Why does the Earth rotate around the sun?

[DaveC426913]

I'm not a 2012 woo-woo-er.

No, but HOT_SOUP might be.

 

[ucf-fisher21]

sneez,

whoops. This experiment just proves that gravity can bend light, not that space is curved.

 

[tiny-tim]

bending of light

whoops. This experiment just proves that gravity can bend light, not that space is curved.

Hi ucf-fisher21!

No, because light has mass (though not rest-mass), so even without space curvature it would be bent by gravity.

You can calculate that general relativity (with curvature of space) produces twice the bending expected without space curvature.

And that experiment did indeed verify (very approximately) the higher figure.

In other words, it proved that gravity can bend light and that the bending is caused by something more than "flat" gravity.

 

[ucf-fisher21]

tiny-tim,

this space curvature...is it the space-time 'fabric' that is being curved? If so, how is time affected?

also, in what dimensions is this curvature taking place?

 

[tiny-tim]

Hi ucf-fisher21!

tiny-tim,

this space curvature...is it the space-time 'fabric' that is being curved?

Yes, "flat" gravity would be in "flat" space-time fabric.

Experiments show that space-time fabric is curved.

If so, how is time affected?

Well, the stronger the curvature, the slower time goes … but I don't know a simple explanation for that.

also, in what dimensions is this curvature taking place?

"Curved" just means that the geometry isn't Euclidean (flat).

It doesn't mean that there's some higher-dimensional flat space in which "real" curvature can be seen.

It's just a word.

 

[ucf-fisher21]

tiny-tim,

isn't time a dimension?... and if time slows down as the curvature increases, wouldn't this curvature physically exist in the dimension of time?

 

[tiny-tim]

tiny-tim,

isn't time a dimension?... and if time slows down as the curvature increases, wouldn't this curvature physically exist in the dimension of time?

ah … now that's a question about time that I can answer …

time is one of the four dimensions of the curved space-time fabric, so it can't be an "outside" dimension for the curvature to be seen in!

 

[ucf-fisher21]

tiny-tim,

Are you saying that for curvature to physically exist, there has to be an 'outer dimension' where it can be seen?
I'm just trying to find out if this curvature physically exists in a dimension (such as time), not if it can be seen from some 'outer dimension.'

 

[tiny-tim]

tiny-tim,

Are you saying that for curvature to physically exist, there has to be an 'outer dimension' where it can be seen?
I'm just trying to find out if this curvature physically exists in a dimension (such as time), not if it can be seen from some 'outer dimension.'

I don't see how curvature can "physically exist" (as opposed to just being geometry) without an 'outer dimension.'

What would you say "physically exist" means, for curvature?

 

[ucf-fisher21]

tiny-tim,

When I say 'physically exists' I mean that its a real thing in our universe with structure, not just real in the mathematical sense. Time is real. We constantly experience it in our lives. If this curvature can affect time (you said it can slow time down), then I think this curvature is a real thing too. How can something that doesn't physically exists, affect something as real as time?

This has nothing to do with what we're talking about, but how do you put a highlighted quote from someone else on the forum into your reply?

 

[H0T_S0UP]

Well I've read that pole switches are consistent with the alignment of the galactic center which does occur every 25000 years or so.

 

[jtbell]

how do you put a highlighted quote from someone else on the forum into your reply?

Hit the "Quote" button at the bottom of that person's post. This starts a new post in the same thread, with the other person's post already pasted into the message-editing window, enclosed between [ quote ] and [ /quote ] tags. (I added spaces between the brackets so the forum software wouldn't interpret them as quote tags.)

When you do this please please please delete quoted material that isn't directly relevant to your response. Anyone who wants to read the whole thing can simply scroll up to it. I mention this because it's very irritating when someone quotes an entire long post and adds only a couple of sentences of his own, which usually refer to something buried in the middle of that huge mass of quoted text.

If you want to quote from a book or article (not another post), you can type in the quote tags yourself: [ quote=Einstein ] blah blah blah [ /quote ]. (Don't include the extra spaces inside the brackets.)

And of course, don't put your own stuff between quote tags. If you want to alternate between his stuff and your stuff, add extra pairs of quote tags as necessary.

 

[DaveC426913]

Well I've read that pole switches are consistent with the alignment of the galactic center which does occur every 25000 years or so.

What is an "alignment of the galactic center"?

(I think you might be reading the wrong books.)

 

[tiny-tim]

When I say 'physically exists' I mean that its a real thing in our universe with structure, not just real in the mathematical sense. Time is real. We constantly experience it in our lives. If this curvature can affect time (you said it can slow time down), then I think this curvature is a real thing too. How can something that doesn't physically exists, affect something as real as time?

Hi ucf-fisher21

Oh yes … in that sense, curvature of space-time definitely exists … we can see it in the experiment you mentioned, in "gravitational lensing", in Shapiro's experiment, in the precession of the orbit of Mercury, and so on …

… how do you put a highlighted quote from someone else on the forum into your reply?

To what jtbell said, I'll just add:
you can also click on the quote tag … it's in the bottom row of tags just above the reply box, three to the left of the X² tag.

Well I've read that pole switches are consistent with the alignment of the galactic center which does occur every 25000 years or so.

Hi H0T_S0UP!

I think you're thinking of the precession of the equinoxes (the direction of the north pole going round in a circle) every (I think) 25,800 years …

but it has nothing to do with pole switches … the timings simply don't match.

 

[DaveC426913]

I think you're thinking of the precession of the equinoxes (the direction of the north pole going round in a circle) every (I think) 25,800 years …

but it has nothing to do with pole switches … the timings simply don't match.

Yes, but I still think he's reading the wrong books. Alignment of the galactic centre is something I've heard tossed about in connection with other woo-woo-isms.

 

[happy.jatt270]

The Earth revolves around the sun, because it does.

Newton found that he could predict the positions of heavenly bodies by using a central force he called gravity.

Einstein found that he could model the same system by assuming that space is curved by massive bodies. The fact is that Einstein's model is more general and works over a wider range of conditions then Newtons model. What we have found, is that Newtons model is an approximation to Einstein's and can be arrived at by dropping "extra" terms that show up when using Einstein's model.

So as long as you are aware of what conditions are suited to Newtons laws they are useful and accurate. Einstein's theory yield more accurate results in all cases but they are much harder to apply. In the world we live in very precise measurements are required to separate the two models.

hey integral that's one and all same thing its density which cause space time chart to conjugate and its again density which cause gravity