>In 500 million years the sun will be too luminous for Earth ro be Habitable

Where do you get this number from? It contradicts this:

>At the end of the next 4.8 billion years, the Sun will be about 67% brighter than it is now. In the 1.6 billion years following that, the Sun's luminosity will rise to a lethal 2.2 Lo. (Lo = present Sun.)

https://faculty.wcas.northwestern.edu/infocom/The%20Website/evolution.html