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Old 12-10-2019, 03:31 PM
Dove (Alan)
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Hello guys,

seriously, why is it accepted that the Earth's obliquity is unchanging apart from a wobble caused by the perturbations of our sister planets?

It is clearly asserted that our axis movement, a decrease of 47" of obliquity per century, will remain wobbling 2-3 about our present obliquity. That is a notion of perpetual motion of Earth's axis if there ever was.

Any one like to check it out ? There is ample evidence for the assertion available on record.

Cheers, Alan.

Omission to last post.

read. 2-3 degrees

Alan.

Last edited by RB; 12-10-2019 at 03:57 PM.
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Old 12-10-2019, 08:07 PM
Ukastronomer (Jeremy)
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I can never understand why perpetual motion is said not to exist

Surely as stated an object in motion will continue unless acted upon by an external force . etc

Then anything travelling in space no matter what speed will be in perpetual motion ???
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Old 12-10-2019, 10:21 PM
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Sunfish (Ray)
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Er. Entropy.
The Universe is winding down. Entropy increases.
Second law of thermodynamics I think can not be avoided.

So no perpetual motion.

A little more complicated than that if you read Carlo Rovelli.
But that is speculative I think.

I can’t see why the earth tilt has anything to do with perpetual motion. I will happily leave that to physicists.
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Old 12-10-2019, 10:37 PM
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Atmos (Colin)
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Where you may be getting confused is the difference between "perpetual motion" in the sense of the Earth rotating, whether it be around its own axis, around the sun or whatever.
This concept and the "perpetual motion machine" which is a very different concept where the power generation of a system is greater than the energy required to keep it running. It is this second concept that breaks the second law of thermodynamics.

Everything in the universe has a certain amount of motion promotional to the kinetic energy is has. This holds true for anything from atoms to galaxies. The energy pool of one body can affect another body. The moon is moving away from the Earth at some 2-3cm per year, as the moon recedes the Earth spins more slowly. This is known as the conservation of angular momentum, it's the same concept as a dancer having their arms out or in while spinning.

Theoretically you can have perpetual (forever) motion if you have something moving through space and it isn't interacting with anything else. It's energy pool remains constant and isn't changing so it'll continue doing what it's doing.
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Old 12-10-2019, 11:02 PM
Ukastronomer (Jeremy)
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In which case perpetual motion can theoretically never be achieved
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Old 13-10-2019, 02:25 PM
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There is nothing in our universe which does not react with something else as far as one can demonstrate now. Radiation,light, gravity, magnetic and electric fields and so on , even when imperceptible has an effect. Moving things , warm things, loose energy. Eventually the universe will be cold and dark and big or squashed up in a tiny non space.
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Old 13-10-2019, 02:44 PM
JA
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Motion that continues for aeons: 1000's, tens of thousands, millions, hundreds of millions of years, etc... is perpetual enough

Best
JA
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Old 13-10-2019, 03:56 PM
Ukastronomer (Jeremy)
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Quote:
Originally Posted by Sunfish View Post
There is nothing in our universe which does not react with something else as far as one can demonstrate now. Radiation,light, gravity, magnetic and electric fields and so on , even when imperceptible has an effect. Moving things , warm things, loose energy. Eventually the universe will be cold and dark and big or squashed up in a tiny non space.
Then there will never BE perpetual motion............... ever
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Old 13-10-2019, 04:20 PM
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In which case perpetual motion can theoretically never be achieved
Tell me what is your definition of Perpetual Motion
Cheers
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Old 13-10-2019, 04:38 PM
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pfitzgerald (Paul)
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FWIW - I would suggest that you may be confusing perpetual motion with simple harmonic motion.
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Old 13-10-2019, 05:03 PM
Ukastronomer (Jeremy)
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Tell me what is your definition of Perpetual Motion
Cheers
it isn't m"MY" definition..............
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Old 13-10-2019, 06:26 PM
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it isn't m"MY" definition..............
Now I remember why I stopped contributing to this forum
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Old 14-10-2019, 07:50 AM
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In which case the universe itself has “perpetual enough” motion fuelled by its initial supercharged state although it could be all that mysterious dark energy doing some pushing.

