Star movment direction in an active galaxy

[David Levy]

Based on Wikipedia:

 

1. Star birth at the center of the galaxy:

"The region where the Scutum–Centaurus Arm arm connects tothe bar of the galaxy is rich in star-forming regions"

"The current hypothesisis that the bar structure acts as a type of stellar nursery,fueling star birthat their centers".

 

 

2. Older stars as move outwards from the center:

"The metallicity of anastronomical object may provide an indication of its age… older stars havelower metallicities than younger stars such as our Sun".

"Across the MilkyWay, metallicity is higher in the galactic centre anddecreases as one moves outwards".

"Population I or metal-rich stars are thoseyoung stars whose metallicity is highest. The Earth's Sun is an example of a metal-richstar. These are common in the spiralarms of the Milky Waygalaxy".

 

 

3. Very Old stars at the dwarf galaxies arround the Milky way:

"Ursa dwarf ellipticalgalaxy: By Wikipedia "The galaxy consists mainly of older stars and there appears to be little to noongoing star formation in the Ursa Minor Dwarf galaxy"

"Antlia Dwarf: ByWikipedia "The galaxy contains stars of all ages but is dominated by oldstars with the age of more than 10 billion year".

 

Question?

 

If the stars are getting older as move outwards from the galaxy center, does it mean that the stars are moving outwards?

Edited May 27, 2012 by David Levy

[JohnStu]

Based on Wikipedia:

 

1. Star birth at the center of the galaxy:

"The region where the Scutum–Centaurus Arm arm connects tothe bar of the galaxy is rich in star-forming regions"

"The current hypothesisis that the bar structure acts as a type of stellar nursery,fueling star birthat their centers".

 

 

2. Older stars as move outwards from the center:

"The metallicity of anastronomical object may provide an indication of its age… older stars havelower metallicities than younger stars such as our Sun".

"Across the MilkyWay, metallicity is higher in the galactic centre anddecreases as one moves outwards".

"Population I or metal-rich stars are thoseyoung stars whose metallicity is highest. The Earth's Sun is an example of a metal-richstar. These are common in the spiralarms of the Milky Waygalaxy".

 

 

3. Very Old stars at the dwarf galaxies arround the Milky way:

"Ursa dwarf ellipticalgalaxy: By Wikipedia "The galaxy consists mainly of older stars and there appears to be little to noongoing star formation in the Ursa Minor Dwarf galaxy"

"Antlia Dwarf: ByWikipedia "The galaxy contains stars of all ages but is dominated by oldstars with the age of more than 10 billion year".

 

Question?

 

If the stars are getting older as move outwards from the galaxy center, does it mean that the stars are moving outwards?

 

 

"Older stars as move outwards from the center"

 

 

 

Could you rephrase that please

[David Levy]

Further your question:

 

 

1. Wikipedia: "older stars have lower metallicities than younger stars"

Therefore: Metallicity decreases as the stars get olders.

2. Wikipedia: "Across the MilkyWay, metallicity is higher in the galactic centre and decreases as one moves outwards".

Therefore: There are older stars as one move outwards from the galactic center of the Milky way galaxy.

 

Hence: do you agree with the following statment?

 

In an active galaxy - Milky way, The stars are moving outwards from the galactic center!!!

 

 

This statment has a huge impact on our understanding of the starting point - Big bang.

More info will be follow!!!

Edited May 28, 2012 by David Levy

[ACG52]

Therefore: Metallicity decreases as the stars get olders.

 

No, it means that the older generation of stars were formed before many supernova created the heavier metals and blew them into space.

 

"Across the MilkyWay, metallicity is higher in the galactic centre and decreases as one moves outwards".

Therefore: There are older stars as one move outwards from the galactic center of the Milky way galaxy.

 

No, it means that there have been a greater number of supernova where there is a greater concentration of stars, and thus more heavy elements are created.

 

Hence: do you agree with the following statment?

 

In an active galaxy - Milky way, The stars are moving outwards from the galactic center!!!

 

No. Your founding premises are faulty. Stars orbit the galactic center.

[David Levy]

You miss the point!!!

"The metallicity of an astronomical object may provide an indication of its age". For more information please see Wikipedia - http://en.wikipedia.org/wiki/Metallicity.

Supernova is a star expulsive. There is no impact on star Metallicity. For more info please see Wikipedia - http://en.wikipedia.org/wiki/Supernova

 

With regards to your reply:

No. Your founding premises are faulty. Stars orbit thegalactic center.

Yes, sure, Stars orbit the galactic center. Never the less, we must verify if the stars are moving outwards on inwards after each orbit cycle...

For example, the moon orbits the Earth. Never the less,based on NASA verification it moves few centimeters outwards every year.

Mars might be another good example for a star is a disc shape system as it orbits the sun;

By Wikipedia:"Landforms visible onMars strongly suggest that liquid water has at least at times existed on theplanet's surface".

