Why is it correct to describe the sun's movements in the sky as apparent motion?

Answer 1

The sun moves along a path which can be plotted against the backdrop of stars. Our ordinary experience doesn't allow us to "see" the sun in its position against this backdrop because of the sun's own extreme brightness. But we can accurately infer its position from our knowledge of the movement of the stars. The sun's path is called the ecliptic. The ecliptic also defines the plane containing earth's orbit, and the ecliptic is the path the earth follows. This would be clear if we could observe earth's orbit from the point of view of the sun.

Answer 2

The Earth spins on its axis, like a gyroscope. However, the Earth's spin axis isn't perpendicular to to the plane of the Earth's orbit, called the ecliptic.

So it's sort of like a gyroscope tipped at a 23 degree angle, forever. So as the Earth goes around the Sun while it is spinning, the Sun _appears_ to move north and south and north again over the course of a year. This causes our seasons.

Also, as we orbit the Sun, it appears to move against the background of stars. The stars are so far away that they don't seem to move.

(Of course, we can't see the stars in daylight, but we know where they are.)

This movement of the Sun through the constellations has been used for centuries by astrologers (not astronomers). For a long time people didn't realise the true cause of the Sun's yearly motions.

Answer 3

the doesn't move at all actually. all the planets are in constant motion around the sun

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The apparent motion of the sun is the way the sun appears to be moving in relation to the motion of the planets around it.

Answer 4

If the sun were not there, the earth would continue eternally moving in a straight line, until

it became captured in the gravitational field of some other star or large massive body.

The mutual gravitational force of attraction between the sun and earth is what bends the earth's

motion into a closed curve that keeps us always at essentially the same distance from the sun.

Answer 5

Inertia, conservation of energy, Keplerian dynamics... Depending on the theory you believe (Newtonian or Einsteinian), it could be a gravitational force, or a distortion of space-time due to the large mass of the Sun.

Answer 6

During the course of a year the Earth completes one orbit around the Sun. To us on Earth we see this as the Sun moving against the background of stars through the year, along an imaginary line which we call the ecliptic.

This ecliptic approximately defines the plane in which the Earth and the other planets orbit around the Sun. The directions to the north and south ecliptic poles are at right angles to this.

The Zodiac is the band of constellations running along the ecliptic.

Answer 7

Maybe you have had this strange experience; many people have. You are sitting on a train, the train perhaps is in a station. You look out your window, and there is another train next to yours, maybe only a meter away. You see that you are moving very slowly and quietly past the train and you watch the people as they sit there watching you. You turn and look out the windows on the other side of the train, and you are disoriented for a moment, almost physically jarred. You are looking at a platform in the station, and you are not moving past it; you are motionless. It is the other train that is moving. It could happen the other way as well; you look at the other train through your window and you are SURE that the other train is moving and you are still. Then you are jarred when you look out the station-side window and realize it is YOUR train that is slowly moving through the station. We are talking about apparent motion, the assumption that something is moving relative to you (or you are moving relative to it), and your assumption is based only on appearance, not reality. The apparent motion of the sun and moon across the sky are amazing examples of the same idea. The earth is NOT a fixed and motionless center of things, but a spinning globe of rock. It appears to us that the sun and moon spin around the earth regularly, but most of that apparent motion comes from the fact that WE are spinning around UNDER THEM.

Another example that is a little more subtle:

This is also train related. Your train is now moving at regular speed along its journey. You can look ahead and see into the car ahead of you. It seems to be moving very strangely, bopping up and down, left and right, in a very odd kind of dance. It very much seems to you that your car is just moving along smoothely on its path. But if you go to that other car and look back, it appears again that the car you are in is moving smoothely, and the car you WERE in is now dancing up and down. The apparent bopping that you see in the other car is really a combination or addition of the irregular movements that the two train cars make as they move; they are connected securely to one another, but not rigidly. There is some give in the connections so they can absorb some of the physical stress that occurs from rigid, unbending connections. The train has to be able to handle curves, inclines and declines.

Answer 8

The rotation of the Earth causes the sun to rise and set each day.

Its the rotation of the earth that brings us sunrise and sunset.

Answer 9

the rotation on earth across the sky it also has to do with the tilt of the earth(23.50

Answer 10

The earth spins round in 24 hours,that's why the sun,moon and stars all seem to rise in the east and travel across the sky and set in the west