There were some calculations I read by a physicist that a ship pushed by an exploding star and whipped around a black hole or two to accelerate at some part of the speed of light could zip far into our future. Easy to speculate I suppose.

Perhaps that it perpetual enough and thankfully no one is junking up the future yet.




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Motion that continues for aeons: 1000's, tens of thousands, millions, hundreds of millions of years, etc... is perpetual enough

Best
JA
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Old 14-10-2019, 03:54 PM
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To throw a cat in among pigeons. As far as the angle of the earth on the orbit, etc. Ancient Races all had a year of 360 Days -- it appears in ancient times the year was 360 Days. But the earth has apparently slowed down to 365 !/4 days [and a bit more that we do not need to discuss for this discussion.]. I am basing this on Archaeology, not Astronomy.

That is practically every ancient race did record the year as 360 days. Then the earth slowed. races from Central America, as well as the middle east described the 5 1/4 extra days that were added as BAD day, demon days, etc.

So perhaps this will throw a spanner into perpetual motion.

And sorry guys, I may not get back to this until Friday.
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Old 16-10-2019, 08:51 AM
Dove (Alan)
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Hello to all.

I address my argument to those who agree with the scientific premise that there is no such thing as perpetual motion, in order that we can proceed to look at some facts concerning the motion of our planet. Namely the misconception in astronomy that earth's angle of obliquity is unchanging and earth will forever remain wobbling around 23.5 degrees due to the perturbations of our sister planets.

Those friends who believe that there is such a thing as perpetual motion, can rest content in the notion that earth will exist forever wobbling around 23.5 degrees obliquity. Cheers Alan.
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Old 20-10-2019, 07:14 AM
Dove (Alan)
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Quote:
Originally Posted by Sunfish View Post
Er. Entropy.
The Universe is winding down. Entropy increases.

I can’t see why the earth tilt has anything to do with perpetual motion. I will happily leave that to physicists.
Hello Sunfish,

The angle of obliquity is mainly a question for astronomy.

It is also a question of planetary motion, a subject that is not fully understood due to neglect.

I put my argument in more detail in my next post.

Cheers, Alan D.

Quote:
Originally Posted by Sunfish View Post
Er. Entropy.
The Universe is winding down. Entropy increases.
Second law of thermodynamics I think can not be avoided.

So no perpetual motion.

A little more complicated than that if you read Carlo Rovelli.
But that is speculative I think.

.

Reply to sunfish (Ray}

Allow me to explain:

1.
You will be aware that the precession ‘circle’ traced on the celestial sphere is centred on the pole of the ecliptic. And is truly described as a circle not a spiral, and when the north pole completes a full circuit it will not return to the same spot to complete a circle, this indicates that it is actually performing a spiral.

This became evident from Isaac Newton’s description of Precession of the Equinoxes, showing that the equatorial plane shifts annually, along the plane of the ecliptic completing a spiral orbit and in accord with it, the north pole of earth’s axis shifts spirally about the pole of the ecliptic. Yet Newton gave no indication or recognition of the spiral nature of Earth’s orbit.

The Precession of the Equinoxes operates in accord with the law of Spiral planetary motion the spiral nature of which, has ever since been ignored by astronomy.

From the foregoing it follows, that the North pole annually moves along on a spiral precession cycle in accord with Earth’s spiral orbit about the equatorial plane.