Hence,in order to enable liquid water, it must have been in a similar zone location as the earth today.

Therefore,in the past it was closer to the sun. So, it surly moved outwards.

 

Conclusion– We might assume that in a disc shape system, the stars are moving outwards!!!

The Milky way is a disc shape system... Never the less, the metallicity gives a solid proof by itself that the stars are moving outwards from the galactic center!!!

 

 

Edited May 28, 2012 by David Levy

[ACG52]

"The metallicity of an astronomical object may provide an indication of its age".

 

Yes, it can provide an indication of which generation of stars it belongs to. It does not mean that as a given star ages, it loses metallicity. In fact, since all heavier elements are created inside stars, as a star ages, it metal content increases.

 

Supernova is a star expulsive. There is no impact on star Metallicity.

 

All elements heavier than iron are produced in supernova explosions and scattered throughout the universe.

 

For example, the moon orbits the Earth. Never the less,based on NASA verification it moves few centimeters outwards every year.

 

Due to a loss of angular momentum.

 

Hence,in order to enable liquid water, it must have been in a similar zone location as the earth today.

Therefore,in the past it was closer to the sun. So, it surly moved outwards.

 

 

You've taken a line from wikipedia (not the best source, just the easiest) and jumped to an unfounded conclusion. Mars was created in pretty much the same orbit it's in now. The spacing of the planets and their orbits follow Kepler's law.

 

Never the less, the metallicity gives a solid proof by itself that the stars are moving outwards from the galactic center!!!

 

 

You don't seem to have a good grasp of how metals are produced or distributed throughout the galaxy, and have therefore taken a brief line from wiki and jumped to another unfounded conclusion.

[Janus]

 

Yes, sure, Stars orbit the galactic center. Never the less, we must verify if the stars are moving outwards on inwards after each orbit cycle...

For example, the moon orbits the Earth. Never the less,based on NASA verification it moves few centimeters outwards every year.

The Moon moves outward due to tidal interaction. The Moon creates a tidal bulge in the Earth and friction between this bulge and the solid Earth leads to an exchange of angular momentum.

There are two reasons that this doesn't work for stars orbiting the galactic center. One is that these stars are evenly distributed around the center, thus they cancel each other out when it comes to forming a tidal bulge. The other is that the galactic center is not a solid body. Even if a bulge formed, there would be no friction between it and the center. Ergo, the mechanism that leads to the Moon's recession does not come into play with stars orbiting in the galaxy.

 

 

Mars might be another good example for a star is a disc shape system as it orbits the sun;

By Wikipedia:"Landforms visible onMars strongly suggest that liquid water has at least at times existed on theplanet's surface".

Hence,in order to enable liquid water, it must have been in a similar zone location as the earth today.

Therefore,in the past it was closer to the sun. So, it surly moved outwards.

 

Mars was able to maintain a higher temp and liquid water because it used to have a thicker atmosphere. This in turn was due to the fact that it used to geologically active. This has two effects. One is that such activity tends to out gas, supplying gasses to the atmosphere. The other is that it allows for the dynamo effect that produces a magnetic field. The magnetic field shields the planet from the solar wind that tends to strip away the atmosphere. Mars, being a much smaller body than the Earth, cooled faster. When its lost it interior heat, it quit adding to the atmosphere and it lost its magnetic shield. The solar wind stripped most of the atmosphere away, leaving Mars as it is today. There is no need for it to have been closer to the Sun.

 

Conclusion– We might assume that in a disc shape system, the stars are moving outwards!!!

 

 

No, we might not, both of your examples are based on erroneous assumptions.

[J.C.MacSwell]

Could the Hubble expansion displace them outward over time? Assuming the expansion is proportional to distance, and gravity is proportional to the inverse square law (though it seems otherwise, if only detectable mass is assumed)...

 

Is there any observable outward movement (how many years might that take?)

[ACG52]

Could the Hubble expansion displace them outward over time? Assuming the expansion is proportional to distance, and gravity is proportional to the inverse square law (though it seems otherwise, if only detectable mass is assumed)...

 

Is there any observable outward movement (how many years might that take?)

 

 

What is 'them'? The Earth-moon system?

 

Cosmological expansion come into play at distances of 200 million light years. On scales smaller than that, expansion is overcome by gravity.

[J.C.MacSwell]

What is 'them'? The Earth-moon system?

 

Cosmological expansion come into play at distances of 200 million light years. On scales smaller than that, expansion is overcome by gravity.

 

them = Stars in a Galaxy as per the OP

 

Obviously any expansion effect is undetectable over the distance to the moon.

 

Is this also true for 100,000 light years? (I don't know)

 

Can gravity exactly compensate for expansion at any scale?

[David Levy]

To ACG52

 

 

 

The knowledge is available at Wikipedia

It's up to us to except or reject it.

