ISF Logo   IS Forum
Forum Index Register Members List Events Mark Forums Read Help

Go Back   International Skeptics Forum » General Topics » Science, Mathematics, Medicine, and Technology
 


Welcome to the International Skeptics Forum, where we discuss skepticism, critical thinking, the paranormal and science in a friendly but lively way. You are currently viewing the forum as a guest, which means you are missing out on discussing matters that are of interest to you. Please consider registering so you can gain full use of the forum features and interact with other Members. Registration is simple, fast and free! Click here to register today.
Reply
Old 18th November 2016, 06:22 AM   #1
wogoga
Critical Thinker
 
Join Date: Apr 2007
Posts: 334
Age and Origin of our Planetary System as a Supernova-Remnant

The age of our planetary system is assumed be around 4.6 x 109 = 9p46 = nine.po four six years. This value can be derived under the reasonable premises that half-lives of radioactive decay have not relevantly changed and that the oldest inclusions found in meteorites are indicative of the age of our planetary system.

The currently prevailing theory of the origin of our planetary system seems to me almost as implausible as the the giant-impact hypothesis concerning the origin of our moon. So I present here an alternative based on the distinction of first- and next-generation stars.

A first-generation star emerges by gravitational attraction from normal galactic matter (primarily hydrogen). First-generation stars can emerge alone or in groups. They grow from randomly generated small seed objects by absorbing further mass and by fusing together with other objects having evolved in the same way. Thus, even the most giant first-generation star has passed through all sizes (i.e. from smaller than Moon to final). A higher mass density in a region of star formation increases the probability of big stars.

In principle, there is a continuous transition from moons to planets to stars. A lonely rogue planet with a moon can be considered a binary star system where one star is small and the other very small.

First-generation stars cannot lead to planetary systems similar to ours. In a multiple object system, where one object has grown to a real sun with thermonuclear fusion whereas the smaller objects remain at the size of planets, all is possible: from completely arbitrary rotation planes of the "planets" to even retrograde orbits. Yet it is highly unlikely that all "planets" lie by chance in more or less the same plane.

The chaotic movements of lots of different masses forming one star ultimately lead to one rotation axis. The corresponding angular momentum can range from close to zero to high. In order to get something similar to our planetary system, a supernova-like explosion of a previous-generation star with substantial angular momentum (rotation speed) is needed.

During gravitational collapse preceding a supernova explosion, the previous-generation star (or at least the star's massive core) becomes a more and more oblate spheroid (due to conservation of angular momentum). The highest pressure and temperature obviously reigns in the center of the star, where a new kind of nuclear chain reaction is eventually triggered.



The pressure (resp. weight) at the center is the same in direction of the vertical rotation axis as in directions on the horizontal equatorial plane. Yet there is more mass between the center and a point on the equatorial plane than between the center and the poles. On the equator, strong centrifugal forces compensate gravitational attraction so that compressing forces (weight, pressure) at the center are the same from all directions.

The supernova chain reaction spreads from the center, and resulting heat and pressure try to accelerate outwards the matter outside this explosion region. The more oblate (flat) the spheroid, the more difficult to accelerate masses outwards in the equatorial plane and the easier are outbursts on the poles.

Depending on chain-reaction type, oblateness and other parameters, this may lead to rather spherical explosions, to bipolar outflows or astrophysical jets through the rotation poles.

In case of favorable conditions, such an explosion can lead to a proto-planetary disk in the equatorial plane of the previous-generation star. During the explosion, much or most of the stellar material is definitively lost into space, since it is expelled at velocities higher than escape velocity. In the equatorial plane, stellar material is expelled at the lowest velocities, because momentum and energy in these directions are distributed among more mass, and explosive power dissipates more easily in polar directions.

A central part of the core of the previous-generation star will probably remain where it is, as explosive forces outwards can lead by actio-reactio (i.e. momentum conservation) to inward forces. Also not all of hydrogen and other elements from outer star layers is accelerated enough to leave the newly created next-generation solar system. A next-generation star can at least in principle also grow further by absorbing matter during its journey through the galaxy.

If this hypothesis presented here is true then our sun is a next-generation star. Its previous incarnation, a substantially bigger star, exploded around 4.6 billion = 9p46 years ago as a supernova and ejected (among lots of material having disappeared in space) more or less homogeneously around its equatorial plane the material which is still gravitationally bound to our sun. This material cooling down and giving rise to meteoroids, asteroids and so on coincides with the start of ticking of what we use as radioactive clocks.

Cheers, Wolfgang
www.pandualism.com/d/origin-planetary-system.html
The main objective of the war on terror is fostering new terrorism in order to justify police-state and surveillance policies

Last edited by wogoga; 18th November 2016 at 06:36 AM.
wogoga is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 18th November 2016, 07:17 AM   #2
catsmate
No longer the 1
 
catsmate's Avatar
 
Join Date: Apr 2007
Posts: 19,886
Originally Posted by wogoga View Post
The age of our planetary system is assumed be around 4.6 x 109
You're actually correct about something.

Originally Posted by wogoga View Post
The currently prevailing theory of the origin of our planetary system seems to me almost as implausible as the the giant-impact hypothesis concerning the origin of our moon.
And now you're back to gibbering nonsense.
__________________
As human right is always something given, it always in reality reduces to the right which men give, "concede," to each other. If the right to existence is conceded to new-born children, then they have the right; if it is not conceded to them, as was the case among the Spartans and ancient Romans, then they do not have it. For only society can give or concede it to them; they themselves cannot take it, or give it to themselves.
catsmate is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 18th November 2016, 07:53 AM   #3
Belz...
Fiend God
 
Belz...'s Avatar
 
Join Date: Oct 2005
Location: In the details
Posts: 78,650
If there was a "predecessor" star at all, where's the resulting black hole or neutron star?

More likely, the sun and solar system compressed from a mass of gass that may have accumulated from several supernovae over time and moved far from the remains of their progenitors.
__________________
Master of the Shining Darkness

"My views are nonsense. So what?" - BobTheCoward


Belz... is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 18th November 2016, 08:19 AM   #4
Crawtator
Critical Thinker
 
Join Date: Apr 2016
Posts: 312
Originally Posted by Argumemnon View Post
If there was a "predecessor" star at all, where's the resulting black hole or neutron star?

