Is it rotating clockwise or anticlockwise?
Experiment 1
The images above are of the wire frame of a planter basket hung upside down from a hook in such a way that it can be set spinning. The frame is dome-shaped.
Note: The second image may appear "inside-out" as if you are looking at the outside of the dome. If so, it is an optical illusion. The view is upwards from underneath, looking at the inside of the dome.
Get yourself a similar basket and hang it at a height so that it hovers just a little above your head height. The perimeter of the basket should be at about the height of your forehead. (This experiment will work best if you stick a clock face to the inside of the basket at the top of the dome, as shown above.)
Stand under it with your head inside the basket.
Set it spinning so that when you look straight ahead the basket spokes seem to be turning in an anticlockwise direction.
Now look straight upwards at the clock face.
It now appears to be spinning clockwise!
Experiment 2
Go out into the street to the nearest power pole standing by the roadside. From a position fairly close to the pole, walk slowly around it.
As you "orbit" the pole, note carefully how the pole appears to shift position (also in a circular fashion) relative to the background of the more distant streetscape.
Note the direction the pole appears to be circling in relative the background scenery. Is it the same as the direction you are going in, or opposite to your direction?
This is an important experiment. It helps us understand the apparent motion of the Sun in its apparent annual circuit of the sky over the course of a year. This motion is not real motion; it is the way things look to us here on Earth as the Earth orbits the Sun over the course of a year. We don't feel the Earth moving, so to us, it looks like the Sun is making a circuit of the heavens relative to the background of the more distant stars. This is the same as the street pole's apparent movement relative to the more distant streetscape. The pole is not really moving; it is the result of our motion as we circle the pole.
The Earth orbits the Sun in the same direction as it rotates on its own axis. That direction is west to east. Is that clockwise or anti-clockwise? It depends on where you look from. If you were looking down on the Earth from above the North Pole, the Earth would appear to be orbiting the Sun (and spinning on its own axis) in an anti-clockwise direction. If you were looking down on the Earth from above the South Pole, the Earth would appear to be orbiting the Sun (and spinning on its own axis) in a clockwise direction.
From the northern hemisphere, the Sun's annual path around the sky seems to be anti-clockwise.
From the southern hemisphere it seems to be a clockwise movement.
This movement is only detectable by observing the Sun's position, day by day, against the background of the more distant stars. Of course we cannot see the stars when the Sun is up during the day, so how can we tell which stars seem to be behind or next to the Sun?
We can observe carefully at the end of the day the exact position on the western horizon that the Sun is setting at. Then, a short time later when the sky is dark enough to see the stars, we can see which stars are about to set at that same position.
The same kind of thing can also be done by observing the eastern horizon at dawn. We can observe which stars are rising just before sunrise at the same spot on the horizon where the Sun rises a short time later.
By making these observations over many days, and collecting the data in an organised fashion, we can compensate for the twilight period when neither the Sun nor the stars are visible by interpolating, thus pinpointing the Sun's position against the stars more accurately.
In its apparent annual motion around the sky, the Sun completes a full circle of 360° over one solar year, which is approx 365.2422 days. Therefore, the rate of this apparent motion is just under 1° of sky per day (360° / 365.2422d).
The Sun's apparent motion among the constelations of the Zodiac
From a northern hemisphere Point of View
From a southern hemisphere Point of View
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The Earth rotates from west to east. (Think of it as Perth chasing Sydney or as New York chasing Madrid.) But is that clockwise or anti-clockwise? The same motion can appear to go either way depending on where it is viewed from. Experiment with the animation below of the rotating Earth. Try viewing it from above the north pole and from above the south pole. (Click the up and down arrow buttons.)
Please play with the arrow buttons
