Re: Fixed Planetary Mass and Dark Matter
« Reply #60 on: July 11, 2018, 12:43:53 AM »
Why does dark matter not forming clumps mean it would not be attracted to centers of gravity? Or, if it is attracted to centers of gravity, why does it then proceed to just shoot straight past it and ignore the fact gravity would act to curve its path or pull it back?
As has been stated before, we do not know what dark matter is yet. So any answers we give at this point are pretty speculative.

One of the top candidates now is WIMPs. Possibly it is so simple as sterile neutrinos. Neutrinos would be attracted to gravity wells, but they are so fast that they won't orbit anything unless it is supremely massive. So if the particles won't orbit, they will just keep on flying through space. "...why does it then proceed to just shoot straight past it and ignore the fact gravity would act to curve its path or pull it back?" Neutrinos are plenty fast enough to escape the gravity well of our sun let alone our planet.

Maybe we should touch on orbits just a bit. If you're moving too slow, your "orbit" is a parabola that intersects the object you are orbiting (aka you crash into the planet/star/whatever). Speed up and you'll get into a circular orbit. Speed up more and the orbit becomes an ellipse (like a comet). Speed up more, and it becomes a hyperbola which is a curve that never returns again but just speeds off into space. This depends on the speed of the orbiting body, the mass of the gravity well, and the distance from the gravity well.

Black holes have plenty of gravity to hold a neutrino at close range. If you are super curious about it, we can dig deeper and look up what the orbital mechanics of neutrinos are really like. Neutrinos move at relativistic speeds, and my orbital mechanics classes never got that advanced. But for now, the question is why don't they hang around gravity wells? As I understand it, they are attracted to gravity wells. And gravity will curve the path of the neutrinos. But the curve is typically not enough to make the neutrino turn around and come back.
« Last Edit: July 11, 2018, 12:45:37 AM by ICanScienceThat »

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Re: Fixed Planetary Mass and Dark Matter
« Reply #61 on: July 11, 2018, 12:55:00 AM »
As has been stated before, we do not know what dark matter is yet. So any answers we give at this point are pretty speculative.
As I've said, I'm happy with speculation. When it comes to arguments by contradiction you only need to establish possibility, not certainty.


Quote
One of the top candidates now is WIMPs. Possibly it is so simple as sterile neutrinos. Neutrinos would be attracted to gravity wells, but they are so fast that they won't orbit anything unless it is supremely massive. So if the particles won't orbit, they will just keep on flying through space. "...why does it then proceed to just shoot straight past it and ignore the fact gravity would act to curve its path or pull it back?" Neutrinos are plenty fast enough to escape the gravity well of our sun let alone our planet.

Maybe we should touch on orbits just a bit. If you're moving too slow, your "orbit" is a parabola that intersects the object you are orbiting (aka you crash into the planet/star/whatever). Speed up and you'll get into a circular orbit. Speed up more and the orbit becomes an ellipse (like a comet). Speed up more, and it becomes a hyperbola which is a curve that never returns again but just speeds off into space. This depends on the speed of the orbiting body, the mass of the gravity well, and the distance from the gravity well.

Black holes have plenty of gravity to hold a neutrino at close range. If you are super curious about it, we can dig deeper and look up what the orbital mechanics of neutrinos are really like. Neutrinos move at relativistic speeds, and my orbital mechanics classes never got that advanced. But for now, the question is why don't they hang around gravity wells? As I understand it, they are attracted to gravity wells. And gravity will curve the path of the neutrinos. But the curve is typically not enough to make the neutrino turn around and come back.
As I said the last time you gave that answer:
However, the problem is simple. If dark matter moves so fast that it could only be captured by the likes of a black hole, then it should not be observable full stop. It would be on the fringes of the universe at every second. It would have shot away while all stars were forming and lacked their intense gravitational pull, expanded outwards with everything and faster than 'clumping' matter. Dark matter at galactic center? Impossible, it would have moved well beyond the regular matter long before there was even a galaxy. Dark matter affecting distant stars? It should have shot past them before they even existed.
You can't have it both ways. If dark matter moves so fast it can escape the gravitational pull of planets, then it should have been able to do the same in the nebulae and such that predate it all.

I am well aware of what orbits are and how they work, you don't have to condescend and explain every little quirk to me. The fact I understand it is why I am asking these questions in the first place.
My DE model explained here.
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Re: Fixed Planetary Mass and Dark Matter
« Reply #62 on: July 11, 2018, 02:35:43 AM »
One of the top candidates now is WIMPs. Possibly it is so simple as sterile neutrinos. Neutrinos would be attracted to gravity wells, but they are so fast that they won't orbit anything unless it is supremely massive. So if the particles won't orbit, they will just keep on flying through space. "...why does it then proceed to just shoot straight past it and ignore the fact gravity would act to curve its path or pull it back?" Neutrinos are plenty fast enough to escape the gravity well of our sun let alone our planet.

Maybe we should touch on orbits just a bit. If you're moving too slow, your "orbit" is a parabola that intersects the object you are orbiting (aka you crash into the planet/star/whatever). Speed up and you'll get into a circular orbit. Speed up more and the orbit becomes an ellipse (like a comet). Speed up more, and it becomes a hyperbola which is a curve that never returns again but just speeds off into space. This depends on the speed of the orbiting body, the mass of the gravity well, and the distance from the gravity well.

Black holes have plenty of gravity to hold a neutrino at close range. If you are super curious about it, we can dig deeper and look up what the orbital mechanics of neutrinos are really like. Neutrinos move at relativistic speeds, and my orbital mechanics classes never got that advanced. But for now, the question is why don't they hang around gravity wells? As I understand it, they are attracted to gravity wells. And gravity will curve the path of the neutrinos. But the curve is typically not enough to make the neutrino turn around and come back.
As I said the last time you gave that answer:
However, the problem is simple. If dark matter moves so fast that it could only be captured by the likes of a black hole, then it should not be observable full stop. It would be on the fringes of the universe at every second. It would have shot away while all stars were forming and lacked their intense gravitational pull, expanded outwards with everything and faster than 'clumping' matter. Dark matter at galactic center? Impossible, it would have moved well beyond the regular matter long before there was even a galaxy. Dark matter affecting distant stars? It should have shot past them before they even existed.
You can't have it both ways. If dark matter moves so fast it can escape the gravitational pull of planets, then it should have been able to do the same in the nebulae and such that predate it all.

I am well aware of what orbits are and how they work, you don't have to condescend and explain every little quirk to me. The fact I understand it is why I am asking these questions in the first place.
I'm sorry I don't know you. I don't know what you know or don't know. I don't want to sound condescending. I just want to cover the basics.

I've asked you to keep to 1 question at a time, so that I could clearly answer each in turn. Let's call question #1 satisfied. This is now question #2. Let's move onto question #2:
"If dark matter moves so fast that it could only be captured by the likes of a black hole, then it should not be observable full stop. It would be on the fringes of the universe at every second. It would have shot away while all stars were forming and lacked their intense gravitational pull, expanded outwards with everything and faster than 'clumping' matter."

