> The solar system passes through the crowded part of our Milky Way galaxy about every 30 million years.

How is that possible? At our sun’s distance from the center of the Milky Way, it’s rotating once about every 225-250 million years [1]. Plus the crowded part would be rotating along with us at roughly the same speed.

[1]https://earthsky.org/astronomy-essentials/milky-way-rotation