From Newsgroup: sci.physics



One of the concepts that have bothered me the most is the idea that the universe is ever exapanding. If space is constantly exanding and we are
in space, then our measuring sticks would also be expanding so we
wouldn't be able to see it and there would be no doppler effect.


This has always puzzled me.


Reuvain

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From Newsgroup: sci.physics

Ruben Safir wrote:

One of the concepts that have bothered me the most is the idea that the universe is ever exapanding.

[_expanding_]

We do not know that. We know that our universe is expanding now and has
been in the past (because we observe the cosmological redshift); but it is uncertain for how long, if at all, this will continue. The reason for that
is that recent observations indicate that the Dark Energy density could be time-dependent (in the current Standard Model of cosmology, it is constant, leading to an exponential expansion). If it decreases, then gravitation
might be able to slow down the expansion after all, and even reverse it, leading to a Big Crunch:

<https://www.quantamagazine.org/is-dark-energy-getting-weaker-new-evidence-strengthens-the-case-20250319/>

If space is constantly exanding and we are in space, then our measuring sticks would also be expanding so we wouldn't be able to see it and
there would be no doppler effect.

No. First of all, you need to realize how large our universe is and how
small everything in it is by comparison. This is best illustrated with numbers:

Terra (Earth) is a planet with a diameter of ca. 12'642 km (if you think
that is big, read on). Sol (the Sun) is a star with a diameter of ca. 1'400'000 (1.4 million) km. The average distance of Terra to Sol is approximately 150'000'000 (150 million) km. The distance to the next star
from Sol, Proxima Centauri, is ca. 4.25 ly (light-years); that is, ca. 4.25 times the distance that light travels in vacuum in one Julian year: ca. 40 *trillion* (short scale) kilometers. Both those stars are two of
approximately 200 billion stars in the Milky Way (each which on average at least one planet) which has a diameter of approximately 200'000 ly. The
Milky Way is one of ca. 200 billion to 2 trillion galaxies in our observable universe which has a diameter of ca. 96 billion light-years. Our entire universe has a diameter that is at least 500 times as large as the
observable one's.

In the words of Douglas Adams, written in or before 1978 already:

"Space [says the Hitchhiker's Guide to the Galaxy] is big. You just won't
believe how vastly, hugely, mind-bogglingly big it is. I mean, you may
think it's a long way down the road to the chemist's, but that's just
peanuts to space."

The expansion of the space of our universe is a metric expansion -- all
length scales are growing --, so the rate at which distances change itself depends on distance. Given the size of our universe (or even only the observable one), the rate at which distances change on everyday scales is (currently) so small that any short-range forces/interactions compensate for the expansion immediately. In fact, within the Local Group (of galaxies) to
of which the Milky Way is one major component, gravitation dominates over
the expansion; the Andromeda Galaxy, the other major component of the Group, and the Milky Way are *approaching* each other (and might merge in several billion years from now) due to gravitation.

To get an idea how small the rate is at which space is expanding at everyday scales, multiply a distance by the Hubble constant, the current value of the Hubble parameter. Measurements of that vary, but so far the concordance
value is ca. (70 km/s)/Mpc. 1 pc (parsec) is the distance an object needs
to have from Sol so that its annual parallax, half the angle under which it
is observed from opposite sides of the orbit of Terra, is 1" (arcsecond, seconds of arc); that is, ca. 3.26 ly.

Second, the cosmological redshift is NOT a Doppler redshift. The galaxies
are not really moving (by comparison) in their local space, but space is expanding and is carrying them away from each other. The cosmological
redshift arises because the light was emitted in a different reference/rest frame than it is received: the length scales were smaller then than they are now, including the wavelengths of light.

Since the expansion is predicted and described by general relativity, it is better to continue discussing this in sci.physics.relativity. X-Post &
F'up2 set.
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Twitter: @PointedEars2
Please do not cc me. / Bitte keine Kopien per E-Mail.
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From Newsgroup: sci.physics

Thomas 'PointedEars' Lahn wrote:

Ruben Safir wrote:

One of the concepts that have bothered me the most is the idea that the universe is ever exapanding.

[_expanding_]

We do not know that. We know that our universe is expanding now and has

"We"???? you mean me, myself and I?


I'm flabgastted that people till this day are testing Positive for
Stupid in these sci newsgroups.

The UNIVERSE IS *NOT* EXPANDING! It *never* has expanded. It remains the
same size it always has been since it existence.


The Big Bang was the 'expansion' of ...space, not the expansion of the universe.


Space is expanding, not the universe.


Imagine an office building...
with a trillion feet of space for office space,
but contains only one office with 500 square feet.

You need to expand your office because your
busines is growing..so you tear the wall down and
add another 500 square feet of office..your're expanding!

The office building remains the same size.

You just got more space for your business...
eventually you take the whole floor and expand to another floor.

In other words, In the beginning, space was created to add heavens and
the earth.


In the beginning, ...

In the...

In

"In" is the operative word.


meaning inside, within, or at a specific place, time, state, or manner, indicating containment, location, duration, or a change of condition
(e.g., in the box, in summer, in love, in half).



https://www.google.com/search?hl=en&source=hp&biw=&bih=&q=define+In


Your office space is contained IN a building.


The Big Bang was the 'expansion' of ...more office space.



What's inside the office space? People?


It's a big office building!


I mean...
BIG!

but plenty of ...space.


for a blue dot.



Next time someone sez the universe is expanding, give them a Stupid
cigar.

and to all the "WE" also.
--
The Starmaker -- To question the unquestionable, ask the unaskable,
to think the unthinkable, mention the unmentionable, say the unsayable,
and challenge the unchallengeable.
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From Newsgroup: sci.physics

The Starmaker wrote:

Thomas 'PointedEars' Lahn wrote:

Ruben Safir wrote:

One of the concepts that have bothered me the most is the idea that the
universe is ever exapanding.

