How big is big?
Start at our own planet and slide outward — past the Sun, past giant stars hundreds of times larger, all the way to the edge of everything we can see.
Slide to travel outward · on-screen sizes are logarithmic (a true scale would make Earth a single pixel).
Light-year
The distance light travels in a year — about 9.46 trillion km. It is a measure of distance, not of time.
Astronomical unit
One AU is the average Earth–Sun distance: about 150 million km. Neptune sits about 30 AU out.
Expanding
The universe is not just big — it is still growing. Distant galaxies are drifting away from us.
13.8 billion years, in order
From a single hot point to the moment you started reading this page.
You are made of stardust
Almost every atom in your body was forged inside a star, then scattered across space when that star died. You are the universe, briefly able to look at itself.