The Expanding Universe -- Why and How We Know It Is Expanding

How does science work? And what's all this about quantum mechanics?

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Scott Mayers
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Re: The Expanding Universe -- Why and How We Know It Is Expanding

Post by Scott Mayers » Fri Apr 26, 2019 1:37 pm

Age wrote:
Fri Apr 26, 2019 10:05 am
Scott Mayers wrote:
Fri Apr 26, 2019 4:09 am
Age wrote:
Thu Apr 25, 2019 6:15 am


But if some stars/galaxies are blueshift, then how does that then conclude that the Universe, Itself, is expanding?

If galaxies are moving closer to us, as you just said andromeda is, then some could say that that, combined with the other blueshift galaxies/stars, is evidence that the Universe, Itself, is NOT expanding.

If redshift is evidence for an expanding Universe, then what is evidenced by blueshift?
The degree of expansion is far less than that of gravity upon local stars or galaxies.
What do you mean by the 'degree of expansion is far less than'?

Do you mean that gravity upon local stars or galaxies is contracting faster than the 'degree of' expansion, which is supposedly happening away from the local stars or galaxies?

Or, some thing else?
Yes. Gravity is stronger and quicker at smaller distances and slower and weaker at longer distances. Expansion is far slower than gravity. Expansion is like adding pieces of space distributed evenly in any given distance. This means that in twice the length of space away from us, one constant amount of space added is twice as much. This makes light that has a fixed speed require twice as much NEW SPACE (which is tiny between us and those near galaxies we can see as blue shifted. But the ones at great distances has that distance plus that distance times the new space added for light to travel through. But light that has already left, and remains constantly so, then has to stretch similar to two people with a fixed length jump rope who move away from each other make the any wave you can create stretched out. You can make, say, one large cycle loop the size of the distance between you. But if you add space between the two people on either side of the rope, the length of the same wavelength (loop-wise) is longer. Since wavelength is what we interpret as color. Anything thing that originally was created as a blue wave, which has a smaller wavelength becomes a different color. Blue is the shorter wavelength side of the spectrum and red the longer. So a 'red-shift' only means the the colors change TOWARDS one of those ends.

If a car moving across your path at 100 miles per hour close up, you might see a blur as it passes you and notice its change. But if it is very far away, it would look like its not moving. This is like noticing the blue shift of closer stars and galaxies but it being very small at great distances.

Now, say that in one second one molecule of space is added between you and the distance of the road one foot in front of you as that the car drove by on. You wouldn't notice its effect for the amount being so tiny. But now add a million feet between you and some object. Then the amount of space added is one million molecules MORE space. Maybe only one million molecules may still be small, like say, the size of the point of a pin.

Now twice the million feet is two million feet away. That space has two million more molecules. If you know your math of exponents, you'd discover that though it is so small close up not to notice a red shift stretch of added distance per second is, there will come a point when the amount of space gets big very fast and then beats the appearance of any relatively tiny blue shift of something moving towards you.

This is where you would ONLY notice red shifts but then measure shorter general movements towards you as slightly less red shifted or those moving away as slightly more red shifted.
Scott Mayers wrote:
Fri Apr 26, 2019 4:09 am
The blue shifts are about the closer stars and galaxies which you cannot notice of the effects of expansion without looking at galaxies at a distance that is greater than the maximum effect of gravity of galaxies.
But what about the blue shift on the more distant galaxies? What do they demonstrate and/or what is interpreted on the blue shift of them?
This is what I find confusing here in this thread and in the other thread 'einstein on the train'.

Now, is 'red-shifting' evidence for the distance of galaxies compared to us, or, the evidence for the direction in which a galaxy is supposedly traveling, compared to us?

The 'evidence' for red-shifting is either for both of them or for one of them. If it is for one of them, which one is it?
As just answered, you wouldn't see the actual colors change as MUCH, the farther away something is as you would closer, just like you can notice a car close up move say ten feet towards or away from you close up but not notice it if it were seen through a telescope where the cars are also moving the same ten feet in different ways. If you use a telescope and guess at how far ten a car moves ten feet when it is 10000 feet away is like being able to notice the difference between 10010 and 9990 feet. [that is 10000 plus or minus 10 feet.] The ten feet is still the same but if it is billions of light years away, you can't tell the actual difference.

