Is DM Gravity Highly Directional?

[common_sense_seeker]

I propose that the DM gravity of a star is much higher on the ecliptic. This would be the reason why galaxies maintain their general disc shape over billions of years. Do any computer galaxy modellers agree that this might be possible?

[Steve100]

I thought you were the one who understood the mechanics of gravity.

Why don't you explain it to us so that we can stop wasting time with the LHC and other ventures?

[common_sense_seeker]

I'm saying that only a simulation model of creation which leads to the pattern of galaxies as observed by the Hubble will give us an understanding of gravity. Nothing is good enough for me until then.

[common_sense_seeker]

Is the thread concept too far out this time?

[Steve100]

Try giving us some sort of explanation, and then we will see.

[common_sense_seeker]

It requires imagination again. Over billions of years what is the reason why stars haven't drifted away above and below the galactic plain? I propose that the only viable explanation is that the stellar (DM) gravitational pull is stronger in this direction, so maintaining the general disc shape.

[D H]

It requires imagination again.
Funny thing about physics: What it really requires is mathematics, and you have given us none.

[Vkothii]

Who'd like to explain the viriality of dark matter? How it's thought to relax over billions of years as a sort of series of layers, around a galaxy?

And why accretion isn't related to dark matter halos (I don't think it is, anyway)?
Accretion disks are the most obvious physical phenomena out there, but I believe that's related to angular momentum and how gas and dust clouds coalesce and eventually collapse, rather than any dark matter (which is believed to be significant only at galactic, not planetary scales).

But maybe I've got it wrong...

[James R]

I propose that the DM gravity of a star is much higher on the ecliptic.

What's DM gravity? (Dark matter gravity?)

Physicists believe dark matter exists in an approximately spherical halo around galaxies, I think.

[common_sense_seeker]

None of you sound as though you know what you're talking about. Is there anybody on this site that has an occupation in this area? It would be nice to hear an expert opinion.

[BenTheMan]

I propose that the DM gravity of a star is much higher on the ecliptic. This would be the reason why galaxies maintain their general disc shape over billions of years. Do any computer galaxy modellers agree that this might be possible?

So "DM gravity" is different from...umm...non-DM gravity?

How does that work?

[BenTheMan]

None of you sound as though you know what you're talking about. Is there anybody on this site that has an occupation in this area? It would be nice to hear an expert opinion.

Glass houses and bricks, son.

[Steve100]

The thing is that we don't really have anything to have a real opinion on, as you haven't even explained your theories.

[common_sense_seeker]

It's a fair point. I'm starting on the maths. Watch out for the new Dark Matter At The Center Of The Earth Theory. You'll know where you heard it first.

[Saxion]

That's just obsurd. If dark matter was in the center of the earth, how the hell did ordinary matter come to surround it, and why doesn't its negative qualities simply blow the earth apart?

[Janus58]

Here's what C_S_S has proposed so far:

1. Dark matter exists at the center of planets and stars

2. This dark matter is the source of the "missing mass"

3. Gravity from DM is directional.

4. This directional nature of DM gravity is responsible for the disk shape of galaxies.


The problems:

1. DM only interacts gravitationally. As a result, it has no tendency to clump together like baryonic matter does due to its interaction through electromagnetic forces. Ergo, there is no mechanism that could cause DM to collect at the center of astronomical bodies.

2. In order to account for the "missing mass" DM is estimated to make up over 80% of the matter in the universe. If DM at the center of astronomical bodies were the source of this missing mass, then 80% of the Earth's mass would have to be due to DM. This means that the density of the material of the deeper layers of the Earth that support the upper layers would have to be 20% of that presently measured. There is no way that you could remove 80% of the Earth's baryonic matter and still hold up its weight against collapse. (DM would provide no structural strength). Besides that, a DM core is inconsistent with measurements of the Earth's inner layers made through primary and secondary seismic waves.

3. If DM were located inside astronomical bodies and was directional, it would have easily been noticed by now, especially if it existed in the amount needed to explain the missing mass. The Earth's gravity would then not be uniform in all directions and there would be large differences in the weight of objects at different latitudes. Also, satellites placed in polar orbits (a common practice) would behave quite differently then they do, and very likely would even be stable.
The same holds true for the Sun, comets come in a random distribution of inclination to the ecliptic, and many spend the majority of their orbit nowhere near it. Yet these comets follow the same type of trajectories as comets near or in the ecliptic.
IOW, there are no observations that support the idea of directional gravity.

4.Spiral galaxies(the type that are disk-like) make up only 60% of the galaxies, the rest being elliptical and irregular. If directional gravity prefers disk-like shapes you would expect a much higher percentage.

