(Or maybe "What are the smallest objects with mass?")

 

I think I may have seen that  mass may be defined  as a body's resistance to being accelerated.

How would that apply to that smallest massive object?

What would  apply the force ? Another massive object?

Does mass  require another massive object to define itself?

Edited June 27, 20223 yr by geordief

Smallest object with mass or object with the smallest mass?

Elementary particles are pointlike.

Smallest nonzero mass? Probably the neutrino, when considering all flavors with the oscillations.

57 minutes ago, swansont said:

Smallest object with mass or object with the smallest mass?

Elementary particles are pointlike.

Smallest nonzero mass? Probably the neutrino, when considering all flavors with the oscillations.

Yes,that was loose language. I was  really after the smallest known  instance of mass .

So it would be the neutrino? (which from memory was at one time considered  massless)

 

Is a black hole considered to be a massive object?

 

I have read that it should be viewed as an extreme curvature  of spacetime.,

 

Can it be both?

 

Are mass and spacetime curvature  somehow the same thing?

2 hours ago, geordief said:

Is a black hole considered to be a massive object?
I have read that it should be viewed as an extreme curvature  of spacetime.,

The event horizon of a Black Hole can be viewed as an extreme curvature of space-time.
A classical Black Hole will conserve mass, angular momentum and charge.
And, as mass is equivalent to energy, those conserved quantities contribute to  energy-momentum which produces space-time curvature ( gravity ).

7 hours ago, geordief said:

So it would be the neutrino? (which from memory was at one time considered  massless)

At one time, yes. But then it was discovered that neutrinos oscillate between the different “flavors” which requires they have mass. The upper limit (measured in energy) is less than 1 eV

5 hours ago, MigL said:

The event horizon of a Black Hole can be viewed as an extreme curvature of space-time.
A classical Black Hole will conserve mass, angular momentum and charge.
And, as mass is equivalent to energy, those conserved quantities contribute to  energy-momentum which produces space-time curvature ( gravity ).

Do different black holes exhibit different degrees of spacetime curvature  (depending on their radius)?

1 hour ago, swansont said:

At one time, yes. But then it was discovered that neutrinos oscillate between the different “flavors” which requires they have mass. The upper limit (measured in energy) is less than 1 eV

Might it be a requirement for a body to be massive that it have an inner structure of some kind?

Edited June 28, 20223 yr by geordief

48 minutes ago, geordief said:

Might it be a requirement for a body to be massive that it have an inner structure of some kind?

No. Fundamental/elementary massive particles show no evidence of having any internal structure. Electron, muon, tau, and the associated neutrinos, all the quarks.

44 minutes ago, swansont said:

No. Fundamental/elementary massive particles show no evidence of having any internal structure. Electron, muon, tau, and the associated neutrinos, all the quarks.

Well if the neutrino  undergoes a change in flavour doesn't that imply  some sort of internal mechanism?

1 hour ago, geordief said:

Well if the neutrino  undergoes a change in flavour doesn't that imply  some sort of internal mechanism?

No. The neutrinos are oscillating between mass eigenstates, but if there were internal structure there would have to be component particles. There's no evidence of this.

 

28 minutes ago, swansont said:

No. The neutrinos are oscillating between mass eigenstates, but if there were internal structure there would have to be component particles. There's no evidence of this.

 

Ok,thanks.

On 6/28/2022 at 5:28 AM, geordief said:

Do different black holes exhibit different degrees of spacetime curvature  (depending on their radius)?

Yes . Tidal forces are a manifestaion of the degree of curvature.
Large BHs have more 'gentle' curvature, lessened tidal forces, and you can pass through the event horizon without getting 'spaghettified'.
For small BHs the tidal forces are much more extreme, and you should bring along tomato sauce and meatballs.

13 minutes ago, MigL said:

Yes . Tidal forces are a manifestaion of the degree of curvature.
Large BHs have more 'gentle' curvature, lessened tidal forces, and you can pass through the event horizon without getting 'spaghettified'.
For small BHs the tidal forces are much more extreme, and you should bring along tomato sauce and meatballs.

Is there any kind of a "sweet spot" between BHs with infinite curvature  and zero curvature?

Or are there any degrees of curvature  that are more interesting  in ways than others?

I don't know what you mean.
Zero curvatue is flat space, with no gravity fields ( maybe global curvature, if any ), absent any energy-momentum  that gives ise to curvature ( like a BH would )
 

36 minutes ago, MigL said:

I don't know what you mean.
Zero curvatue is flat space, with no gravity fields ( maybe global curvature, if any ), absent any energy-momentum  that gives ise to curvature ( like a BH would )
 

An extremely big BH (maybe one that gobbled up all the others ,if that could happen) would have a curvature approaching zero at its EH,is what I was thinking

 

 

 

On 7/2/2022 at 6:30 PM, MigL said:

Large BHs have more 'gentle' curvature, lessened tidal forces

 

On 7/2/2022 at 9:26 PM, geordief said:

An extremely big BH (maybe one that gobbled up all the others ,if that could happen) would have a curvature approaching zero at its EH,is what I was thinking

Are you thinking that a really large black hole would have such gentle curvature that its approaching zero? 

Sounds like the idea 'the universe is just a very large black hole' even though space appears flat. 

23 minutes ago, Intoscience said:

 

Are you thinking that a really large black hole would have such gentle curvature that its approaching zero? 

Sounds like the idea 'the universe is just a very large black hole' even though space appears flat. 

Yes that idea was in  the back of my mind.I don't know how  supported  or credible that would be .

Thank you for this information about this topic.