eli5: How do meteorologists determine when sunrise and sunset occur (down to the minute) if it’s still light or dark outside visually?

Question

I was looking at the weather app and, from where I live, sunset occurs exactly at 7:16 pm. Outside, the sky is a dark blue but still light enough to see and navigate the world. On the weather app it displays “Civil Twilight”, “Nautical Twilight”, and “Astronomical Twilight”. If these sunset periods occur after 7:16, then how do we know that sunset occurs exactly at 7:16 and not at these other time periods?

In: Planetary Science

Answer 1

Because you can do math with the known positions of the sun, earth, and latitude/longitude of the place where you’re trying to get sunrise/sunset times.