Space science, made simple — for everyone.
Cosmic Scale AI is a free collection of interactive tools that makes the size of the universe finally feel real. No textbooks, no jargon, no login.
Why we exist
Ask anyone how big the universe is and you will hear a number: 93 billion light-years, 100 billion stars, 1.4 million kilometres. Numbers that big slide straight off the brain. We built Cosmic Scale AI because the cosmic scale is not a number problem — it is a feeling problem. Once a size becomes something you can touch, zoom, spin or weigh, it stops being homework and starts being a place.
That idea — the human tiny universe — sits at the centre of everything here. Earth is a pale blue dot. Every human who ever lived would fit in a line barely reaching Mars. We are almost not there at all, and somehow we figured all of this out anyway. That contradiction is the best story science has ever told, and it deserves better than a dusty diagram.
What you'll find here
Scale of the UniverseZoom from an atom to the edge of the observable universe in a single scroll. 3D Solar SystemClick any planet for its size, temperature, moons and gravity. Mind-Bender Scale TranslatorTurn black holes and galactic distances into everyday human comparisons. Weight CalculatorFind out what you would weigh on the Moon, Mars or Jupiter — instantly. Birthday in SpaceSee what the sky — and NASA — was doing on the day you were born. Cosmic OrbitA game: slingshot your shuttle past planets and black holes. Pocket Globe 3DSpin a satellite globe, find any country and compare two side by side.How it's built
Every scene on this site — galaxies, black holes, nebulae, pulsars, the whole solar system — is drawn live in your browser with code, not stock photos. It works on phones, tablets and laptops, respects reduced-motion settings for accessibility, and never asks you to create an account. Some tools use NASA's public open data, so the facts come from real missions and observatories.
Who it's for
- Students who understand the formulas but not the scale.
- Teachers looking for something better than a textbook diagram.
- Parents answering "how big is big?" at bedtime.
- Curious humans of any age who still look up.
Built with curiosity, offered free, and always will be. Questions? Say hello.