Does Mass determine our depth in the fabric of space?

[genphis]

I have not posted for a while,but something has been bugging me. I would like help understanding that if mass makes a dent in the fabric of space, does it mean celestial bodies are sitting at different depths in the fabric, and does that mean the less mass in an object you are then more likely to find it at a higher depth.

More importantly does that imply a top and a bottom? ( as in boundary)

please excuse me if this is nonsense

 

[phinds]

It is nonsense. There IS no "fabric" of space. That's just a VERY poor heuristic used in pop-sci presentation. The extent of nearby mass determines how deep in a gravity well we are but that's all.

 

[genphis]

It is nonsense. There IS no "fabric" of space. That's just a VERY poor heuristic used in pop-sci presentation. The extent of nearby mass determines how deep in a gravity well we are but that's all.

Thanks for your reply, but deep implies depth and the nearby mass must also sit in a gravity well and if everything was at the same depth it would suggest space is uniformly flat?

 

[phinds]

Thanks for your reply, but deep implies depth and the nearby mass must also sit in a gravity well and if everything was at the same depth it would suggest space is uniformly flat?

The only way for everything to "sit at the same depth" in a gravity well would be if there were zero mass throughout the entire universe.

 

[genphis]

The only way for everything to "sit at the same depth" in a gravity well would be if there were zero mass throughout the entire universe.

understood, so is there a super gravity well created by the most dense body and all other wells are within this ?

 

[phinds]

understood, so is there a super gravity well created by the most dense body and all other wells are within this ?

I have NO idea where you got such an idea. EVERYTHING is within the gravity well of everything else.

Take anybody anywhere in space. Techincally, everything within its observable universe has a gravitational influence on it. For all practical purposes only the closest objects have any effect on it and close massive objects tend to swamp the rest of the influences.

 

[genphis]

I have NO idea where you got such an idea. EVERYTHING is within the gravity well of everything else.

Take anybody anywhere in space. Techincally, everything within its observable universe has a gravitational influence on it. For all practical purposes only the closest objects have any effect on it and close massive objects tend to swamp the rest of the influences.

so the warping of space is pretty much localised and our trajectory through space time is entirely influenced by the sun, whose trajectory is influenced by?

 

[phinds]

so the warping of space is pretty much localised and our trajectory through space time is entirely influenced by the sun, whose trajectory is influenced by?

Do you think the International Space Station is influenced more by the Sun or by the Earth?

 

[genphis]

Do you think the International Space Station is influenced more by the Sun or by the Earth?

i get the point, i was just thinking about the big picture, so black holes are most likely major architects in the shape of the universe, as they are more likely to occur via star processes in more varied locations. thanks for enlightening me.

 

[phinds]

i get the point, i was just thinking about the big picture, so black holes are most likely major architects in the shape of the universe, as they are more likely to occur via star processes in more varied locations. thanks for enlightening me.

The supermassive BH at the center of galaxies generally make up 1% to 2% of the mass of the galaxy, so for all but the innermost star systems, the black hole has a very small effect. That's after the galaxy has formed. What we don't know is what role the SMBH's play in the formation of galaxies in the first place. That's a major open question in cosmology, as is how the dickens do SMBH's form at all? The formation of the largest ones seem to be a complete mystery

 

[genphis]

The supermassive BH at the center of galaxies generally make up 1% to 2% of the mass of the galaxy, so for all but the innermost star systems, the black hole has a very small effect. That's after the galaxy has formed. What we don't know is what role the SMBH's play in the formation of galaxies in the first place. That's a major open question in cosmology, as is how the dickens do SMBH's form at all? The formation of the largest ones seem to be a complete mystery

Do the largest smbh's not form of normal star processes as per collapsing star?, and do they only consume and not spew out materiel as per Hawkin's radiation?

 

[phinds]

Do the largest smbh's not form of normal star processes as per collapsing star?, and do they only consume and not spew out materiel as per Hawkin's radiation?