More likely, the sun and solar system compressed from a mass of gass that may have accumulated from several supernovae over time and moved far from the remains of their progenitors.
My understanding, although rather limited, is that this is correct. However, looking for a "progenitor remnant" in the form of a black hole or neutron star would be rather ridiculous considering the timescales involved and the movement of our system through the galaxy, not to mention the evolution of the galaxy itself.

I normally lurk on these forums. Rarely post, but I must say: this is the closest to correct that the o.p. has ever been that I can see and it still ends up screwy.
Crawtator is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 18th November 2016, 08:22 AM   #5
Belz...
Fiend God
 
Belz...'s Avatar
 
Join Date: Oct 2005
Location: In the details
Posts: 78,650
Originally Posted by Crawtator View Post
My understanding, although rather limited, is that this is correct. However, looking for a "progenitor remnant" in the form of a black hole or neutron star would be rather ridiculous considering the timescales involved and the movement of our system through the galaxy, not to mention the evolution of the galaxy itself.
Yeah but then there's no way to talk about a "predecessor" star anyway.
__________________
Master of the Shining Darkness

"My views are nonsense. So what?" - BobTheCoward


Belz... is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 18th November 2016, 08:58 AM   #6
Crawtator
Critical Thinker
 
Join Date: Apr 2016
Posts: 312
For the most part, agreed, Argumemnon. In the context of the op, it seems nonsensical. Although there were gen 1 stars (mainstream), the op takes this to an absurdity when the timescales involved for the collapse of material from a gen 1 star to a gen 2 and the solar system is ludicrous. The sun would have left the area where the first star exploded, due to momentum through the MW. The result of all this is that it is much more probable that our star is the child of many separate supernovae materials, collapsed over time.
Crawtator is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 18th November 2016, 09:03 AM   #7
Jrrarglblarg
Guest
 
Join Date: Nov 2010
Posts: 12,673
Welcome to the forum, crawtater.
Jrrarglblarg is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 18th November 2016, 09:53 AM   #8
Dancing David
Penultimate Amazing
 
Dancing David's Avatar
 
Join Date: Mar 2003
Location: central Illinois
Posts: 39,395
Originally Posted by Crawtator View Post
My understanding, although rather limited, is that this is correct. However, looking for a "progenitor remnant" in the form of a black hole or neutron star would be rather ridiculous considering the timescales involved and the movement of our system through the galaxy, not to mention the evolution of the galaxy itself.

I normally lurk on these forums. Rarely post, but I must say: this is the closest to correct that the o.p. has ever been that I can see and it still ends up screwy.
Excellent post!
__________________
I suspect you are a sandwich, metaphorically speaking. -Donn
And a shot rang out. Now Space is doing time... -Ben Burch
You built the toilet - don't complain when people crap in it. _Kid Eager
Never underestimate the power of the Random Number God. More of evolutionary history is His doing than people think. - Dinwar
Dancing David is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 18th November 2016, 09:55 AM   #9
Belz...
Fiend God
 
Belz...'s Avatar
 
Join Date: Oct 2005
Location: In the details
Posts: 78,650
Originally Posted by Crawtator View Post
The result of all this is that it is much more probable that our star is the child of many separate supernovae materials, collapsed over time.
Making us, literally, the best of both worlds.
__________________
Master of the Shining Darkness

"My views are nonsense. So what?" - BobTheCoward


Belz... is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 18th November 2016, 10:13 AM   #10
fuelair
Cythraul Enfys
 
fuelair's Avatar
 
Join Date: May 2006
Posts: 57,992
This is fun!!! You might want to examine some others in Science for ***** and giggles - if you haven't already!!! And welcome in Crawtator!!!!!!!!!


And, don't worry that I am wasting exclamation points - I buy them by the case - saves money!!!!
__________________
There is no problem so great that it cannot be fixed by small explosives carefully placed.

Wash this space!

We fight for the Lady Babylon!!!
fuelair is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 18th November 2016, 01:09 PM   #11
smartcooky
Penultimate Amazing
 
smartcooky's Avatar
 
Join Date: Oct 2012
Location: Nelson, New Zealand
Posts: 10,399
Originally Posted by Crawtator View Post
My understanding, although rather limited, is that this is correct. However, looking for a "progenitor remnant" in the form of a black hole or neutron star would be rather ridiculous considering the timescales involved and the movement of our system through the galaxy, not to mention the evolution of the galaxy itself.

I normally lurk on these forums. Rarely post, but I must say: this is the closest to correct that the o.p. has ever been that I can see and it still ends up screwy.
Even if the OP's predecessor star theory is correct (and I don't think it is) there would be no way to prove or disprove it.

Our planetary system is about 4.6 billion years old, but it it orbits the galaxy roughly every 225 million years. This means we have orbited the galaxy about 20 times since our formation. The likelihood of anything that was near us at our formation (such as a black hole from a SN remnant) still being nearby after just a couple of orbits is remote, let alone after 20 orbits.
__________________
As democracy is perfected, the office represents, more and more closely, the inner soul of the people. We move toward a lofty ideal. On some great and glorious day the plain folks of the land will reach their heart's desire at last, and the White House will be adorned by a downright moron.
- Henry Louis Mencken - Baltimore Evening Sun, July 26, 1920
smartcooky is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 20th November 2016, 08:31 PM   #12
Reality Check
Penultimate Amazing
 
Join Date: Mar 2008
Location: New Zealand
Posts: 23,681
Originally Posted by wogoga View Post
The age of our planetary system is assumed be around 4.6 x 109...
That is wrong - it is measured to be around that value because that is the oldest things we can find in the Solar System.

A fantasy about a "distinction of first- and next-generation stars" does not address the real world where we observe the stages of stellar systems forming from gas clouds. The physics that created the first stars abort 13 billion years ago still exists today and creates new stars today. Simply put gas clouds + gravity = new stars at anything during the lifetime of the universe.

