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Thread: No tilt, no seasons. What effects?

  1. #1 No tilt, no seasons. What effects? 
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    Hello all, first time poster here.

    I've been thinking about an idea/concept recently (ultimately for a novel), so looked for a forum where I might be able to get some interesting feedback regarding it. So, here I am. I hope this is actually the right forum for this, I think it is more Earth science than astrology.


    Earth Tilt and the seasons

    To my understanding we have seasons on Earth because the planet tilts on its axis, meaning that how much sun each hemisphere gets and hence the mean temperature waxes and wains.
    It occured to me that a lot of our weather systems, and more importantly ecological systems (flaura and fauna) are influenced, if not dictated, by the shift in the seasons.

    So I figure that if a planet, like Earth, had no tilt, then it would have no seasons. If it had no seasons its ecology would be drastically different. There would be no seasonal floods or fires, or animal migrations or whathaveyou etc.

    So, I'm interested in what kind of world would be created if the mean temperature at any given point on the planet remained roughly the same with no seasons.
    How would plants/animals grow and breed, how would they interact? what sort of weather paterns would we see? etc etc.

    Any thoughts greatly appreciated.


    <edited to replace 'wobble' with 'tilt' after clarification.>
    <edited to add: people's responses have brought new elements to the debate, so please feel free to read replies and comment on comments and the extra questions raised. Thanks.


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    Administrator KALSTER's Avatar
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    Firstly, the seasons are caused by the TILT of the earth's axis, which is more or less constant. To be precise, there is a very small wobble in this axis, but the emphasis is on very small.


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    Quote Originally Posted by KALSTER
    Firstly, the seasons are caused by the TILT of the earth's axis, which is more or less constant. To be precise, there is a very small wobble in this axis, but the emphasis is on very small.
    Thanks for clarification, I guess I got confused with presessional wobble or whatever. Now you point it out I knew I knew that. Thanks.

    So ok, I'll ask the question again, just replace 'wobble' with 'TILT'.

    The main question really being, what would ecology and weather be like without seasons?

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    Forum Isotope Bunbury's Avatar
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    I'm interested in what kind of world would be created if the mean temperature at any given point on the planet remained roughly the same with no seasons.
    How would plants/animals grow and breed, how would they interact? what sort of weather paterns would we see? etc etc.
    The moist tropical regions of Earth fit your description and are teeming with life. You could start by researching the rainforests.
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    Universal Mind John Galt's Avatar
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    EEls spawn in the Sargasso Sea. The young eels then swim back to their home rivers, several thousand miles away. This is not a clever thing to do, but a consequence of plate tectonice. When their ancestors began this practice millions of years ago their journey was measure in z few hundred miles, at most.
    I mention this, since a planet with active plate tectonics might well have created many such patterns of migration as a consequence of continental movement. There could be a complex range of behaviours, movement, ecological variations, etc that were independent of the somewhat uniform weather conditions at any point on the planet. Those points would have been in a different climate zone in the past.
    It occurs to me, without going into the detail, that such a tapestry of relationships might invoke a novel perception of God and some very interesting creation myths.
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    Quote Originally Posted by Bunbury
    I'm interested in what kind of world would be created if the mean temperature at any given point on the planet remained roughly the same with no seasons.
    How would plants/animals grow and breed, how would they interact? what sort of weather paterns would we see? etc etc.
    The moist tropical regions of Earth fit your description and are teeming with life. You could start by researching the rainforests.
    good suggestion, thanks. Although from initial googling is still appears they do have mild changes in season, and as such have flood plains and such - which surely effects growth of some species. But a good starting point nonetheless.


    Quote Originally Posted by Ophiolite
    I mention this, since a planet with active plate tectonics might well have created many such patterns of migration as a consequence of continental movement. There could be a complex range of behaviours, movement, ecological variations, etc that were independent of the somewhat uniform weather conditions at any point on the planet. Those points would have been in a different climate zone in the past.
    Very interesting addition to my thoughts, thank you, I hadn't considered this before. I will look into it more.

    It occurs to me, without going into the detail, that such a tapestry of relationships might invoke a novel perception of God and some very interesting creation myths.
    Indeed. Naive understanding of why these creatures make such bizarre/worthless/inbred journeys could could a very interesting angle to think from.


    cheers for the feedback, keep it coming
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    Forum Isotope Bunbury's Avatar
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    The only planet in the Solar System with zero tilt is Mercury. I’m wondering if this implies that only planets really close to their sun are likely to have zero tilt, and if so, what are the chances that a planet with zero tilt would be amenable to intelligent life?
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    Quote Originally Posted by Bunbury
    The only planet in the Solar System with zero tilt is Mercury. I’m wondering if this implies that only planets really close to their sun are likely to have zero tilt, and if so, what are the chances that a planet with zero tilt would be amenable to intelligent life?
    Interesting thought, though I think it might be based on too small a sample group (just our system). But maybe I should put a post asking this in the astronomy forum...

