
Physicists Debate Hawking’s Idea That the Universe Had No Beginning - _Microft
https://www.quantamagazine.org/physicists-debate-hawkings-idea-that-the-universe-had-no-beginning-20190606/
======
djsumdog
This seems different than the concept of infinite time, where prior to the big
band there was something the collapsed into a ball of energy and maybe someday
our universe will collapse back again (which has lost merit since we've seen
matter in the universe isn't slowing down in spreading apart, but accelerating
.. meaning in a few trillion years, atoms may be so far apart that light can't
reach anything .. the eventual heat death of the Universe).

In the shuttlecock example, there is an assumption the shuttlecock is the
Universe and there is nothing outside to observe the object. Same with "What's
south of the south pole." It ignores the stars and galaxies past Earth itself.

There is also a theory there could be many other big bangs and universes next
to our own, but they are all accelerating away from each other. We can't see
the one next to ours because it's expanding itself, as is ours, and all these
are moving away from each other. Imagine a room of beach balls and they're all
just inflating, but also moving away from each other at the rate they're
inflating. In you're inside one, it's not only impossible to see another one,
but because of the speed-of-light speed limits, it's impossible to travel to
another one or even provide/disprove it exists.

There are a lot of questions about what, if anything, is outside the
observable universe. Are we sitting in a ball on some gigantic alien's coffee
table?

~~~
dugluak
>> Are we sitting in a ball on some gigantic alien's coffee table?

sometimes I have the same question but quite opposite. What if there are
miniscule worlds right on our coffee table.

~~~
pbhjpbhj
On being given the planetary model of an atom I think it's relatively common
to consider that maybe atoms are mini star systems. That was one of my early
"aw shucks, someone else had that idea already!?" deflationary moments.

~~~
will_brown
That was exactly the early thought and why the commonly accepted image of an
atom with a nucleous and orbiting electrons looks just like a solar system.

Of course that’s not at all what atoms look like or how they behave.

~~~
pbhjpbhj
Do you have a source for that?

AIUI Rutherford's model focussed the mass in the nucleus based-on/inspired-by
Nagaoka's Saturnian model. Then Bohr's model specifically put electrons in
orbit but they were there to explain atomic emission spectra and so needed to
move between orbits - not at all like planets.

I think the thought was that electrons orbited a nucleus in a "planetary" way,
rather than them being actual nano-scale planets.

------
sgentle
Possibly one of the most intriguing ideas I've ever heard is that there is no
difference between "true" in the sense of "1+1=2" and "true" in the sense of
"polar bears exist". The universe isn't described by the mathematics we have
constructed to explain it, it _is_ that mathematics.

In that sense, the question of what happened before our universe is similar to
the question of what happened before 1+1=2... sort of a strange thing to ask.
Our universe exists because it is a coherent tautology.

Of course, like all metaphysical posturing it's almost certainly impossible to
ever know. But I find the elegance of the idea appealing.

Edit: I believe I was thinking of Max Tegmark's mathematical universe
hypothesis, but also a little of David Lewis's modal realism:

[https://en.wikipedia.org/wiki/Mathematical_universe_hypothes...](https://en.wikipedia.org/wiki/Mathematical_universe_hypothesis)

[https://en.wikipedia.org/wiki/Modal_realism](https://en.wikipedia.org/wiki/Modal_realism)

~~~
dr_dshiv
Note that this idea -- that the basis of the universe is math itself -- is
attributed to the presocratic philosopher Pythagoras.

In the ensuing Platonic worldview, it was understood that the world began with
total Oneness. In modern terms, that's treating the entropy of the universe as
equal to 1; there is only one state for the entire universe to be in. Then,
this increases to twoness, between the something and the nothing. As the
something and the nothing interact, that interaction is the threeness; and
from the three, the multitude. They then believed that this resulted in the
formations of geometry which led to the elements, which they expected to
consist of the simplest 3 dimensional shapes. They were pretty much spot on,
except they didn't know that the spherical harmonics of atoms are even simpler
than the platonic forms.

Not a bad cosmology for 2500 years ago. I think there is still a lot of
profound thought to process and consider.

