Hey
I'm writing all this as I always do.
I don't steal other's work, but I let others steel mine.
1: The Earth is one AU from the sun, which is in the habitable zone.
2: The Earth has the right star (other stars such as red dwarfs have violent flares which would wipe out a planet's atmosphere).
3: the Earth has life. (that is a sign that you are in the "goldilocks" zone).
4: Earth has liquid water. (as you drink your cup of water, I"m sure you don't think about how comets crashed onto the early Earth and had enough water to make the oceans you know and love today.)
5: The Earth itself is the right size. which is important ( big "super-earth" planets have a lot of gravitational pull. this pulls in a lot of gas which creates a thick and hot atmosphere not suitable for life as we know it.)
6: The Earth has the moon (the Moon keeps the Earth on its axis which is vital. if the Earth wobbled as though it were a bolling ball, it would have huge climate change problems and the pols would melt.)
7: The Earth has the right atmospheric composition (if the Earth's atmosphere were 3% more carbon the atmosphere would trap way too much light and life would be no more.)
8: The Earth has a magnetic field (the Earth's magnetic field protects the atmosphere from harmful solar flares which could "blow" the atmosphere off.)
9: the earth has a mostly circular orbit (if the Earth's orbit has an eccentricity of about 0.017 which is about as close to a circle as you can get. if its eccentricity were 1 it would come too close to the sun and also go too far which would ruin the icecaps and freeze the equator.)
10: Earth is safe (Not talking about the asteroid belt the Earth is relatively safe. All the big planets are way far back in the solar system and their gravitational influence is tiny.)
11: Earth is in the country (the Solar System is the perfect distance from the center of the Milkyway Galaxy. up close near the black hole (Sagittarius A) at the center there are too many stars. if the solar system were there it would be torn apart.)
12: Nature whens. (If an asteroid were to impact the Earth [as it did when the dinosaurs went extencted} it could most likely recover. 90% of all life was wiped out when the asteroid struck the Earth 65 million years ago. but it recoverd and brought about us humans.)
13: Earth is in the right universe! (This is all very controversial in the field of cosmology, but hypothetically speaking the universe that we live in is perfect for life. if there were other universes and each has slightly different laws of physics, ours would be the perfect one [if you changed the percent of dark matter and dark energy by 150th of a percent the universe would be completely different and could not harbor life.])
14: Earth formed in the perfect stage of the universe. (The universe is constantly changing. you may have heard before that it is expanding. this is true. the universe is constantly getting bigger every moment. and eventually, there won't be enough matter in galaxies to form planets stars and galaxies. it will all be used up.)
Hope it helped
your answerer spiky bob
Please read everything i wrote because it took me an hour to write all that, and think of everything. I only answer questions because I hope to show you not just the answers, but why they are correct as well.
