Direct and Indirect Sunlight

QUIÉN PINTO LA NOCHE ESTRELLADA

The main reason for seasons is the tilt of Earth's axis (NOT the distance to the sun). 

The Earth's axis is tilted by 23.5°

- At some parts of the year, the Northern hemisphere is tilted towards the sun, while the Southern hemisphere is tilted away causing different seasons.

- For example, when it is summer in the Northern Hemisphere, it is winter in the Southern Hemisphere (ref. image).

• The earth is a sphere, so some parts of the earth receives 'direct sunlight', while other parts receives 'indirect sunlight'.

• Direct sunlight is concentrated over a small area and results in more intense heat, while indirect sunlight is spread over a larger area and is less intense (ref. image).

- Solstices occur twice a year, when the tilt of the Earth's axis is oriented directly towards or away from the sun.

- Winter solstice (and the shortest day in the NH): Dec. 21

- Summer solstice (and the longest day in the NH): Jun. 21