--------- On science, religion, meaning, and the Universe.

These topics always bring forth much useful discussion, so I thought I might cross-post something here I wrote recently on them.

It arose from me recommending to one particularly philosophical and scientifically inquisitive student from the class I taught in the summer of 2019 that she read the classic book "The Tao of Physics" by Fritjof Capra, which she promptly did, and then wrote me several questions on it.

My response got kind of detailed and discursive, and I post an edited version of a version I posted to the whole class, thus the short intro. Comments, thoughts, reactions very welcome!

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

Dear All- After reading some part of the Tao of Physics, [Student S.] asked me some questions recently generally about how more mystical vs. scientific worldviews relate and it set me off to answer at some length on this issue, as it comes up quite often in our daily discourse with people of differing backgrounds. Thought this might be of interest to a few others, so here’s a (slightly edited) version of how I responded:

---- Dear Student S: these are very *long* discussion topics that don’t easily admit quick answers — they’re the type of q that humans have wondered about for millenia. I guess i will say in brief: i have found in my life that everyone seeks some kind of answer to why the Universe is here and what causes all the order in it. The large majority of people ascribe some kind of mystical/religious aspects to the answers to these questions, often invoking a God or gods of some form (which goes back many thousands of years to when humans were just beginning to evolve enough to consider these q’s, but far before there was a scientific awareness or understanding of any part of our place in the Cosmos), whereas the other ‘end’ of possible worldviews is that the Universe is totally and entirely material, fullstop, and nothing beyond atoms (and force exchange carriers, neutrinos, dark matter and dark energy of course!) is needed to explain all we see.

Generally, I find that the less scientifically trained people are, the more they start mixing in some amount of the mystical/religious into their worldview, which helps them make sense of the Universe, but you will find very few scientists needing to rely on anything outside of the material to give meaning to the Universe (or their lives). Most of them find enough beauty and wonder and profundity in the Universe simply as it *is*, in all its intricate and grand manifestations, from the chemical, to the biological, to the cosmological, without invoking anything beyond the ‘material’.

*Though* you do on occasion find some scientists that *are* religious, in usually a less literal sense than much of the population, as they have had to square their understanding of the world scientifically with religious doctrines otherwise out there that they have been taught.

E.g. there is simply no room in *any* scientific worldview for the idea of Creation happening 6000 yrs ago, as a certain segments of strict Christians espouse. (Unless you want to say that some God made the Universe 6k yrs ago but with all the pieces of evidence to look like it was created 13.8 Gyr ago in the hot dense phase of the Big Bang — but then, the whole exercise is rather empty, since if i can’t tell those two Universes apart, what’s the point?)

So — I *am* careful never to denigrate or mock any particular worldview, religious or otherwise, because for one, they can be deeply held social or personal views that really give peoples’ life meaning, and to attack this in a derisive way is really to set up an ‘us vs. them’ dichotomy that doesn’t need to happen, and never leads to much good in the world. (In fact, it’s the cause of so much of the strife that’s out there, ultimately.)

Further — every religion of the world — from Buddhism, to Judaism, to Christianity, through to Sikhism, Hinduism, Islam and even animistic or ancestor-worship traditions — has arisen out of some group of people struggling to figure out humanity’s place on the Earth, and in the Universe. How we came to be, how to live with one another and within the ecosystems and among the flora and fauna of the Earth in sustainable, humane, and ethical ways. They all come up with different details, but the essentials are always the same: we are to treat others by the Golden Rule, and with kindness, and humanity. These are ultimately what matter in a given short human life. So I have much respect for every tradition, and in fact, find each of them fascinating in their own right as ways that humans have constructed complex worldviews to deal with ethical, environmental, and social issues over the ages.

There’s very much more that could be written about all this, but anyway — hopefully it starts to address what you were asking!

It’s a quick summary of my way of looking at the world anyway, and everyone has to figure out their own way as their path wends and winds through the world…

How do *you* think about these q’s?

[May 2018] Are THEY out there?

So essentially the number one question everyone has on their mind when they meet an astronomer, and the first question I normally get asked is:

ARE THEY OUT THERE?

Related to this topic, Prof. Sara Seager gave a talk on exoplanets at Stanford in May of 2018.

She is an expert in this area, and gave a fantastic talk. I have my own feelings on the issue, that you can see if you follow the email exchange below I had with Sara in 2013.

