20 Space facts you may not know


Who doesn’t love a good list of astronomical facts? Here are 20 Space facts you may not know. You can test your knowledge and take the quiz. The link is at the bottom of the page.

1. Our Sun is huge!

OK, so maybe you knew this one. But did you know that the sun is 864,000 miles in diameter? You can fit 1,300,000 earths inside of it. And it is so dense that it holds 99.8% of all the mass in our solar system. But it is merely a yellow dwarf star.

2. Neutron stars are small

Neutron stars are the remnants of massive stars after they have gone supernova. The remaining nucleus is around 15 miles across, but they have a mass of 1.5 times our sun! Neutron stars are the closest thing you can get to a black hole. Their gravity can be up to a million billion times Earth’s. They can also spin up to 600 times per second. Yet some still host exoplanets. They are capable of producing heavy elements that makeup everything around us. I could make a whole post on the space facts of a Neutron star.

Neutron Star space facts

3. It’s quiet out there

Sound is simply the vibration of air molecules. The vacuum of space doesn’t have air, so it’s completely silent. If you could survive in space without a space suit, a bomb could go off right next to you, and there would be no sound. You would probably die from the explosion, though.

4. No Moons

Mercury and Venus are the only planets in our solar system with no confirmed moons. This is a baffling fact because there are over 200 moons shared amongst the other planets and dwarf planets in the solar system.

5. Mars has the tallest mountain

Olympus Mons on Mars is the tallest mountain in the entire solar system. At three times taller than Mount Everest, it’s 16 miles high. If you were at the far base of the mountain, the other side of the mountain would be over the horizon.

Olympus Mons

6. The Milky Way is huge

Our home, the Milky Way galaxy, is roughly 110,000 light-years wide. It would take a modern-day spacecraft 450 million years to travel from one side to the other. Before it dies, the sun only has about 22 orbits left around the galaxy.

7. Jupiter has a lot of moons

Jupiter currently has 80 moons. I say currently because astronomers are finding new ones all the time. Some of them are the size of planets themselves.

8. Pluto is tiny

Pluto is smaller than the United States. It is almost half the size of our moon.

9. Uranus is blue because it has gas

Uranus is made up of mostly hydrogen, helium, & methane in its atmosphere. The methane filters out the red light from the sun, and the blue light is reflected back into space. That’s a fantastic space fact.


10. There are more stars in the sky than grains of sand on Earth

There are currently 70 sextillion stars in the observable universe. That’s ten times the amount of sand grains on Earth. It’s true; I counted them. JWST is showing us the cosmos in even greater detail than ever before.

11. Space facts: You get taller in space

Due to the lack of gravity, your spine will elongate if you spend enough time in space. But you will lose the height advantage as soon as you return planet side.

12. The moon is leaving us

The moon moves away from the Earth about 1.5 inches per year. It is causing our days to become slightly longer as the Earth’s rotation slows down. 1.4 billion years ago, a day on Earth was 18 hours and 40 minutes long.


13. You can’t burp in space

With the lack of gravity in space, solids and gases can’t separate, leaving astronauts in a pickle if they get gassy.

14. Ink pens don’t work in space

Ink pens work on gravity as the ink flows down to the ballpoint. In space, this doesn’t happen, so NASA had to develop a pen that would work in zero gravity. It costs millions of dollars to design. The Russians just used pencils.

15. We have 5 dwarf planets

Since Pluto got the shaft and was kicked out of the club, a new sub-category of planets was created. Dwarf planets are smaller planetoids that orbit the sun. The number varies depending on who you ask. The number grows from 5 to 120 based on some parameters.

Dwarf Planets

16. It takes 8 minutes for light to travel from the Sun to the Earth

It’s as if you’re looking back in time. It takes 8 minutes for the light you see outside to travel to you from the sun. Ever wonder why our sky is blue on Earth?

17. The ISS is the largest artificial object in space

The International Space Station is 356 feet long and 250 miles high. It can be seen with the naked eye as it passes overhead at night.


18. The Andromeda galaxy will collide with us

In roughly 5 billion years, the Andromeda galaxy will collide with the milky way galaxy to form a new, much larger galaxy called Milkdromeda.


19. Jupiter’s red spot is old

Jupiter’s famous red spot storm has been encircling the planet for more than 100 years. You can easily fit Earth inside the storm; it is so large.

Jupiter's Red Spot

20. Black holes everywhere

The center of the Milky Way has a supermassive black hole called Sagittarius A. But a new study has concluded that tens of thousands of other black holes are swirling around the galaxy’s center. Some are paired with other stars; some wander around by themselves.

Sagittarius A

Were you paying attention? Take the Astronomy Quiz.

Do you have an interesting space fact that may be little known to others? Let me know. Let’s grow the list! Check out the Odd History list or see what’s new in space.

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