Sunday, April 5, 2009
When Sun shines in the sky, it is day, and when not it is night.
We all know about this today. But long ago, people believed many weird things about the Sun and how it traveled across the sky.
The ancient Greeks believed that the Sun rode across the sky in a chariot drawn by four white horses driven by the god Heleius!
Now we know that the Sun appears to move across the sky because the Earth rotates on its axis.
The Earth always spins at the same speed (about 1000 miles per hour or 2200 kilometers per hour).
Half of the Earth is always in the light and half of the Earth is always in the dark.
With advanced technologies, we are very lucky than our ancestors to see both day and night at the same time.
Have you ever wondered why don't we feel Earth's motion?