Isn’t it amazing to know that there exist two parts of our earth which experience 6 months of daylight and 6 months of night, yes you are right these are 2 poles of earth i.e, North Pole and the South Pole? Now, here comes the question, how does that happen? Let us understand this with reference to the North Pole. As we all know that earth revolves around the sun as well as rotate on its axis from west to east in one complete day, so while half of the earth experiences day at the same time another half experience night, but this rotation of earth is not happening on the straight axis, the earth’s axis is tilted 23.5 degree from straight virtual axis in another words it is tilted 66.5 degrees with respect to orbital plane and due to this tilt earth experience seasons.
Now here we need to understand SOLSTICES. These are the events when the sun reaches the extreme tropics, during solstices tropics virtually become equator sun rays fall perpendicularly on tropics. Let’s take Summer Solstice which falls on 21st June( longest day of northern hemisphere), on this day sun rays falls straight on Tropic of Cancer, now as you know that earth’s axis is tilted so the whole north pole is now exposed to sun during whole rotation if earth would have not been tilted then only half of the pole could experience day at a time as we discussed above. It is amazing to see such a beautiful thing, you can observe such an astonishing phenomenon in some northern parts Arctic region on earth, for example, the Svalbard region of Norway or from Greenland. But here comes one more catch that it is not exactly 6 month day in north pole it is around of 186 days and this extension of day specifically in Northern Pole is due to earth’s position at Aphelion ( far most point from sun on revolving orbit), during revolution earth travels slowest at this position so there is extension of days of summers in northern hemisphere also there is transition period of 24 days when North pole experience semi-darkness. I hope now you understand the reason why North Pole experience 6 months of the day?