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every celestial body, it is said, is part of a 2 or twin body system which revolve around a common centre of gravity, which sometimes lay inside one of the 2 such celestial bodies (because one is bigger than the other) so it looks as if the other is revolving around this ...

is this theory right? can a celestial body never exist independently and be on the constant flight through space but can only exist in coordination of its gravitational pull on and under the gravitational pull of another celestial body? why is that? universe is designed that way ... maybe?
 
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Gravity has no distance limit. any body in the universe exerts a force on any other body. Most are just too distant to have an observable effect. so the earth appears to orbit the sun, but so do the other bound objects in the solar system, such as the moon and Jupiter. it is not just one twin body solution, but multiple solutions that must be considered. This is how Neptune was discovered, by its gravitational influence on Uranus.
it is also how the existence of the hypothesized planet Vulcan was disproved after the effect of gravitational frame dragging was added to the orbital equations for Mercury.
 
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Catastrophe

The devil is in the detail
Ooh! Are you just talking about gravity?

Of course you have the three body problem and the n body problem n -> infinity.
You just go by what has significant effects. With the inverse square law, gravity falls off very quickly; just look at the series - the inverse of
1 4 9 16 25 36 49 64 81 100.

Cat
 

Catastrophe

The devil is in the detail
According to Newton, everything is pulling everything else. However, in practice you only need bother about those heaviest and / or nearest. The force depends directly on the masses so we have M12, but indirectly to the square of the distance apart.44

For simplicity you jusr take the two bodies most concerned. For our Solar System that is usually the Sun and the planet. However, since Jupiter is so large/heavy it may be necessary to take it into consideration. But Jupiter may be on the other side of the Sun. Forces from other planets are usually negligible.

Hope that clears up your question.

Cat
 

IG2007

"Don't criticize what you can't understand..."
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Just look at Jupiter and the Sun, in the books it is written that the Jupiter orbits the Sun. But, actually, Physics says that both the Jupiter and Sun orbit each other at the point where their gravitational force is same. This is one of the perfect examples of a twin body system.

Understood, sir?
 
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Feb 7, 2020
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right, this is a bit closer to what i was saying ...

if you take earth - moon system, or sun - planet x systems where x = mercury to pluto, in each of those cases the twin body systems have been revolving around a common centre of gravity for each individual pair ...

we similarly have stars which exist in 2 each pairs in the universe which revolve around common centres of gravity

when the mass of one of the twin body system participants is higher than the other then the common centre of gravity goes closer to it; when it is too huge or much higher than that of the other sometimes, the common c o g lay inside that single body, which then makes appear as if one member of the twin body system is revolving around the other :) earth - moon system c o g is inside the earth's crust; for the sun - planet x systems the c o g's are all inside the sun, since sun is many many times larger than each of the planets x

read in some popular science books in childhood, just remembered here :)
 

Catastrophe

The devil is in the detail
"This is one of the perfect examples of a twin body system."

This, in itself, is absolutely correct - however, there are more than two bodies in the Solar System, more than two bodies in the Universe.

If there were only Sun and Jupiter you would have two body system - but what about the rest of the Universe? These bodies, even down to particles of dust, are pulling with force proportional to masses and inversely proportional to square of distances (if we can please stick with Newton for the moment).

You are correct about Sun and Jupiter ONLY if you have two body system - but there are more bodies in the Universe.

Cat
 
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Catastrophe

The devil is in the detail
right ... the sun - jupiter one is a very good example of the twin body system :)
Yes, but you must take notice (as Newton said) of every other particle in the Universe - some small, some negligible - but all having some effect.

There are more bodies in the Universe but two!
Just look at Jupiter and the Sun, in the books it is written that the Jupiter orbits the Sun. But, actually, Physics says that both the Jupiter and Sun orbit each other at the point where their gravitational force is same. This is one of the perfect examples of a twin body system.

Understood, sir?
Of course I understood, Sir!
But to a greater or lesser extent every other body in the Universe also must be considered in the picture.
 
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IG2007

"Don't criticize what you can't understand..."
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There are more bodies in the Universe but two!

Of course I understood, Sir!
But to a greater or lesser extent every other body in the Universe also must be considered in the picture.
Yeah, but the thing is, this forum is about twin bodies. That's why I gave an example. Nothing else. I quite know that, sir. The gravity of the sun is the most in the solar system, that's why everything orbits it. I know it quite well, sir.
 