What they CAN tell at those distances is the relative differences in tiny, tiny red shifts only. And most of this can only be noticed of galaxies where you can notice one side slightly red shifted and the other slightly blue shifted but still more red. The average distance to is the center of the galaxy and so the side more slightly slightly blue-shifted is the part moving towards us.
Scott Mayers wrote:
Fri Apr 26, 2019 4:09 am
But you can see the shifting of galaxies further out also clumping gravitationally by those specifically moving perpendicular to our perspective.
What exactly is 'moving perpendicular' to our perspective?
The relative left-right/up-down movements we see of closer galaxies. Like the spiral galaxies that have a center that is the average distance to us but you can tell which side on either side of the center is moving. When whole galaxies are moving closer due to gravity, they have a shift effect that point towards the center of the gravitational cluster. It would still appear only slight. But the overall galaxies as a whole are still redshifted.
Scott Mayers wrote:
Fri Apr 26, 2019 4:09 am
I thought Willy showed this effect using Saturn as a local example of this whereby one SIDE of the planet is relatively shifted blue because that side is moving towards us while the red is shifted as the planet is moving away on the opposite side.
And that is exactly what I wanted to point out. The observed red-shift of distant galaxies might just be one side of the galaxy's spin, which is moving away, relative to us, AND, the blue-shift in those distant galaxies could just be the side of the galaxy which is moving towards us?

There is also the question of could the blue-shift and red-shift seen in distant galaxies be caused by how like the earth moves around the sun not in a perfect circle but sometimes in a towards direction and at other times in an away direction? (There is a word for this movement).

There are also other questions/explanations about what could be happening, which I have been waiting to ask but have just already somewhat answered/explained with your 'gravitational clumping' response, but I will leave them for another time anyway. (Memo for me relative time appearance).
Yes, to the first and second paragraphs. We can notice the shift of us relative to close galaxies to a greater extent than those of a billion light years away, just as the distance of 8 light-seconds is tiny compared to a galaxy 8 billion light years PLUS 8 tiny light-seconds change that far away.

surreptitious57
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Re: The Expanding Universe -- Why and How We Know It Is Expanding

Post by surreptitious57 » Sat Apr 27, 2019 9:55 am

Age wrote:
Absolutely ANY thing COULD start a Universe but WHY even make up such an ASSUMPTION as there was a start to the Universe to begin with ?

Why start LOOKING FOR what COULD do some thing which may NOT have EVER even be a fact in the beginning ?

WHY just carry on ASSUMING / BELIEVING some thing that was after all just a religious BELIEF to begin with ?
I make no assumptions about the beginning of the Universe - it may be infinite or finite - I really dont know

surreptitious57
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Re: The Expanding Universe -- Why and How We Know It Is Expanding

Post by surreptitious57 » Sat Apr 27, 2019 10:21 am

Age wrote:
And again absolutely ANY thing COULD happen but without ANY reasonable explanation of HOW it COULD happen then WHY even LOOK AT that ? WHY NOT just LOOK AT what IS and / or what COULD BE which COULD reasonably happen / be possible instead ? WHY LOOK AT things which NO explanation HAS BEEN given YET. This to me just seems to be a continuation of the BELIEF that the Universe began and so human beings have
been TRYING their very hardest to SEE things that follow on with this ASSUMPTION and BELIEF. To me the idea of space expanding is just an
other ATTEMPT to back up and support a very old BELIEF
Absolutely ANY thing could happen ? What about things that definitely could not happen ? These two categories are entirely separate
Why not just look at what could reasonably happen ? First of all the expansion of space is really happening so its more than reasonable
But way more important is this : its possible that an answer lies beyond the reasonable so restricting all enquiries to just the reasonable
may not provide the answer in question - so only that which cannot be possible should be rejected - everything else should be considered
Why look at things which no explanation has been given ? Are they possible ? Then go look at them
What belief is the expansion of space backing up ? How can it be a belief if its actually happening ?

surreptitious57
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Re: The Expanding Universe -- Why and How We Know It Is Expanding

Post by surreptitious57 » Sat Apr 27, 2019 10:32 am

Age wrote:
But WHY say there is probably NOT a single absolute answer to them ?

Surely there would be a single absolute answer to those questions ? Surely through physics they have only been created one way evolved one way and exist one way . But just because you or human beings themselves have NOT yet found these answers that in NO way is an indication probable
or NOT about if there is a single absolute answer to these questions or not . Basing a probability on any thing other than just what human beings have been thinking about and have so far discovered over a relatively very few short couple of thousand years or so will NOT provide any accuracy
Thinking there is a single absolute answer may produce the wrong answer so it is important to keep an open mind
But saying there is probably not a single absolute answer to them doesnt actually mean there is
More importantly it doesnt restrict looking for all possible answers where there is more than one

Age
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Re: The Expanding Universe -- Why and How We Know It Is Expanding

Post by Age » Sat Apr 27, 2019 10:48 am

surreptitious57 wrote:
Sat Apr 27, 2019 10:21 am
Age wrote:
And again absolutely ANY thing COULD happen but without ANY reasonable explanation of HOW it COULD happen then WHY even LOOK AT that ? WHY NOT just LOOK AT what IS and / or what COULD BE which COULD reasonably happen / be possible instead ? WHY LOOK AT things which NO explanation HAS BEEN given YET. This to me just seems to be a continuation of the BELIEF that the Universe began and so human beings have
been TRYING their very hardest to SEE things that follow on with this ASSUMPTION and BELIEF. To me the idea of space expanding is just an
other ATTEMPT to back up and support a very old BELIEF
Absolutely ANY thing could happen ? What about things that definitely could not happen ? These two categories are entirely separate
Why are the question marks there?