No one has yet taken me up on the bet I mention below -- might *you* be willing to step up, to it? :->

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

Here's the email exchange i had with Sara in 2013:

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

Date: Thu, 10 Oct 2013 

hi Sara- just heard your interview on a TTBOOK podcast ( http://archive.ttbook.org/book/sara-seager-exoplanets-0 ) , and though i liked your energy and enthusiasm, i was a *bit* surprised at one of your comments, and that was that there is a *100%* chance of there being life on another planet.

I was floored by this.

Now -- i'm a cosmologist (doing gravitational lensing), and not in exoplanet work at all, but just before this comment in the interview, you'd admitted that you are an astronomer, not a biologist, and don't know the likelihood of life evolving etc. And then you said "100%"!

Here's the thing -- yes, i believe life is *likely* -- but i also believe we have *ZERO* idea about the true value of several of the 7 factors in the Drake equation [that gives the chance of intelligent life contacting us]. We now only in recent years have a good idea of the astro ones -- how many planets orbit in the habitable zone and such -- but we don't know if the probability of life evolving on any given planet is just small -- or *really* small.

Yes, there are something like ~5e11 stars (or more), and 1e11 galaxies in the observable Universe. So that's 5e22 planets.

What if the chance of life evolving (along with it evolving enough to produce O2 or methane, since we don't need to hear radio signals to see those) is about 2e-23 -- so the total expected number is unity, and we got lucky and happen to be the only ones?

What if?

You may say it's unlikely -- but have you much more to back that up than belief, at some level?

 If so, i'm happy to hear it, because *i* certainly don't know how we'd get to this number!

 (And yes, i know we can make amino acids and whatnot by irradiating a primordial-type mixture with ultraviolet light and such -- that's still far from life. Perhaps *really* far.)

Look -- i would *love* to find evidence of other life within my life *as much* as you or anyone else in the general public (who really care about this, as you rightly point out). I have just long wondered about the Fermi Paradox, and am perhaps less optimistic than many of the Planet Hunters about this (i was a postdoc at Ohio State, and know several of the forefront planet-hunters active in this, so i've definitely been exposed to some of it).

Ok -- thx in advance for any thoughts or info you might be willing to pass on, about this.

cheers--

-Mandeep G.

ps. Another thought i had: apart from info you could pass on to me, i'll tell you what -- even though i'm not sure, and don't have *such* a strong feeling about it, i would be so happy to *lose* a public bet with you on this that i would offer you a $1000 wager (with the money going to an environmental cause of your choice, maybe..?) on something like LongBets in the public arena that we will *not* find incontrovertible evidence of life-producing gases on another planet within what, 15 yrs? Whatever kind of terms you think would seem fair. I would really be happy to take you up on this if you might be willing, and haven't already done so (?)

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

Date: Fri, 11 Oct 2013

From: Sara Seager

Whatever I actually said was (*is always*) preceded by "my personal opinion" or "I can only speculate" or some such. If they cut out that important caveat then I'll have to change how I say it in the future, so thanks for the heads up.

Sara Seager

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

Date: Fri, 11 Oct 2013

From: Mandeep S. S. Gill

hi Sara-

Ok, great, thx much for writing back, appreciate that -- you don't mention the bet idea, so i'm guessing you're not up for that.. though i wish you would be! :-)

I'll start asking around with my exoplanet-hunter friends, see if i could get someone to take it up -- i think it would be a neat thing to be out there in the public to make us all even more excited about future possibilities in finding life Out There.

cheers--

M

So -- about what happened "before the Big Bang"...

***** This is an incomplete rough draft.. but it's the current state of it anyway (6/2018).  Medium-length, maybe ~10 min read at moderate speed.

Related to the post about things we will discovering at in the coming years (here, on FB, from 9/2016), I wanted to write about a question I, and all cosmologists, get very often, quite naturally enough: what happened before 'the Big Bang'?

Now, sometimes the answer you'll hear is that time *started* at the Big Bang, which kind of really doesn't say very much, and is highly not in accord with our commonsense intuitions about how time flows in our normal everyday life -- I mean what does that *mean* anyway?  Of
course, as I've written about in other postings, 'weird' non-intuitive things *do* happen in various domains of our Universe: such as QM (quantum mechanics) taking over at the very tiniest scales, time dilation and length contraction happening at very high velocities and near strong gravitational fields where GR (general relativity) must be used instead of Newtonian gravity, etc.  So the fact that it
*seems* weird to us doesn't intrinsically rule out this answer as a sensible one.