Catastrophe

The devil is in the detail
Then the answer to your point is infinitely simple
(and you know how much I like the word infinite and its derivatives)

This thread leaves out all but two of the bodies in the Universe.
Do you not see that this is rather restrictive?
Does it not leave out just a few important things?
Or, because they are not included in this (albeit) very important locality, does that mean that they can be totally ignored as being of no consequence?

I hope there is a lesson to be learned here.

Cat :)
 

Catastrophe

The devil is in the detail
"Yeah, but the thing is, this forum is about twin bodies. That's why I gave an example. Nothing else. I quite know that, sir. The gravity of the sun is the most in the solar system, that's why everything orbits it. I know it quite well, sir."

Maybe you have heard that the Solar System is not the be all and end all of the Universe? That the Solar System is part of the Milky Way Galaxy. which itself orbits around . . . . . . . . . which itself orbits around . . . . . . . . .

Well, Sir ;) I hope you make a point of getting to know all these things quite well. I wish you every success in your learning as much as possible about this wonderful Universe of ours.

Cat :)
 
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IG2007

"Don't criticize what you can't understand..."
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"Yeah, but the thing is, this forum is about twin bodies. That's why I gave an example. Nothing else. I quite know that, sir. The gravity of the sun is the most in the solar system, that's why everything orbits it. I know it quite well, sir."

Maybe you have heard that the Solar System is not the be all and end all of the Universe? That the Solar System is part of the Milky Way Galaxy. which itself orbits around . . . . . . . . . which itself orbits around . . . . . . . . .

Well, Sir ;) I hope you make a point of getting to know all these things quite well. I wish you every success in your learning as much as possible about this wonderful Universe of ours.

Cat :)
Oh sir, don't call me "sir" please. I know it quite well that there's an infinite universe waiting out there for us to explore. Oof, Relativity becomes quite complex when you put it at an universal scale. I mean, we are on Earth which rotates around itself and orbits the Sun, the Sun orbits Sagittarius A*. Now, the Milky Way also moves, we don't yet know it orbits something or not (most probably it does).

Everything in our solar system orbits the point where the gravity of everything in the solar system except the sun and the gravity of the Sun evens out. The Sun also orbits that point, at least GR says so...
 

Catastrophe

The devil is in the detail
You have learned one lesson. That is very good. That everything orbits a centre of gravity, not an individual body, although that centre of gravity may well lie inside a body.

"Just look at Jupiter and the Sun, in the books it is written that the Jupiter orbits the Sun. But, actually, Physics says that both the Jupiter and Sun orbit each other at the point where their gravitational force is same. This is one of the perfect examples of a twin body system.

Understood, sir?"

Don't you think that I knew that about 70 years ago?
And you are asking me if I understand it?
Don't you think that that might be construed as rather impertinent? ;)
 
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IG2007

"Don't criticize what you can't understand..."
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You have learned one lesson. That is very good. That everything orbits a centre of gravity, not an individual body, although that centre of gravity may well lie inside a body.

"Just look at Jupiter and the Sun, in the books it is written that the Jupiter orbits the Sun. But, actually, Physics says that both the Jupiter and Sun orbit each other at the point where their gravitational force is same. This is one of the perfect examples of a twin body system.

Understood, sir?"

Don't you think that I knew that about 70 years ago?
And you are asking me if I understand it?
Don't you think that that might be construed as rather impertinent? ;)
Sorry, sir, if you think my statement to be impertinent. I realized the thing about two years ago, "when I was just a lad of ten, my computer said to me.
Come here and take a lesson from this lovely Einstein tree" ;) :D

PS : I just modified"The Lemon Tree" a little bit. The Lemon Tree is a song of Peter, Paul and Mary.
 
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Catastrophe

The devil is in the detail
Yes, your statement was/is impertinent;
And what the 'something' does this mean?
Come here and take a lesson from this lovely Einstein tree" ;) :D
PS : I just modified"The Lemon Tree" a little bit. The Lemon Tree is a song of Peter, Paul and Mary."

This is just a meaningless distraction from your rudeness.
 
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Catastrophe

The devil is in the detail
And what is this supposed to mean?
"Come here and take a lesson from this lovely Einstein tree" ;) :D

PS : I just modified"The Lemon Tree" a little bit. The Lemon Tree is a song of Peter, Paul and Mary."

It is just meaningless nonsense intended to distract attention from your rudeness.
 
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IG2007

"Don't criticize what you can't understand..."
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And what is this sipposed to mean?
"Come here and take a lesson from this lovely Einstein tree" ;) :D

PS : I just modified"The Lemon Tree" a little bit. The Lemon Tree is a song of Peter, Paul and Mary."

