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Star in a Box


Have you ever wondered what happens to the different stars in the night sky as they get older? This interactive web-app lets you explore the life-cycle of stars.

Interactive life-cycle

Star in a Box is an interactive web-app which animates stars with different starting masses as they change during their lives. Some stars live fast-paced, dramatic lives, others change very little for billions of years. The web-app visualises the changes in mass, size, brightness and temperature for all these different stages.

Classroom resources

Are you a teacher? Do you want to use Star in a Box in your classroom lessons? These resources are designed to help you to explore the life-cycle of stars with your class.


Star in a Box can handle multiple languages. The simplest way to translate this app is:

  • Fill out the translation forms normal and advanced,
  • Copy the JSON output at the bottom of the page
  • Then either email them to me (contact details on the translation page) or submit a pull request with the language file included.


The code requires Javascript and SVG so you just need a modern web browser to use it.

Note that the Chrome browser has extra security when running locally. This stops Star in a Box getting the language or star property JS files. You will need to start Chrome with the option "--allow-file-access-from-files". On a Mac you can open a terminal and run:

open /Applications/Google\ --args --allow-file-access-from-files

Further reading

More about the Hertzsprung-Russell diagram in LCOGT's SpaceBook.