~~~
andrepd
_> In modern terms, that's treating the entropy of the universe as equal to 1;
there is only one state for the entire universe to be in. Then, this increases
to twoness, between the something and the nothing. As the something and the
nothing interact, that interaction is the threeness; and from the three, the
multitude. They then believed that this resulted in the formations of geometry
which led to the elements, which they expected to consist of the simplest 3
dimensional shapes.

>They were pretty much spot on._

Is it me or is that paragraph completely devoid of meaning? Is it actually
_saying_ anything? This reads like medieval scholastic philosophy: so far up
its own bottom it no longer makes any sense.

~~~
dr_dshiv
I'm curious what you find meaningless about a plausible mathematical origin
story for the universe. You don't sense meaning in the idea of "Oneness" or
"Twoness", I'm guessing? Oneness is clear, I hope and twoness can be
understood as a contrast or gradient (which we know to be necessary for energy
flows). I'd be happy to unpack further.

And by _saying_ something, you mean predicting something? One clear prediction
(from the Pythagorean Democritus) is that the geometries of atoms would
determine their physical properties. Is that meaningful?

I don't know if your comment intends to dismiss all premodern scholarship, but
I would guess that there is more depth and meaning than you may have
personally encountered.

I'd be happy to share some references or further ideas.

------
eternalny1
Pure nothingness has no potential for creation. The laws of physics don't
invent themselves, so it would seem that true "nothing" never existed. I'm not
talking about the quantum soup of the vacuum of space, because that is
something.

If we take Hawking's idea that the universe smoothed out to a zero point where
there was no time and nothing else, how does that point because laws of
physics, gravity, etc? What properties of a zero point (that had no
properties) cause it to create an inflationary universe?

Everything breaks down at that point, because trying to use mathematics or
physics to explain something that existed before mathematics and physics
doesn't work.

~~~
naringas
> Pure nothingness has no potential for creation.

I disagree, pure nothingness has the largest potential for creation because by
virtue of not being there (nor anywhere) it doesn't prevent anything at all
from creating itself.

if this sounds strange is because the concept of nothingness is strange.

rather than asking why is there nothing rather than something, I marvel at how
we can conceptualize 'nothingness' in such a way that we can even think of
these kinds of questions

~~~
bobthechef
You're misunderstanding potential.

Potential cannot exist of its own accord. It is secondary to something already
actual and only then can it be actualized.

If in the beginning there was truly nothing, and I mean also the absence of
any cause that could make things exist, then there is not only nothing to
actualize anything since only actual things can actualize, but not even the
potential to be actualized.

So no, absolute nothing can not produce nothing and can never yield anything
not even in principle.

~~~
philipov
You're speaking in tautologies. If you define "Nothingness" as "That which is
unable to produce anything" and use that to conclude that it is not possible
for there to be nothing at the start of the universe, you are begging the
question. Your axioms trivially contain your conclusion, but why should we
accept those axioms?

~~~
tuesdayrain
As a layman when it comes to physics, I've always had the impression that the
nature of existence _must_ be tautological. If the logic doesn't form a
circle, then any attempt to explain the cause and effect sequence that
resulted in our universe can always be met with a "well why did the first step
occur"?

~~~
philipov
Logic is a human invention. The universe doesn't owe you the ability to
explain the entire chain of cause and effect. Not being able to prove your
axioms is what differentiates science from religion.

~~~
nf05papsjfVbc
By definition axioms can't be proven but they are assumptions which we take
for granted upon which we build science. However, in science, the axioms are
such that they can be observed and discarded if we ever find them to be false.
This is where it differs from religion.

~~~
philipov
I think that using logical fallacies to prove your own assumptions likewise
discards observation in favor of a totalitarian explanation of everything,
which amounts to a religious belief. A key aspect of science is accepting that
our understanding is limited and contingent, whereas religion tends to use
faith to prove itself.

~~~
nf05papsjfVbc
Agreed.

EDIT: _Mostly agreed_. Religion never proves itself. It just demands that you
have faith.

------
abtinf
The explanation I've found most persuasive is to take a purely philosophical
approach: the universe had no beginning and will have no end because those
concepts do not apply. The universe is everything. If there was something that
"caused" the universe, it would just be part of the universe. If there is
something after the universe ends, it would just be part of the universe.
There is nothing outside the universe, if there was it would be part of the
universe.