Pure speculation of course, but hopefully plausible at least...

What if the big bang created a whole bunch of neutrinos. Let's imagine those neutrinos weren't born completely uniform throughout, but with some variation to it. As the young universe expanded, these neutrinos are zooming around in all directions in expanding space. Some of these neutrinos may have been attracted to each other gravitationally and mutually attracted some hydrogen atoms. As the atoms came together, they formed the first stars, but the neutrinos won't clump (as we've discussed), so they simply remain in their orbits around the center of mass as a new galaxy forms around them.

You know about orbits, so you know that in the absence of any other force, an orbit lasts forever. These neutrinos have no other forces on them. They are only affected by gravity, so they continue in orbits. Sometimes getting deflected by a new body (star, whatever) that has formed since their last trip around the galaxy, but not trapped into orbit around this new star. These neutrinos were born outside the gravity well of the star, so they come through it with enough energy to escape again.

There are people working on simulations of this as we speak, and TBH, so far those simulations don't match up with observations very well. So maybe this is completely incorrect. This is merely intended to be one plausible explanation. An hypothesis if you will. But until we can officially disprove it, it does seem to explain how space could be filled with invisible mass, and how that mass has not gotten stuck to the Earth. The galaxies tend to be full of this stuff, but it seems to be diffuse throughout the galaxies. It hasn't "clumped up" to the individual stars for the most part, but seems bound to the galaxies in a very diffuse way.

Does that work?
« Last Edit: July 11, 2018, 02:40:44 AM by ICanScienceThat »

Re: Fixed Planetary Mass and Dark Matter
« Reply #63 on: July 11, 2018, 02:49:08 AM »
And I should add something here about the fantastic speeds of neutrinos. This is quite interesting and I only just learned this while researching these answers.

We can only detect neutrinos that have relativistic speeds. Slower neutrinos are predicted to exist, but we cannot detect them. They would only interact with us gravitationally.

So this means that neutrinos can exist at all sorts of speeds up to very close to the speed of light.

That said, if we are to accept that these neutrinos were born spread throughout space, even the slow ones would not get bound up into our gravity well... not very many of them anyway. This is because the forces that cause matter to clump up do not affect neutrinos. So if a neutrino approaches us, it does so from outside our solar system. As it approaches, it is already on a hyperbolic orbit and is destined to escape once more.

Re: Fixed Planetary Mass and Dark Matter
« Reply #64 on: July 11, 2018, 02:57:34 AM »
A key tenet of RET is dark matter; without such an entity the whole model falls apart. And further, it is true that dark matter is supported by evidence when the world is viewed from the RE perspective, the only way to make sense of the motion of planets and stars (supposedly due to gravity) is by recourse to these dark bodies.
The earliest reference I can find to dark matter as a vague concept is 1884, though this was very slight.
Dark matter only is only needed to explain the motion of stars within galaxies. There's absolutely no need for dark matter to explain anything in the solar system, and therefore dark matter is not a key tenet for round earth. If dark matter does not exist in any form and we actually need to revise general relativity, the new theory would have to have GR as its limit when applied to solar systems, much in the same way GR tends to newtonian gravity if we are dealing with small enough velocities and weak gravitational fields.

So where is its impact on calculations of the Earth's mass? RET does have excuses, but none of them can explain why it is dark matter fails to be attracted to centers of mass like planets. The moon doesn't simply stop orbiting the Earth just because the Sun or Galactic Center exist. If dark matter exists, it should be drawn to stars, moons, planets, according to RET.
There are some estimates of dark matter density in the solar system. Even if you take the upper limits, the amount of dark matter on earth would be around 10-18 times the total mass, completely negligible and undetectable. But why didn't DM clump together as ordinary matter, you might ask?
This is a bit of speculation (I'm no physicist, this is what I understand from reading about the subject). When the universe was hot and small, everything was nearly homogeneous, with small density fluctuations. As the universe expanded, these tended to grow by attracting matter of both kinds from regions around it. But DM is far more abundant than normal matter, so these small density flucutation were growing by pulling more and more DM. But here's the thing: DM is collisionless, and therefore exerts no pressure and it lacks an efficient way of losing energy. So as the density fluctuations grow larger, DM is pulled into it forming a dense cloud (it cannot form solids) that grows more and more, which then pulls also more ordinary matter, up until the point where the universe cooled enough so that structures could be formed. So DM clouds came BEFORE we had actual galaxies, it's ordinary matter that followed the gravitational wells of dark matter, not the other way around. And the reason that DM forms halos is because is frictionless (in addition to not being subject neither to the strong or electromagnetic force), so even if DM is being compacted or falling toward another object, it would just heat up and increase its velocity, not being bounded by the compact object being formed.
But, it does clump in some way; there are subhalos inside the halo, probably some DM filaments. As to why they formed like these, maybe noone knows, or maybe we all would need a course in structure formation to understand, I have no idea.

On a side note, normal neutrinos are probably not the main component of DM: since they move too fast, they wouldn't be able to form structures of the size of galaxies, only clusters.

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Re: Fixed Planetary Mass and Dark Matter
« Reply #65 on: July 11, 2018, 12:28:23 PM »
I've asked you to keep to 1 question at a time, so that I could clearly answer each in turn. Let's call question #1 satisfied. This is now question #2.
It is the same question. Maybe a refinement directed at clarification, but given that if this question goes unanswered then the first remains unanswered, it can hardly be called a separate one.

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Let's move onto question #2:
"If dark matter moves so fast that it could only be captured by the likes of a black hole, then it should not be observable full stop. It would be on the fringes of the universe at every second. It would have shot away while all stars were forming and lacked their intense gravitational pull, expanded outwards with everything and faster than 'clumping' matter."

Pure speculation of course, but hopefully plausible at least...
It isn't speculation. If something moves so fast it can escape the gravity well of our Solar System, then it sure as hell moves fast enough to escape the gravity well of dust clouds with substantially less in the way of escape velocity.

Quote
What if the big bang created a whole bunch of neutrinos. Let's imagine those neutrinos weren't born completely uniform throughout, but with some variation to it. As the young universe expanded, these neutrinos are zooming around in all directions in expanding space. Some of these neutrinos may have been attracted to each other gravitationally and mutually attracted some hydrogen atoms. As the atoms came together, they formed the first stars, but the neutrinos won't clump (as we've discussed), so they simply remain in their orbits around the center of mass as a new galaxy forms around them.
This is the point I have to stop you. What mass? How did they end up in orbit about this mass given it's long before stars could exist and that the whole thrust of your argument was that they'd escape even the mass of a planet or the Sun? As you said, they might be attracted to other particles but there's a far cry between attraction and orbit.
My DE model explained here.
Open to questions, but if you're curious start there rather than expecting me to explain it all from scratch every time.

