Question: What would happen if we had no moon?

Anna Kutner answered on 18 Jun 2015:

As Iain said – Moon’s influence on the life on Earth is immense.
1). Moon is responsible for the lunar tides. Without it we would only have solar tides which account for ~40% of all tides mostly because Sun is much further away than the Moon. As the tides retreat they take lot of material with them (rocks, rebbles, soil, plant material, an occasional small animal etc.). This creates this constant exchang of chemicals which influences the development of oceans’ flora and fauna. Not to mention – help to shape the coastlines around the world. Think – Jurrasic Coast in UK. And finally, we would probably have to forfeit harvesting energy from tides as it would be economically unviable.
2). The Moon slows down Earth’s rotation. Without it the duration of the day would change dramatically – from 24h to 6-8h. That would probably lead to increased winds (think a hurricane season in American Midwest but on a global scale) but also on the evolution of life on Earth. In mere 6-8h we would have to fit a few short hours of daylight and darkness so the species which would evolve (including humas) would be very different.
3). And there is also the matter of Earth’s axis. As it turns out, Moon keeps Earth’s axis a bit tilted (~23 degrees). Thanks do that we can experience day and night during the 24h it takes Earth to make one rotation. But if the angle of the axis changed even slightly the duration of both would change as well. As a result we could end up spending decades in complete darkness followed by decades spent in full sunshine (think a polar day and a polar night but lasting years not months).
Conclusion – if not for the Moon all life on Earth (including us) would look very, very different.