~~~
jerf
That's not an explanation, that's just a relabeling, moving the questions
people have from the label "the universe" to the label "the observable
universe", but neither answering them, nor making them any less relevant.

~~~
abtinf
The universe is everything. By definition, there can be no evidence for
anything outside, before, or after it. Any such evidence would be in the
universe. There are no valid questions about it, nor valid answers. Any claims
about something outside the universe are neither true nor false—they are
completely arbitrary. They have the same intellectual status as God.

~~~
jerf
I addressed what you said, you just blindly re-iterated your point without any
engagement with mine at all.

To spell it out even more clearly, what if "the universe" is larger than the
observable universe? In that case, it would still be reasonable to ask _where
did the observable universe come from_? For instance, if we are a simulation,
you would place the simulator in "the universe", which as a definition is a
fine place to put such a simulator. But it means that questions about _our
observable universe_ would then be fair game.

You're trying to shut down thought by simply redefining terms, but even by
your own definitions, it doesn't work. It's not a sophisticated or well-
thought out position, it's just "I give up entirely, and so should everybody
else" dressed up in pretty clothes that are trying to look cool. You're
welcome to give up in that way, most people do by default after all, but
you've got no grounds to insist that _others_ also give up.

~~~
abtinf
This is precisely the form of argument made by religionists.

------
quotemstr
Cosmology is deeply disturbing if you think about it too long. _Why_ should
the universe exist? What is a causeless cause? How can something come from
nothing? Regardless of the precise mechanisms involved, at _some_ scale, some
kind of steady-state cyclic model seems unavoidable --- the whole idea of
existence not existing is bizarre and puzzling. The only way out of the
causeless effect problem is to nop out of the effect.

~~~
onion2k
That's only disturbing if you believe everything is simple enough that humans
could comprehend it straight away. If you accept that some stuff is beyond our
understanding, and will be for quite a while yet, everything is much less
bothersome. Accept that you are fallible and the universe is fine.

I'm not saying this is easy though.

~~~
chii
> If you accept that some stuff is beyond our understanding

isn't that just an elaborate way to say 'give up'? I asked religious friends
of mine about what god _is_, and the common answer is that it's beyond human
understanding.

I don't believe that people should take things on faith, and accept that
anything is beyond understanding.

~~~
onion2k
_isn 't that just an elaborate way to say 'give up'?_

Accepting that we don't understand something is a first and very necessary
step to even realising there's something to understand. Believing that we have
the answer (eg "God made the universe!") is exactly what shuts down scientific
inquiry and makes people 'give up'. I'm saying literally the opposite of that
- we have to realise there's something to out there to learn in order to try
and learn it.

~~~
jorangreef
If we accept your logic, then believing gravity to be the answer to "why
things fall" would shut down scientific inquiry?

On the contrary, it was belief in the creator that opened up scientific
inquiry in the minds of Johannes Kepler etc.

That the universe was not chaotic, but created by a personal being, led them
to think there must be some order to it that could be studied.

------
d0m
Say we could break any physical rules of our current universe, is there a good
theory that would explain how something might have been created out of
nothing? i.e. imagine for a second that we're in a simulation and that the
current laws of physic are just arbitrary created by a "host". This "host"
could have _very_ different physical laws. Could we think of any theory that
would explain the creation of something out of nothing in this "host"?

I'm very puzzled as to why the universe even exist.. wouldn't it have been
much simpler not to have anything at all? I can only think of one answer: It
couldn't have been otherwise. I.e. physically speaking, it _had_ to happen.

Maybe that's how we should approach the problem? Let's try to "create
nothing"... maybe we'll realize that it's actually impossible to "have
nothing" unless X happens, and maybe we'll figure out that X happening would
explain how our universe was created?

Or said in a different way, maybe the universe is actually "nothing", like it
always was and will always be. But "nothing" may just be physically impossible
so you need "positive" and "negative" things to cancel each other out so that
the end result is "0".

I'm not too sure where I'm going with this, but it reminds me of the quote
"Once you eliminate the impossible, whatever remains, no matter how
improbable, must be the truth." So, whatever the theories about big bang,
multi-verse, universe expanding/collapsing indefinitely or even God-based
theories, all of it comes back to "how did the first thing come out out of
nowhere?" People talk about "Singularity", but this is just "kicking the can
down the road". Still, by kicking the can I guess we keep learning new things,
and maybe someday we will have the technology to answer these questions.
Unfortunately, it seems like answering the next frontier seems to be an order
of magnitude harder (time-wise and cost-wise) than answering the previous
question.

