The Oort cloud as rival to the sun ?

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Jzz

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Our normal experience of gravity is as a benign force, everything in nature is seemingly ordered because of it, the earth and the planets revolve around the sun at fixed distances and speeds, everything is peaceful and innocuous. Yet recent exo-planet images from the JWST suggest that this is far from being the normal state of things. The accepted view of the formation of the solar system, with the gas giants going smoothly around the sun, sucking up the vast majority of matter that surrounded the early sun, seems to be slightly flawed. Instead, a picture emerges of these gas giants constantly moving towards and away from the sun, their immense gravity creating havoc amongst the lesser planets. I had portrayed a scenario very similar to this in my book.

Initially the immense gravity exerted by the sun would pull these gas giants towards itself, as they neared closer to the sun, the side nearest to the sun would begin to evaporate, and the influence of the Oort cloud (more massive then) would pull them back towards the outer horizons of the solar system. The opposing forces of gravity exerted between the two gas giants, Saturn and Jupiter would have ripped the mantle off Mercury and stopped the growth of Mars in its tracks by sucking up all the usable debris in their paths. Eventually, they would have settled into the stable orbits we now see, but before that, as their paths crossed, they tossed Uranus onto its side, so that it is the only planet in the solar system whose axis is tilted towards the horizontal.

It is frightening to think of the forces of gravity these Giants unleashed in the solar system. They are rightly named it would seem.

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Catastrophe

"There never was a good war, or a bad peace."
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Jzz

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I don't think this is going to give the Sun a problem ;)
I was referring to the push me pull you effect , probably the Oort cloud might have exerted a greater effect in times past ? I am just wondering do you disagree with the whole hypotheses or just this part of it ? As I had stated, I have had these ideas for some time now and had referenced them in my book (reference to which has been redacted by moderator, but not important anyway) it is surely one way to explain the undoubtedly violent events that led to the formation of our solar system.
 
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Catastrophe

"There never was a good war, or a bad peace."
I am sorry, I have not seen your book, so I don't know much about your theory, and I have never heard of the 'push me pull you effect'.

I am aware that there are suggestions that the Solar System was in a very dynamic state, with Jupiter moving in to within the Frost Line (or similar alternate name) i.e., inside the distance of the Asteroid Belt). I do have some problems with these, but there are, apparently, 'hot Jupiters', so such larger (gas) planets seem to have the property of retaining their (or most /some of their) gases even in relative proximity to the Sun (which is believed to have been cooler in the distant past).

I can well believe that the Solar System was very different in the past. There was much more room out there for objects further from the Sun, so even a large number very far out could be distantly spaced. There would be very small attractions between the individual objects, and, collectively between objects in the Oort Cloud and inner objects.

Note from the above posts (#2 and #3) that the estimate is between 0.19 and 19 Earth masses. This is to be compared with the Asteroid Belt at only 3% of Moon mass. (3% of 1.2% of Earth mass) so the Oort Cloud objects and Asteroid Belt objects really total almost insignificant amounts compared to the total Solar System mass). Of course, quite large amounts of mass (some planet sized) were lost in the distant past, but I don't believe that these were substantial compared with the mass of the Sun.

Cat :)

P.S. Uranus' inclination is believed to be due collision(s) with large object(s) in the early SS. Most present planets seem to have been involved in collisions, particularly Mercury, Venus, and Earth, as well as Uranus.
 
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Jzz

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Uranus' inclination is believed to be due collision(s) with large object(s) in the early SS. Most present planets seem to have been involved in collisions, particularly Mercury, Venus, and Earth, as well as Uranus.


I guess the title is a bit misleading, good thing that it is framed as a question rather than as a statement.
 

Catastrophe

"There never was a good war, or a bad peace."
Uranus' inclination is believed to be due collision(s) with large object(s) in the early SS. Most present planets seem to have been involved in collisions, particularly Mercury, Venus, and Earth, as well as Uranus.


I guess the title is a bit misleading, good thing that it is framed as a question rather than as a statement.
Yes.

The Oort cloud as rival to the sun ? Gravitationally no, I would have to say.
 
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Jzz

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Yes.

