Gravity

[jajrussel]

If you consider that as a force gravity pulls in an infinite number of directions would it still be the weakest of forces if you applied the same terms to other forces?

 

[koti]

56 minutes ago, jajrussel said:

If you consider that as a force gravity pulls in an infinite number of directions would it still be the weakest of forces if you applied the same terms to other forces?

 

Gravity does not pull from infinite number of directions afterall your feet always stay on the surface of the earth and you never fly away into space. Gravity compared to other forces is extremely weak but its not so obvious...electromagnetism and the strong and weak forces dominate the particle level world where the large scale, planterary and gallactic world is dominated by gravity. Ofcourse you can easly pick up a 1kg neodimium magnet from the ground „defeating” earth’s gravity and you will have problems unsticking that same magnet from a big piece of steel which implies that gravity is much weaker (and it kind of is) than electromagnetism but this is not a good comparison in my opinion... in the large cosmic scale gravity defeats all other forces, black holes being an extreme example. 

[Strange]

32 minutes ago, koti said:

Gravity does not pull from infinite number of directions

Strictly speaking, it does. It is just dominated by the largest nearby mass (the Earth). You will be slightly stretched by the Moon and Sun (like the tides) and everything else in the universe probably has an immeasurably small effect.

But no, this is not the reason that gravity appears weak.

[koti]

5 minutes ago, Strange said:

Strictly speaking, it does. It is just dominated by the largest nearby mass (the Earth). You will be slightly stretched by the Moon and Sun (like the tides) and everything else in the universe probably has an immeasurably small effect.

But no, this is not the reason that gravity appears weak.

I might be wrong but I think jayjrussel might be confused as to a single source of gravity. 

[swansont]

2 hours ago, jajrussel said:

If you consider that as a force gravity pulls in an infinite number of directions would it still be the weakest of forces if you applied the same terms to other forces?

All of the other forces pull in an infinite number of directions, too. Newtonian gravity and electrostatics, for example, have the exact same form of equation.

Gravity being weakest can be assessed by looking at the coupling constants.

http://hyperphysics.phy-astr.gsu.edu/hbase/Forces/couple.html

[jajrussel]

☺ well I am confused...

17 minutes ago, swansont said:

All of the other forces pull in an infinite number of directions, too. Newtonian gravity and electrostatics, for example, have the exact same form of equation.

Gravity being weakest is assessed by looking at the coupling constants.

http://hyperphysics.phy-astr.gsu.edu/hbase/Forces/couple.html

Thanks I read this.

[Itoero]

3 hours ago, jajrussel said:

If you consider that as a force gravity pulls in an infinite number of directions would it still be the weakest of forces if you applied the same terms to other forces?

 

A gravitational field's strength is decided by the present mass. So what does it mean when people say gravity is the weakest of forces?

[jajrussel]

13 minutes ago, Itoero said:

A gravitational field's strength is decided by the present mass. So what does it mean when people say gravity is the weakest of forces?

☺!

[MigL]

I believe the ratio of the Electromagnetic strength compared to Gravitational is generated from the most familiar fundamental particle, the electron. This ratio is approx. 10^39 times greater.

However, since gravity is self-coupling, as you get to even smaller scales, like the Planck scale, where the 'fundamental' mass would be approx. 2*10^-8, the relative strengths are about two orders of magnitude. In Gravity's favor.

[jajrussel]

1 hour ago, swansont said:

 

1 hour ago, jajrussel said:

☺!

Okay now me feelings are hurt! What exactly did I say here that earned a down vote?

[swansont]

3 minutes ago, jajrussel said:

Okay now me feelings are hurt! What exactly did I say here that earned a down vote?

Why are you asking me? 

[jajrussel]

7 minutes ago, swansont said:

Why are you asking me? 

Am I? I hit the submit button by accident. I didn't see the quote I wanted so I selected the proper quote then reposted. I tried to make the original quote selected go away, but apparently after hitting submit you don't make a quote go away.

I could start all over again and try to get it right, but my feelings aren't really hurt, and I would probably just screw it up again. So, sorry...☺

[Itoero]

4 minutes ago, jajrussel said:

Okay now me feelings are hurt! What exactly did I say here that earned a down vote?

Because you answer with a smiley and an exclamation mark. Perhaps I misinterpret you, It looks like you find my question to be silly.

What does gravity being the weakest force mean when you deal with a black hole?

[jajrussel]

3 minutes ago, Itoero said:

Because you answer with a smiley and an exclamation mark. Perhaps I misinterpret you, It looks like you find my question to be silly.

What does gravity being the weakest force mean when you deal with a black hole?

No, actually I thought you understood my question better than anyone else. I'm sorry you misunderstood...

[MigL]

Sorry, forgot units.
Planck mass is about 2*10^-8 Kg.
It is a large mass ( compared to electron's ) because close separations mean hi energy.
And I would like to add that is a calculated ratio, as we can't achieve Planck scale energies to measure it.

Whether that's a more accurate representation of relative strengths, it really makes no difference.
Although some GUTs predict equal strength for all forces at Planck scale.

[koti]

1 hour ago, jajrussel said:

Okay now me feelings are hurt! What exactly did I say here that earned a down vote?

Try not to worry about that instead read MigL's posts. As for the Planck units mentioned, it is accepted that space is quantized meaning it consists of small portions which cannot be divided - this is referred to as Planck length.

[jajrussel]

Okay, i finally remembered what made me ask the question in the first place. It was a video about photons. Now, to see if I can explain in a non confusing way. In the video the photon starts somewhat near the center and works it's way out. The energy of the photon is like tiny. I'm told to think of it as a tiny packet of energy. In my head I am following it back to the source where I am presented with a large amount of energy. Considering the source of energy I may have shot from the hip when I asked myself is it okay to apply the same thought to gravity? Considering swansont's post I thought what? No way they are comparing gravity using wave peaks. That seems to close considering I shot from the hip. I'm still scrutinizing, and probably misunderstanding that reference.

