## Motion of the Sun in the Sky

scienceagogo.com Now let us look at the Sun as it moves through the sky with respect to us as an observer. The Sun moves from east to west, but how we see that depends on where you are on Earth.

For navigation on Earth we use the concepts of North, South, East and West. When you face north, east is on your right and west is at your left. But if you turn around and now face south, east is on your left and west is at your right.

composite graphic based on images from amazon.com and momscancer.blogspot.com

Clockwise (red)
Counter Clockwise (blue)

The Earth rotates towards the East

If you are on the Northern hemisphere, you will be facing south if you want to watch the Sun. So you see the Sun move from east to west, which is from left to right. As a rotation you can say that the Sun moves in a clockwise direction, in the same direction as the hands on a clock.

 Globe image icsm.gov.au (edited)

But if you are on the Southern hemisphere, you have to face north to see the sun. Then east is on your right and you therefore see the Sun move from right to left or in a counter-clockwise direction.

Thinking about the example of you sitting on your bike, what is now moving, the Sun or the Earth? Because only the Sun moves and everything else around you seems stationary, you are inclined to say: “well clearly the Sun is moving with respect to the Earth”, the same as humans have been saying for millennia since ancient times. And it is only because of people like Bruno, Copernicus and Galileo and many others, that after a long struggle, public opinion was finally convinced that it would be more realistic to say that the Earth is rotating on its axis and that this is the reason why we see the Sun, and stars at night, move from east to west. We are, as it were, sitting on a carousel rotating in space and we therefore see all celestial objects move from east to west.

So the Earth rotates about its axis towards the east and it takes about 24 hours to complete one revolution. This means that at the equator you are moving with respect to space around Earth with a speed of more than 1600 km per hour. Here in New Zealand that speed is still some 1200 km per hour. Because we are stuck to Earth because of gravity, and everything else around us moves in the same way, we just don't notice it.

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