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Re: Fixed Planetary Mass and Dark Matter
« Reply #66 on: July 11, 2018, 12:36:48 PM »
There are some estimates of dark matter density in the solar system. Even if you take the upper limits, the amount of dark matter on earth would be around 10-18 times the total mass, completely negligible and undetectable. But why didn't DM clump together as ordinary matter, you might ask?
This is a bit of speculation (I'm no physicist, this is what I understand from reading about the subject). When the universe was hot and small, everything was nearly homogeneous, with small density fluctuations. As the universe expanded, these tended to grow by attracting matter of both kinds from regions around it. But DM is far more abundant than normal matter, so these small density flucutation were growing by pulling more and more DM. But here's the thing: DM is collisionless, and therefore exerts no pressure and it lacks an efficient way of losing energy. So as the density fluctuations grow larger, DM is pulled into it forming a dense cloud (it cannot form solids) that grows more and more, which then pulls also more ordinary matter, up until the point where the universe cooled enough so that structures could be formed. So DM clouds came BEFORE we had actual galaxies, it's ordinary matter that followed the gravitational wells of dark matter, not the other way around. And the reason that DM forms halos is because is frictionless (in addition to not being subject neither to the strong or electromagnetic force), so even if DM is being compacted or falling toward another object, it would just heat up and increase its velocity, not being bounded by the compact object being formed.
The problem is that regular matter would be subject to the same forces; as dark matter was drawn to those fluctuations, it would be too. Sure, it may be less efficient if it occurs in that sweet spot where matter's moved beyond the subatomic, but how could a galaxy form with that halo dragging everything outwards?
I'm aware of the fact that an equal gravitational pull from all directions has net force zero, but that's only going to be the case for a hollow perfect sphere, and even then only for objects right in the middle. No kind of orbit could form around anything when the dust cloud would just be pulled outwards.
My DE model explained here.
Open to questions, but if you're curious start there rather than expecting me to explain it all from scratch every time.

Re: Fixed Planetary Mass and Dark Matter
« Reply #67 on: July 11, 2018, 04:12:37 PM »
I've asked you to keep to 1 question at a time, so that I could clearly answer each in turn. Let's call question #1 satisfied. This is now question #2.
It is the same question. Maybe a refinement directed at clarification, but given that if this question goes unanswered then the first remains unanswered, it can hardly be called a separate one.
A follow-up question is great. Let's keep taking these one at a time.

Let's move onto question #2:
"If dark matter moves so fast that it could only be captured by the likes of a black hole, then it should not be observable full stop. It would be on the fringes of the universe at every second. It would have shot away while all stars were forming and lacked their intense gravitational pull, expanded outwards with everything and faster than 'clumping' matter."

Pure speculation of course, but hopefully plausible at least...
It isn't speculation. If something moves so fast it can escape the gravity well of our Solar System, then it sure as hell moves fast enough to escape the gravity well of dust clouds with substantially less in the way of escape velocity.
I don't think it works that way. Orbits around our sun depend on the velocity relative to our sun. Orbits around the galaxy depend on the velocity relative to our galaxy. For example, imagine we pass a particle that is at rest relative to the galactic center. Such a particle will be in a degenerate orbit heading straight down towards the galactic center, but relative to our sun, it is moving at something like 800,000 km/hr. That is plenty of velocity to escape the sun's orbit. We often think of orbits in simplistic terms based purely on speed, but when you consider something passing from one orbit to another, you have to consider how the relative speeds change when you do this.

Recently we had a visit from an extra-solar body. Oumuamua was from outside our solar system, but certainly it originated from inside our galaxy.
https://theconversation.com/how-i-discovered-the-origins-of-the-cigar-shaped-alien-asteroid-oumuamua-89577

Quote
What if the big bang created a whole bunch of neutrinos. Let's imagine those neutrinos weren't born completely uniform throughout, but with some variation to it. As the young universe expanded, these neutrinos are zooming around in all directions in expanding space. Some of these neutrinos may have been attracted to each other gravitationally and mutually attracted some hydrogen atoms. As the atoms came together, they formed the first stars, but the neutrinos won't clump (as we've discussed), so they simply remain in their orbits around the center of mass as a new galaxy forms around them.
This is the point I have to stop you. What mass? How did they end up in orbit about this mass given it's long before stars could exist and that the whole thrust of your argument was that they'd escape even the mass of a planet or the Sun? As you said, they might be attracted to other particles but there's a far cry between attraction and orbit.
"What mass?" We're imagining a vast cloud of neutrinos and hydrogen (and helium) atoms. Each individual particle in the cloud has a tiny mass. Together, the cloud has a center of mass. As the young universe rapidly expanded, little clouds of particles became separated from each other. The gravitational attraction these clouds had within them holding their particles together was enough to overcome the expansion rate. So the gaps between the clouds expanded leaving these clouds of particles.

How would particles in a cloud like this move? The only appreciable force acting on these particles at first is gravity, so the particles all orbit around the center of mass of the cloud. The cloud is still zooming through space, but as they zoom along, the tiny tug of gravity bends their path slightly. The result is a swirling cloud of particles zooming through space.

You don't need stars nor any concentrated mass in order to have this effect. In fact, the theory goes that the clouds of particles form first. As the particles swirl around, some of them (the atoms - not the WIMPs) bump into each other. Gradually, this bumping causes the atoms to pile up into concentrated "clumps". When a "clump" gets big enough, fusion begins and the first star is born.

Once again, I don't want to sound condescending, but just to cover the bases... The gravity field of a sphere filled with diffuse mass is precisely the same as the gravity field of a concentrated ball of mass at the center of that sphere (assuming you are outside the sphere). For example, if we were to compress the Earth down to a little black-hole, where we are standing now (about 6000 km above the new black hole) we would still feel 9.8 m/s^2 of gravity. Our moon and satellites would happily stay in orbit around the new black hole unaffected by this. This is a silly thought experiment, but the point is, those particles left over from the big bang would indeed orbit inside clouds of particles even though stars had not begun to form yet.
« Last Edit: July 11, 2018, 04:16:38 PM by ICanScienceThat »

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Re: Fixed Planetary Mass and Dark Matter
« Reply #68 on: July 11, 2018, 04:38:53 PM »
"What mass?" We're imagining a vast cloud of neutrinos and hydrogen (and helium) atoms. Each individual particle in the cloud has a tiny mass. Together, the cloud has a center of mass. As the young universe rapidly expanded, little clouds of particles became separated from each other. The gravitational attraction these clouds had within them holding their particles together was enough to overcome the expansion rate. So the gaps between the clouds expanded leaving these clouds of particles.

How would particles in a cloud like this move? The only appreciable force acting on these particles at first is gravity, so the particles all orbit around the center of mass of the cloud. The cloud is still zooming through space, but as they zoom along, the tiny tug of gravity bends their path slightly. The result is a swirling cloud of particles zooming through space.

