Solar eclipses happen when the moon moves between the sun and the earth. The moon blocks the sun when viewed from specific parts of the earth, which makes it look like the moon is covering the sun.

For thousands of years, scientists have been tracking the orbit of the earth around the sun and the moon around the earth, and using some complicated math, they can calculate when the moon will be in between the earth and the sun. It becomes even more complicated when they want to know where on earth the eclipse will be visible, but this has also been done for thousands of years. The basic idea is that scientists know how quickly the moon and earth are moving and, using this data, they can predict where the earth and moon will be in the future. Thank you for your question!

We know the path that the moon takes as it orbits the Earth. We also know the path that the Earth takes as it orbits the sun. When the moon's orbit places the moon between the Earth and the sun, we get an eclipse. Since we know how each object is moving and where they will be at any time in the future, we can know when the eclipses are going to be.

Solar eclipse happens when the moon blocks the light coming from the sun. Since the orbit of our earth to the sun and the orbit of Moon to Earth is known, by building the correct models we can predict the solar eclipse. What I mentioned before is just the simple and general ideas to predict the solar eclipse. In reality, there are other factors the scientists should consider, for example the rotation of Earth and the axial tilts for both the earth and Moon. Just one more thing I want to emphasize, not every place on Earth will have the solar eclipse when it happens.