(OT) Thick Layer Of Magma Found Under American Southwest.
"HFguy" wrote in message
news:uv1hi.10571$9b5.1632@trndny05...
Earth is closer to the Sun in Winter and further away from the Sun
in Summer.
This is true only for the northern hemisphere and it's not what causes the
seasons.
The Earth reaches perihelion - the point in its orbit closest to the Sun -
in early January, only about two weeks after the December solstice. Thus
winter begins in the northern hemisphere at about the time that the Earth is
nearest the Sun. Is this important? Is there a reason why the times of
solstice and perihelion are so close? It turns out that the proximity of the
two dates is a coincidence of the particular century we live in. The date of
perihelion does not remain fixed, but, over very long periods of time,
slowly regresses (moves later) within the year. There is some evidence that
this long-term change in the date of perihelion influences the Earth's
climate.
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