Pyramid Science

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Thursday, July 08, 2010

Eccentricity, Ellipticity, Obliquity And Climate Change

  • Much has been discussed regarding the effects on climate caused by human activities. This may in part be (very loosely) based on fact, but a great deal of 'fact' is conveniently ignored. The emphasis is clearly on a justification for raised taxation. Not the science.
The orbit of any body around another is rarely, if ever, a perfect circle. The theoretical extremes of the eccentricity are a circle and an ellipse and the change from one to another can be caused by several interacting effects. The relative position of a focus (Sun) may possibly not vary a great deal, but the distance of the orbiting object around that focus does change. The extremity of distance of an orbiting body from the focus will increase as circular morphs to elliptical. This will ensure that the orbital distance remains the same and is a prerequisite since the annual orbit is the same. The 'squashed circle'. The more 'squashed' this circle becomes, the closer the body is to the Sun. Hotter.

It should be recognised that the Earth year is currently 365.25 days and many thousands (possibly millions) of years ago may have been less, possibly 360 days. The entire solar system is in motion and the relative (absolute) position in space will change enormously from one 'year' to the next. The appearance is one of stability, but this is the illusion. The effect of global warming and the associated potential for climate change are then (theoretically) very real.

The effect may be the same, though
the interpretation of cause does
change considerably

A more elliptical orbit will have an increased major axis distance from the focus compared to that of a more circular one, but since the circle is 'squashed' even though the distance from the focus increases, the overall orbital distance is not appreciably changed. The velocity between the extremes of the elliptical orbit: the closest to the Sun = perihelion (fastest and hottest) or furthest from the Sun (aphelion) as the (slowest and coldest) will be intermediate to that around the focus (long/short axis). The long axis is the distance from one extreme of the ellipse to the opposite side passing through the centre. The semi-major axis is one-half this value. The ellipticity is the ratio of the semi-major axis distance to that of the focus to the centre. The object could conceivably be oval in shape and other planetary (gravitational) influences will effect change. The relative orbital locations of the planets with respect to each other will continuously change since the 'yearly' revolution for each of the planets is different. Inter-planetary gravitational influence will be constantly different as the relative positions are all in continual variance.

  • NB: the Earth system because of axial tilt ensures that in the northern hemisphere, summer is during aphelion and winter occurs during perihelion. The seasons are a consequence of this obliquity. The majority of land mass in the northern hemisphere and oceans in the south is a prime reason for a hospitable environment. Were this to be the other way around, the temperatures in the north during summer would be much greater and less in the south. The consequences for mammalian survival would be dire: axial precession foretells a grim scenario within the next 10 - 15,000 years or so...

Mercury
  • 88 (Earth) days, 0.38AU
    Venus
    • 225 (Earth) days, 0.72AU
    Earth
    • 365.25 (Earth) days, 1.00AU
    Mars
    • 687 (Earth) days, 1.52AU
    Asteroid Belt
    • Either a failed accretion caused by the opposing Jupiter-Sun gravitational influence or a destroyed planet from collision*
    Jupiter
    • 4332.75 (Earth) days (11 years 315 days), 5.2AU
    Saturn
    • 10759.25 (Earth) days (29 years 167 days), 9.54AU
    Uranus
    • 30687 (Earth) days (84 years 6 days), 19.22AU
    Neptune
    • 60189 (Earth) days (164 years 288 days), 30.06AU
    * Two (or more) objects could have collided by virtue of sharing the same (or very similar) orbital distance from the Sun though with (slightly) different velocities. Such a collision may have been relatively slow, but sufficient for mutual destruction.

    The transit of one object around another continually changes. The square of the orbital circumference as measured by the transit time (Earth) days is proportional to the cube of the radial distance (AU), but only for the truly circular orbit. The velocity of a planet decreases with the radial distance: the further away, the slower its orbital speed according to Kepler's third law:

    Orbits are not perfect circles and so the constancy is only approximate, but the relationship appears to be valid.


