For curious explorers aged 8 to 108

Hello, universe! Let's go exploring.

No big words and no homework. Just real photos from real spacecraft, a few fun facts, and a peek at what space was up to on the day you were born.

The photo behind this page is real: sunrise over Earth, taken by astronauts on the International Space Station.

Big questions, tiny answers

Six things that make the night sky make sense

The questions everyone wonders about, answered in a sentence or two. Grown-ups, it's okay, we won't tell.

What is a light-year?
Sneaky one: it's a distance, not a time! It's how far light zooms in one year, about 9.5 trillion km. The closest star after the Sun is about 4.2 light-years away.
How far away is the Moon?
About 384,000 km on average. That gap is so big that all the other planets in our Solar System could just about squeeze into it, side by side.
What does "orbit" mean?
It's a path around something, held by gravity. A satellite is always falling toward Earth, but it's flying sideways so fast that it keeps missing!
Why do stars twinkle?
Stars don't actually flicker. Their light gets wobbled by moving air above our heads. Astronauts in space see them shine perfectly still.
What is a galaxy?
A gigantic family of stars, gas and dust held together by gravity. Ours is the Milky Way, home to somewhere between 100 and 400 billion stars.
Can we see back in time?
Kind of! Light takes time to travel, so we always see the past. Sunlight is about 8 minutes old. Some galaxies in telescope photos are billions of years old.

A little quiz

Enter your date of birth. We'll find a real space photograph published by NASA on that day, and moments from space history that share your date.

Keep exploring

Space agencies around the world share their discoveries for free. Here are some of the best.