However -- i think there is a simpler way to 'understand' as much as
we can for now the 'beginning', at least from my point of view, and
that is: that our entire current framework of physics breaks down very
close to 'the Big Bang', and we simply cannot understand time before
this point *currently*.

Now - what does *this* mean?

To try to understand this, let's step back and look at what cosmologists mean by the Big Bang picture of the Universe, which is actually simply this: that at some point, our Universe was in a very
hot, dense phase.  And in fact, we can trace our Universe's expansion history *backwards* from the current moment and see all the galaxies streaming towards each other like a movie run in reverse until everything smushes together and there are only particles flying around in a superheated primordial soup -- a very early hot, dense phase.

Now when this movie runs in reverse, all the lengths between all objects shrink, and eventually, clearly, if they all shrink to exactly zero, the whole structure would collapse to a point -- an "infinitely dense" singularity.  BUT -- say we don't let it get there, we stop the movie at a specific point, and to be conservative, let's say that point is 10^-10 sec after the time where things *would* have collapsed to a singular point, which i'll call the 'theoretical zero-time', or TZT  (though we in fact believe we have a pretty good handle much farther back, to a point at least 10^-25 sec post-TZT, and possibly even 10^-35 sec post-TZT).

And let's call *that* (the 10^-10 point) the "theoretical breakdown time", or TBT.  Now, back at that time, the TZT and TBT are hugely different because things are changing so rapidly, but beyond a few min after the TZT, the TZT and TBT look pretty much like the same instant for how the Universe evolved forward.  (Much like just a few minutes makes a massive difference when a baby is first born, or in the first couple of minutes of its life, even though later in life gaps of a few minutes are typically not very significant and for most purposes we can approximate times like that as being the same.)  But in a theoretical sense, *however* miniscule the TBT, there is a 'Universe' of difference between zero time and any nonzero (i.e. finite) TBT whatsoever.  (One way to think of this is that infinity is a very strange concept when you probe more deeply into it, and on a 'logarithmic' scale, the space between any two finite times, small as they might be, can be stretched to an infinite length.  [If this reminds anyone of Zeno's paradox, there is in fact some deep connection there] ).

Now, looking from a grand scale: yes, we believe we understand quite well from the TBT until our current time how things have worked on the largest scale, crazy enough as that sounds.

You might think -- what are you on, man, how do you have
*any* idea this picture is right, how can you trace something back
with so much certainty for 13.7 billion years???

And this would be quite a reasonable response except that -- we have
really *good* reasons that we know this is the right picture thus far.

[Just to throw out a few of them: our ability to see galaxies that from their redshifts are clearly over 13 billion years old, i.e. how they were just a few hundred million years post-TBT, our understanding
of the distribution of galaxies across the sky in 'large scale structure', and the earliest clear photon signature being the 'leftover light from the Big Bang', the Cosmic Microwave Background that is emitted at 380,000 years post-TBT (discussed in this nice 2017 KIPAC blogpost by Kyle Story).  But my favorite, and perhaps the earliest confirmed and measured signature of our current framework, are the elemental abundances predicted by Big Bang Nucleosynthesis, or 'BBN' .]

Now - let us go back to what TZT means, and why i keep using that term vs. the more common "Big Bang" -- and that's because when we say "Big Bang Model" we only mean that *everything* everywhere was in a hot dense expansive phase.  What happens if we try to trace farther back than the TBT is that our current equations *break down*.  They just can't be solved in that domain, and we really have *no* idea before that time.  An analogy might be that you can't solve equations of
fluids in outer space which is empty, or use Newton's equations around black holes where strong gravity takes over, or use wave equations for macroscopic objects in the Universe, etc.  It just makes no *sense* to try to apply the eq's in those domains.

You might ask if that bothers me, or other physicists, and I would say
of course, at some level, this limit on our ability to know things
does, but -- that doesn't mean we *can't* ever understand it.  It
means that right now, we don't get it, and have to be ok with that.
To extrapolate further, to try to think we can know more theoretically
without experimental verification is, to me, closer to philosophizing
which while nearly inevitable given the expansive and wide-ranging
nature of the human brain, has no real scientific grounding as most
working scientists understand that term.  It's fine to do if someone
is interested in engaging in it -- it just doesn't interest *me* or
most cosmologists nearly as much as actually making the slow steady
progress in shining light into the darkness based on experimental
testing that is the fundamental hallmark of what science as an
endeavor separate from our particular species on this Earth *is*.

To me -- it is truly *ok* to be humble in the face of the immensity of the University, the vast expanse of time and space that we with our brief, mayfly-like lives on this little planet, can only ever make
finite stabs at in our time.

