How does the position of Earth's axis at the March and September equinoxes compare to its position at the summer solstice?
To understand how the position of Earth's axis at the March and September equinoxes compares to its position at the summer solstice, we first need to understand the concept of Earth's axial tilt. Earth's axis is an imaginary line around which the Earth rotates, and it is tilted relative to its orbit around the Sun. This tilt is responsible for the changing seasons.
During the summer solstice, which occurs around June 21st in the Northern Hemisphere and December 21st in the Southern Hemisphere, the tilt of Earth's axis is such that one hemisphere (either the Northern or Southern) is tilted directly towards the Sun. This results in the longest day of the year in that hemisphere and the shortest day in the opposite hemisphere.
On the other hand, during the March and September equinoxes, which occur around March 21st and September 21st respectively, the Earth's axis is neither tilted towards nor away from the Sun. During these equinoxes, day and night are approximately equal in duration all over the world. This is because the Earth's axis is perpendicular to the line that joins the center of Earth and the center of the Sun.
So, to compare the position of Earth's axis at the March and September equinoxes to its position at the summer solstice, we can say that during the solstice, one hemisphere is tilted towards the Sun, resulting in longer daylight hours, while during the equinoxes, both hemispheres are equally tilted or not tilted at all, resulting in roughly equal day and night durations worldwide.