Photo: Sylvain Weiller

As this week’s full moon rose in a clear Portland night sky, I happened to be reading Robert M. Hazen’s The Story of Earth, chapter two: The Big Thwack. Hazen’s experience in the subject of Earth’s 4.5 billion year history is impressive, and I never knew basic things about our solar system before reading it; such as Jupiter was vying to be a sun, as were Uranus and Neptune, but due to a variance in stellar “winds,” cooled too fast, and they became gas giant planets, instead.

The Big Thwack is also known as the giant impact hypothesis, that Hazen believes to be the only scientifically plausible origin of our moon. Take a look at this video to see what most likely happened a long time ago, in this galaxy.

What’s not fascinating about that? Especially the name Theia. The goddess child of Earth and Sky, who gave birth to the Moon. I used to lament that the moons of other planets all got names, but ours is just called the moon. Since it was clearly a planet before thwacking into this larger sphere, I will forever refer to her by the true name she deserves.