2.
It will be understood that spiral planetary motion has two inherent functions that are best described as follows:
a.
The first inherent function of the spiral orbit induced by the Sun is as follows.
Each orbit progressively advances the plane of the orbit and of course with it the angle of its axis to the Sun. See Newtons ‘bending moment’ the torque that the Sun ‘tends’ to draw the Earth’s equatorial plane to equate with the plane of the ecliptic, (And of course, eventually to the plane of the Sun, due to the protuberance of Earth’s equator).
b.
The second and basic inherent function of natures spiral orbit is its continuous gravitational movement toward the centre, to the Sun. (see the Newton Hooke correspondence 1679 concerning the movement of matter toward centre, introduced by Dr.Hooke with his elliptispiral form of motion.

Natures spiral is the essence of all planetary motion, as such, it is the dynamism of gravity, of change and life itself.

Due to the impetus of spiral motion throughout the solar system and beyond, no forms of matter can be held in perpetual suspension without change, the spiral motion of matter ensures change absolutely. Everything has a beginning and an end.

So you see Ray, planet Earth cannot be left in suspension wobbling about 23.5 degrees going round and around the Sun perpetually at that fixed angle, because that would be a perpetual motion and consequently science generally does not support the notion of perpetual motion.
.
Cheers Alan

Last edited by RB; 20-10-2019 at 08:06 AM.
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  #17  
Old 21-10-2019, 10:12 AM
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bojan
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Quote:
Originally Posted by astroron View Post
Now I remember why I stopped contributing to this forum
Yep...

Can I offer some badly needed education on precession, see here:
https://en.wikipedia.org/wiki/Precession


And orbital motion of planets, here:
https://en.wikipedia.org/wiki/Orbit

Last edited by RB; 21-10-2019 at 10:35 AM.
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  #18  
Old 21-10-2019, 07:26 PM
morls (Stephen)
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Just out of interest, has anyone or any theory described or modelled the motion of the earth around the sun in such a way that includes the sun's movement as part of the milky way and the milky way's movement as part of the local group?
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Old 21-10-2019, 10:22 PM
gary
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Just out of interest, has anyone or any theory described or modelled the motion of the earth around the sun in such a way that includes the sun's movement as part of the milky way and the milky way's movement as part of the local group?
Hi Stephen,

What is referred to as the secular aberration drift (SAD) is fancy wording that
describes the solar system barycentre's rotational acceleration around the
centre of the galaxy, a point heavily weighted by the supermassive black
hole designated Sagittarius A.

In the year 2000, we went from using the positions of approximately 1500
stars to using the positions of distant quasars for defining RA and dec.
This system we now use is referred to as the International
Celestial Reference Frame (ICRF).

This capability came about through the now routine use of Very
Long Baseline Interferometry (VLBI) where a global network of
radiotelescopes uses the distant quasars as references.

In recent years, they are measuring angles down at the phenomenally
small microarcsecond (μas) level.

So the SAD (our rotation around the centre of the Milky Way) has
been measured at around 5 to 6 μas per year.

The theories of precession and nutation are now refined to mindboggling
levels of precision, as they need to be for everything else to be
measured so accurately, so there is not much that is not accounted for with
respect the Earth's own motion.

They even use VLBI to measure plate tectonic motions down to
one millimetre per year!

In turn the proper motions with respect the Local Group are being
measured and refined as well.

Years ago I had a customer buy from us and I recognised his name
as one of the leading authorities in planetary position theory.

He worked at JPL and I had a brief email exchange with him.
Turned out he was an amateur observer too in his spare time.

He was one of the people responsible for refining the ephemeris for
the Earth, Moon and planets so that, for example, the JPL landers
could more accurately hit their reentry corridors through the
Martian atmosphere.

I told him I had read several of his papers and that we used a subset
of that very emphemeris to compute the positions of the planets.

In turn he was happy to use our device in his spare time to look at the
planets. So I was chuffed by the thought his work had gone through
a full circle.

These ephemeris in their full form will compute the position of any of
the planets to no less 25 metres accuracy and to the Moon within a metre!
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Old 22-10-2019, 06:26 AM
morls (Stephen)
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Wow, thanks Gary.

It's amazing that we are be able to measure our movement around Sagittarius A.
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