This is not at all to diminish the grandeur and profundity of all we
*have* discovered over time -- it continues to amaze *me* how well it
all fits together, everytime i look at the edifice of physical science
that we humans have built over the centuries, and particularly, in the
last one.

But -- there are an infinite number of digits after the decimal point
of any measurement.  And if we can measure to several, we do pretty
well.  In fact, in a couple of instances, we can match to some 15
digits (!!!) in physics.  That's stunning -- and yet, 15, or 20, or
100, or a million or a *gazillion* is in fact 'essentially zero' when
compared with infinity.  Infinity is just a concept that we humans
cannot i believe ever fully 'get'.  We just work with it, as best we
can.

So - I'm ok with where our current framework breaks down, and I am
just continually humbled that in fact we *can* still make progress
going forward with learning more, going farther back, farther out,
farther in.


Btw loosely related to this is the question of how 'big' the Universe is -- another reason we can't really get to the TZT currently is that our current picture doesn't have the Big Bang happening at any particular point in space, and thus the distances between all objects can never shrink to identically zero.  They can get arbitrarily *small*, but as long as they are finite, the entire Universe can still be infinite in extent, and still the same everywhere because the product of any small finite number, however miniscule, and infinity, is still infinity.  However -- we can only see to the observable edge, as far as light has been able to travel in the time since the TBT, and that's it.

----------------------------------  Appendix:

---- Btw, to picture how the expansion works (or contraction, when run in reverse mode), people have different analogies, but i usually picture the structure of space as a 3-dimensional tinkertoy grid, with the lines extending out infinitely in all 6 Cartesian directions from a given vertex (i.e. +/- x, +/- y, +/- z).  Now, what we mean by the expansion of space is that the actual *legs* of the tinkertoy structure are each growing, at the same rate.  And if we sit on *one* particular vertex -- which could represent e.g. our Galaxy -- *every* other vertex (where e.g. another galaxy might sit) is moving away from us, with a velocity in direct linear proportion (in this analogy) to its distance from us, the central vertex (and, of course, our particular vertex is not special -- the same would be true if we switched our perspective to sitting on *another* one of the vertices, and watched what happened with the other vertices in relation to us).

---- BBN is the period from a few sec post-TZT to about a half hour after it -- and it is when nearly *ALL* the helium in our Universe is created. Along with the deuterium, and lithium, as well.  These are all isotopes of the first 3 elements of the periodic table, the simplest 3 nuclei that can be made.  And it happens because this 'hot soup' phase has temperatures fairly about like those at the center of modern stars, and what do we know stars do there?  Well, that's the place where the protons are energetic enough to overcome their normal electrical repulsion, and they smush together (in a couple of different steps) to make: helium. This is exactly what happened in that first half hour of the Universe.

So -- we actually have a pretty good handle on that first half hour post-TZT.

Recent interesting spacey news

http://freezers.reviewed.com/news/japans-pocari-sweat-brings-advertising-to-space?utm_source=taboola&utm_medium=USAT%20Recirc

http://www.smh.com.au/technology/sci-tech/rosetta-comet-landing-philaes-race-to-unlock-comets-secrets-before-batteries-die-20141114-11moyz.html

[May 2007] Some ideas of types of Susy DM LHC might see

From another email to friends back then.

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

hey all- the astronomer postdoc at Caltech i work with asked me a coupla
q's (since i have more of a particle physics background then he does), so
i wrote him back the answers below, thought it might interest you guys
too.

I find it really amazing that despite *all* our efforts, we simply may
*never* see DM directly in our lives on the Earth -- say it ain't so, Mother
Nature!!  I hope very much not..

-M


---------- Forwarded message ----------
Date: Sun, 6 May 2007
From: Mandeep Gill
To: Richard M
Subject: Re: dark matter


R- just saw this email, and though i'm not a total expert in this, i'll say what i know..

On Fri, 4 May 2007, Richard M. wrote:

> Quick question - if dark matter were an LSP, would it be self-interacting?

Generally, yes (it's normally some version of a neutralino in these
scenarios).  If it interacts with normal matter through some extra weak
Susy force, then it will interact with itself as well.  But of course, we
have no way of knowing what the cross-section would be, and it may be so
low that it will *not* interact with itself nor normal matter much, or at
*all* through Susy forces -- in which case LHC will *not* make it.