Also mention has been made of galaxies maintaining their shape for billions of years. But for a rotating galaxy, time scale isn't nearly as important to evolution of shape as is the number of rotations completed since formation. Given the estimated age of the Milky Way (6.5-10 billion years), and the time it takes for the solar system to make one trip around the galaxy(225-250 million yrs), we get a range of 26 to 45 rotations of the galaxy since formation. This is not a lot of rotations for much change in shape to take place.

Lastly, there are objects that are part of the Milky Way(and other spiral galaxies) that do not orbit in the plane of the disk. The galaxy has a spherical halo of old stars and globular clusters. (It was the mapping of this halo that allowed Dr Harlow Shapley to first locate the center of the galaxy, despite the fact the dust in the galactic plane hid it from direct view.)

[common_sense_seeker]

Here's what C_S_S has proposed so far:

1. Dark matter exists at the center of planets and stars

2. This dark matter is the source of the "missing mass"

3. Gravity from DM is directional.

4. This directional nature of DM gravity is responsible for the disk shape of galaxies.


The problems:

1. DM only interacts gravitationally. As a result, it has no tendency to clump together like baryonic matter does due to its interaction through electromagnetic forces. Ergo, there is no mechanism that could cause DM to collect at the center of astronomical bodies.

This is nonsense. My definition of DM is matter which has a higher force of gravitational attraction than baryonic matter due to it's lower entropy. DM is original material which was created before baryonic matter and is highly attractive to it.

2. In order to account for the "missing mass" DM is estimated to make up over 80% of the matter in the universe. If DM at the center of astronomical bodies were the source of this missing mass, then 80% of the Earth's mass would have to be due to DM. This means that the density of the material of the deeper layers of the Earth that support the upper layers would have to be 20% of that presently measured. There is no way that you could remove 80% of the Earth's baryonic matter and still hold up its weight against collapse. (DM would provide no structural strength). Besides that, a DM core is inconsistent with measurements of the Earth's inner layers made through primary and secondary seismic waves.

I'm proposing that 'Missing Mass' is a misnomer. Cavendish assumed the Earth is entirely baryonic, but a DM core would give a lower mass value. The ratio of a star's inner core to it's total size is not known. Therefore the stellar masses could be greatly overestimated.

3. If DM were located inside astronomical bodies and was directional, it would have easily been noticed by now, especially if it existed in the amount needed to explain the missing mass. The Earth's gravity would then not be uniform in all directions and there would be large differences in the weight of objects at different latitudes. Also, satellites placed in polar orbits (a common practice) would behave quite differently then they do, and very likely would even be stable.
The same holds true for the Sun, comets come in a random distribution of inclination to the ecliptic, and many spend the majority of their orbit nowhere near it. Yet these comets follow the same type of trajectories as comets near or in the ecliptic.
IOW, there are no observations that support the idea of directional gravity.

Earth's gravity is weaker at the equator (0.99732g) despite it's extra mass due to the bulge, which is counter-intuitive. The Sun's difference in directional gravity may not be very much as well, but this could be a big factor in the precession of the perihelions. Also the Pioneer gravity probe anomalies could be due to the increased solar gravity as they move away from the ecliptic. Maybe more work on comet trajectories would show this effect.

4.Spiral galaxies(the type that are disk-like) make up only 60% of the galaxies, the rest being elliptical and irregular. If directional gravity prefers disk-like shapes you would expect a much higher percentage.

Nonsense. It depends on how the galaxies were formed. A galaxy could be the result of two smaller merged galaxies for example.

Also mention has been made of galaxies maintaining their shape for billions of years. But for a rotating galaxy, time scale isn't nearly as important to evolution of shape as is the number of rotations completed since formation. Given the estimated age of the Milky Way (6.5-10 billion years), and the time it takes for the solar system to make one trip around the galaxy(225-250 million yrs), we get a range of 26 to 45 rotations of the galaxy since formation. This is not a lot of rotations for much change in shape to take place.

A minor point of argument against my theory. Incidentally, contrary to my earlier statement in the thread, I propose that stellar gravitation is lower in the galactic plane (similar to the Earth).

Lastly, there are objects that are part of the Milky Way(and other spiral galaxies) that do not orbit in the plane of the disk. The galaxy has a spherical halo of old stars and globular clusters. (It was the mapping of this halo that allowed Dr Harlow Shapley to first locate the center of the galaxy, despite the fact the dust in the galactic plane hid it from direct view.)

Again a minor point. My theory does not preclude a spherical halo.



All your arguments are weak. See above for my responses in italics.

[OilIsMastery]

Common Sense Seeker, you are on to something. Makes sense that antimatter electromagnetic forces would travel along circular orbits.

[common_sense_seeker]

Thanks for the support.