Make your location the Sun and see where famous stars would land on Earth if the Sun were an atom, a grain of sand, or a tennis ball. Explore Proxima Centauri, Earendel, and the edge of the observable universe on a real map that makes cosmic distances feel intuitive.

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Hey Product Hunt! I made Tennis Ball Sun because cosmic distances are hard to feel. We hear “4.2 light-years” or “13 billion light-years,” but those numbers rarely feel real. This project puts famous stars onto Earth at human scale so you can see those distances on a map. You can: • place the Sun at your location • shrink it to an atom, a grain of sand, or a tennis ball • explore stars from Proxima Centauri to Earendel and the edge of the observable universe A few fun examples: • Tennis ball Sun -> Proxima Centauri is about 1,933 km away • Atom Sun -> the observable universe starts to fit around Earth I’d love feedback on two things: 1. Is the scale idea immediately clear? 2. Which example feels the most surprising or shareable?

AppSignal — Track your app’s health, errors and performance with ease

Track your app’s health, errors and performance with ease

Tennis Ball Sun

Map star distances onto Earth at human scale

Map star distances onto Earth at human scale