What else do we have?
  • A fantasy about "first -generation" stars smaller than the Moon.
    The first generation of stars were 100s of solar masses.
  • There is no "continuous transition from moons to planets to stars" - moons and planets are not powered by fusion.
    There is a little blurring of lines between brown dwarfs and the lightest stars.
  • The first generation stars cannot lead to planetary systems similar to ours because there was only light elements in the early universe!
  • The statement "Yet it is highly unlikely that all "planets" lie by chance in more or less the same plane" is ignorant - it is physics, not chance, that forms stellar systems as discs.
  • A fantasy of "The chaotic movements of lots of different masses forming one star ultimately lead to one rotation axis".
  • The angular momentum of stellar systems is high because stars rotate and planets orbit! - not "can range from close to zero to high"
    Angular Momentum in the Solar System
  • After an supernova, the "the previous-generation star" is usually a neutron stars and sometimes a black hole.
    Stars that contain a neutron star explode and form a fatter neutron star.
    Stars that contain a black hole explode and form a fatter black hole.
  • A fantasy of a "a new kind of nuclear chain reaction".

Last edited by Reality Check; 20th November 2016 at 08:50 PM.
Reality Check is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 20th November 2016, 09:45 PM   #13
smartcooky
Penultimate Amazing
 
smartcooky's Avatar
 
Join Date: Oct 2012
Location: Nelson, New Zealand
Posts: 10,399
Originally Posted by Reality Check View Post
What else do we have?

► A fantasy about "first -generation" stars smaller than the Moon.
The first generation of stars were 100s of solar masses.
Yes

Originally Posted by Reality Check View Post
► There is no "continuous transition from moons to planets to stars" - moons and planets are not powered by fusion. There is a little blurring of lines between brown dwarfs and the lightest stars.
Yes, but I know what he means (even though he is wrong). It is thought by some that Jupiter is a failed star, and if it had been about 60 times more massive, its core might have fused and it might have become a star. So if there had been sufficient material in our Solar System's primordial disc, its just possible that Jupiter might have become a star. That would make us a binary system, and with the star Jupiter 60 times more massive than it is now, I doubt that life would have arisen, since the orbits of the inner planets would have been vastly different.

Originally Posted by Reality Check View Post
The first generation stars cannot lead to planetary systems similar to ours because there was only light elements in the early universe!
Yes. Solar System's like ours require supernova remnant material to make the heavy elements that lead to rocky planets. I speculate (and I'm happy be be corrected) that solar systems formed by first generation stars could only even have contained gas giant-like planets.

Originally Posted by Reality Check View Post
The statement "Yet it is highly unlikely that all "planets" lie by chance in more or less the same plane" is ignorant - it is physics, not chance, that forms stellar systems as discs.
Yes.
__________________
As democracy is perfected, the office represents, more and more closely, the inner soul of the people. We move toward a lofty ideal. On some great and glorious day the plain folks of the land will reach their heart's desire at last, and the White House will be adorned by a downright moron.
- Henry Louis Mencken - Baltimore Evening Sun, July 26, 1920
smartcooky is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 21st November 2016, 01:50 AM   #14
Jim_MDP
Philosopher
 
Jim_MDP's Avatar
 
Join Date: Sep 2002
Location: N.Cal/S.Or
Posts: 6,810
Originally Posted by smartcooky View Post
...
Yes, but I know what he means (even though he is wrong). It is thought by some that Jupiter is a failed star, and if it had been about 60 times more massive, its core might have fused and it might have become a star. So if there had been sufficient material in our Solar System's primordial disc, its just possible that Jupiter might have become a star. That would make us a binary system, and with the star Jupiter 60 times more massive than it is now, I doubt that life would have arisen, since the orbits of the inner planets would have been vastly different.
...

I take it we can blame that on Clarke.

While his smaller new sun presents a beautiful scenario, and I do love the story, I take it the reality would be rather... terrifying.

__________________
----------------------
Anything goes in the Goblin hut... anything.

"Suggesting spurious explanations isn't relevant to my work." -- WTC Dust.
"Both cannot be simultaneously true, and so one may conclude neither is true, and if neither is true, then Apollo is fraudulent." -- Patrick1000.

Last edited by Jim_MDP; 21st November 2016 at 01:51 AM.
Jim_MDP is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 21st November 2016, 03:00 AM   #15
smartcooky
Penultimate Amazing
 
smartcooky's Avatar
 
Join Date: Oct 2012
Location: Nelson, New Zealand
Posts: 10,399
Originally Posted by Jim_MDP View Post
I take it we can blame that on Clarke.

While his smaller new sun presents a beautiful scenario, and I do love the story, I take it the reality would be rather... terrifying.

Well, yes and no

I first read about the idea that Jupiter was a failed star way back in the mid-1970's; at least seven years before Clarke wrote "2010" Clarke certainly increased the awareness of the theory, and popularized it.
__________________
As democracy is perfected, the office represents, more and more closely, the inner soul of the people. We move toward a lofty ideal. On some great and glorious day the plain folks of the land will reach their heart's desire at last, and the White House will be adorned by a downright moron.
- Henry Louis Mencken - Baltimore Evening Sun, July 26, 1920
smartcooky is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 21st November 2016, 11:04 AM   #16
BazBear
Possible Suspect
 
BazBear's Avatar
 
Join Date: Sep 2008
Location: Slightly Over The Hill, Not Too Far Around The Bend
Posts: 2,569
Originally Posted by smartcooky View Post
Well, yes and no

I first read about the idea that Jupiter was a failed star way back in the mid-1970's; at least seven years before Clarke wrote "2010" Clarke certainly increased the awareness of the theory, and popularized it.
Well, I think that characterizing Jupiter as a failed star is a little silly; IMO it should be considered a pretty successful planet.
__________________
I don't see how an article of clothing can be indecent. A person, yes. - Robert A. Heinlein
If Christ died for our sins, dare we make his martyrdom meaningless by not committing them? - Jules Feiffer
If you are going through hell, keep going - Winston Churchill
BazBear is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 21st November 2016, 12:50 PM   #17
Reality Check
Penultimate Amazing
 
Join Date: Mar 2008
Location: New Zealand
Posts: 23,681
A timely blog article: The Science Of How Solar Systems Begin
Reality Check is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 21st November 2016, 08:28 PM   #18
smartcooky
Penultimate Amazing
 
smartcooky's Avatar
 
Join Date: Oct 2012
Location: Nelson, New Zealand
Posts: 10,399
Originally Posted by BazBear View Post
Well, I think that characterizing Jupiter as a failed star is a little silly; IMO it should be considered a pretty successful planet.
Is this one of those "glass half full v glass half empty" things?
__________________
As democracy is perfected, the office represents, more and more closely, the inner soul of the people. We move toward a lofty ideal. On some great and glorious day the plain folks of the land will reach their heart's desire at last, and the White House will be adorned by a downright moron.
- Henry Louis Mencken - Baltimore Evening Sun, July 26, 1920
smartcooky is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 22nd November 2016, 08:53 AM   #19
Dancing David
Penultimate Amazing
 