The problem is that stars cannot form that are even remotely big enough to leave a really big SMBH if/when they go supernova and the problem with their growing by "eating" surrounding matter is that things don't fall in directly, they form an accretion disk, not all of which falls in. There hasn't been enough time in the universe so far for such disks to allow the growth of the biggest SMBH's.

We could keep going on this thread until it has turned into a full course on basic cosmology. I would recommend instead that you read such a book or books.

 

[genphis]

The problem is that stars cannot form that are even remotely big enough to leave a really big SMBH if/when they go supernova and the problem with their growing by "eating" surrounding matter is that things don't fall in directly, they form an accretion disk, not all of which falls in. There hasn't been enough time in the universe so far for such disks to allow the growth of the biggest SMBH's.

We could keep going on this thread until it has turned into a full course on basic cosmology. I would recommend instead that you read such a book or books.

maybe it raises a question about the age of the universe, and whether they are remnants of possible older universes ? but thanks again for the information regards genphis

 

[phinds]

maybe it raises a question about the age of the universe, and whether they are remnants of possible older universes ?

No, it does not. Again, read some basic cosmology before forming any theories or floundering about any more. It's best to come at this stuff systematically.

 

[genphis]

No, it does not. Again, read some basic cosmology before forming any theories or floundering about any more. It's best to come at this stuff systematically.

I will do some revising on the subjects thanks

 

[PeterDonis]

if mass makes a dent in the fabric of space

As phinds said, this is a pop science description that is not really useful when you try to work out the actual physics. What's more, even as a pop science description, it only applies to isolated static gravitating bodies. The universe does not fit that description, so even as a pop science description your suggestion does not apply to the universe as a whole.

 

[genphis]

As phinds said, this is a pop science description that is not really useful when you try to work out the actual physics. What's more, even as a pop science description, it only applies to isolated static gravitating bodies. The universe does not fit that description, so even as a pop science description your suggestion does not apply to the universe as a whole.

understood, are all the celestial bodies set in decaying orbits around there gravitational influences, i am trying to understand whether the universes motion has direction ( i suspect direction is relative) but i am having trouble grasping the fact that we are falling around the sun and the sun itself is falling around it's gravitational influence and so on, is that correct?

 

[phinds]

understood, are all the celestial bodies set in decaying orbits around there gravitational influences, i am trying to understand whether the universes motion has direction ( i suspect direction is relative)

It does not. That would imply a preferred reference frame and there is no such thing

but i am having trouble grasping the fact that we are falling around the sun and the sun itself is falling around it's gravitational influence and so on, is that correct?

It is correct for things that are in orbit

 

[PeterDonis]

are all the celestial bodies set in decaying orbits around there gravitational influences

If you look at an isolated bound system, this is more or less correct. But the universe as a whole is not an isolated bound system.

i am having trouble grasping the fact that we are falling around the sun and the sun itself is falling around it's gravitational influence and so on, is that correct?

A given body, like the sun, is part of multiple isolated bound systems. The sun is part of the solar system, which is part of the Milky Way galaxy, which is part of the Local Group of galaxies, which is part of (IIRC) the Virgo supercluster that includes multiple groups of galaxies all bound to each other. At each level, you can view one system as having some kind of orbit in the next larger system.

But, as above, the universe as a whole is not an isolated bound system, so there is no useful sense in which the highest level of bound systems (superclusters) can be said to have an "orbit" in the universe as a whole.

 

[genphis]

If you look at an isolated bound system, this is more or less correct. But the universe as a whole is not an isolated bound system.
A given body, like the sun, is part of multiple isolated bound systems. The sun is part of the solar system, which is part of the Milky Way galaxy, which is part of the Local Group of galaxies, which is part of (IIRC) the Virgo supercluster that includes multiple groups of galaxies all bound to each other. At each level, you can view one system as having some kind of orbit in the next larger system.

But, as above, the universe as a whole is not an isolated bound system, so there is no useful sense in which the highest level of bound systems (superclusters) can be said to have an "orbit" in the universe as a whole.

so the only uniform direction relates to the expansion of the universe ? thank you for clearing up some of the fog in my thoughts

 

[PeterDonis]

so the only uniform direction relates to the expansion of the universe ?

