[NatureNS] Expand Universe or Tired Light

ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none;
ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com;
ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=dalu.onmicrosoft.com;
From: Patrick Kelly <Patrick.Kelly@Dal.Ca>
To: "naturens@chebucto.ns.ca" <naturens@chebucto.ns.ca>
Thread-Topic: [NatureNS] Expand Universe or Tired Light
Thread-Index: AQHWL6HG65Z5ThZP5U+xhTj7aTlMHA==
Date: Thu, 21 May 2020 18:58:11 +0000
References: <8485a90e-7c49-1a8f-f0a7-17f7b5263668@glinx.com>
Accept-Language: en-CA, en-US
authentication-results: chebucto.ns.ca; dkim=none (message not signed)
Precedence: bulk
Return-Path: <naturens-mml-owner@chebucto.ns.ca>
Original-Recipient: rfc822;"| (cd /csuite/info/Environment/FNSN/MList; /csuite/lib/arch2html)"

next message in archive
next message in thread
previous message in archive
previous message in thread
Index of Subjects

Index of Subjects
--_000_662E3D62D8C04C61B811727C09E501F9dalca_
Content-Type: text/plain; charset="Windows-1252"
Content-Transfer-Encoding: quoted-printable

Interference won't work either. Unlike water waves, which travel in a mediu=
m, which can physically interact, light waves do not travel through a mediu=
m at all, so they pass by and through each other with no effect.

(In the last 1800s, Michaelson and Morley devised an experiment to look for=
 the "aether" though which it was though that light propogated. Their exper=
iment proved there is no such thing.

https://en.wikipedia.org/wiki/Michelson%E2%80%93Morley_experiment)

You can get waves to interfere with each other if they come from a single s=
ource and pass though a narrow slit, and then a double slit, but the constr=
uctive and destructive only occurs in a limited area, and affects their amp=
litude, not their wavelength. Plus, the size of the slip would only affect =
waves of a certain wavelength. You can prove this to yourself at a beach. T=
ake a whole bunch of stick, and line them up in a row parallel to the shore=
. Space them about 3 or 4 wavelength apart. The waves will just ignore them=
. If you keep filling it to get the gaps close to the size of the wavelengt=
h you will then see some interference and if you take lots of sticks and ma=
ke the gaps a lot smaller than the wavelength, you will see that the waves =
will now reflect off the barrier. (That is why radio telescopes can be made=
 with, what looks like chain link fencing material. The wavelength of radio=
 waves is sol long compared to the gaps that they just see it as a smooth s=
urface.

The other problem is that at the large scale the structure of the matter in=
 the universe is "frothy" like soap bubbles with large voids with almost no=
 galaxies, and galaxies found in sheets, filaments and lumped together in c=
luster and supercluster where these come together. So any process that depe=
nds on light interacting with matter, would have to produce identical effec=
ts on electromagnetic radiation of all wavelengths,  coming through all man=
ner of distributions of matter AND give results that are exactly the same a=
s those of an expanding universe which is predicted by relativity, a theory=
 which has passed (perfectly) every test we have been able to devise for it=
 as the technology to do so has advanced.

Humans used to be comfortable with the idea that Earth was at the centre of=
 everything. Turned out we aren't but then we though we were near the centr=
e of the Milky Way. It turned out that we aren't but we though that we were=
 in the only galaxy. Turned out we aren't, there are billions of them. Scie=
nce does not care about what makes humans feel good.....

The universe also is highly unlikely to have perpetual renewal. There was a=
 time when it was though that there was enough matter (including dark matte=
r) to eventually slow the expansion. That is no longer the case. The rate o=
f expansion appears to be increasing due to dark energy. This is an outward=
 "pressure" that appears to be a property of space-time (Einstein's cosmolo=
gical constant that he later though was zero) and the universe expands, the=
re are more and more cubic metres from which the dark energy can act. The e=
ventual result is the heat death of the universe.

There are already large prats (the vast majority, actually) of the universe=
 which is unobservable to us. As the expansion rate continues, more and mor=
e distant objects will disappear. Almost all regular matter in the universe=
 is in the form of stars or gas and dust. For the vast majority of stars (i=
ncluding the Sun), at the end of their life they puff off a bit of their ou=
ter atmosphere and end up as a white dwarf star. They can no longer produce=
 energy and slowly cool off becoming black dwarves. They are quite small=85=
 the mass of the Sun packed into a ball the size of Earth and kept from col=
lapsing farther by electron degeneracy pressure.

For the small number of stars about 2-10 times the mass of the sun, they en=
d up producing a supernova explosion, throwing some material back into spac=
e with the rest ending up as a neutron star. Again, they can no longer prod=
uce energy and slowly cool off becoming black. They are even smaller=85 the=
 mass of the Sun (or a bit more) packed into a ball the size of Halifax and=
 kept from collapsing farther by neutron degeneracy pressure.

The really massive stars end up as black holes as they have so much leftove=
r mass that neutron degeneracy pressure cannot stop the collapse. On the lo=
w end they produce supernova and end up as a black hole=85 on the high end =
they simply wink out leaving behind a black hole.

So all stars end up as a dead object that either slowly cools off, or in th=
e cases of black holes go cold right from the start. You can always make mo=
re stars, but there you run into a problem. You need gas* and dust** from w=
hich to form them.

About 25% of the galaxies are classed as elliptical. They used up all their=
 gas and dust in a massive burst of star formation when they formed. As the=
 stars in there galaxies "turn off" they cannot be replaced. The Milky Way =
is classed as a spiral galaxy and about 70% of galaxies fall into this type=
. About 15% of their mass is still in the form of gas and dust, so they, at=
 least for now, they are capable of forming new stars, but a time will come=
 when they too run out of gas and dust. About 5% of galaxies are "irregular=
" and while they have about 50% of their mass in gas and dust they are quit=
e small. It is though that many of them formed from collisions between spir=
al galaxies (common in clusters) an the stars are so far apart they can eas=
ily pass through each other, the same cannot be said of clouds of gas. They=
 are also undergoing massive star formation, likely due to the shock waves =
in the gas caused by the encounter.

So, in the grad scheme of things, a bit depressing, but as there are still =
many billions of years to go, I would not be too worried about it, especial=
ly as the Sun is going to fry the earth in about 4 billion years when it go=
es through its red giant phase.....

Pat

*The gas in our galaxy is 97% hydrogen and helium, with the other 3% compos=
ed of metal. Note that in astronomy, "metal" is the term used for all the c=
hemical elements which are neither hydrogen nor helium.. The early universe=
 started with no metal. Again, observ