[_expanding_]

We do not know that. We know that our universe is expanding now and has

"We"???? you mean me, myself and I?

I'm flabgastted that people till this day are testing Positive for
Stupid in these sci newsgroups.

The UNIVERSE IS *NOT* EXPANDING! It *never* has expanded. It remains the
same size it always has been since it existence.

The Big Bang was the 'expansion' of ...space, not the expansion of the universe.

Space is expanding, not the universe.

--------------------------------------------

Space is space, it dosen't expand.




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From Newsgroup: sci.physics

On 12/28/2025 09:47 AM, squalk wrote:

The Starmaker wrote:

Thomas 'PointedEars' Lahn wrote:

Ruben Safir wrote:

One of the concepts that have bothered me the most is the idea that the >>>> universe is ever exapanding.

[_expanding_]

We do not know that. We know that our universe is expanding now and has

"We"???? you mean me, myself and I?


I'm flabgastted that people till this day are testing Positive for
Stupid in these sci newsgroups.

The UNIVERSE IS *NOT* EXPANDING! It *never* has expanded. It remains the
same size it always has been since it existence.


The Big Bang was the 'expansion' of ...space, not the expansion of the
universe.


Space is expanding, not the universe.

--------------------------------------------

Space is space, it dosen't expand.

The "space-frames" and "frame-spaces" represent the concepts
of objects or substances (eg, the point-particles the aggregates
or the waves the bulk) their locales, then that motion itself is
a sort of omni-present contraction and relaxation, of the relative
in the absolute.

If you believe science its data, and thusly, you know,
_all the data_, the universe's age grows millions and
millions of years every few years, about things like
"running constants" where also particles get smaller
every few years, between the sky survey and the CODATA.
Then about explaining why "Dark Energy" has for the
after the inflationary cosmology the expanding universe,
the terms have evolved from things like "tired light"
to "redshift distortion", about what true matters of
the optical must make for super-classical models of
the motion, as it may be, of light.


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From Newsgroup: sci.physics

squalk wrote:

The Starmaker wrote:

Thomas 'PointedEars' Lahn wrote:

Ruben Safir wrote:

One of the concepts that have bothered me the most is the idea that the >>>> universe is ever exapanding.

[_expanding_]

We do not know that. We know that our universe is expanding now and has

"We"???? you mean me, myself and I?

Astrophysicist/cosmologists. The scientific community.

I'm flabgastted that people till this day are testing Positive for
Stupid in these sci newsgroups.

The UNIVERSE IS *NOT* EXPANDING! It *never* has expanded. It remains the
same size it always has been since it existence.

Observationally falsified.

The Big Bang was the 'expansion' of ...space, not the expansion of the
universe.

The Big Bang _is_ the expansion of the space of our universe. AFAWCS it is ongoing.

Space is expanding, not the universe.

Our universe is to good approximation well described by spacetime,
particularly the FLRW metric

ds^2 = -dt^2 + a(t)^2 [1/(1 - k r^2) dr^2 + r^2 (d Omega)^2],
(d Omega)^2 = (d theta)^2 + sin^2(theta) (d phi)^2,

where a(t) is the scale factor at the cosmological time t -- which is
currently increasing --, and r, theta and phi are spatial (spherical) coordinates. So our universe and space are inseparable concepts: When we
say "space" in cosmology, we mean the space *of our universe* (at least the observable one).

[Notice that this is different from colloquial use where "space" often
is a shorthand for "outer space", i. e. the space of our universe outside
Terra's atmosphere.]

Space is space, it dosen't expand.

Wrong, too. We can *observe* the expansion and evolution of our universe because we can observe galaxies as they were in the past: The light that
they emitted takes time to get to us. The farther an object is away, the earlier the light was emitted that reaches us now:

<https://youtu.be/Fqfap3v0xxw?t=791&si=ro2EG6Cx9Sqg05hr>
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PointedEars

Twitter: @PointedEars2
Please do not cc me. / Bitte keine Kopien per E-Mail.

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From Newsgroup: sci.physics

Thomas 'PointedEars' Lahn wrote:

squalk wrote:

The Starmaker wrote:

Thomas 'PointedEars' Lahn wrote:

Ruben Safir wrote:

One of the concepts that have bothered me the most is the idea that the >>>> universe is ever exapanding.

[_expanding_]

We do not know that. We know that our universe is expanding now and has >>

"We"???? you mean me, myself and I?

Astrophysicist/cosmologists. The scientific community.

I'm flabgastted that people till this day are testing Positive for
Stupid in these sci newsgroups.

The UNIVERSE IS *NOT* EXPANDING! It *never* has expanded. It remains the >> same size it always has been since it existence.

Observationally falsified.

The Big Bang was the 'expansion' of ...space, not the expansion of the
universe.

The Big Bang _is_ the expansion of the space of our universe. AFAWCS it is ongoing.

"the expansion of the space of our universe. "??? does that even mean anything??


Let me put it this way...

you only occupy 5% of the office building.


95% of space contains nothing, you occupy just 5%.


There is no universe..
it's just a few grains of sand.


In the beginning, ...

beginning means Time, ..spacetime

in the spacetime.

IN.

primarily indicating a state of being inside/within something (a place,
time, condition)


beginning


the point in time or space at which something starts.


IN time
IN space
IN spacetime.
--
The Starmaker -- To question the unquestionable, ask the unaskable,
to think the unthinkable, mention the unmentionable, say the unsayable,
and challenge the unchallengeable.
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