is there a possible natural explanation for the seasons?

[SpringKing]

A 'wobbly orbit' is one possible scientific explanation.

[Kienn]

Now, correct if I am wrong, but this is my theory:

From what I understand, the Earth's seasons are roughly the equal only because it is nearly a sphere.

This world is not spherical, but more oblong, elongated. It permits more areas to receive more sun, decreasing spring and autumn, and increasing winter and summer. Its tilt allows seasons, and for and one pole to have a huge amount of cold, and the other to not (We don't get much news of Winter in the far south, only the north, do we)

Now I do know that this is impossible, as any object(minus dust clouds, exploding objects, etc.) of that size must be spherical. But if we ignore some of gravities laws (isn't it just a theory ;) ) it works, seasonally.

Also, we get absolutely no mention of two stars. I mean, hey, that would be cool and all, and make sense, but the planet would have to be very far away, so life as we know it could come into existence.

Doesn't really work...

Poles would still have equal degrees of summer and winter if the only difference were being oblong compared to Earth.

It also wouldn't decrease spring or autumn - these just correspond to times of the year when the planar component of the axis of rotation is pointed tangentially along the orbit of the planet, rather than radially towards the center of the orbit.

It would still result in predictable cyclical seasons, not variable.

Lastly as you said objects the size of planets have to be nearly spheres (Earth is actually a slightly flattened sphere due to its rotation).

[The Kinkslayer]

Either the blue eyed giant from Old Nan's story or a wizard (GRRM) did it!

I like better the notion of winter being really a little ice age caused by massive volcanic activity near Asshai with years of summer being just normal earth style years.

[Werthead]

The seasons were the same as ours once, but a 'preternatural' event threw them out of balance thousands of years ago (this was the original cover blurb for AGoT). The shattering of the Arm of Dorne (the Children overreaching with magic) or the Long Night and the subsequent War for the Dawn are both possible contenders for this event. So it may be that before the end of the books, whatever unbalanced the seasons and the world will be reversed (the defeat/destruction of the Others, dragons and all magic?) and the seasons will become more like our own.

GRRM is a huge SF fan and I've often wondered if he was inspired by Brian W. Aldiss's Helliconia Trilogy, featuring the best-realised fictional planet in the history of SF. Helliconia is located in a double star system and the Sun-like star it orbits in turn circles a blue supergiant, with both normal seasons (caused by the orbit around the smaller star) and 'Great Seasons' caused by the orbit around the supergiant. These Great Seasons are over 3,000 years long, with seasons lasting for roughly 700 years each.

[King of Vaes Tolorro]

thanks, it made sense in my head, but ok.

Also, take that creationists! Evolution And Gravity are "just" theories. So feel free to jump off a building any time. I am sure Jehovah, Elohim, Allah, the Heathen Gods, and Brahm will save you.

Ok, Ok, don't jump off a building, just learn that Theory in science means a well-substantiated explanation of some aspect of the natural world, based on knowledge that has been repeatedly confirmed through observation and experimentation.

[Iskandros]

Probably just magic. At first I thought about the Doom as a possible reason, but then I remembered that was rather recent, so it's not that.

[RedShirt47]

I´ve never really thought about them as "seasons" like we understand them, but as short ice ages (for winter) and the time between (summer).

This is how I always think of "winter" also. We get mini Ice Ages in the real world although they are measured in decades rather than years.

As for knowing a year, I assume that in "summer" there is still an orbit around the sun and so there is a longest day and a shortest day and this cycle is a year rather than a number of seasons.

A supernatural explanation seems most likely although what it does is unlikely to be explained. I imagine it must put some kind of barrier to to block the sun as "winter" is dark as night all the time. Although I guess it could have tilted the planet.

Do we know if "Winter" is global? Does it even reach all the seven kingdoms? Does anyone in Dorne or Essos ever mention "Winter is Coming"?

I know the Maesters in Oldstown declare winter and inform all the lords that winter is here but over in Mereen there doesn't seem to be any talk of a shift in seasons.