EXPLAINER: Why nightfall is coming early - understanding Earth's tilt

             Why is it so dark so early? Understanding the earth's tilt

A friend recently asked why it is getting dark as early at 6pm unlike other times when darkness would start creeping in way past 7pm.

To answer this, a basic understanding of Earth's geographical structure is necessary.

First, Earth, does not stand straight up as it orbits the Sun. Instead, it is slightly tilted at an angle of about 23.5 degrees.

This tilt is what causes the different seasons throughout the year, and it is the reason we get more sunlight in summer and less in winter.

Now, here is why we have darkness trickling in earlier than usual - particularly for countries that experience winter, when days are shorter and nights longer.

Those living in the Northern Hemisphere have shorter days in winter because as the earth rotates around the sun, we are tilted away from its light.

Places affected are North America (including the United States), Europe, Northern part of South America, Northern two-thirds of Africa and most of Asia.

This happens when earth’s axis is not straight up and down, but at an angle.

This is also why it is cooler.

Meanwhile, the people in the Southern Hemisphere, which includes countries like Australia, South Africa and Indonesia, have shorter and colder days in what is considered summer months.

Throughout the year, different parts of Earth receive the Sun's most direct rays.

 This is why when the North Pole tilts toward the Sun, it is summer in the Northern Hemisphere.

When the South Pole tilts toward the Sun, it is winter in the Northern Hemisphere.

The shortest day of the year is called the Winter Solstice, and it usually falls around December 21.

On this day, the Sun takes its shortest journey across the sky, and the amount of daylight is at its lowest.

After this, the days slowly start getting longer again, leading up to spring and summer.

If you lived closer to the North Pole, during winter, there are places where the sun doesn’t rise at all for several days or even weeks!

This is called the Polar Night.

In contrast, during the summer, there are places where the sun does not set. This is called the Midnight Sun.