3. Right rotation and sidereal periods

Planets in the solar system have different rotation periods. For example, the rotation period of Earth is 24 hours whereas it is 9.8 hours in Jupiter and 243 days in Venus. If we live in Jupiter, we will have about 5 hours of day and 5 hours of night. If we follow the same biorhythm as on Earth, we can have ~3 hours of working time, ~3 hours of rest, and ~3 hours of sleeping time. Suppose there’s a heavy traffic jam on the way to work, we might have to come back as soon as we arrive working place. If we try to sleep, we may have to get up as soon as we fall a sleep. So, living in such a planet will be very inconvenient and unproductive.

Another problem of living in such a planet is that we will have very strong wind all year round. Planets with short rotation period will have very strong Coriolis force due to fast rotation. Strong Coriolis force causes strong wind. If there is a strong wind all year round, it would be diffcult to grow crops in the field since it will cover dust on top of grass and uproot plants. If there's no grass, grass-feeding animals would have extincted long times ago. Same situation applies to human too. If we can not grow crops, we could not have survived in such planet.

Planet with long rotation period can cause problems too. If the planet rotates slowly, convection won’t occur in the inner core. If there’s no convection, magnetic field won’t be generated. If there’s no magnetic field in planet, harmful ultraviolet and cosmic rays bombard living creatures and destroy DNAs. So, planet with small rotation period will not be a suitable place to live either.

Sidereal period is another important factor that affects survival of life on planet. Sidereal period of Earth is 365 days and can provide 3 months of seasons per year. Unlike Earth, sidereal period in Mercury is only 88 days and each season spans only 3 weeks. On Earth, most crops require one or two seasons from sowing to harvesting. If one season is only 3 weeks, crops will not have enough time to grow and will cause a serious food shortage problem. Planets with long sidereal period cause problem too. Neptune has sidereal period of 164 years and each season spans about 40 years. Living on such a planet will be not so comfortable since we don't want to have 40 years of hot summer or 40 years of cold winter.