Is the sun nearer to the Earth at it's zenith or at sunset/ sunrise?

Question

Children in Year 6 were doing an experiment about shadows and light. The experiment was to prove that the nearer a light source was to an object, the larger the shadow. So the question of shadows being shorter at noon and longer at sunrise and sunset came up.

Answer 1

The short answer to your question is that during a 24 hour day there is absolutely no change in the distance between the Sun and the Earth.

If you take a flashlight and secure it far away from a wall and then hold a pencil next the the wall pointed at the flashlight, you're going to see a very small shadow. If you then rotate the pencil about the center so that it's pointing away from the flashlight, you'll see a long skinny shadow. The distance between the center of the pencil and the flashlight hasn't changed, but the pencil has rotated causing the length of the shadow to change.

Same principle. Forget the whole oval orbit thing. That's not the question you asked; and even if it was, for all practical purposes the effect is 100% indistinguishable without highly sensitive (and expensive) equipment.

Answer 2

It all depends on how you look at it, and how close we are to our Perihelion or Aphelion. If you are talking about the Earth as a whole - then this is how it works:

If we are at or past the perihelion of our orbit (the point closest to the sun) but have not reached the aphelion (the point farthest from the sun) yet, then at sunrise the sun is closer to Earth than it is at noon, which is closer than it is at sunset also. The next day, we will be slightly farther away from the sun.

If we have reached or passed the aphelion of our orbit but have not reached the perihelion yet, then at sunrise the sun is farther from Earth than it is at noon, which is farther away than it is at sunset also. The next day, we will be slightly closer to the sun.

Now - if you want to pretend the Earth doesn't move in orbit, only take into account the rotation of the Earth and determine if YOU are closer to the sun at sunrise/zenith/sunset - at midnight (approximately) you are farthest away from the sun. As dawn approaches you get closer, and eventually by the time the sun has reached it's zenith, you will be closest to the sun, and as sunset approaches, you move away from the sun.

Taking into account the fact that the Earth DOES orbit the sun at the same time, it is impossible to tell without an exact picture of our orbit.

Answer 3

At the zenith we are 4000 miles closer to the sun. As the sun is on average 93,000,000 miles away this is a very small difference.

The diference during the year is quite large 91,500,000 miles in January and 94,500,000 miles in July. We get 7% more heat from the sun in January than July but because it is winter in the UK the low angle and short days results in less heat for us.

Answer 4

The Earth is closer to the Sun at two seperate times of the year, since the orbit is a slight oval.

The shadow changes at different times of the day because of the suns position in the sky.
When its midday and the sun is right above, the shadow is smaller because of the amount of you that can be seen from directly above, as opposed to from the side or the front.

Answer 5

For all practical purposes, there is no difference in the distance. The shadows are shorter at noon because of the angle of the sun on the objects and not the distance. The students were not taught all the information.

Answer 6

At it's zenith. Sunrise and sunset depend on the rotation of the earth, not it's proximity to the sun.

Answer 7

If you take a ball and hold it at out arm's length and rotate it about its vertical axis, is it nearer to you when you start rotating it or when it's halfway through its rotation?

Answer 8

there is no difference it is the earth that is rotating.to give us night and day.