You don't need stars nor any concentrated mass in order to have this effect. In fact, the theory goes that the clouds of particles form first. As the particles swirl around, some of them (the atoms - not the WIMPs) bump into each other. Gradually, this bumping causes the atoms to pile up into concentrated "clumps". When a "clump" gets big enough, fusion begins and the first star is born.

Once again, I don't want to sound condescending, but just to cover the bases... The gravity field of a sphere filled with diffuse mass is precisely the same as the gravity field of a concentrated ball of mass at the center of that sphere (assuming you are outside the sphere). For example, if we were to compress the Earth down to a little black-hole, where we are standing now (about 6000 km above the new black hole) we would still feel 9.8 m/s^2 of gravity. Our moon and satellites would happily stay in orbit around the new black hole unaffected by this. This is a silly thought experiment, but the point is, those particles left over from the big bang would indeed orbit inside clouds of particles even though stars had not begun to form yet.
Yes, masses are present, but they are not to the degree you require. While your analogy does correctly describe the RET point of view, it is a little misleading; it would be better to say that were you to blow up the Earth until it was nothing but a sparse field of dust, existing on the edge of that field somewhere out in the orbit of Mars, were the Earth back together again the gravitational pull on you would be the same. A sparse cloud of dust exerts next to no force on its outer reachers which is, after all, where dark matter would be going in the absence of any stronger forces.
I assume your overview on orbits earlier was to bring in the concept of relative speed, but given that only regular matter is going to clump (as you say, covering bases, but by conservation of momentum even in vacuum two particles lose speed in any real situation) dark matter will always outspeed it by an increasing margin, keeping it well beyond the dust cloud before anything larger than a molecule would come into existence.
Without large masses there's not going to be any orbit or any significant impact on what would, for a WIMP, have to be a straight-line path bound directly out of the cloud.

Nothing would slow WIMPs down, and it's quite a while before any significant centers of mass exist that might curve their path, if they are to end up being captured.
My DE model explained here.
Open to questions, but if you're curious start there rather than expecting me to explain it all from scratch every time.

Re: Fixed Planetary Mass and Dark Matter
« Reply #69 on: July 11, 2018, 05:15:59 PM »
"What mass?" We're imagining a vast cloud of neutrinos and hydrogen (and helium) atoms. Each individual particle in the cloud has a tiny mass. Together, the cloud has a center of mass. As the young universe rapidly expanded, little clouds of particles became separated from each other. The gravitational attraction these clouds had within them holding their particles together was enough to overcome the expansion rate. So the gaps between the clouds expanded leaving these clouds of particles.

How would particles in a cloud like this move? The only appreciable force acting on these particles at first is gravity, so the particles all orbit around the center of mass of the cloud. The cloud is still zooming through space, but as they zoom along, the tiny tug of gravity bends their path slightly. The result is a swirling cloud of particles zooming through space.

You don't need stars nor any concentrated mass in order to have this effect. In fact, the theory goes that the clouds of particles form first. As the particles swirl around, some of them (the atoms - not the WIMPs) bump into each other. Gradually, this bumping causes the atoms to pile up into concentrated "clumps". When a "clump" gets big enough, fusion begins and the first star is born.

Once again, I don't want to sound condescending, but just to cover the bases... The gravity field of a sphere filled with diffuse mass is precisely the same as the gravity field of a concentrated ball of mass at the center of that sphere (assuming you are outside the sphere). For example, if we were to compress the Earth down to a little black-hole, where we are standing now (about 6000 km above the new black hole) we would still feel 9.8 m/s^2 of gravity. Our moon and satellites would happily stay in orbit around the new black hole unaffected by this. This is a silly thought experiment, but the point is, those particles left over from the big bang would indeed orbit inside clouds of particles even though stars had not begun to form yet.
Yes, masses are present, but they are not to the degree you require. While your analogy does correctly describe the RET point of view, it is a little misleading; it would be better to say that were you to blow up the Earth until it was nothing but a sparse field of dust, existing on the edge of that field somewhere out in the orbit of Mars, were the Earth back together again the gravitational pull on you would be the same. A sparse cloud of dust exerts next to no force on its outer reachers which is, after all, where dark matter would be going in the absence of any stronger forces.
I assume your overview on orbits earlier was to bring in the concept of relative speed, but given that only regular matter is going to clump (as you say, covering bases, but by conservation of momentum even in vacuum two particles lose speed in any real situation) dark matter will always outspeed it by an increasing margin, keeping it well beyond the dust cloud before anything larger than a molecule would come into existence.
Without large masses there's not going to be any orbit or any significant impact on what would, for a WIMP, have to be a straight-line path bound directly out of the cloud.

Nothing would slow WIMPs down, and it's quite a while before any significant centers of mass exist that might curve their path, if they are to end up being captured.

It's hard to take it much further if you refuse to accept the facts that seem improbable to you.

"Yes, masses are present, but they are not to the degree you require." You state this without saying how much mass is present and exactly what degree it is you think I require.
Let me jump in and offer that these clouds of particles would have a mass on the order of trillions of solar masses. Just how much mass do you think it requires?

"A sparse cloud of dust exerts next to no force on its outer reachers[sic]..." A sparse cloud of dust exerts precisely the same amount of force at its outer reaches as it would were the same amount of mass compressed into a single point at the center of mass of that cloud. Here is Gauss's Law. This is a rather nasty mathematical derivation, and I'd rather not get that deep into the math. If you like, work through it and prove that it is correct. Gauss came up with this to describe electric fields, but it works for any field with spherical symmetry such as gravity. https://physics.info/law-gauss/

Another way of looking at it is that the force of gravity can be broken down into the attraction between yourself and each little particle that is pulling on you. Add up all these tiny forces, and the total sum is the gravity you feel. If this were a single mass at a point, it's trivial to calculate the force of gravity at any distance from that point. If you split up that mass into a whole bunch of points evenly distributed within a sphere, you can add together how much pull each of them has on you from your position. Some of those points will be closer to you, some farther away. Add up all the forces, and you get the same exact amount you had when it was all in a single point.

"...given that only regular matter is going to clump (as you say, covering bases, but by conservation of momentum even in vacuum two particles lose speed in any real situation) dark matter will always outspeed it by an increasing margin, keeping it well beyond the dust cloud before anything larger than a molecule would come into existence."
Once again I will bring your attention to relative speed. All the particles in the cloud are moving together as a cloud. If we imagine that the universe burst forth from a single point (just for simplicity here), all the particles in our cloud share virtually the same velocity relative to that starting point. They only differ from one another by a very tiny amount. If we change our reference frame to the center of the cloud as it zooms through space, we see that all the particles are orbiting the center of mass of their cloud. So yes, when the particles collide, they dump velocity within this reference frame and fall towards the center of mass of the cloud. But remember, our WIMPs are staying in pace with that same center of mass that our atoms are falling towards.

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Re: Fixed Planetary Mass and Dark Matter
« Reply #70 on: July 11, 2018, 09:19:11 PM »
It's hard to take it much further if you refuse to accept the facts that seem improbable to you.