~~~
dmbaggett
You might be interested in _Our Mathematical Universe_ by Max Tegmark. He
tries to argue that, fundamentally, the universe is "just math." In other
words (glossing over enormous complexity here) if the basic axioms of math are
true, the universe must exist.

I have to admit I didn't fully buy the line of reasoning. But it's very
interesting.

~~~
RcouF1uZ4gsC
> if the basic axioms of math are true

Isn't the problem that you can't prove axioms. We intuitively "know" them to
be true but without proof.

~~~
crazygringo
You can't use deduction to prove them... but you use induction to show them to
be statistically non-violated through experience so far.

------
kazinator
The word "beginning" is contextualized to the concept of time, and time is an
abstraction that exists _within_ the universe. To say that the universe has a
beginning is to say that time has a beginning. But that is nonsensical;
something only has a beginning if its existence is preceded _in time_ by other
existence. The existence of time can't be preceded in time by the existence of
something else. For that to have meaning we need some "meta-time". "Meta-time"
can only exist in a "meta-universe": a larger, imaginary universe in which we
are embedding "our" universe. Well, did _that_ larger one have a beginning,
and why would we even consider it a separate universe at all?

------
Zenst
The start of the Universe was the start of time. My personal theory is that
when matter enters a black hole, some of that matter (in some form) gets
snapped out of space-time, emerging at time 0, at 0,0,0 coordinate. With all
the black holes over time, all venting into the same space and time, producing
lots of matter in a single space at the same start of time, which would create
a big bang.

Just a theory, but one I've not fully proved, nor disproved.

Of course this would mean that the future created the past, and a bit of a
paradox, but not entirely impossible.

~~~
kbmax
Slightly different but related thought: what if inside of each black hole
singularity is another universe? The stuff it collects ends up in this other
universe. Which would mean our universe is just "inside" the black hole of
another.

Then perhaps the accelerating expansion of spacetime we detect here has
something to do with the accelerating accumulation of mass of our "parent"
black hole.

~~~
Zenst
That would add an interesting spin upon multiverses. Without a doubt, black
holes and understanding them are very much key to many unanswered and unknown
questions.

------
dmix
The linked 1981 source document "Astrophysical Cosmology" proceedings from the
Vatican look's interesting (Hawking's raw talk is at page 575 in the PDF):

[http://www.pas.va/content/dam/accademia/pdf/sv48pas.pdf](http://www.pas.va/content/dam/accademia/pdf/sv48pas.pdf)

The preface mentions the academy was from 1603 and Galileo Galilei was a
member.

------
gavanwoolery
I have _very_ little knowledge of astrophysics, but I thought it would be an
interesting idea if the universe constantly recycled itself. That is, every so
often it collapsed in on itself and produced another big bang. Theoretically
some parts of the universe would have already achieved escape velocity, but
the rest of it is gradually gravitating towards some center of mass. Is such a
thing even feasible?

~~~
svachalek
A few decades ago, that was widely believed as the most likely state of the
universe. However, it's now known that the big bang is essentially still
accelerating and this is blamed on an unknown force called "dark energy". It
doesn't have much effect within galaxies, but galaxies themselves are blowing
away from each other at ridiculous speeds.

~~~
XorNot
Well it's more that space itself is expanding. It doesn't affect small scales
because other forces collapse everything back together fast enough to overcome
it. If the increase in dark energy is consistent though, eventually it'll be
expanding so fast not even our atoms can hold themselves together.

------
golover721
For me the hardest idea to grasp is the concept of “nothing”. It seems to me
that is something the human brain cannot possibly comprehend. There is always
something as far as our senses are concerned. I guess that’s why the idea of
nothingness after we die so such a hard notion to comprehend.

~~~
JudgeWapner
I can momentarily stun myself if I concentrate long enough on the idea of
"what if there was just nothing? No universe, no cosmos, no light, no time, no
matter. Just nothing." Think about that for a minute or two.

~~~
andrepd
I have _exactly_ the same thought, to a tee.