    7744 (88 x 88) days/0.38AU x 0.38AU x 0.38AU =
    • 141128
    50625 (225 x 225) days/0.72AU x 0.72AU x 0.72AU =
    • 135634
    133407.6 (365.25 x 365.25) days/1AU x 1AU x 1AU =
    • 133408
    471969 (687 x 687) days/1.52AU x 1.52AU x 1.52AU =
    • 134395
    18772722.6 (4332.75 x 4332.75) days/5.2AU x 5.2AU x 5.2AU =
    • 133509
    115761460.6 (10759.25 x 10759.25) days/9.54AU x 9.54AU x 9.54AU =
    • 133327
    941691969 (30687 x 30687) days/19.22AU x 19.22AU x 19.22AU =
    • 132633
    3622715721 (60189 x 60189) days/30.06AU x 30.06AU x 30.06AU =
    • 133373
    The obliquity of the Earth is the change in its axial tilt and it is estimated to take around 41,000 years to move from 21.5deg to 24.5deg and back again. Currently it is about 23.5deg. The precession of this axial shift defines the 'wobble' of the Earth's motion at any specific tilt angle: 26,000 years. So the Earth precesses around its axis at a specific angle that itself changes over time. The orbit of this rotating object that precesses, changes between a flattened ellipse to a more circular shape over an estimated 100,000 years. What this means is that the Earth orbit from any one year to the next fluctuates, albeit by a very small amount, and the planet's position in space relative to the Sun will never be the same from one year to the next.
       Even Earth's Moon rotating once on its own axis for every single 'orbit' about the Earth has a gravitational interaction resulting in two Earth tides (each approximately 45 minutes later) every day. One 'orbit' takes about 30 days = a 12 deg positional eastward shift every day and 12/360 x 24hrs = 0.8hrs (48 mins).
       Tides are (on average) 48mins later every subsequent day.
       The heat radiated by the Sun and absorbed by the Earth's atmosphere will constantly increase/decrease over the thousands of years that these related movements occur. The climate of the planet changes because the distance of the Earth from the Sun is always changing. And the Sun is getting warmer.

    • As an observation, Jupiter's average 'year' is 11.86 Earth years (= 4332.71/365.25 Earth days) and sunspot activity appears to have maxima every 11 or so years, but it is not likely that Jupiter's orbital gravitational influence would affect the Sun's activity: the tiny Jovian speck having such an effect on the comparative enormity of the Sun just doesn't make a lot of sense. However, any gravitational changes of the Sun caused by the sunspots (relatively cooler areas on the Sun's surface or photosphere) could, however, affect the orbital transit of all celestial bodies within its sphere of influence. Sunspots involve magnetism and gravity and magnetism could be related.

       The three cycles are operating simultaneously and since the relative periods are so diverse, synchronicity cannot happen (accepting that the time-periods are correct). A complete precession (26,000 years) cycle through 6degs (21.5degs -> 24.5degs -> 21.5degs) occurs roughly 4 times for every eccentricity cycle (100,000 years) where obliquity (41,000 years) happens only two and one-half times. The position in space at any moment and the changing gravitational influences caused by the constant motion of the planets ensures the radiation from the Sun is never constant either. The result:

    Climate Change

    Comment

    • Actual denials of climate change are rarely voiced, though the single reason for it being caused by human activity is vehemently challenged. It is clearly politically and financially motivated and crude attempts at ridicule are simply accusations of 'deniers of climate change'. This is the classic response of those who define fair and reasonable challenge as conspiracy theory and such accusers are nauseatingly hypocritical simply by ignoring mainline science and their own arrogance by attempting to shift understanding by prosyletising their beliefs. The patronising "holier-than-thou" attitude defines the stance of such people as no case is ever put that can be properly argued.

    It's as ridiculous as it is nauseating

    A true scientist knows the cosmological (or cosmogony) arguments. At the very least they should do. Before pontificating about their version of the truth based on untruth or incomplete (known) argument. Cherry-picking is like statistics. Any story can be told with massaging. Truth can never be 'massaged'.

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