The Southern Hemisphere's Summer and the Equator

When does the sub-solar point reach the Equator after the Southern Hemisphere's Summer?

What happens on March 21st after the Southern Hemisphere's summer?

Answer:

The sub-solar point reaches the Equator on March 21st after the Southern Hemisphere's summer.

After experiencing summer in the Southern Hemisphere, one significant event takes place on March 21st – the sub-solar point aligns with the Equator. This occurrence signifies the transition to autumn in the Southern Hemisphere, marking the autumnal equinox.

During the autumnal equinox, the sun crosses the celestial equator, resulting in equal day and night durations for locations on Earth. As the sub-solar point gradually moves northward along the Equator after the Southern Hemisphere's summer, it eventually reaches this point on March 21st.

This alignment of the sub-solar point with the Equator symbolizes the beginning of autumn in the Southern Hemisphere. It is a pivotal moment in the Earth's orbit and has implications for the changing seasons and lengths of daylight experienced in different parts of the world.