Earth isn't the only planet with seasons, but they can look wildly different on other worlds

It's easy to take this cycle for granted here on Earth, but not every planet has a regular change in seasons..

So why does Earth have regular seasons when other planets don't?..

When a planet has perfect alignment between the axis it orbits on and the rotational axis, the amount of sunlight it receives is fixed as it orbits around the Sun assuming its orbital shape is a circle..

Low obliquity, meaning the rotational spin axis is aligned with the planet's orientation as it orbits around the Sun, leads to stronger sunlight on the equator and low sunlight near the pole, like on Earth...

My research group wanted to understand how habitable these planets are, and whether these exoplanets also have wild obliquities, or whether they have moons to stabilize them like Earth does...