------
dghughes
Whenever I see an image like the one in the article of a cone showing the
start of the universe it reminds me of something being shot. Or an object with
great velocity striking a stationary object. One end is the point of impact
and the cone is the debris spraying outward.

------
SomeOldThrow
What does it even mean to ask “what happened before time”? The question seems
nonsensical to me.

~~~
ASalazarMX
It's nonsensical to wonder what happened in our universe before it existed,
but if our universe has an external superuniverse, it's not illogical to
wonder what happened there that caused our universe to exist.

~~~
SomeOldThrow
> if our universe has an external superuniverse

This is also meaningless, scientifically: there is nothing you can measure
which is outside the universe. Things like a holographic universe are
inherently untestable. I hope we continue looking for testable things, but
this speculative path rapidly leads away from science and physics and into
"linguistic tricks to confuse humans". It's not even philosophy at that point,
it's just arguing over semantics.

~~~
AgentME
There are still ways we can reason about it. If we come up with a model of a
super-universe and then find that model says that universes like ours are more
likely to exist, then it can be evidence for the super-universe. We could
possibly use the model of the super-universe to make predictions about our own
universe.

~~~
SomeOldThrow
> If we come up with a model of a super-universe and then find that model says
> that universes like ours are more likely to exist, then it can be evidence
> for the super-universe.

That's not evidence FOR the superverse, just like we can inherently not rule
out the idea of the
[https://en.wikipedia.org/wiki/Evil_demon](https://en.wikipedia.org/wiki/Evil_demon)
deceiving our every perception.

At best, this is untestable philosophy that's fun to debate over drinks. At
worst, it's a tedious discussion about the semantics of existence and time.

Don't get me wrong! We could discover interesting things about our universe
looking for holes, but there's no indication this problem is tractable.

~~~
AgentME
If the evil demon theory made specific predictions that turned out to be right
and weren't predicted by other theories, then it would be a useful theory.
It's possible for a theory of a super-universe to do that.

Imagine if we came up with a super-universe theory that said that the super-
universe could only spawn sub-universes which followed conservation of energy
plus several other laws no one had ever thought to test before (and weren't
implied by any other theories), and as we started testing for those other
laws, every single one we tested turned out to hold in our universe.

(If that happened, it would be reasonable to look for simpler theories that
also predicted those other laws too, but it's possible that the super-universe
theory would turn out to be the simplest possible theory that fits. Theories
should be judged by the complexity of their rules, not by the number or
complexity of things they predict; a simple theory that implies a large
ensemble of universes can be better than a more complex theory that implies
only our world or what we can see is real.)

------
her_tummy_hurts
I don’t thunk my brain could handle no beginning

~~~
jvagner
With all respect, I think we generally live in a human society that has been
built around that very constraint.

~~~
sarego
Curious to know why that is. Would you mind expanding?

~~~
jdironman
Because if we have not beginning, we have no purpose. If we have no purpose,
this is all really for nothing. I am not arguing whether it is or not, or
whether there is a beginning, but lets look at it this way... You woke up this
morning, that was the beginning of this day at night you will rest. Now, lets
say there is no memory or record of 'waking up' beginning, we therefor cannot
anticipate an end and everything we do now may feel for some less meaningful.
I don't really know. I am just expressing my under-educated overthinking take
on it.

~~~
antidesitter
Countered the downvote because I’m interested in this line of reasoning. Could
you expand on that? Why do you think having no memory of “waking up” to
existence makes it less meaningful?

I'm reminded of the following quote by Alan Watts from _The Way of Zen_ :

 _To the Taoist mentality, the aimless, empty life does not suggest anything
depressing. On the contrary, it suggests the freedom of clouds and mountain
streams; wandering nowhere; of flowers in impenetrable canyons, beautiful for
no one to see, and of the ocean surf forever washing the sand, to no end._

