Please help me understand the expansion of space

If you had a microscope you could see the space inside of your measuring ruler. You could see the space inside your eyeballs. At these close proximities, what can one measure with, that is not also in expansion?
We are lucky to be living in the universe when it is young enough to allow us evidence of it's passing.

 

Log in or Sign up to hide all adverts.

http://en.wikipedia.org/wiki/Accelerating_universe

the universe is expanding, this is an indisputable fact

what we were talking about untill you so rudely interupted us with a completely unrelated topic was the WHY

secondly, this expansion has NOTHING to do with black holes and the expansion of galaxies, thats different.

the expansion of the universe is the Galaxies all getting farther away from each other, individual stars have little or no individual movement (ie they move along with their galaxy)

and why the fuck are we talking about sin curves? what does that have to do with this?

but i still have more unanswered questions

you would make a really bad Phd student

DM

 

Log in or Sign up to hide all adverts.

not quite;

when people think of expanding space, they think of everything in the universe getting farther apart.

in reality it is only the galaxies that are moving away from each other, the space between stars stays more or less the same.

DM

 

Log in or Sign up to hide all adverts.

Still wrong. place a drop of milk into water and it spreads out.... this doesn't meant the glass is getting any bigger.

 

except galaxies are hardly drops of milk, they are held together by their own gravity.

they are a lot more like a balloon with dots on it, if you blow the balloon up the dots don't expand very much but the distance between them expands massively. so does the volume of the balloon

look http://skyserver.sdss.org/dr1/en/astro/universe/universe.asp

you are saying that Hubble was wrong and that the greatest discovery about how the universe works since the discovery of the atom was wrong

DM

 

I made no such claim of Hubble. I only forced you to provide information that mathematically made you point more viable. The key words were "increased at a linear function of their distance."

But you still have yet to explain If a blueshift will have the same type of outcome. It seems paradoxical to say something is growing because it is moving away, then provide no evidence for the same reasoning if objects are moving closer together.

 

hmmmm, reasoning you say

try this

Andromeda is blueshifted, it will eventually collide with the milky way, moving closer together thus the distance between them contracts.

and "increased at a linear function of their distance." simply means that the ones that are farther away are moving faster, you cant mathematically prove it it is provable only through observation.

and another thing for the last time:

THE OBJECTS THEMSELVES DO NOT GROW, ONLY THE DISTANCE BETWEEN GALAXIES CHANGES DUE TO UNIVERSAL EXPANSION

DM

 

does the distance contracting imply that you are contracting space and therefore shrinking the universe?

So your saying gigantic objects picking up speed as they get further out and violating all known newtonian laws is proof of expansion and not flaws of mathematical observation. Sure I'll buy that

Please Register or Log in to view the hidden image!

Ok fine we will use your analogy. so we got twelve balloons with marbles in them packed into an open area. Find a way to blow up each balloon equally so that the outer areas disperse faster without adding any additional mass of air into the balloon itself.

Or take five cups and place them in a group. then spread them out. Have we "made space"? No... it was there and has always been there to say space expanded is only to imply it moved from one area to another.

or move to the "outside" of the universe where a large grouping of galaxies are headed for a stronger gravitational force.

Serious Deja Vu...

 

no, although the "space" may remain the same the and energy in it expands thus the universe that is composed by that matter and energy expands.

no, simply that the ones that are farther away and thus farther back in time are moving faster thus the universe is slowing down

Remember light speed distance=time

exept that you dont need to add any mass because there is no (or very little) mass in space

we have increased the circular amount of space encompassed by the cups, a rough analogy but it works reasonably well

Please Register or Log in to view the hidden image!

no idea what this means

 

Seems to make replying to her moot.

 

ahhhhhhhhhh

Please Register or Log in to view the hidden image!

it all makes sense now

 

The idea of space being like the surface of a balloon is helpful, because it shows why space has no centre.
If you think of it like the contents of a balloon, you run into problems,
the main one being "What is outside the balloon?"
There is no outside.

If you make two dots on the surface of a half blown up balloon and then pump more air in, the dots will move further apart.
That is what the expansion of space is like.

If you mark a tiny x on the balloon to mark the position of our sun,
and then draw a little ring just outside it to indicate a distance of 13.75 Billion light years, that is as far as we can see in space.
Of course the surface of the balloon is much bigger than that, but we can only see that far back into time.
That's all the time there is.

In comparison with space and matter, time is very tiny indeed.
Mathematicians and Cosmologists, confronted with the vastness and massiveness of the first two, and the inadequate length of the third, came up with the idea of expansion. It is the best theory we have.

Going back to the little circle we have drawn on the balloon.
When we look into space using the latest telescopes, we can see almost to the edge of this little circle.
But the primitive universe that we see there no longer exists.
What we are seeing is an illusion, because the space that far away actually looks much the same as ours does.

We see it like that because the light is taking Billions of years to reach us.
It's like when we see lightning, and then a few seconds later hear the thunder.

Once you have understood the balloon analogy, mentally pop the balloon.
It is not a description, just a tool.
In order to make it comprehensible, we have had to reduce the number of dimensions to two. (-ish)
Our human brains can just about make sense of three.
Mathematicians, with a comfort zone which means that they don't have to visualise anything, think there are ten plus.

As someone very clever once said, (paraphrased)
"If you think you understand it fully, that's because you haven't understood it at all"
We are like myopic ants climbing a leaf, trying to comprehend the garden.
I made that up. Quote me in future!

What happened to Lady Gaga, anyway?
Sorry, my mistake, Lady Historica.

 

two cars can drive away from each other, increasing the distance between them but not the distance between the occupants of the car (ie none of the people in one car will get farther away from each other). both cars will appear readshifted if they were moving at the velocities of galaxies

now imagine an infinite number of cars each speeding away from every other car but slowly slowing down.

yeah its kind of like that.

oh and about photons, they are particles but they are also waves and since they are massless they behave a lot more like energy than matter. so they don't really count.

DM

 

He's got you there Fraggle

Please Register or Log in to view the hidden image!

 

Well, there's a lot of charged partlcles from the solar wind, and that the solar system is moving through an interstellar medium--a cloud of gas and dust. Intergalactic space is a more rarified medium, but there are large clouds of hydrogen out there. Our galaxy is sort of connected to a large incoming stream of some of this gas. There are large plumes of gas and dust that leave the galactic disk and "fall" back towards it as well.

 

what? source please that sounds like a very contradictory statement

but to answer your question

firstly as i have already explained; because something is moving away from everythign else in no way means that it is getting bigger. space does not "expand of its own accord" the matter within that space is being carried by the same forces that were given to it by its creation.

it is an affront neither to physics or semantics, i believe that inertia is very well understood by the physics community.

secondly, on the galactic level, especially for spiral galaxies the mutual attraction between all the stars, black holes and the dark matter surrounding the galaxy is enough to keep the expanding force mostly in check. returning to inertia "objects in motion stay in motion until acted upon by an outside force" on the (cosmologically speaking) small scale of stars and galaxies gravity is enough of a force to overcome the inbuilt momentum of matter.

DM

 

ah okay that explains it

i disagree with basically all of that, so if you could direct me to one of these Cosmology experts *cracks knuckles* id like a chat with them.

i wont waste out time talking about something we both disagree about.

thanks

DM