"Yes, masses are present, but they are not to the degree you require." You state this without saying how much mass is present and exactly what degree it is you think I require.
Let me jump in and offer that these clouds of particles would have a mass on the order of trillions of solar masses. Just how much mass do you think it requires?

"A sparse cloud of dust exerts next to no force on its outer reachers[sic]..." A sparse cloud of dust exerts precisely the same amount of force at its outer reaches as it would were the same amount of mass compressed into a single point at the center of mass of that cloud. Here is Gauss's Law. This is a rather nasty mathematical derivation, and I'd rather not get that deep into the math. If you like, work through it and prove that it is correct. Gauss came up with this to describe electric fields, but it works for any field with spherical symmetry such as gravity. https://physics.info/law-gauss/
I am well aware of that. I specifically quoted it. It is not that it is improbable to me, but rather that it does not mean what you are claiming it does. Yes, if you condensed the cloud to one body right at its center it would have the same effect on the WIMPs, the problem is that center is going to be a hell of a long way away. Just look at it proportionately; this is a cloud of disparate particles, maybe a handful clumped together, but it is not a solid mass. And it is the total mass of a galaxy composed of tiny specks, so that's going to be a huge size.

I can crunch the numbers for this if you want more solid proof. The mass of the milky way, according to the first result I get on google, has upper bound 2x1042kg.
Let's adjust for things to make the central gravity unreasonably strong. Each speck of dust is going to be 1kg (obviously really much less) and 1m away from the nearest, just to make the calculations simple. The two overestimations should cancel each other out given they would have opposing effects; 1kg spread out over 1m3.
So we have a ball containing 2x1042 points, thus a radius contains about 7.8x1039 points in a straight line, and so that many metres. So if we shrink all the mass down to one point, all that tremendous mass, we can see the effect it has at that distance. In the same way g=9.8ms-2 is said to be the gravitational value on Earth under RET, the gravitational constant for something on the outer edge of the cloud is 2.2x10-48ms-2.
That is the equivalent to the g=9.8 value, so that is significantly less than that of the Earth, so if a WIMP won't be captured by the Earth it isn't going to be caught up by that cloud. And that's on the edge of the cloud, because that's where the force would be strongest; anywhere inside the cloud and you can't just swap it with a mass at the center because there's dust on the outside too acting to oppose the force from the dust in the other direction; on the edge of the cloud you have the mass of the whole thing pulling in one direction, and even then it is piddling compared to even just the pull of the RE moon, let alone the Earth or the Sun.
Yes, you can argue that it should be less than 1m, and maybe I miscounted a significant figure at some point, but that is a lot of orders of magnitude to make up for.

The problem is that the distance simply is too great for the mass to exert that much force.

Quote
"...given that only regular matter is going to clump (as you say, covering bases, but by conservation of momentum even in vacuum two particles lose speed in any real situation) dark matter will always outspeed it by an increasing margin, keeping it well beyond the dust cloud before anything larger than a molecule would come into existence."
Once again I will bring your attention to relative speed. All the particles in the cloud are moving together as a cloud. If we imagine that the universe burst forth from a single point (just for simplicity here), all the particles in our cloud share virtually the same velocity relative to that starting point. They only differ from one another by a very tiny amount. If we change our reference frame to the center of the cloud as it zooms through space, we see that all the particles are orbiting the center of mass of their cloud. So yes, when the particles collide, they dump velocity within this reference frame and fall towards the center of mass of the cloud. But remember, our WIMPs are staying in pace with that same center of mass that our atoms are falling towards.
The WIMPS keep pace with the initial lone particles; the moment they start clumping, all through the cloud, they'll be outspeeding. Yes, initially you have relative speed, but with no significant gravitational force because, well, they're just particles. You need more of a mass for anything approaching an orbit to be even possible.
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Re: Fixed Planetary Mass and Dark Matter
« Reply #71 on: July 11, 2018, 09:44:22 PM »
I'm really trying to be patient. I'll try once more.
The mass of our cloud of particles = the mass of a galaxy.
The size of our cloud of particles = the size of a galaxy.
Our cloud of particles is going to coalesce into a galaxy... that's why I'm choosing these dimensions for the example.
So if the eventual galaxy can hold one of these particles in its orbit, then the original cloud could hold that same particle in its orbit.
In fact, the cloud of particles only exists at all because of the mutual gravitation between the particles. The particles too far from the cloud escape off during the expansion. Maybe they are part of the next cloud over, or maybe they just get left behind in intergalactic space. The particles close enough to stay gravitationally bound form a cloud.

There are some base fundamentals you don't seem to grasp. The most profound of which is simple Galilean relativity. I'm sorry if I'm sounding condescending, but I keep trying to explain, and you keep responding in a way that demonstrates you have missed the point. I'll have to try to simplify if I can to cover what you have missed.
"...if a WIMP won't be captured by the Earth it isn't going to be caught up by that cloud..."
The WIMP isn't "caught up" by the cloud. The WIMP was born in the cloud. It has always been a part of the cloud.

Why isn't it caught up by the Earth then? You do understand that objects can be bound to orbit within the galaxy but still have escape velocity from the sun right? So far, we've sent a few probes out of our solar system, so we understand it is possible to escape the sun's gravity. Here's an article on this question from Cornell:
http://curious.astro.cornell.edu/about-us/156-people-in-astronomy/space-exploration-and-astronauts/satellites-robotic-space-craft/973-will-the-pioneer-and-voyager-probes-ever-leave-the-milky-way-beginner
tl;dr: The pioneer and voyager probes are on escape trajectories from the sun, but will not escape the galaxy.

"...the gravitational constant for something on the outer edge of the cloud is 2.2x10-48ms-2."
I won't bother checking your numbers. They aren't relevant. No matter how small the gravity is, an object moving slowly enough relative to the cloud's center of mass will orbit it.

You may be thinking, "Aha! But you said WIMPs are moving super fast!" Yes. Relative to the Earth, they are likely to be too fast to be captured. But how fast do they move relative to the galactic center? How fast are they moving relative to that initial particle cloud? Remember we said the entire particle cloud was born with essentially identical velocity? Well the particles just barely on the outer edge are moving with a speed of zero away from the center. They'll begin descending in their orbits back towards the center at that point. Or if they are in perfectly circular orbits, they just chill out there going round the center.

"The WIMPS keep pace with the initial lone particles; the moment they start clumping, all through the cloud, they'll be outspeeding."
Why? What would cause the WIMPs to outspeed the cloud suddenly? When the atoms start to clump, what force will push the clumps away from the cloud?

