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Old 03-24-2020, 07:18 PM
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Originally Posted by Chronos View Post
Well, Newton was prior to the known discovery of Uranus, at least. Galileo made a few observations of it, but didn't realize at the time that that's what he was observing. Under ideal conditions, it can even be seen by the naked eye.
Fair enough.

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Originally Posted by manson1972 View Post
I'm not an astrophysicist or a rocket surgeon, but even I can see that a paper that says the distance varies by 1.85 million miles is inconsequential to the 91 - 94 millions miles the distance usually varies.

People don't review these papers before they get published?
1.85 million miles is about 2% of the Earth's orbital radius - if that kind of motion really happened, it might have some effect on climate. But this motion isn't real - it's a misunderstanding of how orbital mechanics works.
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Old 03-25-2020, 08:51 AM
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Originally Posted by Chronos View Post
Well, Newton was prior to the known discovery of Uranus, at least. Galileo made a few observations of it, but didn't realize at the time that that's what he was observing. Under ideal conditions, it can even be seen by the naked eye.
That was Neptune that Galileo recorded!

The first definitely recorded sighting of Uranus was by Flamsteed in 1690. (But not recognized as a planet, of course.) That was 3 years after Principia was published so right in the midst of the Newton timeline.

Both cases so close and yet ...
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Old 03-25-2020, 10:03 AM
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Originally Posted by manson1972 View Post
I'm not an astrophysicist or a rocket surgeon, but even I can see that a paper that says the distance varies by 1.85 million miles is inconsequential to the 91 - 94 millions miles the distance usually varies.

People don't review these papers before they get published?
I am an astrophysicist and it's not immediately obvious to me why that variation is inconsequential. Just as an analogy, the Earth's temperature varies by 100+ degrees F at any given location, but 1 degree rise in the global average temperature is significant.

Papers do get reviewed, but reviewers aren't always right. And journals don't always find a completely impartial reviewer.
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Old 03-25-2020, 01:28 PM
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If Jupiter suddenly vanished, there would be a big effect on Earth's climate. But that isn't going to happen.

The important point is that, whatever the details of the complicated "dance" that Earth, Sun and Jupiter engage in, it is a fairly stable periodic dance that was much the same millions of years ago and will be much the same millions of years from now. Whatever effect Jupiter will have on the Earth's climate is already accounted for in the status quo.

Jupiter's gravitation, along with Saturn's, does cause the eccentricity of Earth's orbit to vary in a long two-frequency cycle. This is the slowest of the Milankovitch cycles which cause cycles in Earth's climate. But even these effects don't depend on average Earth-Sun distance or average insolation: the climate changes are caused by the distribution of the arriving sunlight in season and latitude. (When the Ice Age ended 12,000 years ago, the Earth was closer to the Sun during the Northern Hemisphere's summer than it is now.)
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