Dancing David's Avatar
 
Join Date: Mar 2003
Location: central Illinois
Posts: 39,395
Originally Posted by BazBear View Post
Well, I think that characterizing Jupiter as a failed star is a little silly; IMO it should be considered a pretty successful planet.
Or a tiny brown dwarf
__________________
I suspect you are a sandwich, metaphorically speaking. -Donn
And a shot rang out. Now Space is doing time... -Ben Burch
You built the toilet - don't complain when people crap in it. _Kid Eager
Never underestimate the power of the Random Number God. More of evolutionary history is His doing than people think. - Dinwar
Dancing David is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 7th January 2017, 11:54 AM   #20
wogoga
Critical Thinker
 
Join Date: Apr 2007
Posts: 334
Originally Posted by wogoga in #1 View Post
The currently prevailing theory of the origin of our planetary system seems to me almost as implausible as the the giant-impact hypothesis concerning the origin of our moon. So I present here an alternative based on the distinction of first- and next-generation stars. ...

If this hypothesis presented here is true then our sun is a next-generation star. Its previous incarnation, a substantially bigger star, exploded around 4.6 billion = 9p46 years ago as a supernova and ejected (among lots of material having disappeared in space) more or less homogeneously around its equatorial plane the material which is still gravitationally bound to our sun. This material cooling down and giving rise to meteoroids, asteroids and so on coincides with the start of ticking of what we use as radioactive clocks.

Originally Posted by Argumemnon in #3 View Post
If there was a "predecessor" star at all, where's the resulting black hole or neutron star?

The remnant of the previous-generation star is our Sun. There is no reason to assume that every exploding star must turn into a neutron star (let alone into a logically impossible black hole). A lot of pressure is needed in order to compress atomic nuclei and electrons into neutrons. The more mass a star loses during an explosion, the less likely is the outcome of a neutron star.

Are there arguments suggesting that normal stars (such as our sun) cannot have at its center a pure neutron-core?

According to common sense, every neutron star must have outer layers consisting of conventional stellar matter. Surface neutrons of neutron stars would simply decay into atomic nuclei and electrons because of lacking pressure from outside. Own weight cannot be enough, even in case of extremely high gravity.


Originally Posted by smartcooky in #13 View Post
Solar systems like ours require supernova remnant material to make the heavy elements that lead to rocky planets. I speculate (and I'm happy be corrected) that solar systems formed by first generation stars could only have contained gas giant-like planets.

My use of first-generation star and next-generation star does not depend on whether stars are formed from "fresh" or from "remnant" material. Every star having (more or less continuously) grown from galactic matter is considered a first-generation star. Next-generation stars can only emerge by explosions of previous-generation stars.


Cheers, Wolfgang
pandualism.com/d/origin-planetary-system.html

Last edited by wogoga; 7th January 2017 at 12:12 PM.
wogoga is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 7th January 2017, 01:38 PM   #21
Captain_Swoop
Penultimate Amazing
 
Captain_Swoop's Avatar
 
Join Date: Jun 2010
Posts: 19,054
Originally Posted by wogoga View Post

Are there arguments suggesting that normal stars (such as our sun) cannot have at its center a pure neutron-core?

According to common sense, every neutron star must have outer layers consisting of conventional stellar matter. Surface neutrons of neutron stars would simply decay into atomic nuclei and electrons because of lacking pressure from outside. Own weight cannot be enough, even in case of extremely high gravity.


Cheers, Wolfgang
Common sense?

What about the lack of magnetism, xrays and gravity associated with neutron stars.
Captain_Swoop is online now   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 7th January 2017, 02:37 PM   #22
Lukraak_Sisser
Illuminator
 
Join Date: Aug 2009
Posts: 3,274
By that same common sense the core of Jupiter should have nuclear fusion, or be as dense as interstellar hydrogen.

we know the types of forces needed to create a neutron star, we know the mass of the sun and we therefore can caluculate the fact that no, the sun does not have a pure neutron core.

I do always wonder at the hubris we humans can display be assuming our 'common sense' can be applied on (inter)stellar or (sub)nuclear scales. Nature does not care whether you find something logical.
For instance, I cannot really wrap my head around a bose-einstein condensate, but that does not mean I assume that they do not exist because I do not fully understand how they work.
Your relying on logic is the same as the old logical puzzle that says an arrow can never hit a moving target because the target is always slightly further away. It may *sound* logical to your mind, but you'd still get skewered.
Lukraak_Sisser is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 7th January 2017, 04:21 PM   #23
fuelair
Cythraul Enfys
 
fuelair's Avatar
 
Join Date: May 2006
Posts: 57,992
Who is Wolfgang Gasser? One listed is an actor and the other is vaguely related to motorcycles. None is astrophysics/related.
__________________
There is no problem so great that it cannot be fixed by small explosives carefully placed.

Wash this space!

We fight for the Lady Babylon!!!
fuelair is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 7th January 2017, 05:07 PM   #24
JayUtah
Penultimate Amazing
 
JayUtah's Avatar
 
Join Date: Sep 2011
Posts: 16,465
Originally Posted by fuelair View Post
Who is Wolfgang Gasser?
Wogoga's real name, I suppose.
JayUtah is online now   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 7th January 2017, 06:15 PM   #25
fuelair
Cythraul Enfys
 
fuelair's Avatar
 
Join Date: May 2006
Posts: 57,992
I asked purely because the name was in one of his sites listed but there is no scientist of that name popping up on a search, and the only person listed is a German actor (IMDB) and the US motorcycle guy....

It is in the first line of the new parts of post 20, not the quoted parts.
__________________
There is no problem so great that it cannot be fixed by small explosives carefully placed.

Wash this space!

We fight for the Lady Babylon!!!
fuelair is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 8th January 2017, 03:45 PM   #26
Jim_MDP
Philosopher
 
Jim_MDP's Avatar
 
Join Date: Sep 2002
Location: N.Cal/S.Or
Posts: 6,810
Originally Posted by fuelair View Post
I asked purely because the name was in one of his sites listed but there is no scientist of that name popping up on a search, and the only person listed is a German actor (IMDB) and the US motorcycle guy....

