1. God commanded, “Let there be light,” but it didn’t happen for nearly half a million years. That’s how long after the Big Bang the universe took to expand enough to allow photons (light particles) to travel freely.
2. Those photons are still running loose, detectable as the cosmic microwave background, a microwave glow from all parts of the sky.
3. Light moves along at full “light speed” — 186,282.4 miles per second — only in a vacuum. In the dense matrix of a diamond, it slows to just 77,500 miles per second.