That is, if DM interacts *only* gravitationally (e.g. gravitino DM) --
which is entirely theoretically allowed (and in fact i'm told, rather
generic in string theory models, which have plenty of particles that don't
interact through the Standard Model forces, that is, don't carry those
quantum numbers, but charges of other forces we haven't seen yet) -- *all*
the DM could've been made just after the Big Bang when gravity was strong
and temps high, and then pretty much just have never interacted again
after that.

Now for particle physicists (and maybe some cosmologists too) this is an
incredibly depressing potential scenario -- way more than the idea of
the Universe being open and ever-expanding to a cold death, which i know
personally brings you down, because while that's billions of years in the
future (and who the heck knows, maybe we'll find we can tunnel to
alternate Universes in the meantime..! ;-) ) if we can't *see* DM in a
collider or otherwise on Earth, then that is something that is going to
impact *our* very scientific lives!

So there's nothing that rules out this
logical possibility, *but* there are plenty of scenarios that it's *not* the
case, and i know people are hoping badly to see DM sometime soon.

> Does it depend on which is the lightest particle?

Well, by definition LSP *is* the "lightest Susy particle", right, so it's
the last particle in a decay chain, and it has nothing it can decay to
(and this is only in Susy models with externally imposed R-parity
conservation -- which was a symmetry first cooked up to prevent proton
decay, and turned out to result in a very nice DM candidate later).  So i
guess the answer is no, in that sense.

> And if so, would we be able to see the carrier particle?

Generally not, because it's going to decay so quickly (like the W+- or Z0)
that it will only be a virtual particle in Feynman diagrams, and never
actually detectable.  e.g. the W or Z never leave tracks in a detector, we
just know that they were the force carriers from the daughter particles in
the decay.

Hope that helps a bit..?!

If you have some more specific followup q's, or models in mind, feel free
to ask.

-M

[Apr 2007] Lensing, DM, the LHC, and the palpable tension

Another one taken from an old-time email to a MD friend who is highly interested in physics and astro as well..

-M


Greg-

On Tue, 10 Apr 2007, Greg R. wrote:

> Mandeep,
>
> So you study "weak gravitational lensing?" You must be
> familiar with the recent publications on the
> time-evolving distribution of the dark matter scaffold
> allegedly from "homogeneous" to "clumpy" consistencies

Yep, some of the folks i worked with at Caltech are partly responsible for
some of those images, indeed,

> ... although the images I have seen are not quite as
> cut & dried, but perhaps it is true--I suspect it
> is--which may be more clear should they get data
> closer to the beginning of our Universe rather than
> just halfway back (I am sure that is easier said than
> done).

Yes, we are slowly getting there though, we can see some of the brightest
galaxies all the way back to about 1 billion years post-Big Bang now, and JWST
-- the successor to the Hubble Telescope, with about 10 times the
collecting area or so -- will go even further, and see many more back
then, when it's launched in 7 or so years (currently it's planned for
launch in 2013, and parts of it are being steadily built, the mirrors
ground, etc.).  [Hah -M in 2014]

> I was intrigued with the MOND theory as a description
> of the dark matter effect, but that idea has taken an
> observational hit recently and I have not heard much
> of a rebuttal.

Well, those MOND (Modified Newtonian Dynamics) guys are always writing
papers, trying to make their models work (and yes, the Bullet
Cluster observations of DM separated from galaxy cluster gas seen last
year, which is what you're referring to, is a hard one for them).

But DM is much the preferred explanation for most cosmologists. But - at some level, it
ain't really really there until you see it.  That is, until we actually
detect DM directly in detectors on Earth, it's gonna be hard to fully
"believe" in it.  That's how it goes.

People have been trying hard to find it for a long, long time, with many
different types of detectors, but the cross section with normal matter may
be so low - or nonexistent - that it's never seeable.  We don't know yet.

LHC *may* see it in decays of heavy particles that require momentum
balancing (the same way that neutrinos were first theorized in 1932 by
Pauli).  at LHC we have about 2-3 years before we'll know for pretty sure
if it's easily visible there.  or we'll see whatever else is out there.
we have about 5-10 more to be totally sure whether it sees something new..
or not.  So it's a darn exciting time for particle physicists [i'd still say that now, in 2014.. maybe just a bit less emphatically, now].

The tension in the air is *palpable*, let me tell you.

-M

[Jan 2007] Know any of the Winter Hexagon stars .. or at least Orion..?

So this is taken from an email back in 2007 to a friend  who was enthused to learn something about the stars of the sky, so i sent her some info, which hopefully others will also enjoy learning about if unfamiliar with it from before.