~~~
jdironman
I like that idea. I think the world is a beautiful place, and I think also
that humans can be a beautiful species at the times they come together. What
is that one quote? "All that wander are not lost." I believe we can find peace
with our existence and mortality and its something we have to remind ourselves
of that individually it is not forever, and how it will end in general is not
yet perceived.

~~~
ionised
All of the worst things in human history have happened as a result of mob
mentality or 'humans coming together'.

On the contrary, the only times humanity doesn't sap me of the will to live is
when I'm dealing with people on an individual basis.

> All that wander are not lost.

I feel like you're misunderstanding that quote as well.

It's supposed to be _" Not all who wander are lost"_ and it refers to loners,
wanderers, vagrants and explorers that never settle down and 'plant roots'.

The idea being that there are plenty of people that exist like that and enjoy
that way of life. Other people with families and steady jobs tend to look at
them as if they are 'lost', without truly understanding what it is to walk the
earth.

------
mensetmanusman
Of course the Universe can arise from nothing. Especially when you give
nothing specific properties beyond ‘not anything.’

------
sonnyblarney
I misinterpreted the direct idea of 'Big Bang' at a very young age and thought
that the nature of time changed over time, ergo, 'the beginning' could never
be achieved (even if you could travel backwards in time), i.e. it's
'infinitely far back' similar to how time changes for traveller/observer as
one approaches the speed of light.

Only in any given time frame could one mark 'the start', but that would be a
misinterpretation.

So time did have a 'start' but it was 'infinity ago'.

I realized at some point this has nothing really to do with 'Big Bang', but
later I've come back to the idea as at least novel!

It's fun to see smart people contemplating alternative things.

~~~
senorjazz
> It's fun to see smart people contemplating alternative things.

It certainly is. Most recent theory I heard of whilst staying up too late
watching youtube videos, was by Roger Penrose on CCC (Conformal cyclic
cosmology) [1]

My very basic understanding of it (probably wrong understanding though) was
that the universe is mathmatical, thus mathmatical tricks are valid constructs
when understanding the universe. Once the universe has expanded to heat death,
it will have infinite size and zero mass which is the same as having 0 size
and infinite mass which will cause a big bang and another universal epoch.

I'm probably remembering it all wrong, but as a layman who enjoys watching
much smarter people than I contemplate and try to explain these thing, I found
the idea very interesting

\--------------------------------

[1]
[https://www.youtube.com/watch?v=FVDJJVoTx7s](https://www.youtube.com/watch?v=FVDJJVoTx7s)

or maybe

[https://www.youtube.com/watch?v=sM47acQ7pEQ](https://www.youtube.com/watch?v=sM47acQ7pEQ)

------
tectonic
I really enjoyed "Why Anything? Why This?" by philosopher Derek Parfit.

[http://www.sfu.ca/~rpyke/cafe/parfit.pdf](http://www.sfu.ca/~rpyke/cafe/parfit.pdf)

------
canada_dry
> Just as a shuttlecock has a diameter of zero at its bottom most point

As a lay person this - right from the starting block - is what messes me up.
I.e. something that exists cannot logically have a zero diameter part.
Anything zero does not exist.

Most related theories have similar kinds of initial premise that you must just
accept.

~~~
klank
> something that exists cannot logically have a zero diameter part

Do elementary particles exist?

~~~
ars
Elementary particles have size delineated by the forces that act on them.

The concept of a "physical size" has no meaning, since particles don't act
upon each other that way.

But the forces do not have a zero size, and that's important.

------
jihadjihad
For an eloquent companion piece, I would highly recommend this essay:
[http://nautil.us/issue/16/nothingness/the-bridge-from-
nowher...](http://nautil.us/issue/16/nothingness/the-bridge-from-nowhere)

------
chantelles
Distances between our limited repetitive Universe Origin Debates and meaning
describe how our intellectual ecosystem interferes with knowing. That is
something, at least.

------
anigbrowl
If it's shaped like a shuttlecock then it will have a nodal center - a causal
echo, if you like - in its early phase but some time after the beginning.

------
resters
Cognitive biases and the vast cultural/religious narratives around
cosmogenesis make it next to impossible to reason about the universe in this
way.

------
EdwardDiego
Am I wrong, or are they arguing on matters of belief rather than evidence?

~~~
sonnyblarney
The word is 'speculation' not 'belief' that that's pretty much what all
science is. The evidence usually comes later.

~~~
EdwardDiego
There I was thinking that the scientific method involved falsifiable
hypotheses - so how are they going to prove or disprove their respective
beliefs? I'm getting string theory flashbacks where half of the physics
community is into it, the other half is not, and no-one can prove anything,
but they still have a grand old time arguing about it anyway.

~~~
semi-extrinsic
The trouble is, unless you have a grand old time arguing vague ideas, you
might not find the ideas that can lead to new falsifiable hypotheses.

