Why are there only four seasons?

Answer 1

The cause is the tilt in the earths axis, as the earth moves around the sun the axis moves away, causing the earth to move or "lean back and forth" if you will. An example would be like where i live. I live in Michigan, we have all 4 seasons. In the summer Michigan is pointed more towards the sun making it hotter and vice versa for winter.

Answer 2

Just a convenient convention.

The seasons form a continuum, and is is to suit our needs, we subdivide it and label them Winter, Autumn, Summer, Spring.

ANSWER:

The four seasons correspond to the tilt of the Earth as it goes through it's yearly cycle around the sun.

Answer 3

The Earth's "seasonality" (both the variation of the Sun's position over the horizon and the changing daylengths during the year) results from a number of physical factors: 1) its 365-day revolution about the Sun; 2) its 24 hr. rotation; 3) the 23.5 degree tilt of its axis; 4) its fixed axial alignment; and 5) its "sphericity" (the Earth's oblate presentation to the sun's parallel rays.

Mainly, know this--the Earth tilts, fixedly, during it revolution around the Sun. Because of this tilt, the Earth will travel through a stretch of its revolution where one global hemisphere (northern or southern) tilts toward the Sun (summer), while the other tilts away from the Sun (winter). Spring and Autumn equinoxes constitute equal days of 12 hr. daylight and stand as halfway points between the Summer and Winter extremes or solstices (days of maximum and minimum daylight).

Answer 4

Because the way the Sun obits around