It is in the first line of the new parts of post 20, not the quoted parts.

It's Wogoga.
Check out his Pandualism site. You may find yourself quoted there... along with virtually everyone here (and on other fora) who has ever disagreed with him.

I've tried to read some of the lengthy page layouts, but I find the labeling extraordinarily lazy and chaotic. Perhaps that's an attempt at following an academic format... but it doesn't work for me.
__________________
----------------------
Anything goes in the Goblin hut... anything.

"Suggesting spurious explanations isn't relevant to my work." -- WTC Dust.
"Both cannot be simultaneously true, and so one may conclude neither is true, and if neither is true, then Apollo is fraudulent." -- Patrick1000.
Jim_MDP is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 9th January 2017, 08:40 AM   #27
steenkh
Philosopher
 
steenkh's Avatar
 
Join Date: Aug 2002
Location: Denmark
Posts: 5,436
Originally Posted by wogoga View Post
Are there arguments suggesting that normal stars (such as our sun) cannot have at its center a pure neutron-core?
Yes, helioseismologyWP.
__________________
Steen

--
Jack of all trades - master of none!
steenkh is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 9th January 2017, 08:43 AM   #28
wogoga
Critical Thinker
 
Join Date: Apr 2007
Posts: 334
Originally Posted by wogoga in #20 View Post
According to common sense, every neutron star must have outer layers consisting of conventional stellar matter. Surface neutrons of neutron stars would simply decay into atomic nuclei and electrons because of lacking pressure from outside. Own weight cannot be enough, even in case of extremely high gravity.
Originally Posted by Lukraak_Sisser in #22 View Post
By that same common sense the core of Jupiter should have nuclear fusion, or be as dense as interstellar hydrogen.

By 'common sense' I mean 'simple, transparent, logically consistent reasoning'. It should not be confused with 'superficial reasoning' or 'prejudiced reasoning'.

High pressure resp. temperature is obviously a prerequisite for nuclear fusion. So, it is a very simple common sense conclusion that Jupiter's core cannot have nuclear fusion, if pressure and temperature are not high enough.

According to common sense, neutrons consist of protons and electrons plus mass-equivalent of compression energy. Neutrons are not stable outside atomic nuclei, and they decay into protons and electrons. Neutrons do not decay into quarks, and the involvement of neutrinos is only inferred from dogmatic premises.)


Originally Posted by wogoga in #1 View Post
During gravitational collapse preceding a supernova explosion, the previous-generation star (or at least the star's massive core) becomes a more and more oblate spheroid (due to conservation of angular momentum).

For a time I have become suspicious of whether this is actually true.

Three principles are relevant for contraction of rotating stars under conservation of angular momentum.
  • Since angular momentum is proportional to r ∙ v, our rotation speed v becomes inversely proportional to r (radius, distance from rotation axis). During contraction, gravity-potential energy is converted into kinetic energy of rotation.
  • Since concerning centrifugal forces F = m ∙ v2 / r, these forces turn out to be inversely proportional to the third power of r.
  • Gravitational forces are inversely proportional to the second power of radius.
If this is correct, then contraction of a star increases centrifugal forces more than gravity, entailing star oblateness.

There are even "normal" stars with substantial equatorial bulges:
Achernar is a bright, blue star about 3,150 times more luminous than the Sun. As of 2003, Achernar is the least spherical star in the Milky Way studied to date. It spins so rapidly that it has assumed the shape of an oblate spheroid with an equatorial diameter 56% greater than its polar diameter. Since it is actually a binary star, its highly distorted shape may cause non-negligible departures of the companion's orbital trajectory with respect to a Keplerian ellipse. (Wikipedia)
Some neutron stars may even resemble more discs than spheres.

By the way, spin up (rotation speed increase) of a neutron star could simply be the result of further contraction (not yet fully accomplished).

Cheers, Wolfgang
www.pandualism.com
wogoga is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 9th January 2017, 10:02 AM   #29
JayUtah
Penultimate Amazing
 
JayUtah's Avatar
 
Join Date: Sep 2011
Posts: 16,465
Originally Posted by wogoga View Post
By 'common sense' I mean 'simple, transparent, logically consistent reasoning'. It should not be confused with 'superficial reasoning' or 'prejudiced reasoning'.
Nor should it be confused with scientific reasoning. Just because something can be said to be simple, transparent, and logically consistent doesn't mean it's the right answer. The scientific method was set up precisely to alleviate the limitations of common sense in discovering the laws of nature.
JayUtah is online now   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 10th January 2017, 02:23 PM   #30
Reality Check
Penultimate Amazing
 
Join Date: Mar 2008
Location: New Zealand
Posts: 23,681
Originally Posted by wogoga View Post
The remnant of the previous-generation star is our Sun. ...
A lot of ignorance: This is a neutron star.
  1. The Sun is a "remnant" of many former stars which underwent nova and supernova to form the gas cloud that collapsed to make the Sun.
  2. There is no assumption that every exploding star forms a neutron star.
  3. Black holes are physically possible - in fact the laws of physics demand that black holes form in appropriate situations , e.g. massive starts that supernova !
  4. Gravity provides the pressure to create neutron stars.
  5. The surface gravity of neutron stars is millions of g. This compresses any material that surrounds the neutron star until it fuses. Thus any normal star (such as our sun) cannot contain a "pure neutron-core" because it results in a supernova and a fatter neutron star!
  6. According to science a neutron star cannot have an outer surface of "conventional stellar matter".
    They may have a layer of ordinary matter.
  7. Neutrons do not "simply decay into atomic nuclei".
Reality Check is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 10th January 2017, 02:57 PM   #31
Reality Check
Penultimate Amazing
 
Join Date: Mar 2008
Location: New Zealand
Posts: 23,681
Originally Posted by wogoga View Post
According to common sense, neutrons consist of protons and electrons plus mass-equivalent of compression energy. Neutrons are not stable outside atomic nuclei, and they decay into protons and electrons.
Common sense tells us that neutrons do not exist because we have never seen a neutron ! It is scientific evidence that tells us about neutrons.
It is abysmally ignorant to assert that neutrons consist of protons and electrons because protons have a spin 1/2, electrons have a spin of 1/2. Thus a composite particle can only have a spin of 0 or 1. Neutrons have a spin of 1/2.
"compression energy" is a delusion. Free neutrons decaying into protons and electrons only is a lie.

