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Buckethead
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Spiral galaxies of course rotate around one axis perpendicular to the plane, but has anyone measured if any spiral galaxies are also rotating about an axis through the plane or about any other axis?
Not when looked at correctly. There is one axis of rotation and that is the most concise way to look at it. It can be decomposed into two components. Our brain likes to conceptually decompose the rotation into rotations around two axis because of the symmetry of the gyroscope, the great dominance of the rotation around the mechanical axis of the gyro, and the obvious motion of that mechanical axis.Buckethead said:a gyroscope spinning on a pedestal has two axes of rotation.
This got me thinking about a different problem where the gyro is spinning and also rotating around another axis parallel to the gyro axis, but offset. I don't think that I can say that the motion can be represented by a rotation around a single axis. The axis are parallel, so a single axis creating that motion would also have to be parallel, just offset. But I don't think that a single axis could create that motion. I may have been confusing the angular momentum with the actual physical motion.Buckethead said:If I spin a sheet on paper on a desk while simultaneously rotating it around an axis that is parallel to and intersects the desk, that this is only spinning on one axis?
Chronos said:A galaxy is not a rigid body and N body systems, like a galaxy, have very complex interactions rendering all individual orbits unique. The orbital axes and inclination of any gravitationally bound system can therefor only be generalized. Don't forget orbits are necessarily elliptical and everything tugs on everything else,.
Vanadium 50 said:Why do you think taking a galaxy with cylindrical symmetry and adding a cylinderically symmetric distribution of dark matter will yield a cyllinderically asymmetric angular moment?
Go to StartPage and do a search on "polar ring galaxy."Buckethead said:Spiral galaxies of course rotate around one axis perpendicular to the plane, but has anyone measured if any spiral galaxies are also rotating about an axis through the plane or about any other axis?
Wow, that's great! Thanks for turning me on to that. This doesn't directly address my question, but I'm glad I just learned something new!CygnusX-1 said:Go to StartPage and do a search on "polar ring galaxy."
In real life there is never such a thing as perfection, so I don't see a point to this objection. The variation in the inclinations is only +-3.5 degrees. It would be very difficult for there to be one with a 30 degree inclination, for example.Chronos said:The orbital plane of the solar system, aka the ecliptic, is only approxmately flat , The orbital inclination and even center of mass between each planet and the sun is unique and dynamic, not fixed.
Buckethead said:Spiral galaxies of course rotate around one axis perpendicular to the plane, but has anyone measured if any spiral galaxies are also rotating about an axis through the plane or about any other axis?
I can't parse this. Did you mean to say "revolve" anywhere?stefan r said:Spiral galaxies rotate around their galaxy clusters. The cluster's axis of rotation is mostly independent of the galaxy's axis of rotation.
russ_watters said:I can't parse this. Did you mean to say "revolve" anywhere?
Spiral galaxies are a type of galaxy characterized by a flat, rotating disk of stars, gas, and dust, with a central bulge and spiral arms extending from the center. They are one of the most common types of galaxies in the universe.
Spiral galaxies rotate around a central axis, with the stars and gas moving in a circular or elliptical path. The rotation is caused by the gravitational pull of the galaxy's mass, which is mostly made up of dark matter.
The multiple axes of rotation in spiral galaxies refer to the rotation of the disk and the rotation of the bulge. This is significant because it suggests that spiral galaxies may have formed through the merging of smaller galaxies, each with their own angular momentum.
Scientists study the rotation of spiral galaxies through a technique called spectroscopy. This involves measuring the Doppler shift of light from different parts of the galaxy to determine the speed and direction of their motion. Other methods, such as studying the distribution of mass and using computer simulations, are also used.
Yes, there are other types of galaxies, such as irregular and lenticular galaxies, that also have multiple axes of rotation. However, spiral galaxies are the most common type with this feature, and their rotation patterns provide important insights into the formation and evolution of galaxies in the universe.