Seeing further: the story of science & the Royal Society — 14 PAUL DAVIES

1. 1. The Copernican principle, which states that our situation in the universe is not special, has been remarkably reliable in astronomy and cosmology, though it initially failed regarding planets in the solar system.
2. 2. Earth's moon is unusually large for its planet, formed by a Mars-size impact, making such a moon rare among earthlike planets.
3. 3. The apparent coincidence between the ratio of electromagnetic to gravitational forces and the age of the universe in atomic units is explained by an observer selection effect, not a changing force of gravity.
4. 4. The discovery that terrestrial microbes thrive in extreme environments has renewed optimism that life might be widespread in the universe, despite the lack of a theory for life's origin.
5. 5. If life is discovered on Mars, it may not indicate a second genesis because Earth and Mars have exchanged rocks containing microbes, potentially cross-contaminating both planets.
6. 6. A shadow biosphere of alien microbes on Earth, with a different origin from known life, would confirm that life emerges readily in earthlike conditions.
7. 7. The multiverse theory, though speculative, suggests that our universe is one of countless bubble universes with different physical laws, and only a tiny fraction are bio-friendly.
8. 8. The Goldilocks enigma—why our universe's laws are just right for life—can be explained by observer selection in the multiverse: we can only exist in a bio-friendly bubble.