This question seems to be very childish or not serious at first.But you can also understand them in such a way that one wants to know the influence that the two objects exert on the earth and us.
Sun: First of all, the most obvious thing: Without the sun, the earth would not only be too cold for human life[1 . It not only protects the Earth with its magnetic field from cosmic “radiation”[2 . Without its gravity, the Earth would roam the Milky Way together with other planets in our solar system until it is captured by a very heavy object (star, “star corpse”) to orbit or plunge into it.Without a star, like the Sun, it is very likely that not even a planet, like Earth, would form.
Moon: Should ensure that the precession of the Earth’s axis remains quite stable at approx. 23°.If they were to fluctuate significantly, this would have a very significant impact on the climate and its stability. Whether evolution would have made it to humans or humans (and other organisms) would survive the strong climate fluctuations would be questionable?
Without the moon, the tides would be much weaker, as only the sun could cause them.If necessary. certain ecosystems would not or would not exist to the extent that, for example, wadden seas. However, I cannot say whether this would have a major impact – even indirectly – on human beings.
The moon has also severely slowed down the earth’s rotational speed due to the tidal effect.The day would probably not be longer than 8-10 hours. This, too, would have a significant impact on the climate and weather. Due to the strong fluctuations, some sources postulate wind speeds of several hundred km/h. This would have a dramatic impact on the flora and fauna of the earth. There would certainly not be a human being as we know him today. [3[4
I have only touched on a few important topics here and tried to cover them with online sources.There may be more influences of the two celestial bodies that are important to us, but which I did not think of.
In summary, we as human beings need both objects.But without the sun, no life would be possible at all.