Re: Fixed Planetary Mass and Dark Matter
« Reply #72 on: July 11, 2018, 11:11:19 PM »
The problem is that regular matter would be subject to the same forces; as dark matter was drawn to those fluctuations, it would be too. Sure, it may be less efficient if it occurs in that sweet spot where matter's moved beyond the subatomic, but how could a galaxy form with that halo dragging everything outwards?
I'm aware of the fact that an equal gravitational pull from all directions has net force zero, but that's only going to be the case for a hollow perfect sphere, and even then only for objects right in the middle. No kind of orbit could form around anything when the dust cloud would just be pulled outwards.
First, the bold part is wrong. A hollow uniform sphere has zero gravitational force anywhere inside, not just the middle.

Now to the main part: while ordinary matter is subject to the same forces as DM, the opposite is not true. Ordinary matter has pressure, friction and is subject to the EM force, all of which are important in the process of losing energy and creating compact objects such as planets and stars. Also, the structure formation is continuous; while density fluctuations grow and attract more DM, it also attracts more baryonic matter (in smaller quantities), up until they reach a critical density and collapse. As with any gravitational collapse, the center of the collapsed object is the densest, not the outer parts. The halo will keep growing by accretion or mergers, and at some point the universe will have cooled enough so that ordinary matter can make gravitationally bound structures, and so on until the galaxy is formed. For cold DM, the structure formation is called bottom-up: first smaller structures are formed, then grow through mergers or accretion.
We can therefore expect that the density profile of ordinary and dark matter roughly matches (with DM decreasing a lot more slowly); we do not expect DM to form objects of the size of planets or stars however, and will remain diffuse in a large ellipsoidal halo

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Offline J-Man

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Re: Fixed Planetary Mass and Dark Matter
« Reply #73 on: July 12, 2018, 12:13:37 AM »
4 pages on something that isn't even known to exist. Dark Matter is like Santa Claus, the presents are under the tree so surely Santa exists.

"and although no solid direct evidence of dark matter has been detected"

https://www.space.com/20930-dark-matter.html

The earth is flat, it is measurable and proven.
What kind of person would devote endless hours posting scientific facts trying to correct the few retards who believe in the FE? I slay shitty little demons.

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Offline JRowe

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Re: Fixed Planetary Mass and Dark Matter
« Reply #74 on: July 12, 2018, 12:14:46 AM »
I'm really trying to be patient. I'll try once more.
The mass of our cloud of particles = the mass of a galaxy.
The size of our cloud of particles = the size of a galaxy.
Our cloud of particles is going to coalesce into a galaxy... that's why I'm choosing these dimensions for the example.
So if the eventual galaxy can hold one of these particles in its orbit, then the original cloud could hold that same particle in its orbit.
The cloud should be significantly larger than the galaxy; after all, the outer edges need to be pulled inwards to coalesce and form even just the outermost stars. That is the point. And even then you have what the outermost edges of the galaxy is. To just use the milky way as an example, scientists can't yet fully explain how on earth a spiral galaxy is actually stable (the 'winding problem.') and that's the stars significantly closer to galactic center than the edges of the cloud would be.
Plus most of what objects near the edges of the galaxy orbit around are the stars themselves. Only galactic center can be modelled by the equivalence you brought up, and yes stars orbit galactic center but it's another example of why the equivalence does not perfectly translate over. Add into that the larger cloud on top of everything else...


Quote
"...if a WIMP won't be captured by the Earth it isn't going to be caught up by that cloud..."
The WIMP isn't "caught up" by the cloud. The WIMP was born in the cloud. It has always been a part of the cloud.

Why isn't it caught up by the Earth then? You do understand that objects can be bound to orbit within the galaxy but still have escape velocity from the sun right? So far, we've sent a few probes out of our solar system, so we understand it is possible to escape the sun's gravity. Here's an article on this question from Cornell:
http://curious.astro.cornell.edu/about-us/156-people-in-astronomy/space-exploration-and-astronauts/satellites-robotic-space-craft/973-will-the-pioneer-and-voyager-probes-ever-leave-the-milky-way-beginner
tl;dr: The pioneer and voyager probes are on escape trajectories from the sun, but will not escape the galaxy.
There might be some terminology confusion here. Sure, it exists in the location of the cloud, but to be caught up in the gravitational influence of the forming cloud and thus be basically permanently captured by it is a whole other problem. Yes, something can be caught up in the galaxy but still escape the Sun's gravity, but if something cannot escape a significantly weaker pull than that of the Earth or Sun then it definitely wouldn't escape the Sun. As explained, a galaxy dispersed into a large cloud does not exert a large enough force, which has been shown both mathematically and logically.

Quote
You may be thinking, "Aha! But you said WIMPs are moving super fast!" Yes. Relative to the Earth, they are likely to be too fast to be captured. But how fast do they move relative to the galactic center? How fast are they moving relative to that initial particle cloud? Remember we said the entire particle cloud was born with essentially identical velocity? Well the particles just barely on the outer edge are moving with a speed of zero away from the center. They'll begin descending in their orbits back towards the center at that point. Or if they are in perfectly circular orbits, they just chill out there going round the center.

"The WIMPS keep pace with the initial lone particles; the moment they start clumping, all through the cloud, they'll be outspeeding."
Why? What would cause the WIMPs to outspeed the cloud suddenly? When the atoms start to clump, what force will push the clumps away from the cloud?
I went over that: conservation of momentum. Imagine two particles colliding and clumping together. Perhaps they're both heading directly out of the cloud, perpendicular to its local 'surface.' In that case one hits the other from behind, and then has to expend energy to accelerate it and thus decelerates. (eg: 1m+2m=2m*v, v=1.5<2 to walk through a quick conservation of momentum equation as an example, particles with mass m and velocities 1 and 2, v the velocity of the clump) and that's the ideal case. If their direction isn't directly out there's more wasted energy that doesn't head out of the galaxy.
Dark matter will never be subject to that because it doesn't clump. Hence it keeps its velocity, hence my point.




The problem is that regular matter would be subject to the same forces; as dark matter was drawn to those fluctuations, it would be too. Sure, it may be less efficient if it occurs in that sweet spot where matter's moved beyond the subatomic, but how could a galaxy form with that halo dragging everything outwards?
I'm aware of the fact that an equal gravitational pull from all directions has net force zero, but that's only going to be the case for a hollow perfect sphere, and even then only for objects right in the middle. No kind of orbit could form around anything when the dust cloud would just be pulled outwards.
First, the bold part is wrong. A hollow uniform sphere has zero gravitational force anywhere inside, not just the middle.

Now to the main part: while ordinary matter is subject to the same forces as DM, the opposite is not true. Ordinary matter has pressure, friction and is subject to the EM force, all of which are important in the process of losing energy and creating compact objects such as planets and stars. Also, the structure formation is continuous; while density fluctuations grow and attract more DM, it also attracts more baryonic matter (in smaller quantities), up until they reach a critical density and collapse. As with any gravitational collapse, the center of the collapsed object is the densest, not the outer parts. The halo will keep growing by accretion or mergers, and at some point the universe will have cooled enough so that ordinary matter can make gravitationally bound structures, and so on until the galaxy is formed. For cold DM, the structure formation is called bottom-up: first smaller structures are formed, then grow through mergers or accretion.
We can therefore expect that the density profile of ordinary and dark matter roughly matches (with DM decreasing a lot more slowly); we do not expect DM to form objects of the size of planets or stars however, and will remain diffuse in a large ellipsoidal halo
True, I rushed that, thank you.
Still, I'd argue the halo isn't going to be uniform or a sphere, so the gist stands. I'll get to the rest later, it's late where I am and I'm far too tired to visualise and go through what you're saying. Looking forward to it though.
My DE model explained here.
Open to questions, but if you're curious start there rather than expecting me to explain it all from scratch every time.

