Solar flux. At a right angle (like noon), more sunlight hits the ground than it does later in the day. Like wind hitting a sideways piece of paper.
I understand how you got this notion, with the poor state of our education system, and I don’t blame you because it does make some sense. But the tilt IS the overwhelming cause, like how a paper’s tilt affects how quickly it falls.
Distance would have an effect, but it’s such a tiny contribution on the planet. For perspective, it takes 8 minutes for sunlight to reach us. And at the same speed, light can circle the planet’s surface 7 and 1/2 times in a single second. All of this with a logarithmic magnitude falloff…
Space is big. Distance doesn’t matter unless it’s a vast distance. If distance caused the seasons, we’d be fucked by the earth’s elliptical not-quite-circular orbit… which surely varies by at least our minuscule radius.
If you’re still not convinced, congratulations on your trolling. Because on our sphere, nowhere can face the sun directly without in fact being closer than the rest of the planet’s surface. So you’ve found the perfect misconception to rouse other people’s tempers as they try to circumvent your tautologous ‘‘evidence’’.
Seasonal changes are governed by many things. The present season, yes, is one of the biggest contributors. But if we somehow got some ventilation pumping air in from Antarctica, and replacing it with air from Sudan, we’d be able to regulate global temperature despite how perpendicular parts are.
This is the dream I aspire to. The great North-South AtmoSwap. Birds will appreciate not needing to fly continents away every year. Maybe they’ll be able to settle down and start a culture.