14 DAY TRIAL // We have taught ourselves to believe that all the planets have roughly circular orbits around stars and have changed much over the years, but the truth is far from this presumption. Planets, like all bodies in the universe have highly elliptical orbits, where the 'central' orbited body is situated in one of the focal points of the ellipse. Not only that, but these elliptical orbits tend to oscillate in shape more and more, as time passes and will eventually widen, so that, in the remote future, the Earth will be farther away from the Sun than currently is, thus it will receive less sunlight during the year.
Michael Wysession, professor of Earth and planetary science at Arts & Sciences at Washington University, says that, in the short run, the Earth experience from time to time more elliptical orbits, which usually span as much as 100,000 years, shocking conclusion if one takes into consideration the fact that some of the ice ages the Earth went through occurred once every 100,000 years. Not surprisingly, calculations reveal that the ice ages and the more elliptical orbits coincide.
That's also the reason why we have calendars that have leap years, such as 2008 in which the month of February has 29 days. If we wouldn't add up a day once every four years, the winter solstice, which occurs on December 21, would wander so far that it would actually take place in the midspring, according to our calendars.
Do not fool yourselves, the year is not exactly 365 days, it is actually 365 days and a quarter. That quarter makes up for the day we add every four years in order to compensate for Earth's imperfect orbit. The same is available for the day, however the nature takes the task of compensating this time. An Earth day is about 23 hours 56 minutes and 4 seconds long! However, for Earth to point exactly towards the same place in the sky, it has to spin a bit more around its axis so that the day would have exactly 24 hours. The 3 minutes and 56 seconds are added by the planet's revolution around the Sun.
Furthermore, the natural belief is that the seasons on our planet are determined by how far or how close we are in relation to the Sun. That is utterly false! In fact, when the Earth is situated in the Perihelion, the closest point to the Sun, in the northern hemisphere is winter. The seasons are determined by Earth axis tilt towards the Sun, meaning that, when the northern hemisphere is pointing towards the Sun, it actually receives more Sun light, determining a heating of the northern hemisphere, thus the summer season.
Also, the seasons are greatly affected by the fact that the southern hemisphere has less land that the northern one, and heats up more slowly due to the large bodies of water that dominates it, which means the winters should usually be severer. Wysession argues that in the future, during the winter season, the Earth will end up in the Aphelion position in its orbit, and in Perihelion during summer, which will further increase the temperature differences between the two seasons. Forget about global warming for now, we'll have way more trouble on our heads in 12,000 years!