To me, knowing the stars a bit makes the whole night sky much more "friendly" to me.  Just knowing that my entire life, those same stars will be up there, wherever i am on the Earth, and all i have to do is look up and i can see light from stars coming to me from 10 or 20 or 50 or thousands of
years ago, is kind of comforting, in some deep way, to me.

I personally think it's kind of cool, and just enjoy learning and knowing about this aspect of the natural world around us -- after all, the hemisphere above is half of what you see when you're
outside!

Enjoy, and if this leads anyone else to know any of the stars that are up in the Winter night sky, i'd by most cheered to hear about it.. :-)

-M

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

hi Arden- Ok, this is the really cool free program i told you about, totally easy to download and install, and they have Mac, Windows and Linux versions:

  http://www.stellarium.org/


and here's a good site where you can download the pdf and see all the stars:

  http://www.midnightkite.com/starcharts.html


Now specifically for the Winter Hexagon, i found several good sites:

- This shows the configuration and describes some of the mythology of the
constellations involved:

  http://homepage.mac.com/kvmagruder/bcp/aster/constellations/win6.htm

- This shows you more realistically what it will look like in the night sky if you check it out..  but the real sky will look probably still very different to you than this (it does to me):

  http://antwrp.gsfc.nasa.gov/apod/ap021106.html

- This one's interesting, has kind of a 'spiritual' interpretation of it all:

  http://www.souledout.org/nightsky/winterhexagon/winterhexagon.html

- And this is a few year old article that describes it from a newspaper-type perspective, has some good info (of course, the planets move, so ignore all the stuff about them):

  http://www.msnbc.msn.com/id/3812467/

That's a start -- there's a whole lot more, but just get out there and see
if you can identify all 6 stars in the Hexagon, and then we'll talk some
more! :-)

-M

[Jan 2007] The "shape" of the Universe, etc.

So this is taken from a writing in 2007, something i posted to an astronomy bulletin board of a general interest group back then.

I tried to answer a q about what "shape" the Universe is, and point the questioner to good sources for this kind of stuff.

-M

---------- Forwarded message ----------

Date: Wed, 10 Jan 2007 

From: Mandeep S.S. Gill 

Subject: Cosmology post on C-surfing

Hey there Caz-  ok...

It's hard to discuss some aspects of cosmology "reasonably", as they don't correspond to our common sense intuitions of "shape" etc. -- the very small and very large get very *weird* compared to our daily lives.  yet -- it *is* the Universe we live in.

Now, as far as what shape the Universe is..  it appears right now that our Universe is of infinite volume, and *always has been* ever since "just after" the Big Bang.  where just after means epsilon after, any number greater than zero. and since we can't really understand the Universe back beyond a certain point with our current physics (certainly before the Planck Time of 10^-42 seconds, and possibly even later than that), we simply can't *ask* those questions at the current moment in physics.

Or rather, you can *ask* (you can always ask of course), it's just that physics won't offer any meaningful answer for you.  It's as good as philosophical theorizing at that point, which is of course how *all* of these kinds of questions were addressed before we could make numerical sense out of parts of the world.  The domain that we can understand has always expanded. It's not clear that there's a limit, or an end whatsoever in fact -- but we already understand a huge amount now about how things work, and what we do get is dazzlingly breathtaking and stunningly beautiful at times.

Ok, let's get back to it:  an infinite Universe can't exactly be said to have a "shape", as it spreads everywhere.  But -- we already know from experiments that the intrinsic geometry of the Universe is very close to "flat" vs. spherical or hyperbolic (these words are in analogy with 2 dimensions), and there are some theoretical (though yet unproven) reasons cosmologists have to believe that is *exactly* so.

As to a pointer to a good book to read on these matters -- well, i've last been reading some of George Gamow's popular work, which is good.  

For something more recent, i guess i'll go ahead and recommend Wikipedia on cosmology, on the whole i've had good experience with info on their site, most often (in science at least) reasonably correct, even if it's at times incomplete.  Always a decent place to begin.

-M

[Oct 2006] Review of a kids' cosmology book from a 'Spirited' perspective

This is a review of a kids' science book i wrote in 2006 on Amazon, edited a bit, the original is here:

http://www.amazon.com/review/R2OU4XO845UNEH/ref=cm_cr_rev_detup_redir?_encoding=UTF8&asin=158469033X&cdForum=Fx1817EPNTXQ4P&cdPage=1&cdThread=Tx3L0DZZMJB9PTF&newContentID=Mx27NBIQ2MJJB24&newContentNum=4&store=books#Mx2AE2QJMRJREL9

 because i liked the book *so* much, and i was happy to get a note from the publisher back then asking if they could excerpt from my review and include it in the next edition :-) (which i agreed to).