~~~
raattgift
[https://en.wikipedia.org/wiki/Abductive_reasoning](https://en.wikipedia.org/wiki/Abductive_reasoning)

Modern cosmology got kicked off in the 1700s by observations of "nebulae" that
showed many of them were collections of stars, and in particular that some
were much much much larger and more distant than others. Just before WW I the
absorption and emission line structures of the spiral ones were discovered to
be strikingly similar except the smaller (in angle) dimmer (in apparent
magnitude) ones were squashed into the red.

Just after WW I is when spiral nebulae were identified as anything remotely
like our modern understanding of spiral galaxies. 1920:
[https://en.wikipedia.org/wiki/Great_Debate_(astronomy)](https://en.wikipedia.org/wiki/Great_Debate_\(astronomy\))
[poor Shapeley, so bright and so so wrong on this point] about five years
after a working theory of post-Newtonian gravitation was even available, and
almost exactly two years after General Relativity aced its first observational
test in the solar system. Up to that point even the greatest names in
astronomy (even Einstein) believed everything in the sky was within or in a
close (~ kiloparsecs) orbit around the Milky Way.

Towards the end of WW II and just after radio astronomy became important,
particularly the study of the 21cm hydrogen gas line, which was clearer than
the red-squashed lines of visible light passed through prisms, and in
particular different limbs of galaxies had different redshifts, proving
rotation. Some three decades later, the 21cm redshift difference between the
inner and outer parts of a number of galaxies showed that there is non-
Newtonian gravitation obviously at work in large galaxies. (Also
coincidentally around that time, the cosmic microwave background was
discovered, but it was some years before the small anisotropies in it could be
studied -- BOOMERaNG and COBE in particular to start with).

The evidence in all these cases arrived in advance of vague ideas, and forced
the hunt for tractable explanations for the evidence _in its totality_ ,
rather than as individual stand-alone pieces. One of the biggest pieces to fit
in is of course the highly successful standard model of particle physics,
which also was driven by evidence arriving kinda by surprise somewhat
concurrently with surprise evidence from cosmological observations.

The result is the "concordance cosmology", \Lambda-CDM, which concords with
all the available data (well, or rather it's updated as new data shows up from
various observatories and experiments). It's certainly subject to speculation:
what's the microscopic description of dark matter? is the cosmological
constant actually uniform everywhere in spacetime? is there a non-
cosmological-constant term required to match new data for the Hubble flow?
These are pretty big questions, but they're forced on us by the in-your-face
obviousness of the metric expansion of space, and the peculiar motions of
galaxies within clusters, and the outer parts of galaxies around the inner
parts. Also, what's going on in "the dark ages"? We have an obvious gap
between the surface of last scattering and the first starlight, but the
details of the observed first starlight and the cosmic microwave background
don't interpolate as well as one would naively expect. And we have so many
exabytes of data about the latter (and a lot of data about early galaxies too)
that vague ideas die quick deaths: they don't even get a chance to generate
new "falsifiable hypotheses", they are generally born inconsistent with some
existing data.

The "trick" is abduction: trying to reason out a simple-enough-to-be-useful
explanation that fits the known data.

Of course, you can get away with wild speculation and vague ideas in areas
where there is little to no data at present. Anything before the electroweak
decoupling is anyone's guess, as is anything much more than a trillion years
in the future, or far outside the Hubble volume.

------
gauravjain13
Perhaps tangential, but: Why is science up for “debate”? We could all offer
opinions around the edges of present-day human understanding, but is there any
merit to these debates? Feels like a lot of fluff. I wish Feynman were still
around.

~~~
thatoneuser
I think that's the most interesting part of science - the place where
brilliant minds hypothesize and ponder about what may be. Sure it's fluff but
we'd no doubt say similar of Einstein prior to his publications in the early
1900s if we were there then.

We live in a world of echo chambers. Where people can't imagine thoughts other
than what they've been fed. I think that while this isn't rigorous, it's a
healthy thing in moderation.

------
Ericson2314
The article is vague in the topology. No boundary or also infinite?

~~~
antidesitter
The article has an image illustrating the no-boundary proposal.

------
hirundo
> “Asking what came before the Big Bang is meaningless ... It would be like
> asking what lies south of the South Pole.”

