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View Full Version : Earth's tilt at 0, 45 and 90 degrees



Armilus
2004-Jun-16, 07:04 PM
The Earth's axis is currently tilted at 23 degrees. What would we notice different in our lives if that angle had been 45 degrees? And 90 degrees (like Uranus)? And 0 degrees?

Dgennero
2004-Jun-16, 07:26 PM
It would, of course, chiefly affect the seasons:

- at 0 degrees, we'd have no seasons, only climate zones depending on latitude

- at 45 degrees, the seasons would be more pronounced

- at 90 degrees, this place would be pretty uncomfortable, since one hemisphere would be cold and dark for almost half a year, the other hot.

Jpax2003
2004-Jun-16, 10:01 PM
It would, of course, chiefly affect the seasons:

- at 0 degrees, we'd have no seasons, only climate zones depending on latitude

- at 45 degrees, the seasons would be more pronounced

- at 90 degrees, this place would be pretty uncomfortable, since one hemisphere would be cold and dark for almost half a year, the other hot.Well, I would suggest that it would be dark and cold for about a quarter year. The poles would both be receiving sunlight during either equinox. It would be interesting to see how weather would work in such a system. A heavy snow would probably settle near the darker pole while the other pole melted and became a desert. The best areas would be along the equator, where a good mix would occur year round. With our dynamic troposphere I suspect that even the dark side would get heat energy transported to it during their winter. but I would like to hear from a mmeteorologist about this, I may want something like this in a story I am writing, and I would want it to be accurate. I suspect that arable lands may be limited to 45 N to 45 S

Meteora
2004-Jun-17, 05:18 AM
The way it looks to me:

0 deg - no seasons, as was stated. Weather systems would probably be less dramatic, due to lessened temperature variations across the globe.

45 deg - more dramatic seasons, plus total darkness (I don't mean "lack of light," but rather "lack of sunshine during any part of the day") for at least one day a year outside the 0-45 degree latitude ranges, instead of the current 0-66.5 degrees. The "Arctic Circle" and "Antarctic Circle" would be 21.5 degrees closer to the equator. The polar regions would have much warmer summers and somewhat colder winters. Weather systems would probably be more energetic, due to the greater temperature variations.

90 deg - extreme heat and cold (depending on time of year) at the poles, with varying weather in-between. The sun at the north pole would appear overhead on "highest sun day," then it would spiral slowly downward over the next 3 months, until it sinks below the horizon for 6 months. It would then rise, and spiral upward for 3 months to the starting point. As it is now, the sun angle never exceeds 23.5 degrees at the poles. In this scenario, the sun would be equivalent to noon at the equator for quite some time. The earth's heat transport mechanisms would mitigate some of this, but the polar regions would be, I would think, uninhabitable. Even the equatorial region would be ugly around the time the sun is overhead at the poles. The equatorial area would resemble the poles at the equinoxes (as they actually are - sun going around at the horizon), and would be fairly cool. With the major heating differences across the globe, the jet streams would be extremely strong, and would likely stir up some hefty storms at the surface. They would also be placed differently, possibly resulting in some truly weird weather.

Of course, too, land distribution would make a lot of difference, as would seasonal melting and thawing of large quantities of water.

The whole concept is hard to envision and makes my head hurt. :D

Anyway, that's what I came up with. Anyone else have better ideas???

Armilus
2004-Jun-18, 11:55 PM
Is there any event that could alter that 23 degrees, increase or decrease, by even a degree, within a century? Is there anything that could do it suddenly? Has axis shift been observed on any other planet within historical time?

Brady Yoon
2004-Jun-19, 04:14 AM
Has axis shift been observed on any other planet within historical time?

The tilt of the Earth's axis changes in a cycle of 41,000 years, the other cycles being precession and the change in eccentricity of Earth's orbit. These three processes are known as Milankovitch cycles.


Is there any event that could alter that 23 degrees, increase or decrease, by even a degree, within a century?

A giant asteroid impact might do it. The impact that created the moon probably caused the Earth's axis to tilt. However the impact must truly be monstrous; large enough to threaten to break the Earth up. The object that killed off the dinosaurs 65 million years ago would severely damage the Earth's ecosystem, but it hardly effect the geology of Earth.

milli360
2004-Jun-19, 04:12 PM
Has axis shift been observed on any other planet within historical time?

The tilt of the Earth's axis changes in a cycle of 41,000 years, the other cycles being precession and the change in eccentricity of Earth's orbit. These three processes are known as Milankovitch cycles.
And there's the Eulerian free wobble known as the Chandler Wobble (period 14 months), as well as the seasonal forcing (period 12 months), which is about half of the Chandler Wobble. And there is a long term component on top of those, which is a true polar wander, wherein the time-averaged position of the center of those wobbles has shifted over the last century.