Basic science education and connecting with the larger public who are enthused about science research is extremely important to me, and is something i've done a good amount in the past, and care about a good bit.  So seeing great examples with a very different paradigm than our society has worked with for many decades (and in some sense, centuries) such as those in this book, is quite cheering to me.

It's clear the public *is* very ready and hungry even, for a different approach to science than has been traditionally taken by purely mechanistically-minded scientists for a long while..

-M

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

I'll preface this by saying that i'm an experimental cosmologist (working
on weak gravitational lensing to determine galaxy cluster dark matter
profiles) and have also worked in high energy particle physics, so i come
at this book from a particular angle of having a fairly in-depth
background of the subject matter.

Having said this, i want to *strongly applaud* this book, and would like
to point out that of the several reviews given above, most are quite
positive, and the only two highly negative ones are simply *missing the
point* of the book -- it is *not* supposed to give anyone a detailed
explanation of cosmology as we understand it scientifically today.  there
are plenty of other books to do that.  Rather -- this book is supposed to
try to make some sense of what our current picture is in a much more
organic, humane, emotional, spiritual, and yea, *cosmic* sense than most
of the popular or scientific literature of cosmology out there today does.

For those familiar with Carl Sagan's work, and particularly "Cosmos" from
the 1980's -- this is very much done in that vein, and i am pretty sure
Carl would have heartily approved.

As a reader might gather from my words, i don't fit fully into the classical
stereotype of scientist with a mechanistic, rational,
Universe-as-clockwork type view that has been the primary paradigm in
science since Cartesian times, but then, neither did Carl, and neither do
more and more modern scientists.  And Carl's manner of conveying science
resonated with the public profoundly and has inspired likely more individuals than that of *any* other
modern physical scientist.

Further, i have thought deeply about the human aspects of science also in

my journey along the scientific path, and it's clear to me that the

paradigm one uses to describe whatever our scientific picture of the

Universe and how it came into being and how it evolved up until today is,

at any given time in human history, is critical in how we approach not

only science, but every aspect of our lives, from our interactions with

Nature, to how we treat non-human animals, to our picture of and dealings

with others of our own species.  when it comes down to it, how we picture

the non-living aspects of our Universe and its whole history, *matters*, a

lot.

And i love the way that J. Morgan and D. Andersen picture it in this book

(and i also hope to communicate directly with them sometime).  I love how

they interpret and explain their understanding of everything from the Big

Bang itself, and what came "before", to the limitations in our current

picture of cosmology, to the specific aspects of BBN (Big Bang

Nucleosynthesis), initial star formation, galaxy evolution, and supernova

processes, leading ultimately to *us*.

No, this is not going to appeal to every scientist out there, nor every

person -- but i would suggest this is from not a lack in the *book*, but

from some measure of the imagination needed in our species and society to

evolve to a more mature species in our wondrous Universe.

Also, the glossary, more detailed cosmic timeline history, book

references, and quotes from working scientists in the back are also quite

appreciated and helpful to point people in good directions for more

in-depth understanding and further reading.

There could be much more said about many of these topics, but let me

simply close by saying that i came across this book while dropping in on a

local conference of an environmental group in my area, and

the title intrigued me enough to start paging through it.  and even after

realizing it was a children's book, the flow of the words and the

wonderful evocative paintings drew me in to continue reading it.  and it

is a *rare* book or paper on cosmology (and believe me, i have occasion to

read a good number) that brings tears to my eyes with their beauty and

power to stir the soul, as certain lines in this book did.

In Spirit, Community, and Adventure-

MSSG

[Nov 2006] The mind-blowing 'humongousness' of the Universe

Oct 2014: This is an excerpt of a many-years old email I sent to friends which I wrote during my transition from a particle physicist to a cosmologist, trying to wrap my head around just how incomprehensibly and crazily large the Universe really is, to me at least.

It  stops fairly abruptly partway through (we were about to land in Columbus, Ohio, coming from a conference/'summer school' in Puerto Vallarta, Mexico), but gives some sense of my thinking and feeling on these matters at that time.

---

Sun, 19 Nov 2006.

Hi there all:

So I'm on my way back on de plane (boss) to C-bus and I'll take this time to write my second, and final, report on the conference (conf) and school.

