Gravity - is it really there?

[chad kincham]

Anyone else ever notice that the explanation of gravity that uses a stretched out sheet with a bowling ball sunk into it to show how a planet’s mass bends space, thus causing other objects to be drawn to it by falling down into the resulting sunken area, requires an already existing gravitational pull, to pull the bowling ball down into the sheet, and pull objects down into the sunken area of the sheet?

 

[Kylie]

Anyone else ever notice that the explanation of gravity that uses a stretched out sheet with a bowling ball sunk into it to show how a planet’s mass bends space, thus causing other objects to be drawn to it by falling down into the resulting sunken area, requires an already existing gravitational pull, to pull the bowling ball down into the sheet, and pull objects down into the sunken area of the sheet?

Yeah, I've heard a lot of scientists say it's not a great way to illustrate it.

I look at it like a grid, and when you place objects on it, the gridlines are drawn towards the object.

 

[essentialsaltes]

Anyone else ever notice that the explanation of gravity...

It's an illustrative analogy, not an explanation. No spandex is involved in GR.

 

[FrumiousBandersnatch]

Yeah, I've heard a lot of scientists say it's not a great way to illustrate it.

I look at it like a grid, and when you place objects on it, the gridlines are drawn towards the object.

I think the rubber sheet analogy is a good first step physical visualisation before introducing a more abstract 3D grid distortion. A few people may get confused that gravity is being used to illustrate gravity, but they're missing the illustrative point of the analogy.

 

[JohnEmmett]

but they're missing the illustrative point of the analogy.

there is no analogy

because it is not understood

 

[FrumiousBandersnatch]

there is no analogy
because it is not understood

The analogy is with the Einsteinian model of gravity.

 

[JohnEmmett]

The analogy is with the Einsteinian model of gravity.

probably the best analogy we have. That doesn’t actually make it much good.

 

[FrumiousBandersnatch]

there is no analogy

probably the best analogy we have. That doesn’t actually make it much good.

Somewhat contradictory... and your link agrees that it's an analogy to Einsteinian gravity.

 

[JohnEmmett]

Einsteinian gravity.

as I said, we don't understand gravity…

 

[essentialsaltes]

as I said, we don't understand gravity…

Speak for yourself.

 

[JohnEmmett]

Speak for yourself.

does not apply

 

[Hans Blaster]

does not apply

Your failure to understand gravity is not reflective of others who do understand it.

 

[JohnEmmett]

Your failure to understand gravity is not reflective of others who do understand it.

could be that aliens understand…

 

[SelfSim]

could be that aliens understand…

What are 'aliens' and how do you come to understand them?

 

[JohnEmmett]

What are 'aliens' and how do you understand them?

the Hopi Tribe of Arizona constructed their land to match the Orion constellation with the help of otherworldly gods

 

[SelfSim]

i) They've 'called it home' for only 1,000 years .. and you call that 'ancient'?
ii) The dude describing Orion's 'left' shoulder and 'right' shoulder has got all that back to front, therefore the tribe has been living at the wrong site for 1,000 years! Misled by their aliens, they are!

 

[JohnEmmett]

i) They've 'called it home' for only 1,000 years .. and you call that 'ancient'?

the Hopi remember the first world

& Atlantis

 

[Hans Blaster]

the Hopi remember the first world

& Atlantis

Graham Hancock is a terrorist. He has destroyed the thought processes of so, so, many people.

 

[JohnEmmett]

Graham Hancock is a terrorist.

this is called a straw man argument


From Wikipedia

 

[FrumiousBandersnatch]

this is called a straw man argument
From Wikipedia

No, it's not. It's an opinion.