    In this case, I assume it can happen at a habitable distance from the systems star, but you raise an interesting point. Thanks.

    Edit to add: I think I'm right in saying that, due to Mercury's rotation, it has extremely long days and nights, which in itself could pose an interesting ecological question.
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    Just to make one further point: the Earth's orbit is elliptical with the focus of the earth-sun COG being within the Sun itself.

    This means there are times during Earth's year when it is further away from the Sun than at others. The total solar radiation arriving at the surface will, therefore, be affected, as per the square of the distance (or ratio of apogee to perigee), and would therefore, if there is any significant difference, provide planet-wide cooler and warmer seasons without the need for any axial tilting.

    I do not know the eccentricity of the Earth's orbit or if it makes a significant difference, but I may have read somewhere that our closest approach to the Sun is usually during the Northern Hemisphere Summer. Don't know if that's correct, but it might explain Antarctica!
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    Quote Originally Posted by sunshinewarrio
    Just to make one further point: the Earth's orbit is elliptical with the focus of the ...<snip>... to the Sun is usually during the Northern Hemisphere Summer. Don't know if that's correct, but it might explain Antarctica!
    Funny you should bring this up, I was just thinking about this factor. It is still quite possible to have seasons without any tilt, due to eccentricity. I need to find out how much influenece this plays on our seasons. Thanks for adding.

    It would appear that the requirements for a seasonless planet would have to be very precise with 0 eccentricity and 0 tilt. Given the size of the universe I'm sure the factors could come together somewhere to make it happen though. ANd I'm still interested in hypothetical interpretations of what sort of world this would create.

    So, the quetion is still open for more responses. Given the hypothetical planet has 0 tilt AND 0 eccentricity.
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    Quote Originally Posted by UKDutyPaid
    Quote Originally Posted by sunshinewarrio
    Just to make one further point: the Earth's orbit is elliptical with the focus of the ...<snip>... to the Sun is usually during the Northern Hemisphere Summer. Don't know if that's correct, but it might explain Antarctica!
    Funny you should bring this up, I was just thinking about this factor. It is still quite possible to have seasons without any tilt, due to eccentricity. I need to find out how much influenece this plays on our seasons. Thanks for adding.

    It would appear that the requirements for a seasonless planet would have to be very precise with 0 eccentricity and 0 tilt. Given the size of the universe I'm sure the factors could come together somewhere to make it happen though. ANd I'm still interested in hypothetical interpretations of what sort of world this would create.

    So, the quetion is still open for more responses. Given the hypothetical planet has 0 tilt AND 0 eccentricity.
    And let's not forget tidal effects. As denizens of tidal pools are aware - each tide is a mini-season.
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    Quote Originally Posted by sunshinewarrio
    And let's not forget tidal effects. As denizens of tidal pools are aware - each tide is a mini-season.
    That's assuming this hypothetical planet also has a hypothetical moon of course... 8)
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    Earth really is quite Unique isn't it? Not that I mean that in gest.
    "If you wish to make an apple pie from scratch, you must first invent the universe". - Carl Sagan
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    Quote Originally Posted by svwillmer
    Earth really is quite Unique isn't it? Not that I mean that in gest.
    Aye, thinking about things like this really does shine a light on it's complexity and balance. Which is why I wanted to open the discussion. I figured so much of life on earth is influenced by these factors that if you changed them, what would be the result/product?
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    Quote Originally Posted by UKDutyPaid
    Quote Originally Posted by sunshinewarrio
    And let's not forget tidal effects. As denizens of tidal pools are aware - each tide is a mini-season.
    That's assuming this hypothetical planet also has a hypothetical moon of course... 8)
    The Sun affects tides too - hence the difference between Spring and Neap tides.

    I suspect the idea of a purely affectless planet/star system would be difficult to assess, given that for whatever speculation you set up, there will be some other minor fluctuation/aspect that can still be brought up to demonstrate a lack of total symmetry (which is what, I suspect, you seek).

    The Equatorial Rainf Forests can, however, as others have pointed out, be considered to be effectively seasonless and, in the depths of the Congo, Amazon or New Guinea, to be tideless too.

    They are still, however, affected by the cycle of day and night, unless you want to remove that cyclical influence too...

    Finally, even on a planet with hypothetical 0 eccentricity in orbit and 0 axial tilt, you will still have something akin to seasons (and certainly climatic differences) based not just upon latitude but also on land-sea distribution: London is further North than almost any USian city (bar those in Alaska), yet has a 'milder' climate than New York, Kansas City or Chicago, for instance (working from memory here).
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    Thanks for the reply, excellent stuff.
    Quote Originally Posted by sunshinewarrio
    The Sun affects tides too - hence the difference between Spring and Neap tides.
    But surely only when there is eccentricity in the orbit creating such fluctuations?

