes into Earth, your vacation plans for the Bahamas are canceled. Permanently.

Until late 2016, scientists estimated that there were about 200 billion galaxies in the observable universe. Thanks to new research based on images from the Hubble telescope, researchers say they were off by, well, a lot. Now, they think there are at least 2 trillion galaxies out there waiting to be explored. Fire up the Enterprise, we've got work to do!

Sound waves need some sort of medium -- be it water, air, or something else -- to travel. Because space is a vacuum, there's no way for sound to move through the expanses of the universe. So no one really can hear you scream.

The Moon has distinct dark areas in shapes that could be interpreted as a man's face. It is a man -- a big scary man who watches you sleep at night. Or basalt, a dense, dark rock that fills many of the Moon's craters -- you can decide which statement is appropriate for your belief system.

A blue Moon is when there are two full moons in a month. It happens once roughly every three years. It occurs because there are more days in calendar month than there are in a moon cycle (29.5 days).

The Moon's rotation is exactly the same as its orbital period around Earth. So it's true -- we see only one side of the Moon from our perspective.

The Sun is much, much larger than the Moon. But it is also much farther from Earth, so from our perspective, the two appear to be about the same size. Pro tip: If you decide to test this theory, please don't stare at the Sun unless you want your eyes to melt and ooze out of your skull holes.

The Hubble Space Telescope, which was blasted into orbit in 1990, is still one of NASA's crowning achievements. Its instruments have helped researchers make many amazing discoveries about our universe in the decades since it was activated.

The Milky Way is our home galaxy, which contains perhaps 100 billion stars. On a dark night, you can see the "milky" streak of some of these stars stretching across the sky.

In the early 17th century, Johann Lippershey (a German-Dutch spectacle maker) filed patent paperwork for a basic telescope. He may (or may not) have been the first person to build a telescope, but either way, his ideas helped advance a fundamental tool of astronomy.

Please tell me you got this one correct. All of the planets in our solar system revolve around the Sun, including the Earth. The ancient Greeks were the first to begin dispelling the myth that the Earth was the center of the universe.

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