I really liked MigL's answer and was tempted to jump behind it and say, yep this is exactly what I meant... But no it wasn't. Sadly, it was just me watching a video, having a thought, and then questioning accepted science, just because that seems to be my nature. So thanks everyone.

4 hours ago, swansont said:

All of the other forces pull in an infinite number of directions, too. Newtonian gravity and electrostatics, for example, have the exact same form of equation.

Gravity being weakest can be assessed by looking at the coupling constants.

http://hyperphysics.phy-astr.gsu.edu/hbase/Forces/couple.html

I copied this from the hyperphysics page (The strength of the gravitational force can be related to the force between two selected masses.)

[Itoero]

1 hour ago, jajrussel said:

No, actually I thought you understood my question better than anyone else. I'm sorry you misunderstood...

I'm sorry then, I fixed it.

[jajrussel]

49 minutes ago, jajrussel said:

Okay, i finally remembered what made me ask the question in the first place. It was a video about photons. Now, to see if I can explain in a non confusing way. In the video the photon starts somewhat near the center and works it's way out. The energy of the photon is like tiny. I'm told to think of it as a tiny packet of energy. In my head I am following it back to the source where I am presented with a large amount of energy. Considering the source of energy I may have shot from the hip when I asked myself is it okay to apply the same thought to gravity? Considering swansont's post I thought what? No way they are comparing gravity using wave peaks. That seems to close considering I shot from the hip. I'm still scrutinizing, and probably misunderstanding that reference.

I really liked MigL's answer and was tempted to jump behind it and say, yep this is exactly what I meant... But no it wasn't. Sadly, it was just me watching a video, having a thought, and then questioning accepted science, just because that seems to be my nature. So thanks everyone.

I copied this from the hyperphysics page (The strength of the gravitational force can be related to the force between two selected masses.)

There was actually a question I was going to ask with this post, but by the time I figured out how to get rid of the orange high lite that was attached to my cursor I figured out that I was misinterpreting the statement. Then I realized that once again I managed to mess up the post because it shows up as an edit. Time for a nap...

18 minutes ago, Itoero said:

I'm sorry then, I fixed it.

Thanks!

Edited February 3, 2018 by jajrussel
It was not my intent to edit. I can't seem to post without everything ending up combined?

[beecee]

7 hours ago, jajrussel said:

If you consider that as a force gravity pulls in an infinite number of directions would it still be the weakest of forces if you applied the same terms to other forces?

 

Let me as a lay person try and answer your question in as simple a fashion as possible in Newtonian fashion.. There are four known forces....the strong nuclear, the weak nuclear, electromagnetism and gravity. Per capita, or per fundamental particle, the strong nuclear force is by many orders of magnitude  stronger then gravity...But this force  only acts over very short ranges, within the range of atomic distances. Likewise the weak nuclear force. So we really don't experience these too much in every day life.

We do though experience the EMF which is also per fundamental particle stronger then gravity and like gravity acts over long distances, falling off as per the inverse square of the distances involved. But the EMF  tends to cancel itself out due to opposing positive and negative charges.

Gravity though while acting over long distances, is totally accumulative and is also only attractive. In effect, gravity has no limitations, and can be increased ad-infinitum as mass is gathered. Gravity is why we have stars, it is why stars can form BHs, and why BHs have an EH from which nothing can ever escape.

[koti]

20 minutes ago, beecee said:

Let me as a lay person try and answer your question in as simple a fashion as possible in Newtonian fashion.. There are four known forces....the strong nuclear, the weak nuclear, electromagnetism and gravity. Per capita, or per fundamental particle, the strong nuclear force is by many orders of magnitude  stronger then gravity...But this force  only acts over very short ranges, within the range of atomic distances. Likewise the weak nuclear force. So we really don't experience these too much in every day life.

We do though experience the EMF which is also per fundamental particle stronger then gravity and like gravity acts over long distances, falling off as per the inverse square of the distances involved. But the EMF  tends to cancel itself out due to opposing positive and negative charges.

Gravity though while acting over long distances, is totally accumulative and is also only attractive. In effect, gravity has no limitations, and can be increased ad-infinitum as mass is gathered. Gravity is why we have stars, it is why stars can form BHs, and why BHs have an EH from which nothing can ever escape.

If I may, I will add to your post that gravity is the curvature of space-time so when dealing with describing reality with GR which works well in large scales (when it doesn't work well in small scales the issue still seems to be there even or especially in QFT's) there seems to be an issue with gravity being a force. The other day I had a conversation with #Mordred and I "complained" that gravity is referred to as a force and he seemed to share my disappointment. Science is ofcourse still open to detecting a graviton but until that happens I wish that gravity would be referred to as curvature which is a property of space-time and not a force - it might be confusing especially to laypeople like myself or jajrussel.  

[MigL]

All depends on how you define a field.
And different models use different definitions.

In the Newtonian model, gravity is defined as the gradient of a vector field ( potential).

In the GR model, the metric tensor is the field ( potential ), and the metric tensor is basically space-time curvature or geometry.
As AJB once said "In GR, geometry is the field".
 

 

[Bender]

Gravity not being a force depends on context and definition. In most situations considering gravity a force works great.

Likewise, the weak interaction doesn't feel very force like in the conventional sense of a predictable mechanical force.

[swansont]

Once you get to the nuclear scale (i.e. invoking quantum mechanics) weak and strong are often discussed as interactions rather than forces.

[mistermack]

Why does magnetic attraction reduce so quickly over distance, compared to gravity? ( I don't know the answer ).