Is Space Bumpy?

Bear with me here...

Let's use the rubber sheet and bowling ball analogy for sake of simplicity.
The bowling ball is the sun, and it's bending of the rubber sheet,
represents the effect it's gravitational waves have on space. Now we drop a
baseball on the sheet, and we'll call it Jupter. Now we have a second
stretch on the sheet. Now let's add the other planets, the moons, the
asteroid belt, some comets, some random heavy objects, planet x, etc.

Our sheet is now going to be bent, stretched and mangled in many directions.
If a beam of light traveling space enters this mess, it can? would? be bent
in potentially many directions. It's speed would be affected by the gravity
in the area correct?

How then can we be sure where it came from?
How can we be sure of it's true speed?

BV.

"Benign Vanilla" schreef in bericht
...
Bear with me here...

Let's use the rubber sheet and bowling ball analogy for sake of
simplicity.
The bowling ball is the sun, and it's bending of the rubber sheet,
represents the effect it's gravitational waves have on space. Now we drop
a
baseball on the sheet, and we'll call it Jupter. Now we have a second
stretch on the sheet. Now let's add the other planets, the moons, the
asteroid belt, some comets, some random heavy objects, planet x, etc.

Our sheet is now going to be bent, stretched and mangled in many
directions.
If a beam of light traveling space enters this mess, it can? would? be
bent
in potentially many directions. It's speed would be affected by the
gravity
in the area correct?

How then can we be sure where it came from?
How can we be sure of it's true speed?

BV.


There's alot of space between all those masses and for a lightbeam to be
really curved it has to get relatively close. Anyway... If you see a star in
a certain direction, it's located in that direction. If you'd remove all the
masses in between which curve the space, it would be located in an other
direction.
The light beam's speed is never affected by the gravity and in fact always
follows a straight line.
It always comes from the straight path you're looking at.
It's true speed (in vaccuum) is always "c".

You're right on space being bumpy, but space is so spread out and masses so
far apart, the bumps are relatively very small.

"F. Kuik" wrote:

"Benign Vanilla" schreef in bericht
...

[snip]

If a beam of light traveling space enters this mess, it can? would? be
bent
in potentially many directions. It's speed would be affected by the
gravity
in the area correct?

How then can we be sure where it came from?
How can we be sure of it's true speed?


There's alot of space between all those masses and for a lightbeam to be
really curved it has to get relatively close. Anyway... If you see a star in
a certain direction, it's located in that direction. If you'd remove all the
masses in between which curve the space, it would be located in an other
direction.
The light beam's speed is never affected by the gravity and in fact always
follows a straight line.

It indeed follows a "straight line" -- the technical term is
"geodesic" -- through space, but where the space is curved so will be
the path of the light. You could only see the curvature from a
more-than-three-dimensional perspective; it looks straight from a
point of view embedded in our spacetime.

It always comes from the straight path you're looking at.
It's true speed (in vaccuum) is always "c".

I might add that light traversing a gravitational gradient ('uphill'
or 'downhill' on the rubber sheet) *is* affected, but it's the
frequency that changes, not the speed. Going 'up' -- away from a mass
concentration -- it's red-shifted; going 'down', blue-shifted.

You're right on space being bumpy, but space is so spread out and masses so
far apart, the bumps are relatively very small.

True; the effects are quite small. But stars very near our line of
sight to the Sun (observed during a solar eclipse) -- their light
passing obliquely across the slope of its 'gravity well' -- appear
measurably displaced from their 'Euclidean' positions. This was
predicted by Einstein's general theory of relativity, and was borne
out by observations made during a total eclipse not long after it
came out (1919?). Although I gather that later analysis has turned up
problems with the experiment, a great deal was made of it at the time.

--
Odysseus

"Odysseus" schreef in bericht
...
"F. Kuik" wrote:

"Benign Vanilla" schreef in
bericht
...

[snip]

If a beam of light traveling space enters this mess, it can? would? be
bent
in potentially many directions. It's speed would be affected by the
gravity
in the area correct?

How then can we be sure where it came from?
How can we be sure of it's true speed?


There's alot of space between all those masses and for a lightbeam to be
really curved it has to get relatively close. Anyway... If you see a
star in
a certain direction, it's located in that direction. If you'd remove all
the
masses in between which curve the space, it would be located in an other
direction.
The light beam's speed is never affected by the gravity and in fact
always
follows a straight line.

It indeed follows a "straight line" -- the technical term is
"geodesic" -- through space, but where the space is curved so will be
the path of the light. You could only see the curvature from a
more-than-three-dimensional perspective; it looks straight from a
point of view embedded in our spacetime.


Yeah what is "straight" defined as then? I like to say that if space is
curved, the path the light follows through it is "straight" space. It just
depends on where you are etc.

It always comes from the straight path you're looking at.
It's true speed (in vaccuum) is always "c".

I might add that light traversing a gravitational gradient ('uphill'
or 'downhill' on the rubber sheet) *is* affected, but it's the
frequency that changes, not the speed. Going 'up' -- away from a mass
concentration -- it's red-shifted; going 'down', blue-shifted.

You're right on space being bumpy, but space is so spread out and masses
so
far apart, the bumps are relatively very small.

True; the effects are quite small. But stars very near our line of
sight to the Sun (observed during a solar eclipse) -- their light
passing obliquely across the slope of its 'gravity well' -- appear
measurably displaced from their 'Euclidean' positions. This was
predicted by Einstein's general theory of relativity, and was borne
out by observations made during a total eclipse not long after it
came out (1919?). Although I gather that later analysis has turned up
problems with the experiment, a great deal was made of it at the time.


Yeah but I as I said I wouldnt call space "bumpy". If you would take a large
piece of space like it was 10 square meters of sheet. You wouldnt even see
the bumps. You'd need a microscope

Floris

Keep in mind gentlemen that it is the bending of light that give us a
better view of very distant objects. Einstien figured that out for us
before we detected gravity focusing. Bert

Is space bumpy ?
Yes !
(Well, according to theory, yes, also, light-speed doesn't change, but i
don't trust that. They tell us that light speed slows down when it passes
through matter, like atmosphere, or water, for examples.
However, "space" is supposedly filled with gas-clouds, dust-clouds,
"dark-matter", etc, surely that would slow the bugger down a bit similarly
?)