There is no direction to the expansion of the universe, as phinds said.

 

[Mister T]

Thanks for your reply, but deep implies depth

In this case, though, the depth in a gravity well refers to a lower energy, not a lower height.

 

[genphis]

There is no direction to the expansion of the universe, as phinds said.

i am curious as to how something can be said to be expanding without relative direction to support the observation?

 

[PeterDonis]

i am curious as to how something can be said to be expanding without relative direction to support the observation?

The expansion is the same in all directions.

 

[Mister T]

i get the point, i was just thinking about the big picture, so black holes are most likely major architects in the shape of the universe, as they are more likely to occur via star processes in more varied locations. thanks for enlightening me.

Distribution of dark matter may be the thing that's responsible for the distribution of matter in the universe.

 

[genphis]

The expansion is the same in all directions.

just trying to define " no direction " the fact it expands in all directions, still implies direction?

 

[PeterDonis]

the fact it expands in all directions, still implies direction?

If we look at the universe around us, we see that it's expanding--distant galaxies are moving away from us. If we look at the expansion in different directions from us, it looks the same no matter which direction we look. (The more precise term is that the expansion is isotropic.)

 

[genphis]

In this case, though, the depth in a gravity well refers to a lower energy, not a lower height.

If we look at the universe around us, we see that it's expanding--distant galaxies are moving away from us. If we look at the expansion in different directions from us, it looks the same no matter which direction we look. (The more precise term is that the expansion is isotropic.)

is this describing that the space in between the galaxies is expanding? as oppose to the galaxies moving away?

 

[PeterDonis]

is this describing that the space in between the galaxies is expanding? as oppose to the galaxies moving away?

No. "The space is expanding" is a common pop science description, but it's not really correct. The galaxies moving away is what we directly observe (more precisely, we observe their redshifts, and we interpret those as the galaxies moving away because that's the only explanation that leads to a model that matches all observations).

 

[genphis]

No. "The space is expanding" is a common pop science description, but it's not really correct. The galaxies moving away is what we directly observe (more precisely, we observe their redshifts, and we interpret those as the galaxies moving away because that's the only explanation that leads to a model that matches all observations).

so the singularity to inflation describing space being simultaneously created during expansion is not correct?, are all galaxies moving away at the same rate?

 

[Mister T]

so the singularity to inflation describing space being simultaneously created during expansion is not correct?, are all galaxies moving away at the same rate?

Do a google search for "Hubble's Law". The further away the galaxy, the faster it's moving away.

 

[genphis]

Do a google search for "Hubble's Law". The further away the galaxy, the faster it's moving away.

will do thanks for your time guys, i have a lot to think about kind regards to you all

 

[PeterDonis]

so the singularity to inflation describing space being simultaneously created during expansion is not correct?

No. As I said before, that's a pop science description.

Also, if you are looking at the inflation era (which, btw, might not have begun with an initial singularity--we don't know how it began at this point), there were no galaxies then. The only "thing" in the universe was the field driving inflation; that was what was "expanding" (but working out what that term actually means in this context is somewhat complicated since the field is not an "object" or made of "objects" in the ordinary sense).

are all galaxies moving away at the same rate?

No, because they're not all at the same distance from us. The rate of recession we observe for a galaxy depends on its distance from us.

 

[genphis]

No. As I said before, that's a pop science description.

Also, if you are looking at the inflation era (which, btw, might not have begun with an initial singularity--we don't know how it began at this point), there were no galaxies then. The only "thing" in the universe was the field driving inflation; that was what was "expanding" (but working out what that term actually means in this context is somewhat complicated since the field is not an "object" or made of "objects" in the ordinary sense).
No, because they're not all at the same distance from us. The rate of recession we observe for a galaxy depends on its distance from us.

is this to say that the galaxies formed statically in the field and they are moving relative to the fields expansion?

 

[phinds]

so the only uniform direction relates to the expansion of the universe ? thank you for clearing up some of the fog in my thoughts

No, it does not. There IS no "uniform direction" for the expansion of the universe. Again, if this were the case it would imply a preferred frame of reference and there is no such thing.

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