Re: Fixed Planetary Mass and Dark Matter
« Reply #75 on: July 12, 2018, 02:03:03 AM »
The cloud should be significantly larger than the galaxy; after all, the outer edges need to be pulled inwards to coalesce and form even just the outermost stars.
Why is the cloud significantly larger than the eventual galaxy? Sure it's a little bigger. For one thing it's probably closer to spherical than the eventual disk it is destined to become. Is that really a point you want to get hung up on here?

Plus most of what objects near the edges of the galaxy orbit around are the stars themselves. Only galactic center can be modelled by the equivalence you brought up, and yes stars orbit galactic center but it's another example of why the equivalence does not perfectly translate over. Add into that the larger cloud on top of everything else...
I simply do not follow you. The stars at the very outer edge of the galaxy orbit the galaxy. The combined mass of everything within the galaxy pulls on those stars, and they orbit the galactic center. We used to think that it was the combined mass of all the stars that made up the mass of a typical galaxy. Now we're starting to ponder if perhaps we were very wrong about that. What we're discussing is the idea that it isn't the stars alone providing all that mass, but something new we call dark matter.

Yes, something can be caught up in the galaxy but still escape the Sun's gravity, but if something cannot escape a significantly weaker pull than that of the Earth or Sun then it definitely wouldn't escape the Sun. As explained, a galaxy dispersed into a large cloud does not exert a large enough force, which has been shown both mathematically and logically.
No it has not been shown. You keep repeating that a cloud of gas doesn't exert much gravitational force, but that is simply not correct. The cloud has as much mass as the eventual galaxy. If you accept that stars can orbit the galaxy, then those same stars will orbit the cloud just fine. The vast distances make these forces tiny, and those tiny forces make for tremendous orbits. We're talking about orbits the size of an entire galaxy.

So if the cloud has a mass of trillions of solar masses, and we've agreed that it has sufficient mass to hold atoms in orbit, why can it not hold WIMPs in orbit?

"The WIMPS keep pace with the initial lone particles; the moment they start clumping, all through the cloud, they'll be outspeeding."
Why? What would cause the WIMPs to outspeed the cloud suddenly? When the atoms start to clump, what force will push the clumps away from the cloud?
I went over that: conservation of momentum. Imagine two particles colliding and clumping together. Perhaps they're both heading directly out of the cloud, perpendicular to its local 'surface.' In that case one hits the other from behind, and then has to expend energy to accelerate it and thus decelerates. (eg: 1m+2m=2m*v, v=1.5<2 to walk through a quick conservation of momentum equation as an example, particles with mass m and velocities 1 and 2, v the velocity of the clump) and that's the ideal case. If their direction isn't directly out there's more wasted energy that doesn't head out of the galaxy.
Dark matter will never be subject to that because it doesn't clump. Hence it keeps its velocity, hence my point.
2 particles collide during their orbits around the galaxy, and they stick. Their final velocity will presumably be the average of their previous velocities right? We had a particle going 1.0 and another going 2.0. They collide, and the new particle goes 1.5. Ok. So? Presumably both particles were in orbit around the galaxy before they collided. So at this point velocities ranging from 1.0 to 2.0 are stable orbits within this galaxy. 1.5 will still be a stable orbit for the new particle. What is your point? Your point is that the stars will fall in towards the galactic center? Especially they'll get pushed down to the galactic disk. Right? And the WIMPs won't. Yeah they will get all jostled around, but they are going to remain diffuse. They still can't escape the gravity well of the galaxy. All those stars falling down towards the center of the galaxy isn't going to let the WIMPs escape.

Re: Fixed Planetary Mass and Dark Matter
« Reply #76 on: July 12, 2018, 04:42:47 AM »
I hesitate to post a video with NDT here on FES, but this is the best layman's explanation of dark matter I've ever seen.

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Offline JRowe

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Re: Fixed Planetary Mass and Dark Matter
« Reply #77 on: July 12, 2018, 12:43:48 PM »
The cloud should be significantly larger than the galaxy; after all, the outer edges need to be pulled inwards to coalesce and form even just the outermost stars.
Why is the cloud significantly larger than the eventual galaxy? Sure it's a little bigger. For one thing it's probably closer to spherical than the eventual disk it is destined to become. Is that really a point you want to get hung up on here?

Plus most of what objects near the edges of the galaxy orbit around are the stars themselves. Only galactic center can be modelled by the equivalence you brought up, and yes stars orbit galactic center but it's another example of why the equivalence does not perfectly translate over. Add into that the larger cloud on top of everything else...
I simply do not follow you. The stars at the very outer edge of the galaxy orbit the galaxy. The combined mass of everything within the galaxy pulls on those stars, and they orbit the galactic center. We used to think that it was the combined mass of all the stars that made up the mass of a typical galaxy. Now we're starting to ponder if perhaps we were very wrong about that. What we're discussing is the idea that it isn't the stars alone providing all that mass, but something new we call dark matter.

Yes, something can be caught up in the galaxy but still escape the Sun's gravity, but if something cannot escape a significantly weaker pull than that of the Earth or Sun then it definitely wouldn't escape the Sun. As explained, a galaxy dispersed into a large cloud does not exert a large enough force, which has been shown both mathematically and logically.
No it has not been shown. You keep repeating that a cloud of gas doesn't exert much gravitational force, but that is simply not correct. The cloud has as much mass as the eventual galaxy. If you accept that stars can orbit the galaxy, then those same stars will orbit the cloud just fine. The vast distances make these forces tiny, and those tiny forces make for tremendous orbits. We're talking about orbits the size of an entire galaxy.

So if the cloud has a mass of trillions of solar masses, and we've agreed that it has sufficient mass to hold atoms in orbit, why can it not hold WIMPs in orbit?
The cloud has enough mass as the eventual galaxy over a larger area. That isn't me being pedantic, it's a huge factor here and absolutely worth getting 'hung up on.' Gravity is meant to form the stars and galaxy by drawing dust inwards to certain points, not out to the border of the cloud. You have to account for everything moving inwards as they settle into dubiously stable orbits around galactic center, on top of moving inwards to form the outermost stars, and all that's under the assumption that the edges of the cloud always had a stable orbit and never shot off anyway (which after all is the origin of the whole thing).
And that's ignoring the fact that there's still major debate as to whether galaxies are formed by one or multiple clouds. If it's multiple then this is even more relevant because you don't even get a cloud having the mass of a galaxy.