It is just meaningless nonsense intended to distract attention from your rudeness.
Now, I understand what you meant to say.


"Just look at Jupiter and the Sun, in the books it is written that the Jupiter orbits the Sun. But, actually, Physics says that both the Jupiter and Sun orbit each other at the point where their gravitational force is same. This is one of the perfect examples of a twin body system.

Understood, sir? "

This sir is not you Cat sir. This sir refers to akashrao. I know that you are an octagenarian, why would I ask you that, sir?
 
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Catastrophe

The devil is in the detail
Now, I understand what you meant to say.


"Just look at Jupiter and the Sun, in the books it is written that the Jupiter orbits the Sun. But, actually, Physics says that both the Jupiter and Sun orbit each other at the point where their gravitational force is same. This is one of the perfect examples of a twin body system.

Understood, sir? "

This sir is not you Cat sir. This sir refers to akashrao.
Then why did you reply to me:
"Yeah, but the thing is, this forum is about twin bodies. That's why I gave an example. Nothing else. I quite know that, sir. The gravity of the sun is the most in the solar system, that's why everything orbits it. I know it quite well, sir."
 
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IG2007

"Don't criticize what you can't understand..."
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Then why did you reply to me:
"Yeah, but the thing is, this forum is about twin bodies. That's why I gave an example. Nothing else. I quite know that, sir. The gravity of the sun is the most in the solar system, that's why everything orbits it. I know it quite well, sir."
I thought that you said it because it can confuse akashrao. This forum is about twin bodies, and the jupiter is the heaviest planet in the Solar System. I know that you know it. I do not underestimate you, sir.

Oh, now I understood, you used the word "sir" in a tone of sarcasm.
 
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Catastrophe

The devil is in the detail
I thought that you said it because it can confuse akashrao. This forum is about twin bodies, and the jupiter is the heaviest planet in the Solar System. I know that you know it. I do not underestimate you, sir.

Oh, now I understood, you used the word "sir" in a tone of sarcasm.
"Oh, now I understood, you used the word "sir" in a tone of sarcasm."
ABSOLUTELY no way! I believe you are incredible for your age!
 

Catastrophe

The devil is in the detail
Here is something I believe Indian Genius will enjoy. You remember that we talked about the two body system, in particular about Sun and Jupiter. Remember I said that just having a title about two bodies does not make the rest of the Universe(s) go away? Well I’m going to post about NGC5033. What, you complain, it doesn’t exist. It isn’t in the title! Well, sorry, it does exist and if you ascend to your roof you will find it at Right Ascension 13h 13m 25.5s and Declination +36o35’38 – well, I must admit that I haven’t been out to look. Anyway, for the sake of not arguing, let’s assume it is there, twinkling away at 10.8 magnitude (do galaxies twinkle, or just stars? I’ve forgotten. (If you want to check on that magnitude the reference is "NASA/IPAC Extragalactic Database" (http://nedwww.ipac.caltech.edu/). Results for NGC 5033.

Anyway, I bet you are asking, what has this to do with two bodies mutually attracting? Well, I hope we have agreed that there are more than two astronomical bodies in the Universe(s). So I want to discuss NGC5033.

NGC 5033 and the nearby spiral galaxy NGC 5005 comprise a physical galaxy pair. The two galaxies weakly influence each other gravitationally, but they are not yet close enough to each other to be distorted by the tidal forces of the gravitational interaction. The fainter irregular galaxy IC 4182 is also a member of this group. Obviously this group of galaxies will adjust to their own cog (centre of gravity) and our Sun and planet Jupiter are so far away that they can be counted as negligible. Actually, they are around 40 million light years away, so I am sure you will agree that the contributions gravity wise are pretty much zero.

BTW I should have mentioned that NGC5033 is a Seyfert Galaxy which, as you know, means that it is one of the two largest groups of active galaxies, along with quasars..

Now integral field spectroscopic observations of the centre of NGC 5033 indicate that the Seyfert nucleus is not located at the kinematic centre of the galaxy (the point around which the stars in the galaxies rotate). This suggests that this galaxy has undergone a merger.

The galaxy appears to have two different centres due to the conflict between the former centre and the centre after the merger. It also suggests that they have not yet (as of 40 million years ago ;) ) sorted out where their cog is!

I think you might enjoy this because it shows the complete contrast between the two body scenario and the idea of two galaxies colliding and working out where the cog will be.

Seriously, I promised you something to stretch your brilliant brain. I hope this does.

Cat :)
 
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