The Oort cloud as rival to the sun ? Gravitationally no, I would have to say.
For me or you to take a pontifical stand on such an issue is probably bordering on the ludicrous. Given that stars such as our sun are formed out of massive hydrogen clouds and given also the composition of our solar system, there can be no doubt that a lot of activity took place in the past. For instance, it is fairly apparent that either our sun had a rival sister star at some time in the history of the solar system, which exploded OR more likely that the gas cloud from which our solar system originated, at some time or the other had come across the debris of such a former star and had swept it up. Such an event might even have acted as the catalyst for the birth of our star. There are also theories, supported by computer simulations that there might have been five gas giants at one time instead of the present four and that the fifth giant gas planet had been expelled from the solar system. Imagine the violence that such an event would have entailed. Another popular hypotheses is that the earth had a sister planet named Theia that collided with the earth early in the formation of the solar system around 4.5 billion years ago. Given all this activity, does my theory of planetary migration towards and away from the sun sound so bizarre as to be completely untenable? I believe not.

Certainly the planets took time to form, and the outer gas cloud in primordial times might certainly have had enough mass to cause the migratory patterns I refer to. In any case to take the present state of the Oort cloud or the solar system as a reference point is surely not scientific. In short anything could have happened, but the story of what really happened might get clearer as the James Webb Telescope continues its exploration of the Universe.
 

Catastrophe

"There never was a good war, or a bad peace."
Jzz, Yes. All this is totally hypothetical imagination. Be honest. You were not there. I was not there. We both have ideas of what it might have been like.

In short anything could have happened, but the story of what really happened might get clearer as the James Webb Telescope continues its exploration of the Universe.
My emphasis.

In principle, I agree. Regarding the JWST, the same thing was probably said about Hubble, and will be said about what succeeds the JWST. In short
anything could have happened
, but meanwhile we can all have fun exercising our imaginations.

Cat :) :) :)
 
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Regarding hypothesized gravitational effects of the Oort Cloud:

From what I have read, the Oort Cloud is shaped more like a spherical shell than like the accretion disk that formed the planets and the other stuff all the way out to and including the Kuiper Belt. If it is basically shell shaped, then the net gravitational effect inside it would be minimal to nothing, depending on how "lumpy" the distribution of mass really is. A perfectly uniform thickness spherical shell does not exert any 1/r^2 forces (gravitational, electrostatic, etc.) because the geometry is such that the force from one side of the shell cancels the force from the other side at all points inside the shell.
 
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Unclear Engineer is correct, inside a uniform shell there is no net gravitational force.

The Sun does not "attract" planets inward due to its gravity. The Sun exerts a radiation pressure that lifts objects in orbit around it into higher orbits.

The Sun has tidal bulges raised by objects in orbit around it. Those bulges would be swept eastward due to the rotation of the Sun thus exerting a force on the object and raising it to a higher orbit (assuming the object is in a prograde orbit in the same plane as the Sun's rotation).

No two body system can eject one of the bodies.

Three body systems can raise and lower orbits and eject bodies from the system.

Collisions can tilt objects and change their rate of rotation.

I may have forgotten a few.
 
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Jzz

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The Sun does not "attract" planets inward due to its gravity. The Sun exerts a radiation pressure that lifts objects in orbit around it into higher orbits.
That might be one way to look at it but it seems to go against both relativity and Newtonian gravity.
 
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I was reacting to your statement: "Initially the immense gravity exerted by the sun would pull these gas giants towards itself."
A single planet in orbit around the Sun will not be pulled into the Sun. The fact that gas giants move inward and outward is due to them exchanging angular momentum with each other.
 

Jzz

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I was reacting to your statement: "Initially the immense gravity exerted by the sun would pull these gas giants towards itself."
A single planet in orbit around the Sun will not be pulled into the Sun. The fact that gas giants move inward and outward is due to them exchanging angular momentum with each other.
I am in perfect agreement. Thst was what I was trying to say all along!
 
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Catastrophe

"There never was a good war, or a bad peace."
And, for comparison, here is some information on the Kuiper Belt:

Beyond Neptune, at distances between 30 and 100 AU, is the Kuiper belt. It is estimated that about 35,000 rocky/icy objects of around 100 to 200 km (60 to 120 miles) across, and millions of smaller bodies exist here, but because of their distance from Earth, and their small size, only around 100 have so far been observed.
Source: Universe from the Big Bang to Black Holes, Ed. Pam Spence, Collins Discovery Guides, 2016.


Cat :)
 
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The Kuiper belt's 35,000 objects, averaging 90 miles in diameter, only equals about 5% of the volume of Earth.
Oort cloud may have about 5 times the mass of Earth.
Asteroid belt mass is but .04% mass of Earth.
 

