According to some scientists, when our solar system formed about four billion years ago, there was a collision between a planet about the size of Mars and the planet that would become Earth.
This collision knocked the Earth for quite a loop causing a 23.5-degree tilt relative to the Sun.
The leftover debris eventually formed the Moon. Amazingly, the Moon’s gravity acts as a stabilizing force to maintain that 23.5-degree angle. That tilt is also why there are four distinct seasons in locations away from the equator. By the time humans appeared, the Earth had settled into an incredibly stable cycle that we benefit from today. Man is unique in that we can alter our environment to make it more livable. In cold weather, fire can heat any dwelling, but it took humanity until the 20th century to effectively deal with the heat and humidity of summer. With air conditioning combined with a heating system to form HVAC, our comfort now lasts all year round. The sad truth is that nothing lasts forever. The Moon is slowly moving away from the Earth at about 1.5 inches each year. In a few billion years its stabilizing influence will be gone. We can’t control that, but we can control the health of our HVAC systems. Seasonal maintenance will include a springtime cleaning and checking for any damage from the cold winter, a summer tree or hedge trimming to keep areas around the condenser unit clear, a furnace check in the fall before the cold weather arrives again, and a check of the homes carbon monoxide monitor in winter. If you include seasonal filter changes, then you can sit back and ponder what Earth might have been like without that 23.5-degree tilt.