Science Buddies: "Ask an Expert"

Sir,
I want to ask some details regarding the orbit of the Earth around the Sun.
(1)First of all as we know that earth is somewhat round.
Now as the poles(south pole and north pole) are extremely cold than that of the equator of earth.I mean this differences in temperature between the equator and the poles is due to the distance from to earth's equator being less than the distance from sun to the earth's poles.
(2)So similarly if we look towards the elliptical orbit of earth around the sun we notice that the orbit has the one nearest point with the sun and the one farthest point with sun known as Periapsis(nearest point from sun which 147 millions km) and Apoapsis(farthest point from sun which is 152 millions km).
So there is much difference between the distances of periapsis and apoapsis.
Still when earth is on apoapsis, there is no extreme coldness(here extreme coldness means such coldness where humans can't survive), similarly when earth is on periapsis there is no extreme warmness(here extreme warmness means such hotness where humans can't survive). So why is this so.
As i had mentioned in point (1)I want to say that due to minor difference in distances from earth's equator to earth's poles there is a lot difference in temperature.But there is no much difference in temperatures in situations at Periapsis and Apoapsis as i had mentioned in point(2).
According to point(1) there should be alot differences between temperatures in peripsis and apoapsis situations.But this is not so.
That's why I want to know the answer for my this query.Hope you may answer this.

Hi SannSave,

Is this question related to a K-12 science fair project? If so, please describe the scientific question you are trying to answer or the hypothesis you are trying to test. If this is not related to a K-12 science project, then a different set of online forums would be a better place for your question.

Briefly, however, the difference in the distance from Earth's equator to the Sun and Earth's poles to the Sun is not the reason that the poles are colder than the equator. The difference is only about 22 km, or 0.00000014 times the distance from the Earth to the Sun--not enough to make a difference in temperature. Instead, the difference in the temperatures at the poles and at the equator is due to the fact that sunlight hits the equator "head on" but hits the poles at a glancing angle. You can learn about why that makes a difference in temperature by doing this activity:

http://serc.carleton.edu/sp/library/gui ... asons.html

Even though there is a ~5 million km difference between the Earth-Sun distance at periapsis and apoapsis, that only amounts to a 3% difference in the amount of solar energy hitting the Earth at periapsis and apoapsis because the distance from the Earth to the Sun is so large (150 million km). This slight difference does not cause major temperatures differences during the course of a year.

It is really a good reply. I was searching for these information. Thank you.

It was really informative post..