Our solar system is a passenger on a galactic rollercoaster. Part 2 reveals how the Sun, carrying Earth, orbits the Milky Way's core at 491,000 mph, completing a circuit every 230 million years. We ...

When you buy through links on our articles, Future and its syndication partners may earn a commission. Credit: X-ray: NASA/CXO/UMass/Z. Li & Q.D. Wang, ESA/XMM-Newton; Infrared: NASA/JPL-Caltech/WISE, ...