 

If it is stated at Wikipedia: "olderstars have lower metallicities than younger stars". While you claim: It does not mean that as a given star ages, it loses metallicity...

 

Then, sorry, I have no intention to argue about it...

 

If you have a solid proof that your statement is correct than please forward this update to Wikipedia...

Edited May 28, 2012 by David Levy

[ACG52]

them = Stars in a Galaxy as per the OP

 

Obviously any expansion effect is undetectable over the distance to the moon.

 

Is this also true for 100,000 light years? (I don't know)

 

Can gravity exactly compensate for expansion at any scale?

 

 

It's not that gravity exactly compenstates, it completely overwhelms. It's not that the expansion is undetectable over distances of less than 200 million lightyears, it doesn't happen at all. It tries to, but it's like an ant banging up against a brick wall. The ant tries to knock it down, but nothing happens.

 

To ACG52

 

 

 

Theknowledge is available at Wikipedia

It's up to us toexcept it or reject.

 

If it is stated at Wikipedia: "olderstars have lower metallicities than younger stars". While you claim: It does not mean that as a given star ages, itloses metallicity...

 

Then, sorry, I have no intention to argueabout it...

 

 

 

If you have a solid proof that your statementis correct than please forward this update to Wikipedia...

 

 

 

'Older stars' means stars of the previous generation. Stars that were created longer ago. They do not mean that stars lose metals as they age. To the contrary, as individual stars age they create metals via stellar nucleosynthesis. (Since you're a big fan of wiki, here's the link: http://en.wikipedia.org/wiki/Stellar_nucleosynthesis)

 

And please don't confuse wikipedia with an education.

[David Levy]

There is a way to verify the star age!!!

It is state very clearly at Wikipedia how they do it.

 

With Regards to the Stellar nucleosynthesis: Did you find any info that it is considered as a valid system for star age verification?

 

Anyhow, Ifyou have better knowledge how to verify the star age, then please let Wikipedia know about it.

 

I would mostly appriciate to get a reply from Wikipedia about this highly important issue.

Edited May 28, 2012 by David Levy

[ACG52]

No one is talking about star age verification. I was explaining something which you clearly misunderstand, to wit, the phrase 'star's age'.

 

If you read the link on stellar nucleosynthesis, you will see that as individual stars age, they produce metals.

 

But there are some things which are simply not meant to be.

Edited May 28, 2012 by ACG52

[J.C.MacSwell]

It's not that gravity exactly compenstates, it completely overwhelms. It's not that the expansion is undetectable over distances of less than 200 million lightyears, it doesn't happen at all. It tries to, but it's like an ant banging up against a brick wall. The ant tries to knock it down, but nothing happens.

 

 

 

Well, obviously over some distances of 200 million light years it is happening (45-50 km/s) or it would not happen at all, period.(correct?)

 

You mean within Galaxies?

 

Edit:"obviously" may not be my best choice of word with regard to that rate at that distance...

Edited May 28, 2012 by J.C.MacSwell

[Janus]

There is a way to verify the star age!!!

It is state very clearly at Wikipedia how they do it.

 

 

 

You are misinterpreting what they meant. In this case, "Older stars are less metallic than younger ones" is akin to saying the "Older people are more likely to to have driven a stick shift than younger people". It does not mean that people drive stick shifts more as they get older, but that stick shifts were more prevalent when people who are older now learned to drive.

 

In the same way, Older stars are less metallic because when they first formed the universe as a whole was less metalic.

 

You need to take the whole context in which the statement is made. To wit, from the Wikipedia article:

 

The metallicity of an astronomical object may provide an indication of its age. When the universe first formed, according to the Big Bang theory, it consisted almost entirely of hydrogen which, through primordial nucleosynthesis, created a sizeable proportion of helium and only trace amounts of lithium and beryllium and no heavier elements. Therefore, older stars have lower metallicities than younger stars such as our Sun.

Contents

 

 

 

Stellar populations are categorized as I, II, and III, with each group having decreasing metal content and increasing age. The populations were named in the order they were discovered, which is the reverse of the order of their formation. Thus, the first stars in the universe (low metal content) were population III, and recent stars (high metallicity) are population I.

 

 

Note the "may" in the first sentence, and then the later statements that indicate that the low metallicity is due to when the stars formed and the amount of metals available for them at that time. At no point do they claim that stars become less metallic as they age.

[ACG52]

Well, obviously over some distances of 200 million light years it is happening (45-50 km/s) or it would not happen at all, period.(correct?)

 

 

At 200 million lightyears from a gravitationally bound system, such as the Virgo galactic group, of which our galaxy is a member, expansion happens, at the rate of 73 km/sec/megaparsec.

 

Closer than 200 million lightyears to any galactic group, gravity overcomes expansion.

 

Keep in mind, the universe is pretty damn big.