Space Facts for Kids

You might think Mercury is the hottest because it’s closest to the Sun, but nope! Venus wins the heat contest with a sizzling average surface temperature of 473°C.

That is hot enough to melt lead—a metal you might use in a pencil lead or fishing weight! Why? Because Venus is wrapped in a thick atmosphere mostly made of carbon dioxide that traps all the heat.

This runaway greenhouse effect is so intense that there’s almost no temperature difference between the day side and the night side, or even the poles and the equator. It’s hot all the time!

The Sun isn't just a big, bright light—it’s the ultimate heavyweight champion of our neighborhood! It holds a staggering 99.86 percent of the entire mass of the Solar System.

Think of everything in space around us: all eight planets, every moon, every asteroid, every comet. Put it all on one giant scale, and the Sun is still heavier by almost all the remaining 0.14 percent!

It’s so massive that about one million Earths could fit inside it. Talk about being the center of attention!

The International Space Station (ISS) isn't just an American or Russian project—it’s a giant floating clubhouse built by an amazing global team!

The Space Station Intergovernmental Agreement was signed by fifteen countries back in 1998 to make this happen.

The core partners are the US, Russia, Canada, and Japan, but that agreement includes eleven Member States of the European Space Agency too. That’s cooperation on a galactic scale for kids' science!

The Sun is our closest star, obviously, but the next nearest star is Proxima Centauri, and it is 4.25 light-years away.

A light-year is how far light travels in one year—that’s about 9.46 trillion kilometers! So, light from Proxima Centauri takes 4.25 years to reach your eyes.

If you could zoom there in the fastest rocket, it would still take you about 6,300 years to get there. Talk about a long road trip!

Our Sun is huge, but the star UY Scuti makes it look like a tiny marble! UY Scuti’s radius is estimated to be 1,708 times wider than our Sun’s.

If you could swap our Sun for UY Scuti, its outer edge would reach beyond the orbit of Jupiter—that's the 5th planet out!

This giant red supergiant is so big that the volume inside it could hold almost 5 billion Suns!

We aren't just floating still; our entire Solar System is on a massive merry-go-round called the Milky Way galaxy!

It takes us about 230 million years to complete just one orbit around the galactic center. That means the last time we were in this spot, dinosaurs were walking the Earth!

We are zooming along at a speed of about 515,000 miles per hour (829,000 kph) just to keep up the pace on this ride!

On March 18, 1965, Soviet cosmonaut Alexei Leonov bravely became the first human to leave his spacecraft and float freely in the vacuum of space!

His historic extravehicular activity (EVA) only lasted 12 minutes and 9 seconds, but it was long enough for his suit to balloon up so much he almost couldn't get back inside!

This test paved the way for all future spacewalks, showing scientists how the human body handles working outside the capsule.

Black holes are super weird, but the biggest ones are ultramassive, like TON 618, which is estimated to be 66 billion M☉ (solar masses)!

That’s 66,000,000,000 times the mass of our Sun!

It's so unbelievably heavy that its size (Schwarzschild radius) is 1,300 Astronomical Units across—that’s more than 40 times the distance from Neptune to the Sun!

Those famous rings around Saturn? They aren't solid hoops, but billions of chunks of ice and rock orbiting the planet!

The particles are mostly made of water ice, ranging in size from tiny specks of dust up to chunks as big as a school bus!

It’s like a giant, glittering cosmic snowball fight happening millions of miles away from us.

We are all constantly moving! Our entire Solar System is hurtling around the center of the Milky Way galaxy at an incredible speed of 515,000 miles per hour.

That’s fast enough to travel from New York to Los Angeles in about 5 minutes!

Even with that insane speed, because space is so huge, it still takes us about 230 million years for one full lap!