Free neutrons decaying into quarks is your fantasy, not the real world where free neutrons decay into protons, electrons and neutrinos.

Neutrinos not being involved is an ignorant idea from a crank web site. You do not know about the violations of conservation of energy, momentum and spin that in beta decay that lead to the discovery of neutrinos !

It is ignorant to ignore books on modern particle physics and quote a few sentences from the 1984 "A Sociological History of Particle Physics" to create a lie about neutrinos being questioned. That has not been the case sie 1934.

Last edited by Reality Check; 10th January 2017 at 03:04 PM.
Reality Check is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 13th January 2017, 08:49 AM   #32
wogoga
Critical Thinker
 
Join Date: Apr 2007
Posts: 334
Binary Pulsars as Remnants of Fast Rotating Single Stars

Originally Posted by wogoga in #28 View Post
If this is correct, then contraction of a star increases centrifugal forces more than gravity, entailing star oblateness.

There are even "normal" stars with substantial equatorial bulges:
Achernar is a bright, blue star about 3,150 times more luminous than the Sun. As of 2003, Achernar is the least spherical star in the Milky Way studied to date. It spins so rapidly that it has assumed the shape of an oblate spheroid with an equatorial diameter 56% greater than its polar diameter. Since it is actually a binary star, its highly distorted shape may cause non-negligible departures of the companion's orbital trajectory with respect to a Keplerian ellipse. (Wikipedia)
Some neutron stars may even resemble more discs than spheres.

What will happen to Achernar after definitively having burned out? Independently from intermediate states (such as red-giant phase or star explosion), transformation into a neutron star is a reasonable hypothesis. Neutron stars have densities in the order of atomic nuclei (~ 1017 x 3 kg/m3 = 17p3 kg/m3) and have typical radii in the order of 10 km = 4p1 meter. Equatorial radius of Achernar is ~ 10 solar radii ≈ 8 million km = 9p8 m ≈ 10p1 m.

Since centrifugal forces increase proportionally with decreasing radius (#28), a reduction in radius by 6 decimal powers (i.e. from 10p1 m by factor 6p1 to 4p1 meter) would lead to an increase in rotation speed by the same factor 6p1. In case of Achernar, equatorial rotation speed is already ~ 0.1% of light-speed = 7n1 c ≈ 5p3 m/s = 300 km/s. An increase by 106 = 6p1 would therefore lead to a rotation speed in the order of 1000 c = 3p1 c (i.e. thousand times faster than the speed of light).

It is obviously that one neutron star alone cannot take over all the angular momentum. What can happen is the following: During the process of shrinkage, the original star decays into a central part and an orbiting ring. The ring condenses more and more into discontinuous fragments until in the end only one such fragment remains. Thus we get a binary pulsar, with both components within the surface of the original star.

Even if the new companion originating from the ring has enough mass to turn into a neutron star, its axial rotation speed should be substantially lower than the one of the central remnant. This star consists of the central and polar parts of the original star. Most of the angular momentum of the ring remains orbital momentum (as opposed to axial), also when condensing to one single companion.

Maybe binary pulsar PSR J0737-3039 with orbital period of only 2.4 hours could be the remnant of one single fast-rotating star such as Achernar.


Cheers, Wolfgang
pandualism.com/d/origin-planetary-system.html
wogoga is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 13th January 2017, 08:52 AM   #33
MikeG
Now. Do it now.
 
MikeG's Avatar
 
Join Date: Sep 2012
Location: UK
Posts: 24,804
Originally Posted by Jim_MDP View Post
I take it we can blame that on Clarke.
Immanuel Velikovsky, perhaps?
__________________
"The Conservatives want to keep wogs out and march boldly back to the 1950s when Britain still had an Empire and blacks, women, poofs and Irish knew their place." The Don That's what we've sunk to here.
MikeG is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 15th January 2017, 12:46 PM   #34
Reality Check
Penultimate Amazing
 
Join Date: Mar 2008
Location: New Zealand
Posts: 23,681
Originally Posted by wogoga View Post
What will happen to Achernar after definitively having burned out?
Followed by a fantasy, wogoga based on ignorance !
  • The change of the rotation speed of spinning objects with a change in radius is due to the conservation of angular momentum.
  • Special relativity also applies to stars - it is relativistic angular momentum that you have to use. In SR no massive object can reach the speed of light. So there is not a increase of speed by 6 orders of magnitude corresponding to a radius decreasing by 6 orders of magnitude.
  • It is gravity that holds a star together - ignoring that is ignorant.
  • Achernar is a main sequence star with a mass of about 7 solar masses. It will become a white dwarf not a neutron star.
    Neutron stars form from the collapse of large (10–29 solar masses) stars.
  • It is not "6 decimal powers". White dwarfs are about "typically 0.8–2 % the radius of the Sun".

Last edited by Reality Check; 15th January 2017 at 12:59 PM.
Reality Check is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 18th January 2017, 06:41 AM   #35
wogoga
Critical Thinker
 
Join Date: Apr 2007
Posts: 334
Originally Posted by wogoga in #32 View Post
Since centrifugal forces increase proportionally with decreasing radius (#28), a reduction in radius by 6 decimal powers (i.e. from 10p1 m by factor 6p1 to 4p1 meter) would lead to an increase in rotation speed by the same factor 6p1. In case of Achernar, equatorial rotation speed is already ~ 0.1% of light-speed = 7n1 c ≈ 5p3 m/s = 300 km/s. An increase by 106 = 6p1 would therefore lead to a rotation speed in the order of 1000 c = 3p1 c (i.e. thousand times faster than the speed of light).
Originally Posted by Reality Check in #34 View Post
Special relativity also applies to stars - it is relativistic angular momentum that you have to use. In SR no massive object can reach the speed of light. So there is not an increase of speed by 6 orders of magnitude corresponding to a radius decreasing by 6 orders of magnitude.

The simplest hypothesis concerning high-speed momentum is the one of Einstein: Momentum p equals relativistic mass m[v] times velocity v. This relation p = m[v] ∙ v is enough to assess angular momentum well enough for our situation.

During star contraction, gravity-potential energy is transformed into other energy forms such as heat, kinetic and compression energy. Thus, relativistic mass m[v] remains in principle unchanged, since it is proportional to total energy (see Controversy over Mass-Energy-Equivalence & Photon Mass).