    I suspect the idea of a purely affectless planet/star system would be difficult to assess, given that for whatever speculation you set up, there will be some other minor fluctuation/aspect that can still be brought up to demonstrate a lack of total symmetry (which is what, I suspect, you seek).
    Indeed, which is one reason I raise the debate, to see if it is even possible for such a thing to exist.
    As to symmetry, that is an interesting observation. it is clearly a necessity for such a planet, yet not something I had really noticed! you analysed my psyche dammit! Am I so lopsided I seek balanced perfection lol

    The Equatorial Rainf Forests can, however, as others have pointed out, be considered to be effectively seasonless and, in the depths of the Congo, Amazon or New Guinea, to be tideless too.
    that seems true enough, so there is lots of evidence and things to look at there for equatorial regions for the hypothetical planets ecosystem. But what about further from the equator? how might life sustain itself there?

    They are still, however, affected by the cycle of day and night, unless you want to remove that cyclical influence too...
    Not something I specifically want, although the idea of changing the rotational speed of a planet to affect this +/-24 hours could also create come interesting hypotheses on animal and plant behaviour.

    Finally, even on a planet with hypothetical 0 eccentricity in orbit and 0 axial tilt, you will still have something akin to seasons (and certainly climatic differences) based not just upon latitude but also on land-sea distribution: London is further North than almost any USian city (bar those in Alaska), yet has a 'milder' climate than New York, Kansas City or Chicago, for instance (working from memory here).
    Another interesting point. I'm sure that weather patterns are greatly affected by the landmass below it, and hence air temperature and make-up etc. I just wonder how much of these weather systems are also seasonally driven.


    But as a result of your point there, I'm going to add another question(s) to the mix:
    How much affect on the weather system would the actual continental make-up of a planet have? How different was the weather over a continent lke Gondwana Land as opposed to the spread out land masses we have today? (assuming they had the same atmospheric content.) How different would weather be on a planet that is mostly sea covered? or mostly land based?
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    Quote Originally Posted by UKDutyPaid
    How much affect on the weather system would the actual continental make-up of a planet have? How different was the weather over a continent lke Gondwana Land as opposed to the spread out land masses we have today? (assuming they had the same atmospheric content.) How different would weather be on a planet that is mostly sea covered? or mostly land based?
    The Permian extinction, in which 90% of species perished, was probably - in large part - a consequence of climatic changes related to the formation of Pangea.
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    UKDutyPaid, how long is a day going to be on this planet ? 24 hours, 6 months, years ?
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    Quote Originally Posted by Cat1981(England)
    UKDutyPaid, how long is a day going to be on this planet ? 24 hours, 6 months, years ?
    I don't have a set idea, but I do think a change from our 24hr cycle could yeild some interesting changes within the ecosystem, with regards to relationships between day/night animals, how their activities effect each other, and how plants might grow differently.

    I appreciate this thread is actually pretty vague in terms of details I'm after. I guess it's more an open discussion. I was hoping I could take some responses and start to fashion a more complex idea if I thought it could be done, or would make an interesting world for a novel.
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    Have you read Ringworld? It's been so long I don't remember, but there's no obvious reasons why there should have been seasons on that artificial planet, so Larry Niven might have beaten you to it.
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    Just mention, 0 eccentricity for a star-planet system is impossible. A planet and a star orbit around their common center of gravity and that will always be towards one side of the star's center, and so the orbit will always be elliptical. Two stars with the exact same mass would orbit in a circular orbit around their CoG, but two objects with dissimilar masses will always orbit as an ellipse.

    Also must be noted that any other planet will affect the planet's orbit too, and will also affect the star.

    Also, even with 0 tilt, the temperatue would be hotter on the equator and colder on the poles as the angle of incidence of light would vary slightly with latitude, the same as the thick of air that light should traverse.
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    Quote Originally Posted by Lucifer
    Just mention, 0 eccentricity for a star-planet system is impossible. A planet and a star orbit around their common center of gravity and that will always be towards one side of the star's center, and so the orbit will always be elliptical. Two stars with the exact same mass would orbit in a circular orbit around their CoG, but two objects with dissimilar masses will always orbit as an ellipse.

    Also must be noted that any other planet will affect the planet's orbit too, and will also affect the star.

    Also, even with 0 tilt, the temperatue would be hotter on the equator and colder on the poles as the angle of incidence of light would vary slightly with latitude, the same as the thick of air that light should traverse.
    eek, help from the devil... *checks soul*.
    Thanks for input, very helpful additions. And yeah I'm aware even with 0 tilt there will still be temperature differencial, what I'm interested in is each latitude remaining mostly constant. Although if 0 eccentricity is impossible, then maybe there will always be seasons.. interesting...

    isn't the universe fascinating!

    oh and Bunbury, no I haven't read Ringworld, maybe I should check it out. thanks.
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