Gravity

[Strange]

21 minutes ago, mistermack said:

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

Because it is a dipole (north and south poles). So they tend to cancel each other out more as you get further away (and they get relatively closer together).

[swansont]

To expand on what Strange said, monopole fields fall off as 1/r^2, while dipole fields fall of as 1/r^3

[mistermack]

Thanks, I get that.

I've got a mental picture of a magnet being like a short pipe in a fluid, with liquid circulating in at one end and out at the other, and the field being like the motion in the fluid around it.

And gravity being like a pipe sucking fluid in, but with nothing coming out. The fluid motion around the first pipe will drop off quicker than the second. 

[Strange]

Tidal force also falls off with inverse cube of distance; this seems to be a sort of mirror image of the magnet case.

[Butch]

Please forgive me if I am rehashing something, I really tried to read all of this post...

Gravity appears much stronger than the other forces of nature because it has the greatest influence on our normal scope of experience... A simple proof that gravity is weaker is that a magnet can lift cars into the air.

I believe this would hold true even in a black hole?

Edited March 9, 2018 by Butch

[Strange]

18 hours ago, Butch said:

Please forgive me if I am rehashing something, I really tried to read all of this post...

Gravity appears much stronger than the other forces of nature because it has the greatest influence on our normal scope of experience... A simple proof that gravity is weaker is that a magnet can lift cars into the air.

I believe this would hold true even in a black hole?

Notarially. Gravitational force would get increasingly strong until the tidal forces ripped the car apart from the magnet, and then ripped apart the car and the magnet.

[Butch]

4 hours ago, Strange said:

Not really. Gravitational force would get increasingly strong until the tidal forces ripped the car apart from the magnet, and then ripped apart the car and the magnet.

But the tearing(stretching actually)would be uniform, although the dimensions would change the car would still be attracted to the magnet, no?

[Strange]

1 hour ago, Butch said:

But the tearing(stretching actually)would be uniform, although the dimensions would change the car would still be attracted to the magnet, no?

Until they were ripped apart by gravity ...

[Butch]

On 3/10/2018 at 6:44 PM, Strange said:

Until they were ripped apart by gravity ...

You mean at the point where we have no knowledge of what happens? Check your math, after all forces near a black hole are relativistic, if you were an observer within the same frame as the car and the magnet you would not notice anything unusual... Who is to say you could not survive the transit?

[Strange]

13 minutes ago, Butch said:

You mean at the point where we have no knowledge of what happens?

No. Long before that. For any reasonable size black hole the tidal forces would be quite enough to tear you apart before you fall through the event horizon. For larger black holes you might survive the event horizon but you would be very rapidly torn apart after that.

[Butch]

7 minutes ago, Strange said:

No. Long before that. For any reasonable size black hole the tidal forces would be quite enough to tear you apart before you fall through the event horizon. For larger black holes you might survive the event horizon but you would be very rapidly torn apart after that.

Torn apart in pieces that are how large?

[Strange]

3 minutes ago, Butch said:

Torn apart in pieces that are how large?

Ultimately atoms and maybe even the atoms would be torn apart. 

https://en.wikipedia.org/wiki/Spaghettification#Inside_or_outside_the_event_horizon

[Butch]

29 minutes ago, Strange said:

Ultimately atoms and maybe even the atoms would be torn apart. 

https://en.wikipedia.org/wiki/Spaghettification#Inside_or_outside_the_event_horizon

I will grant you that such forces might kill a living organism, you will have to go further to convince me of the destruction of matter... Time and space are being affected by a gravitational force that follows the inverse square... also we must factor in initial momentum of the visitor and the angular momentum of the black hole. Perhaps Mr. Hawking would have something surprising to say on the subject.

I see distortion along a path, not destruction of matter or even of a system. Of course everything about the path would be relativistic, no?

Perhaps this deserves a topic?

Let us not forget that ultimately we are speaking of em fields when we speak of matter.

Edited March 12, 2018 by Butch

[Strange]

1 minute ago, Butch said:

Time and space are being affected by a gravitational force that follows the inverse square...

Which is why tidal forces exist. You don't even need a black hole to tear things apart: https://en.wikipedia.org/wiki/Roche_limit

 

[Butch]

1 minute ago, Strange said:

Which is why tidal forces exist. You don't even need a black hole to tear things apart: https://en.wikipedia.org/wiki/Roche_limit

 

I am going to have to study some on this, these ideas are not something I have given thought to contesting before.

Atoms and molecules... Even compounds and macro structures are not held by gravitational force only.

Thank you, Strange you have me thinking.