spiral galaxies

[harry]

Hello All

The question that I have with the spin is this.

Do all galaxies go through varies phases and shapes during their evolution.

[nomystics]

tell me what "direction" is up.

Philosophically speaking, the human mind is capable of forming any question. This however does not mean the question is logically or scientifically valid.

For example, standing at the north pole, the order to "point to the east" seems like a reasonable request but clearly the only direction is south.

These type of questions, to a scientifically trained mind, are instantly recognized as invalid or metaphysical and are not pursued as a matter of course. In fact, they cannot be asked, but it doesn't stop people from asking them and even more people from formulating answers to them and even more people believing in those answers.

You might as well ask "what is the meaning of life, the universe, and everything in it?" Or is there a god?

The answer, as far I remember, is 49.



Seriously, I don't mean to be disparaging of the question. We must always question and honour the inquisitive mind. Its just that like my handle, I try to eliminate the mystical aspects and keep things grounded in reality.

Empirical evidence, like democracy, isn't perfect, but its the best we have.

[harry]

Hello Nomystics

What are you trying to say?

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Ok I think there is a pattern in the evolution of stars and formation of galaxies and Black holes.

Once this pattern is worked out I would assume it could apply to the infinite universe not just the part we see.

[John Russell]

Hello Nomystics,

I believe you don't understand the question. It is not metaphysical nor philisophical nor even religious in nature. It is scientific. Why does the galaxies spin in ANY direction, north, south, east, west, whatever u like. If it is gravity, then explain. If black holes, explain. If by some other force. explain....in scientific terms.

Thank you,


John

[BMAONE23]

tell me what "direction" is up.

As odd as it sounds, it is only logical that "up" is any direction that is in opposition to the direct force of gravity.

[Qev]

Hello Nomystics,

I believe you don't understand the question. It is not metaphysical nor philisophical nor even religious in nature. It is scientific. Why does the galaxies spin in ANY direction, north, south, east, west, whatever u like. If it is gravity, then explain. If black holes, explain. If by some other force. explain....in scientific terms.

Well, it's basically a result of the combination of the random motions of gas clouds and the always-attractive force of gravity. Any two gravitating masses, unless they have zero lateral velocity relative to each other, are going to follow curving paths around a common center of gravity. So given any two (or more) massive gas clouds moving through space, they'll inherently, due to gravity, convert their linear motion through space into angular motion around each other. Due to friction and other effects, the majority of the gases will eventually confine themselves to the plane of rotation of the greatest amount of mass.

As for where all the random velocities came from, probably small-scale quantum effects during the initial stages of the Big Bang were magnified by inflation.

[Martin]

Exactly what I said but only l-o-n-g-e-r.

[eyecapitain1]

Just as the side slew of planetary rotation,combine with the constant downforce of gravity to the center of a moving mass,causes huricanes and typhoon to rotate,galaxies experience the same phenomena
Qev nailed it!
Many random processes acting as a collective to give us beautifull views of the billions of lovely spiral galaxies scattered like art work through the cosmos.
Enjoy! many who lived for this never had the opportunity to experience the wonders we can see from our easy chairs here.
Three more cheers for APOD!

[Qev]

Exactly what I said but only l-o-n-g-e-r.

What can I say, I'm spammy.

[harry]

Hello All

Can an elliptical galaxy form a spiral galaxy?

or

Can a spiral galaxy form an elliptical galaxy.

What would cause such changes?

[Galactic Groove]

Can an elliptical galaxy form a spiral galaxy?

Interesting... I guess we could start by taking a look at the relative ages of both forms of galaxies. Assuming we find a distinctive difference between their ages, we may hypothesize one type "could" become the other over time...

[Pete]

Hello All

Can an elliptical galaxy form a spiral galaxy?

or

Can a spiral galaxy form an elliptical galaxy.

What would cause such changes?

observations of actual systems and simulations of merging galaxies on a computer suggest that merging spirals create elliptical galaxies.

http://curious.astro.cornell.edu/galaxies.php

[harry]

Hello Pete

I read your link.

Its not what I was after but! for now it will do.

It makes the following note:

What do mergers leave behind? Both observations of actual systems and simulations of merging galaxies on a computer suggest that merging spirals create elliptical galaxies. The gas in the progenitor spiral galaxies is used up in making stars which subsequently eject heavier elements and dust from the system, and the collision is forceful enough to randomize the orbits of the stars in the incoming disks into a spheroidal shape. Different types of galaxies are therefore intimately linked by galaxy evolution and mergers: spiral galaxies evolve into elliptical galaxies, and irregular galaxies are galaxies in the process of becoming one or the other!

Which basically says what I mean?

There is some form of recycling process that enable spiral to elliptical and elliptical to spiral and so on.