Angular momentum of a given sample (particles of a small region) of a collapsing star is L = p ∙ r = m[v] ∙ v ∙ r, where velocity v is orthogonal to distance from rotation axis r. Since an increase of v cannot (relevantly) change relativistic mass of the sample m[v], a reduction of r by factor 106 = 6p1 = six.po one could only be compensated by an increase of v by the same factor. And this is obviously impossible in our situation.


Originally Posted by Reality Check in #34 View Post
It is gravity that holds a star together - ignoring that is ignorant.

Let us again assume a star rotating as fast as Achernar and with a mass high enough for a neutron star to form. My claim: Gravity cannot hold such a star together, because due to conservation of angular momentum, contraction to a neutron star would lead to rotation speeds v >> c. If you think that a neutron star can take over the whole angular momentum of such a collapsing star, please explain!


Originally Posted by Reality Check in #34 View Post
Achernar is a main sequence star with a mass of about 7 solar masses. It will become a white dwarf not a neutron star.
Neutron stars form from the collapse of large (1029 solar masses) stars.

As far as I understand, approximate size, oblate form and rotation speed of Achernar are more or less empirical facts derived from straightforward (optical) principles, whereas its mass is derived from a complex theory, i.e. from less secure premises. In any case, the difference between 7 and 10 solar masses is not really big. And I used Achernar only as an illustration.

Cheers, Wolfgang
Kinetic energy at atmospheric reentry from lunar mission
wogoga is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 18th January 2017, 09:15 AM   #36
phunk
Illuminator
 
phunk's Avatar
 
Join Date: Aug 2007
Posts: 3,884
Originally Posted by wogoga View Post
What will happen to Achernar after definitively having burned out? Independently from intermediate states (such as red-giant phase or star explosion), transformation into a neutron star is a reasonable hypothesis. Neutron stars have densities in the order of atomic nuclei (~ 1017 x 3 kg/m3 = 17p3 kg/m3) and have typical radii in the order of 10 km = 4p1 meter. Equatorial radius of Achernar is ~ 10 solar radii ≈ 8 million km = 9p8 m ≈ 10p1 m.

Since centrifugal forces increase proportionally with decreasing radius (#28), a reduction in radius by 6 decimal powers (i.e. from 10p1 m by factor 6p1 to 4p1 meter) would lead to an increase in rotation speed by the same factor 6p1. In case of Achernar, equatorial rotation speed is already ~ 0.1% of light-speed = 7n1 c ≈ 5p3 m/s = 300 km/s. An increase by 106 = 6p1 would therefore lead to a rotation speed in the order of 1000 c = 3p1 c (i.e. thousand times faster than the speed of light).

It is obviously that one neutron star alone cannot take over all the angular momentum. What can happen is the following: During the process of shrinkage, the original star decays into a central part and an orbiting ring. The ring condenses more and more into discontinuous fragments until in the end only one such fragment remains. Thus we get a binary pulsar, with both components within the surface of the original star.

Even if the new companion originating from the ring has enough mass to turn into a neutron star, its axial rotation speed should be substantially lower than the one of the central remnant. This star consists of the central and polar parts of the original star. Most of the angular momentum of the ring remains orbital momentum (as opposed to axial), also when condensing to one single companion.

Maybe binary pulsar PSR J0737-3039 with orbital period of only 2.4 hours could be the remnant of one single fast-rotating star such as Achernar.


Cheers, Wolfgang
pandualism.com/d/origin-planetary-system.html
Your basing your math on the equatorial radius and velocity, but the neutron star won't be formed by the star shrinking, it will be formed by the star exploding and blowing away all of those outer layers while compressing the core. What will become the neutron star is just the core of the current star, not the whole thing.
phunk is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 18th January 2017, 01:37 PM   #37
Reality Check
Penultimate Amazing
 
Join Date: Mar 2008
Location: New Zealand
Posts: 23,681
Originally Posted by wogoga View Post
The simplest hypothesis concerning high-speed momentum is the one of Einstein: ...
The simplest hypothesis is that you are displaying abysmally ignorance about physics, wogoga, specifically Special Relativity. When speeds get high we have to use relativistic angular momentum. If you bothered to learn what this is you would know that the tangential velocity of a rotating body is limited to c.
Quote:
For a particle moving in a curve, the cross product of its angular velocity ω (a pseudovector) and position x give its tangential velocity
u = ω x {\displaystyle \mathbf {u} ={\boldsymbol {\omega }}\times \mathbf {x} } {\displaystyle \mathbf {u} ={\boldsymbol {\omega }}\times \mathbf {x} }
which cannot exceed a magnitude of c, since in SR the translational velocity of any massive object cannot exceed the speed of light c.
...
For a rotating rigid body rotating with an angular velocity ω, the u is tangential velocity at a point x inside the object. For every point in the object, there is a maximum angular velocity.
Your crank web site does not make ignorant statements correct. The outdated and not used concept of relativistic mass depends on speed. As any body contracts, conservation of angular momentum means that the speed of its surface increases. The relativistic mass of that surface thus increases.

Repeating ignorant statements does not change the physics. Ignoring relativity means that a surface can have any speed, even >> c. Including relativity means that the surface never reaches c.

Neutron stars always "take over" the whole angular momentum of their collapsing star because of a basic law of physics - the conservation of angular momentum !

Denying the real world and your example only leaves you with
Originally Posted by Reality Check View Post
Followed by a fantasy, wogoga based on ignorance !
  • The change of the rotation speed of spinning objects with a change in radius is due to the conservation of angular momentum.
  • Special relativity also applies to stars - it is relativistic angular momentum that you have to use. In SR no massive object can reach the speed of light. So there is not a increase of speed by 6 orders of magnitude corresponding to a radius decreasing by 6 orders of magnitude.
  • It is gravity that holds a star together - ignoring that is ignorant.
  • Achernar is a main sequence star with a mass of about 7 solar masses. It will become a white dwarf not a neutron star.
    Neutron stars form from the collapse of large (10–29 solar masses) stars.
  • It is not "6 decimal powers". White dwarfs are about "typically 0.8–2 % the radius of the Sun".
.