Quote
2 particles collide during their orbits around the galaxy, and they stick. Their final velocity will presumably be the average of their previous velocities right? We had a particle going 1.0 and another going 2.0. They collide, and the new particle goes 1.5. Ok. So? Presumably both particles were in orbit around the galaxy before they collided. So at this point velocities ranging from 1.0 to 2.0 are stable orbits within this galaxy. 1.5 will still be a stable orbit for the new particle. What is your point? Your point is that the stars will fall in towards the galactic center? Especially they'll get pushed down to the galactic disk. Right? And the WIMPs won't. Yeah they will get all jostled around, but they are going to remain diffuse. They still can't escape the gravity well of the galaxy. All those stars falling down towards the center of the galaxy isn't going to let the WIMPs escape.
My point is that you cannot use relative speed because the speed of regular matter is constantly going to be decreasing, while the mass is not going to be increasing. The WIMPs outspeed, and even if I granted your claim that they were somehow captured at the start, they won't remain as such.
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Offline JRowe

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Re: Fixed Planetary Mass and Dark Matter
« Reply #78 on: July 12, 2018, 01:34:03 PM »
Now to the main part: while ordinary matter is subject to the same forces as DM, the opposite is not true. Ordinary matter has pressure, friction and is subject to the EM force, all of which are important in the process of losing energy and creating compact objects such as planets and stars. Also, the structure formation is continuous; while density fluctuations grow and attract more DM, it also attracts more baryonic matter (in smaller quantities), up until they reach a critical density and collapse. As with any gravitational collapse, the center of the collapsed object is the densest, not the outer parts. The halo will keep growing by accretion or mergers, and at some point the universe will have cooled enough so that ordinary matter can make gravitationally bound structures, and so on until the galaxy is formed. For cold DM, the structure formation is called bottom-up: first smaller structures are formed, then grow through mergers or accretion.
We can therefore expect that the density profile of ordinary and dark matter roughly matches (with DM decreasing a lot more slowly); we do not expect DM to form objects of the size of planets or stars however, and will remain diffuse in a large ellipsoidal halo
Dark matter has no limitations on its movement, I agree with that.
My issue still has to be with the effect of gravity on dark matter though. It would not need to form any actual structure, particularly if it collisionless. Take the RE moon and its orbit around the Earth's core; why not have dark matter do the same within the Earth? You could have tonnes of the stuff in the same location. That's a halo, the same structure you're talking about, just less diffuse.
The only reason I can see for it to be as diffuse as you've said is that it lacks an efficient way to lose energy, though they overlaps with the discussion I've had with ScienceThat; it needs to lose energy if it's to be present at all to affect the galaxy, especially galactic center.
I may be misunderstanding what you're saying, but it still doesn't quite seem to work.
My DE model explained here.
Open to questions, but if you're curious start there rather than expecting me to explain it all from scratch every time.

Re: Fixed Planetary Mass and Dark Matter
« Reply #79 on: July 12, 2018, 03:51:11 PM »
Let me try to summarize your issues:

1) You don't agree that a particle cloud can exert gravity upon itself.

Perhaps a mental exercise will help.

Imagine a galaxy made of stars. Hopefully you agree that these stars have gravity, and they pull on each other. They orbit each other in a big disk.

Now imagine we take those stars and smash them up into little chunks. Asteroids... just rocks. Take the same amount of mass you had with the stars and just smash it into rocks and spread them evenly throughout the area the stars occupied. Hopefully you agree that these rocks still have gravity. I think you'll agree that they can still orbit each other. They have the same mass as the stars, so they have the same overall gravity. So they can still orbit each other in a big disk.

Now pulverize those rocks down into dust and spread the dust out. Same mass, just spread out again. Same mass = same gravity. The dust cloud should orbit happily in a big disk.

If the stars can orbit each other, then rocks can orbit each other. If rocks can orbit, then dust can orbit. If dust can orbit, then particles can orbit.

Absolutely the dynamics are different. Each step is more chaotic and diffuse than the one before, but we started out with a galaxy full of stars, and that's already pretty chaotic and diffuse in the first place.

So hopefully, that clarifies that a cloud of particles which are bound together gravitationally can exist. All you have to do is agree that such a thing can exist.

2) You keep saying that anything with enough speed to escape the sun has enough speed to escape the galaxy.

Let's imagine shooting a probe to Mars.

We start out on Earth. First we must get into Earth orbit. It takes a lot of energy to achieve orbital velocity around the Earth.

Next we must escape Earth's orbit. We point our rocket parallel with Earth's orbit around the sun and accelerate. We must achieve enough speed to get into a hyperbolic orbit around Earth and escape Earth orbit.

We are now in an elliptical orbit around the Sun. We want to intercept Mars, so this ellipse has to have an apogee at least out past Mar's orbit. We started at the Earth, so the perigee is at least as small as Earth's orbit.

We fly in this ellipse around the Sun until we get close to Mars. We are now in a hyperbolic orbit around Mars. We are going too fast to stay in orbit around Mars. We know this for a fact because we started outside of Mar's orbit - we were orbiting the Sun. We can approach Mars from the front or from the back, but no matter how we approach, we are going fast enough to escape Mar's gravity on a hyperbolic path. Orbits are symmetrical. If you started out from beyond orbit, you are going to escape again.

So we burn our rockets again to slow down and settle into a stable orbit around Mars.

Finally, the point of that exercise... We just demonstrated that going from orbit around a star (the Sun) to orbit around a planet (Mars) requires that we slow down. The same is true for going from orbit around a galaxy to orbit around a star. You can't do it without slowing down.

You can absolutely be in orbit around the galaxy and not in orbit around any particular star. Passing close to any star will not force you to stick to it.

3) Finally, you imagine that the clumping up of matter makes it "slow down".

The kinetic energy of the system does slow down as objects coalesce, but you seem to be mistakenly applying that kinetic energy to the speed of the objects when compared to the speed of the cloud they are travelling with. The easiest way to avoid that trap is to simply imagine that this particular cloud is stationary. The particles are orbiting around a central point that is the one true fixed point in space. All other galaxy clouds are speeding away from this one, but this one is holding still. I'm just applying Galilean relativity here... the old "pour a cup of tea while you're on a speeding train" bit.

Now, when 2 particles collide, and they lose energy, does the rest of the cloud speed away from them? Of course not, the cloud isn't going anywhere. The cloud is just orbiting a fixed central point. So maybe the 2 particles drop to a lower orbit within the cloud... and thus the cloud contracts a little. But they stay with the cloud.

Summary:
So I think those are your 3 issues with this model, and hopefully those are 3 mental exercises that help you to understand what standard science says about those issues. All 3 of these appear to be misunderstandings about how this stuff is understood to work. This stuff is pretty complex, but if you take each concept one at a time, it does all work out nicely.
« Last Edit: July 12, 2018, 03:53:22 PM by ICanScienceThat »