Why is it colder at the North and South Poles?

Question

Doesn't the sunlight disperse equally over all parts of the Earth?

Answer 1

Further away from the sun.  Snow reflects heat.  

Also, the poles are at a sharper angle to the incident heat radiation from the sun, 23.4 degrees from horizontal.  Whereas the incident heat at the equator is 23.4 degrees from vertical.

http://calgary.rasc.ca/images/earth_rota...

Hence, the incident heat from the sun is more "spread out" at the poles.

The ocean currents are more a symptom of the difference in temperatures, rather than a cause.

I guess if the heat radiation hits the atmosphere at an oblique angle, then it is more likely to be reflected as well (that's how total internal reflection in optical fibres works).

http://commons.wikimedia.org/wiki/Image:...

http://en.wikipedia.org/wiki/Critical_an...

Answer 2

The distance itself is pretty insignificant, considering the millions of miles between them. It is a fraction of a per cent further from a pole to the sun than from the equator.

The biggest single factor is the amount of atmosphere that the sunlight has to travel through, as the different layers of atmosphere trap or allow light and heat through. As the poles do not face directly up to the sun, and are at 90 degrees to it, the light that reaches them travels through a much thicker atmosphere before it reaches the ground/ sea level. The sun's rays are absorbed or blocked by these rays, so the intensity of light and heat is less.

The next factor is that the convection currents in the oceans add to this- the warmer oceans at the equator then push north and south, cooling as they move towards the colder parts, before the water sinks and is pushed back towards the equator. An example of such a current is the gulf stream which makes the soutwest of England- Cornwall etc- comparatively warmer than other places a similar distance north of the equator- Eastern Europe for example, or the Baltic coast.

I hope that helps, take care.

Answer 3

Because of the angle the Poles are to the Sun, the light (and heat it carries with it) are less direct.  This means that the sunlight "skips" off the surface, never being absorbed by the ground which in turn never gets a chance to heat the atmosphere.

To get a better visual of this, take a basketball and a lamp.  Point the lamp at the ball and note the direct light at the ball's middle (equator).  Then, note the angle of the light on the top of the ball.

Answer 4

cause thats how god wanted it to be and because it is further away from the sun.

Answer 5

Because the earth is round and the sun is over the equator so the poles are almost hidden from its rays.

Answer 6

The Earth is tilted on its axis, so the poles are in darkness for about 5 months of the year, plus they are further from the equator, and therfore further from the sun

Answer 7

They are further away from the sun

Answer 8

The poles are the farthest away from the sun.

Answer 9

no, sunlight does not disperse equally on the earth's surface..

since the 2 poles are located on the top and the  bottom of the planet, they're tilted at an angle that is similar to how we see a sunset or a sunrise, the sun's rays are stretched so much in the earth's atmosphere that it loses much heat so the atmosphere there is much colder and stuff

Answer 10

They aren't significantly further away from the sun.

It's because sunlight falls on them at more of an angle, so it's more spread out (and so weaker). To understand this think of sunlight falling directly onto a piece of card, straight on. It will warm the card. But if you now tip the card 45 degrees some of the sunlight misses it and so less it hitting it. If you continue to tip the card till it is almost edge-on to the sun then most light is missing the card and only a tiny bit hits it. The light that does hit it is spread out across the whole card, so each bit of card gets less sun and so less warmth.

There's another effect too. Light hitting the equator goes straight through the atmosphere. However, towards the poles the light comes through the atmosphere at a big angle so a lot more heat is absorbed.