Last edited by Reality Check; 18th January 2017 at 01:41 PM.
Reality Check is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 22nd January 2017, 05:35 AM   #38
wogoga
Critical Thinker
 
Join Date: Apr 2007
Posts: 334
Originally Posted by wogoga in #35 View Post
During star contraction, gravity-potential energy is transformed into other energy forms such as heat, kinetic and compression energy. Thus, relativistic mass m[v] remains in principle unchanged, since it is proportional to total energy (see Controversy over Mass-Energy-Equivalence & Photon Mass).
Originally Posted by Reality Check in #37 View Post
As any body contracts, conservation of angular momentum means that the speed of its surface increases. The relativistic mass of that surface thus increases.

Relativistic mass is equivalent to total energy. So your claim implies that huge amounts of energy are transferred from elsewhere to the equatorial surface particles in order to increase relativistic mass as much as needed. The slowly rotating matter near the center and the poles of the star actually can lose energy during contraction due decreasing gravity potential. Yet even if all this mass/energy were transferred to the fast rotating particles close to the equator, this could never be enough to take over all the angular momentum, even if speed v of this resulting equatorial ring would reach c. And we agree on the impossibility of v ≥ c.


Originally Posted by Reality Check in #37 View Post
Neutron stars always "take over" the whole angular momentum of their collapsing star because of a basic law of physics - the conservation of angular momentum !

What would be the minimal radius rmin to which our Sun could shrink without rotating at v ≥ c, assuming conservation of (relativistic) mass m and angular momentum L?
  • The suns mass: m = 1030 x 1.99 kg = 30p199 kg ≈ 30p2 kg = thirty.po two kilogram
  • "On average, helioseismology yields S = 1.92 10^41 kg m^2 s^-1 for the angular momentum of the Sun" (Source). Thus: L ≈ 41p2 kg ∙ m/s ∙ m.
  • Max. angular momentum at given r and m can be reached by distributing the whole mass m close to the equator, i.e. on a rotating ring resp. circle: L = m ∙ vmax ∙ r where vmax = c
  • We get: rmin = L / (m ∙ c) ≈ 41p2 kg ∙ m/s ∙ m / (30p2 kg) / (8p3 m/s) = 11p1 / 8p3 m = 3p1 / 0p3 m ≈ 2p33 m = 330 m
This means: Even by fully transforming into a rotating ring, momentum conservation alone would prevent our Sun from shrinking below a radius of ~ 330 m.

Equatorial rotation speed of the sun is ~ 2 km/s = 3p2 meter. Equatorial rotation speed of Archernar is ~ 300 km/s = 5p3 m, more than 100 times higher. Equatorial radius of Achernar is ~ 10 times the radius of our Sun. Thus (assuming differential rotation not too different from our Sun's) we get:
  • L/m = v ∙ r is at least 3p1 = 1000 times higher, and rmin for Achernar thus ~ 1000 times bigger than for the Sun
This means: Even if Achernar turned by contraction into a ring rotating at c, a minimal radius of ~ 2p33 m ∙ 3p1 = 5p33 m = 330 km would be necessary in order to take over the original angular momentum. In the case of a uniformly rotating sphere, radius must even be bigger (probably in the order of 6p1 m = 1000 km). For comparison, radius of a corresponding neutron star is only ~ 4p1 meter = 10 km)!


Originally Posted by phunk in #36 View Post
Your basing your math on the equatorial radius and velocity, but the neutron star won't be formed by the star shrinking, it will be formed by the star exploding and blowing away all of those outer layers while compressing the core. What will become the neutron star is just the core of the current star, not the whole thing.

I agree. If all the outer parts containing the highest "density" of angular momentum are blown away then the problem disappears. Yet there may be situations where all the excessive angular momentum cannot escape from such a star's gravity.

Even if we assume that only the innermost 10% = 9n1 of radius with 0.1% = 7n1 of volume of such an Achernar-like star turn into a neutron star (without transferring angular momentum to the outer layers), my rough calculation of post #32 would still result in an equatorial rotation speed of 10 c. And a rotation speed of 10 c is impossible as of 1000 c.

Cheers, Wolfgang

My commentary on the Obama-Trump transition:
internationalskeptics.com/forums/showthread.php?p=11676056#post11676056
wogoga is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 22nd January 2017, 05:48 AM   #39
MikeG
Now. Do it now.
 
MikeG's Avatar
 
Join Date: Sep 2012
Location: UK
Posts: 24,804
Originally Posted by wogoga View Post
.........What would be the minimal radius rmin to which our Sun could shrink without rotating at v ≥ c,........
If you ask stupid questions, you'll get stupid answers. There are no stars rotating faster than C. There is nothing in the universe rotating faster than C. There is no theoretical way of anything travelling faster than C. You've wasted too long with this nonsense. Turn your thoughts to something useful.
__________________
"The Conservatives want to keep wogs out and march boldly back to the 1950s when Britain still had an Empire and blacks, women, poofs and Irish knew their place." The Don That's what we've sunk to here.
MikeG is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Old 23rd January 2017, 09:43 AM   #40
phunk
Illuminator
 
phunk's Avatar
 
Join Date: Aug 2007
Posts: 3,884
Originally Posted by wogoga View Post
I agree. If all the outer parts containing the highest "density" of angular momentum are blown away then the problem disappears. Yet there may be situations where all the excessive angular momentum cannot escape from such a star's gravity.

Even if we assume that only the innermost 10% = 9n1 of radius with 0.1% = 7n1 of volume of such an Achernar-like star turn into a neutron star (without transferring angular momentum to the outer layers), my rough calculation of post #32 would still result in an equatorial rotation speed of 10 c. And a rotation speed of 10 c is impossible as of 1000 c.
No, it wouldn't result in a rotation > c. As Reality Check pointed out, you are using classical momentum in a case where you need to think relativistic. It's not a linear relationship, momentum approaches infinity as v approaches c. You can conserve any amount of momentum without v exceeding c.
phunk is offline   Quote this post in a PM   Nominate this post for this month's language award Copy a direct link to this post Reply With Quote Back to Top
Reply

International Skeptics Forum » General Topics » Science, Mathematics, Medicine, and Technology

Bookmarks

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -7. The time now is 04:24 PM.
Powered by vBulletin. Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.

This forum began as part of the James Randi Education Foundation (JREF). However, the forum now exists as
an independent entity with no affiliation with or endorsement by the JREF, including the section in reference to "JREF" topics.

Disclaimer: Messages posted in the Forum are solely the opinion of their authors.