Sun in a Million

The Case for the Rarity of Our Solar System Strengthens

It's easy to take our solar system for granted. After all, the universe holds countless stars and planets. Why wouldn't we expect to find more planetary systems similar to ours? Before getting too comfortable with such a thought, . . .

we must take into account the fact that our current, life-friendly configuration of planets in orbit about our star, the Sun, has not always been as it now is.

Astronomical research reveals that our solar system began with five rocky planets: Mercury, Venus, Theia, Earth, and Mars; and five gas giants: Jupiter, Saturn, Uranus, Neptune, and an unnamed planet slightly smaller than Uranus. Early in the system's formation, a remarkably choreographed event brought Theia into...