Mark _australia said...
If it is endless
and it is expanding...
what is it expanding into....?
just wondering.
Hello.
It's not expanding into anything. It is just expanding. There isn't anything else.
What is the economy expanding into? (that's a bad example, will edit)
And if red shift is the only reason we reckon it is getting bigger, well fk me that is just dumb. Truly.
Red Shift is not the only reason we reckon it's getting bigger.
As NotWal was saying above Red Shift is observable evidence of the universe expanding. General Relativity actually theorised an expanding universe prior to this, and required it to work, so Einstein added a variable to his equations that could be modified to make it work. Fudge factor. Later Einstein kicked himself for introducing this variable. An expanding universe model does not require the variable at all. Some Russian guy took Einstein's work at face value, even though Einstein didn't himself, and asked Hubble for some observable evidence; enter Red Shift. Later the
Special General Relativity theory came out, without any fudge factor (I may have names back-to-front or wrong, but that's the important gist of it).
Another reason a static universe wouldn't (didn't) work was gravity. Gravity.
Gravity. To argue that the universe is static and infinitely old you have to argue against gravity, another very observable piece of evidence. It's also very simple to understand; You have the universe with all its galaxies and stars and matter, over time gravity will bring them all together. The Big Crunch. If the universe was indeed infinite in age this would have happened already. Or gravity doesn't exist. For an infinitely old, static universe you'd need some sort of magic material pushing the galaxies
away from each other. And you're back with expansion, or something even weirder.
Also the background microwave radiation,
that I just realised answers the original question in this thread! That horizon I was imagining is extreme red shift, an elongation of the wavelengths. I'm not sure how long a wavelength we can pick up, or even how long it can be? This is all in my head. Anyway, the background microwave radiation, that is redshifted light from the early universe, so red shifted it has become microwaves, is the
same in every direction. An infinitely old, static universe doesn't explain this nearly as well as an expanding one, which would be the same in every direction. Also the universe is, on a large scale, the same in every direction.
Yeah look, it is hard to imagine a three dimensional (i'm ignoring time to make it easier) universe expanding equally in all directions, without stepping outside it, which you can't. The best analogy is that balloon one, where it is a two dimensional plane expanding in all its two dimensional directions at once from every point equally. [pant pant]. It's easier in mathematics as you just add another dimension to an array or whatnot.
Fun microwave experiment to measure the speed of light: put a piece of paper in your microwave oven and turn it on. Measure the distance between the holes you'll get in the paper and compare with the specs of your microwave oven. They match and you can calculate the speed of light. Not as hard as it first seems.
Yet another reason we reckon it's getting bigger is that distant objects are moving away from us faster than closer ones. Blow up a ballon a little. Put some dots on it. Blow it up some more. The dots that were further away from us are now even more further away than the ones that were right next to each other. Again, the infinitely old and static universe only works here if we go altering the speed of light to fit, and there's no proof of that, and you're still left with small details breaking the theory like ...gravity. You have to fudge in
more variables than the expanding universe model.
It all fits. I think there are some other pieces of evidence to I've forgotten.
To reiterate and summarise: The theory was accidentally discovered by Einstein, discarded, then proved by Feinman and Hubble. Einstein rewrote. Evidence includes gravity, red shift, background microwave radiation and the universe being the same in every direction.
Summary of evidence, all observable:The universe is the same in every direction (on a large scale, obviously).
The further away an object the faster it is "moving" away from us.
The universe hasn't collapsed in on itself from gravitational forces.
OK that is me being abrasive deliberately but it does highlight how cosmology and theoretical physics is maybe about faith, religion and hypothesis more than empirical observation ... well, more than (pretty much) every other field of science is.
If my surgeon last month ascribed to the priinciples of "science" as practiced by cosmologists, he'd have not got near me with a blade !!!!
I dunno man. There is a lot of compelling evidence, and a lot of gaps, and where there is no evidence there is hypothesis, and it is clearly labelled as such. the snippets I mention above, you must admit, are somewhat compelling. Especially since the maths (that I don't understand but trust other do) adds up.
As for your abrasive character I like it.
[insert excellent graphic I can't find that illustrates a universe expanding from every point]Found it:
www.exploratorium.edu/origins/hubble/tools/center.html
On another note, while contemplating all this today, I am such a small piece of the universe (observing and thinking about itself) that I am irrelevant. But, the universe's size and scale are so large that it is irrelevant to me. All this is interesting but perhaps holds very little meaning to my life. Nonetheless interesting and worth continuing research. (more so than military research).
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