Second sentence or question, Are you saying you are now certain of some things?
surreptitious57 wrote:
Sat Apr 27, 2019 10:21 am
Why not just look at what could reasonably happen ? First of all the expansion of space is really happening so its more than reasonable
Is the so called expansion of 'space' actually and really the Truth? Or, is that just what you have read and/or have been told is really happening?
surreptitious57 wrote:
Sat Apr 27, 2019 10:21 am
But way more important is this : its possible that an answer lies beyond the reasonable so restricting all enquiries to just the reasonable
may not provide the answer in question - so only that which cannot be possible should be rejected - everything else should be considered
Why look at things which no explanation has been given ? Are they possible ? Then go look at them
What belief is the expansion of space backing up ? How can it be a belief if its actually happening ?
But is it ACTUALLY happening?

If yes, then what is space AND how can it expand?
If now, then okay.
If I do NOT know, then okay also.

By the way what is "actually happening" can very easily and simply become a belief. This occurs when a human being believes in or of some thing.

You say you do NOT do belief so, although you do disbelieve some things, you may not be aware of just how quickly, simply, and easy beliefs can occur to some people.

Also, are those four question marks here questions that you would like me to answer?

surreptitious57
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Re: The Expanding Universe -- Why and How We Know It Is Expanding

Post by surreptitious57 » Sat Apr 27, 2019 11:04 am

Age wrote:
Are you saying you are now certain of some things ?
Inasmuch as I am certain of some things as it is actually possible to be
But absolute certainity is something to be avoided where ever possible

surreptitious57
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Re: The Expanding Universe -- Why and How We Know It Is Expanding

Post by surreptitious57 » Sat Apr 27, 2019 11:10 am

Age wrote:
Is the so called expansion of space actually and really the Truth ?
Yes the [ not so called ] expansion of space is actually really the truth
As it is happening right now and has been observed happening as well

Scott Mayers
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Re: The Expanding Universe -- Why and How We Know It Is Expanding

Post by Scott Mayers » Sat Apr 27, 2019 11:15 am

@Age

I was hesitant to respond to a prior post in which you again rallied back on me about 'assumptions', something that others here are also a bit frustrated with you on. I'm trying not to be rude and know that this may not be something you intend. So I want to just note in this post something about 'assumptions' that I don't want to raise again and won't respond to again because it is getting exhausting to try.

The word "assumptions", can literally be translated as "As YOU, the same it is for ME". It's not important if this is the literal origin of the word but it stands to reason that this is the intentional meaning as it is for things like logic and/or science.

As such, assumptions are ONLY the pretenses BETWEEN two or more people that is needed to move forward with anything. When I question the world, I default NOT to assume anything in my own investigations of my reality. Because I cannot read through another mind, I require gambling that those other beings out there, like you and all other 'people' in my perspective are only sensations with respect to my consciousness as far as I can tell.

I cannot control most other things outside of my mind. This tells me that reality is greater than I am at least with respect to my present self. All of reality COULD be only MY universe but because I cannot MAKE other things fit perfectly to my will, I have to infer this means that there are other factors out there that I have to try to try different things in order to see if those things I'm sensing is like me. When I 'poke' this world of my senses, the feedback I get needs to 'bounce' back something I expect and when this occurs and can continue to test, those things out there that 'reflect' my call tells me they are something that 'senses' me as I sense it.

This is the 'assumption' factor. I cannot KNOW anything for certain unless it reflects me perfectly. When it reflects back to me (ie. feedback), if it is absolutely what I expect [like a 'ping' that bounces back to acknowledges something is out there], the sensations that are perfectly in my control DEFINES ME. So, for instance, when I 'look' out and see some face in front of me that moves in every way exactly as I do, it confirms to me that is 'me'. That I happen to be looking in the mirror can be one such experience.

Reality is not as predictable for all things. For those things that I may try to ping but cannot get a reflected expected acknowledgement from, I infer this as something perfectly not me nor like me. If I cannot manipulate it at all and I am unable to get it to feedback as I wish, these things I am sensing for which I'm trying to test are things that are NOT me nor LIKE me.

As to other people, though, I would sense some partial power to ping. If I have hope to communicate with it, it needs to reflect back some things that I send (ping) and then I have to acknowledge its own pings to me. Once this is done, we have a 'link' to each other. This is the 'assumption' in its most basic form.

So assumptions are only a type of agreement that is 'pretended' for the sake of further communicating.

