Planets — what you see — Things to do

Which level?

Choose by the older end of a band, or read together. Nothing is locked and nothing is hidden — what changes is how much of the sky is listed and which pages are offered.

We read togetherread together, up to 9: The smallest sky: 27 things you can find from a garden, a short line each, and a question you answer by going outside.
I like readingabout 9 to 12: The site as it is written, with a wider sky. The cosmic ladder and the far end of the catalogue wait one level up.
I like working things out12 and up: Everything: the whole catalogue, and the seven rung pages that work out how anybody knows a distance.

About the cosmic ladder

The seven rungs are the argument the site is built on: how anybody knows a distance, one step at a time. They lean on school maths — ratios and angles, then squares and cubes, then how light fades with distance. That is about what a twelve-year-old has met, which is why this level starts at twelve. Each rung shows its sum in the open, with what it means said in words beside it, so the argument can be followed without doing any of them.

About the writing

Plain, but not written down. Measured, each level's pages sit near the top of the ages it names, so choose by the older end. The astronomy is not simplified either. If a page feels heavy, that is the page and not the reader — the control makes the sky narrower, not the words easier.