Catastrophe

"There never was a good war, or a bad peace."
I like to quote sources, so we can display dates and other interesting information, so I quote
Universe from the Big Bang to Black Holes Ed Pam Spence Collins Discovery Guides 2016
The Oort cloud has never been actually observed - its existence was suggested by the Dutch astronomer J H Oort to explain the trajectories and number of long period comets . . . . . . comets have been observed coming directly from that far out and it is the logical explanation for their origin.
Cat :)
 

Catastrophe

"There never was a good war, or a bad peace."
Bill, do you have a source ref of this please?

Oort cloud may have about 5 times the mass of Earth.
NASA gives a factor of 1.9. I appreciate any such estimate is largely guesswork. ;)

The mass of the Oort cloud - NASA/ADS (harvard.edu)

The estimated total mass is 1.9 earth masses. The probable error in the estimate is about one order of magnitude. Most of the mass of the Oort cloud is concentrated in the size range of the observed long-period comets. The mass estimate is consistent with either cometary formation among the outer planets, or in satellite fragments of the primordial solar nebula.
Cat :)
 
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Catastrophe

"There never was a good war, or a bad peace."
The Oort cloud as rival to the sun ?

Anyway, whichever result seems to give a resounding NO as the answer.

The mass of the sun is 1.989 x 10^30 kilograms, about 333,000 times the mass of the Earth, so if Oort cloud is 5 times Earth mass (to take an easy figure), then Sun is 66,600 the mass of the Oort cloud. If Oort cloud were same as Earth mass, then Sun would be 333,000 times Oort cloud.

Cat :)
 
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Jzz

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Anyway, whichever result seems to give a resounding NO as the answer.

The mass of the sun is 1.989 x 1030 kilograms, about 333,000 times the mass of the Earth, so if Oort cloud is 5 times Earth mass (to take an easy figure), then Sun is 66,600 the mass of the Oort cloud. If Oort cloud were same as Earth mass, then Sun would be 333,000 times Oort cloud.
True, today. What about in the past? The number of dwarf planets, comets and asteroids, seems formidable.
 

Catastrophe

"There never was a good war, or a bad peace."
Jzz, the question is The Oort cloud as rival to the sun ?
not
The Oort cloud as danger to the Earth?
I don't think that the Oort cloud (let alone the dwarf planets, comets and asteroids put together) was ever "rival" to the Sun. In fact, I don't really understand the meaning of the question.

You, yourself, stated in post #6
I guess the title is a bit misleading, good thing that it is framed as a question rather than as a statement.
Can you explain, please, what you meant by "rival"? Did you mean endanger? Compete with gravitationally? I think this would better enable us to understand what you were getting at. :)
I think that we all understand that there are various ideas about the history of the Solar System, some suggesting that major planets ejected a lot of smaller bodies from the Solar System, or at least modified their orbits. This would seem to endanger the smaller bodies, rather than the Sun?

In fact, is the term "endanger" (or "rival") rather anthropocentric? Would lumps of rock (assuming they were uninhabited) feel endangered or rivalled by having their orbits modified?

I hope that it goes without saying that it is simply the ideas or semantics that I am asking about.

Cat :) :) :)
 

Catastrophe

"There never was a good war, or a bad peace."
Jzz, may I quote from your post #1?

The accepted view of the formation of the solar system, with the gas giants going smoothly around the sun, sucking up the vast majority of matter that surrounded the early sun, seems to be slightly flawed. Instead, a picture emerges of these gas giants constantly moving towards and away from the sun, their immense gravity creating havoc amongst the lesser planets. I had portrayed a scenario very similar to this in my book.
Is this really the case? Are we not, perhaps, dealing with two different times?

May it not be the case that it first required the formation of objects of various sizes by accretion, then these multitudinous objects were acted on by the Sun and/or larger bodies? I cannot see that this is at variance with the suggested view. Don't forget, we are looking at what might have happened over periods of billions of years.


Cat :)
 
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"Its total mass is not known, but, assuming that Halley's Comet is a suitable prototype for comets within the outer Oort cloud, roughly the combined mass is 3×1025 kilograms (6.6×1025 lb), or five times that of Earth."
Alessandro Morbidelli (2006). "Origin and dynamical evolution of comets and their reservoirs of water ammonia and methane". arXiv:astro-ph/0512256.
 

Catastrophe

"There never was a good war, or a bad peace."
Thank you Bill, for the reference. But I have not changed my opinion that the Oort cloud is pretty puny compared to the Sun.

As a matter of interest
Finally, these issues are revisited in the light of a new model of giant planets evolution that has been developed to explain the origin of the late heavy bombardment of the terrestrial planets.
have you taken this any further?

Cat :)
 
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