Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Don_1 on 21/01/2010 12:19:06
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All the planets have an irregular orbit. Earth has an elliptical orbit. There will be times when all the planets are at their closest to the Sun (and therefore Earth's orbit) when they are aligned and when Earth is at its furthest from the Sun in the same alignment.
Does the gravitational force from such an alignment alter Earth's orbit? If so, would this be a permanent alteration and what difference could it have on Earth's axis in relation to the Sun at different points throughout its orbit?
In other words, could our axis be pointing toward the Sun while at our furthest from the Sun today and pointing toward the Sun while at our nearest to the sun in a billion years time after enough encounters with the suitably aligned planets?
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Are we heading towards nearly circular or more elliptical at the moment
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If I understand the chart correctly, it looks like Earth is approaching most circular and will be there in 25,000 years.
Fortunately, the range of tilt is not all that extreme.
I don't suppose there is any connection between this cycle and ice ages?
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I don't suppose there is any connection between this cycle and ice ages?
That's roughly what was in my mind Geezer. But I was rather more wondering if, at the extremes, during times of high eccentricity with the axis pointing toward the Sun at the furthest point from the Sun compared to times when the axis is pointing toward the sun when Earth is at its nearest to the Sun, what difference would be felt on Earth.
Have I explained myself here? I know what I'm asking, but reading the question, I'm not sure I understand what I'm cackling about.
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Er, well, I think that's a good question D1 (hope you don't mind the abbreviation).
The extremes are, a lot of tilt, versus no tilt at all. If there was no tilt at all, there would be no seasons in the temperate zones. It would be perpetual spring (or autumn) there.
If there was a large amount of tilt, the seasonal variations in the temperate zones would become much more pronounced. For example, London might actually be inside the Arctic Circle.
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Yes, you see I haven't made myself clear, have I? No surprises there!
Try this, what would be the difference in conditions when midsummer occurs at these two different points? This is assuming that Earth's elliptical orbit has been shifted by the influence of the other planets, or whatever, so the same time of year (ie summer) occurs when Earth is at different distances to the Sun.
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There, clear as mud!
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I don't suppose there is any connection between this cycle and ice ages?
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http://en.wikipedia.org/wiki/Milankovich_cycles
I've superimposed eccentricity over the bottom two graphs.
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Fascinating! I did not know that.
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Yes, you see I haven't made myself clear, have I? No surprises there!
Try this, what would be the difference in conditions when midsummer occurs at these two different points? This is assuming that Earth's elliptical orbit has been shifted by the influence of the other planets, or whatever, so the same time of year (ie summer) occurs when Earth is at different distances to the Sun.
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There, clear as mud!
Ah! I don't think the seasonal variations have too much to do with the Earth's distance from the Sun. I suppose there must be some effect, but it may not be very great. The major contributor to seasonal variation is the tilt of the Earth. The Earth spins on an axis that is not perpendicular to a line drawn between the Earth and the Sun. If it was perpendicular, there would be no seasonal variation at all.
I don't think the alignment of other planets has too much influence on the Earth's orbit around the Sun. There must be some influence of course, but I think it's probably too small to have any measureable effect on the energy the Earth receives from the Sun.
Mind you, this might well be a load of load of old cobblers, but it sounds pretty good, don't you think? Personally, I think it's always best to speak with great authority when you have no idea what you're really talking about.
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http://english.pravda.ru/science/earth/106922-0/
"The earth is now on the brink of entering another Ice Age according to a large and compelling body of evidence from within the field of climate science. Many sources of data which provide our knowledge base of long-term climate change indicate that the warm, twelve thousand year-long Holocene period will rather soon be coming to an end, and then the earth will return to Ice Age conditions for the next 100,000 years.
Ice cores, ocean sediment cores, the geologic record, and studies of ancient plant and animal populations all demonstrate a regular cyclic pattern of Ice Age glacial maximums which each last about 100,000 years, separated by intervening warm interglacials, each lasting about 12,000 years."