Isn't Polaris Australis south of the South Pole? Was Hawking imagining an
Earth-shaped space that isn't embedded in a larger space?

~~~
weego
A stars position can't be defined as being south of somewhere. South exists as
a logical construct of our magnetic poles. Once you lose that you have no
relative measure to work with. The same is possibly true of time.

~~~
djsumdog
But the trouble with the South Pole and Shuttlecock metaphors is that you
assume those objects are literally everything; all matter. If you define the
Universe as Everything there is (seen and unseen; where what we see is the
"Observable Universe") there is no outside location from which to observe it
in entirety.

That's where the analogy really breaks down, but I guess it's still a useful
thought experiment so long as you realize the limits to the domain.

~~~
BurningFrog
There can still be an unobservable (to us) universe outside ours.

If you assume the universe started N billion years ago, there is an event
horizon expanding at the speed of light that fit this definition of an
"observable universe" for us while allowing for an infinite number of equal
universes, some of which are partially shared with ours.

------
openfuture
The world is just one big "console.assert(false, world)"

------
kumarvvr
Curiously,Indian philosophy also propounds that the universe has neither a
beginning nor an end.

~~~
SketchySeaBeast
I think it might actually be more unique for western philosophy/religion to be
building a narrative with a beginning, middle, and end - a lot of other
ancient cultures seemed to see things as a cycle - for instance, we see in the
Mayans that they saw the world as a series of cycles. It makes sense in early
traditions to not have a beginning and end - if there's no track of "progress"
in a historical fashion, it would be hard to visualize any sort of long
lasting change in the cycle.

~~~
roland00
It was Aristotle's Unmoved Mover being incorporated into Christian Thought
around AD 50 via Philo of Alexandria that changed Monotheistic religion of God
being the Organizer of All Things from Chaos into the Creator of All Things
out of Nothing, Ex Nihilo. Beforehand Monotheistic Religions believed God was
a creator but he created out of chaos and imbued the formless with a specific
form.

Likewise simultaneously around the time of Aristotle during the time of the
Hellenistic Era, The Seleucid Empire arose from the fires of Alexander the
Great Empire. The 2nd king in the Seleucid Dynasty decided to make a universal
time calendar that just increments again and again past individual rulers and
this change the nature of stories tremendously in the empire.

When Time Became Regular and Universal It Changed History
[https://aeon.co/essays/when-time-became-regular-and-
universa...](https://aeon.co/essays/when-time-became-regular-and-universal-it-
changed-history)

When Antiochus I Soter in 281, after his father death decided to keep the
calendar his father created (and he had already served 10 years as a co-ruler
prior from 291 to 281.) And not start over it started the various populations
that were opposed to the Seleucid authorities to tell apocalyptic tales of the
end of days, not just the end of the ruler / authority but the end of
everything. Especially since later Seleucid rulers such as Antiochus IV
Epiphanes (175 BC to 164 BC) seem to limit Jewish religious rights, though
Historians are not sure if this true (it may have been about taxes and other
areas of authority.) Well there was a rebellion in 167 BC and the internal
Jewish Warriors succeeded from the Seleucid Empire (The Maccabees Rebellion.)
Well the rebellion was successful and they were independent for 130 years
(though lots of civil wars for authority) and only in the end succumb to the
Romans except the Jewish People saw the Romans __at first __as liberators for
they still feared various Greek / Hellenistic empires and the Jewish People
thought he romans were better.

\-----

TLDR: Cyclic thinking and Creation from Something / Chaos was actually the
norm in monotheism, only during the Hellenistic (Greek Influenced) / Roman Era
did this shift to Creation out of Nothing (Ex Nihilo) instead of Creation out
of Chaos. But yeah read the article I linked to.

~~~
SketchySeaBeast
Zoroastrianism had to concept of a universe that starts with nothing and comes
to an end as far back as the 6th century BCE.

But I agree, adding a concrete understanding of time really helps to cement
the linear narrative.

~~~
swatkat
Check out Nasadiya sukta[0] in Rigveda.

[https://en.wikipedia.org/wiki/Nasadiya_Sukta](https://en.wikipedia.org/wiki/Nasadiya_Sukta)

~~~
SketchySeaBeast
Cool - Is there a similar verse describing the end?

