To our present knowledge the universe is expanding evenly in all directions having a Hubble constant of 73.5 (m/s)/Mpc, give or take. Large structures that are not bound to each other sufficiently by gravity move away from each other along with space.
However structures that are bound gravitationally such as galaxies, are not stretched out along with space. They stay together while space is expanding underneath them. Due to this, all objects within a galaxy will move through space towards the center of the galaxy with a speed given by gradient of expansion across the galaxies radius. The further the object from the center, the faster it will travel across space towards the center of the galaxy.
At the same time however the galaxy is rotating, therefore all object in the galaxy will suffer the Coriolis effect associated with the rotating disc of the galaxy because they each move inward on the disc that stays constant in the expanding space.
Due to this, objects would appear to accelerate according to the value of the Coriolis acceleration at the point where the object is located relative to the center of the galaxy which is given by the angular velocity of the object and the speed gradient at that distance.
Is there a flaw in my observation or could this have a real effect in the way galaxies rotate and implicitly be a substitute for the existence of dark matter.
In physics, the Coriolis effect is an apparent inflection of stationary objects when they are viewed from a circumerfal reference frame rotating.
A rotating frame of reference is a special case of a non-rotating reference frame that has rotation relative to an inertial reference frame. An everyday example of a rotating reference frame is the surface of the Earth....
Perhaps try by experimenting. You can watch water go down the toilet bowl on opposite sides of the hemispehere and the directions are different. Just swish!
A rotating frame of reference is a special case of a non-rotating reference frame that has rotation relative to an inertial reference frame. An everyday example of a rotating reference frame is the surface of the Earth....
Perhaps try by experimenting. You can watch water go down the toilet bowl on opposite sides of the hemispehere and the directions are different. Just swish!
POLY FRACT
Myth. The direction of rotation is much more influenced by imperfections in the shape of the bowl and direction of the jet when flushed. It takes very careful design to detect coriolis effects in such a small system. Now, if you observe large systems like hurricanes and typhoons the effect is much greater, but even there the odd backward rotation is seen.
Grumpy
QUOTE
Perhaps try by experimenting. You can watch water go down the toilet bowl on opposite sides of the hemispehere and the directions are different. Just swish!
Myth. The direction of rotation is much more influenced by imperfections in the shape of the bowl and direction of the jet when flushed. It takes very careful design to detect coriolis effects in such a small system. Now, if you observe large systems like hurricanes and typhoons the effect is much greater, but even there the odd backward rotation is seen.
Grumpy
QUOTE
Due to this, all objects within a galaxy will move through space towards the center of the galaxy with a speed given by gradient of expansion across the galaxies radius
This seems to be an unsupported assumption. Furthermore, it is contradicted by observation.
QUOTE (AlexG+Aug 29 2009, 06:20 PM)
This seems to be an unsupported assumption. Furthermore, it is contradicted by observation.
I see what you mean. Observation confirms that galaxies keep their sizes. This is my point exactly: they keep their size in an expanding universe. They are indeed not collapsing towards the center of the galaxy but space is stretching evenly in all directions, so because they stay the same size, they must be moving through space.
Let's take the balloon and glue little pieces of thread to points on the balloon. As we inflate the balloon, the threads will move away from each other. However the free end of the threads will always stay at the same distance from the glued end, while the balloon is stretching underneath the free end, moving outwards evenly from the glued end. Therefore, the free end, relative to the space underneath is moving inwards at considerable pace: (the ~73.5 (Km/s)/Mpc is quite significant over the diameter of a galaxy)
correction: the correct number is: ~73.5 (Km/s)/Mpc
No, it isn't significant. First of all, you neglect error bars and source when you quote that figure. Second, you neglect the dynamics of the galaxy. Finally, you neglect any theoretical basis to consider bound systems like the galaxy.
The radius of the galaxy is about 0.0184 Mpc. The related Hubble velocity would be no more than 1.4 km/s, but the velocity of the sun relative to the center of the galaxy is about 220 km/s, so the Hubble effect, even if it applied would be negligible. Something has to hold the galaxy together against the tendency for stars to move in straight lines and that something is greater than the Hubble expansion.
The radius of the galaxy is about 0.0184 Mpc. The related Hubble velocity would be no more than 1.4 km/s, but the velocity of the sun relative to the center of the galaxy is about 220 km/s, so the Hubble effect, even if it applied would be negligible. Something has to hold the galaxy together against the tendency for stars to move in straight lines and that something is greater than the Hubble expansion.
G'day from the land of ozzzzz
The actual movement of stars is towards the centre of the galaxy. We notice this in the movements and growth of stellar black holes as they get closer to the centre.
The formation of jets from the centre Nucleon (BH) ejects matter in reforming the galaxy. Both of these processes are well documented.
This paper may be of interest.
http://lanl.arxiv.org/abs/0809.2330
Hydrodynamics of structure formation in the early Universe
Authors: C. H. Gibson (UCSD), T. M. Nieuwenhuizen (University of Amsterdam), R. E Schild (Harvard)
(Submitted on 14 Sep 2008)
[Moderator: You do not support your claims about the movements of the stars and you have been warned repeatedly in the past of posting article abstracts without any discussion of their contents or why they relate to the thread. Therefore you are suspended 15 days. In addition, the article preprint is nearly a year old without a record of being submitted for publication -- a fatal flaw in a paper which asserts fatal flaws.]
The actual movement of stars is towards the centre of the galaxy. We notice this in the movements and growth of stellar black holes as they get closer to the centre.
The formation of jets from the centre Nucleon (BH) ejects matter in reforming the galaxy. Both of these processes are well documented.
This paper may be of interest.
http://lanl.arxiv.org/abs/0809.2330
Hydrodynamics of structure formation in the early Universe
Authors: C. H. Gibson (UCSD), T. M. Nieuwenhuizen (University of Amsterdam), R. E Schild (Harvard)
(Submitted on 14 Sep 2008)
QUOTE
Abstract: Theory and observations reveal fatal flaws in the standard LambdaCDM model. The cold dark matter hierarchical clustering paradigm predicts a gradual bottom-up growth of gravitational structures assuming linear, collisionless, ideal flows and unrealistic CDM condensations and mergers. Collisional fluid mechanics with viscosity, turbulence, and diffusion predicts a turbulent big bang and top-down viscous-gravitational fragmentation from supercluster to galaxy scales in the plasma epoch, as observed from 0.3 Gpc void sizes, 1.5 Gpc spins and Kolmogorov-fingerprint-turbulence-signatures in the CMB. Turbulence produced at expanding gravitational void boundaries causes a linear morphology of 3 Kpc fragmenting plasma-protogalaxies along vortex lines, as observed in deep HST images. After decoupling, gas-protogalaxies fragment into primordial-density, million-solar-mass clumps of earth-mass planets forming 0.3 Mpc galactic-dark-matter. White-dwarf-heated planet-atmospheres give dimmed SNe Ia events and false gamma-ray-burst luminosity distances, not dark-energy-Lambda. Quasar microlensing observations rule out no-hair black hole models and require galaxy-dark-matter to be planets-in-clumps.
[Moderator: You do not support your claims about the movements of the stars and you have been warned repeatedly in the past of posting article abstracts without any discussion of their contents or why they relate to the thread. Therefore you are suspended 15 days. In addition, the article preprint is nearly a year old without a record of being submitted for publication -- a fatal flaw in a paper which asserts fatal flaws.]
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