I'm using some terms related to computing (like ping and acknowledge) because these are the first steps for any two things to communicate like this. For everything my computer does on the Internet, it pings, waits for an expected copy in a given time. If it comes, then I wait for it to send its own distinct ping (computers can do this simultaneously but animals need to 'prove' it is acknowledgable too).

My point is only to express that assumptions are required ONLY between two or more beings. We still don't actually KNOW each of us are 'real' beings like ourselves.

Science is a subset of philosophy that restricts communication and procedures to the lowest common denominator and is specifically a logic of the senses. As such, a stricter set of assumptions have to be negotiated about senses, the logic used and agreed procedures. This doesn't require being a part of an institute. So we here could DO science among ourselves in the same way we discuss other philosophical things.

I don't know if this suffices and won't care nor respond if this is not something you care to agree to or not. So this is the last I'm mentioning this point and don't want to argue with you on this.

What is needed to understand for the topic of expansion is some principle assumptions. One is the Cosmological Principle. I prefer the Perfect Cosmological Principle which assumes things in the past or future has to be of the same kind of physics that respects the senses we use locally.

Working definition of the Perfect Cosmological Principle:(1.0) All things we sense are to be interpreted as 'equally' observable in kind to our local sensation in space, matter, energy, and time. Since Cosmology is about observing things at a remote distance that won't feedback information by poking it unlike things in a controlled lab, this means that we assume everything we see has no special place and so will interpret things anywhere to appear SIMILAR (isotropic) no matter where you are in the universe and has an equal similar distribution of things (homogeneous).

surreptitious57
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Re: The Expanding Universe -- Why and How We Know It Is Expanding

Post by surreptitious57 » Sat Apr 27, 2019 11:16 am

Age wrote:
By the way what is actually happening can very easily and simply become beliefs
Only things which are false or cannot be demonstrated can actually be labelled beliefs
Any thing that is happening and is known to happen can not be belief by any definition

Age
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Re: The Expanding Universe -- Why and How We Know It Is Expanding

Post by Age » Sat Apr 27, 2019 11:23 am

surreptitious57 wrote:
Sat Apr 27, 2019 11:04 am
Age wrote:
Are you saying you are now certain of some things ?
Inasmuch as I am certain of some things as it is actually possible to be
But absolute certainity is something to be avoided where ever possible
Okay, so we agree that 'space', itself, may in fact NOT be expanding at all, correct?

Age
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Re: The Expanding Universe -- Why and How We Know It Is Expanding

Post by Age » Sat Apr 27, 2019 11:24 am

surreptitious57 wrote:
Sat Apr 27, 2019 11:10 am
Age wrote:
Is the so called expansion of space actually and really the Truth ?
Yes the [ not so called ] expansion of space is actually really the truth
As it is happening right now and has been observed happening as well
Lol

So you ARE in fact absolutely CERTAIN of this, correct?

Age
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Re: The Expanding Universe -- Why and How We Know It Is Expanding

Post by Age » Sat Apr 27, 2019 11:26 am

surreptitious57 wrote:
Sat Apr 27, 2019 11:16 am
Age wrote:
By the way what is actually happening can very easily and simply become beliefs
Only things which are false or cannot be demonstrated can actually be labelled beliefs
Any thing that is happening and is known to happen can not be belief by any definition
Can a person NOT believe it is happening when it is "happening"?

surreptitious57
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Joined: Fri Oct 25, 2013 6:09 am

Re: The Expanding Universe -- Why and How We Know It Is Expanding

Post by surreptitious57 » Sat Apr 27, 2019 11:33 am

Age wrote:
Okay so we agree that space itself may in fact NOT be expanding at all
No we absolutely do not agree about this at all

Where there is evidence for something I accept it as true and there is evidence for the expansion of space
And so I accept it as true and will carry on accepting it unless future evidence contradicts present evidence

surreptitious57
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Re: The Expanding Universe -- Why and How We Know It Is Expanding

Post by surreptitious57 » Sat Apr 27, 2019 11:41 am

Age wrote:
Can a person NOT believe it is happening when it is
Yes they can but the principle is the same : not believing something that is true / believing something that is false
Though if something is demonstrably true when there is evidence to support it then it no longer has to be believed

Age
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Re: The Expanding Universe -- Why and How We Know It Is Expanding

Post by Age » Sat Apr 27, 2019 11:22 pm

surreptitious57 wrote:
Sat Apr 27, 2019 11:33 am
Age wrote:
Okay so we agree that space itself may in fact NOT be expanding at all
No we absolutely do not agree about this at all

Where there is evidence for something I accept it as true and there is evidence for the expansion of space
And so I accept it as true and will carry on accepting it unless future evidence contradicts present evidence
Okay, I am now getting closer to understanding your views, I hope. You accept that space is expanding, but you are NOT at all open that space may NOT be expanding. Is this correct?

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