Now the rest of the conf went well and finely too, though as I'd said earlier, because I'd sort of been fulltime at all the talks at the school and put so much energy into it, I had to sit back more during the conf also, much of it was on topics I don't have a burning interest in at the moment.  Though I certainly consider myself still a particle physicist, I just am not keen on the details of every number that continues to confirm the "Standard Model" (our current best picture of particle physics) to umpteen more digits - let's turn on the LHC (the Large Hadron Collider) and watch them sparks fly!  Be they Higgs, or sparticles, or extra-dimensional gravitinos, let's see 'em!!  And that's pretty much the feeling I'm gonna have from now until the LHC  really turns on for bidness sometime in 2008 [hah, in 2010 or so, actually, -M].

The neutrino stuff is pretty cool though, and it seems that we'll be learning lots even from the long, steady experiments of the next few years: in Japan: Kamland, SuperK and in a few years T2K, Double Chooz fairly soon in France, and then at FNAL: Miniboone, Minos, Numi, Sciboone and potentially Minerva and Nova.

Then of course there are the big underground experiments all over: IceCube, Antares, SNOlab, and other future potential ones, but these are more about watching for supernovae, and/or other galactic/extragalactic sources, vs. being able to disentangle the neutrino mass hierarchy itself, of which theta_13, the Majorana/Dirac nature, the normal/inverted scenario, and eventually CP violation in the neutrino sector are the pressing issues in the mid-term future.

In any case - cosmology is where I got the most excited, by far, at this thing.  It's just because it's moving *fast* and there's so much to be done and learned.  And yes, the high energy physics (HEP, generally roughly synonymous with "particle physics") folk have a newfound respect for what cosmology can tell us, in neutrino masses, in info on dark matter constraints and such things.  And more than anything, for the precision. Yeah, fine, they're not going to get 12 digit precision in anything, anytime soon, because there are so many open questions about the inflation scenario, primordial abundances etc. - but man, think on it - this is the *whole Universe* we're talking about!  It's a big place!!  And as I keep saying to people "infinity is a big 'number' " !  I really don't think humans can exactly grasp it.  Infinity really is *that* -- it goes on for flippin *ever*. There is *nobody* who said that we get any final theory. 

I personally don't sit around and think grand great design thoughts about the Ultimate Theory and all that - I don't have time for that.  I, very much like Feynman, would like to apply myself to those problems I can *solve* or at least make some headway on in this life.  Because science is so terribly staggeringly beautiful, just what all we know already, and can describe, in squiggly lines on paper. We, on this tiny little blue planet, what we can know about this really indescribably humongous Universe?

I guess it started hitting me sometime late in our conf just how different our world is than say that of Galileo and people around his time.  Part of it is incremental, as we realized the other planets were
indeed separate bodies like the Earth, and then started getting a handle on their (at that time) staggeringly enormous distances compared to those on the surface of the Earth, and then figured out that the stars were other Suns, like our own, then figured out the structure of our Galaxy, then that there were *other* Galaxies -- which is, it seems, where it ends.  For now.  There are plenty of *theories* about what may be beyond that, a multiverse etc., but the Universe to me is mind-boggling enough.

And I will honestly confess that working now on cosmology as I do and thinking about these other systems so glibly on a daily basis - 100 million, a billion, 10 billion light years away, we throw the terms around like dominoes, easily, fluidly - I am staggered by it, at times.  Truly.

Maybe it took me a while to feel it in my bones, but it's this:  we have an Earth, even the ancients knew it was round, and we humans can go pretty much *anywhere* on it, by this point, or even send probes to those parts where we can't, in the deepest oceans.

Ok, fine, then come planets, which were initially quite a big shock, what are they there for???  But as we now know, we relate, we've even exchanged some gas and dust here and there during birth (yes, rather womblike) and later too.  A bit weird, but not so far, relatively.

Then - stars.  This is kind of weird, yes, no doubt.  A lot of stars, throughout the Milky Way galaxy (about 300-400 billion, it seems).  Can't say anyone feels at "ease" with this.

But then - the other galaxies.  Just freaking *billions* of them.  We don't even really know how to count them (because they get dim way back close to the Big Bang, 13.8 billion years ago).  And since we haven't fully stopped reeling from the realization of how many *stars* there are in our one local home galaxy, how do we even make sense of so many others?

How do we make *SENSE* of them?

I don't know.

I really don't know.  And if it seems like the first and most naïve question that a child would ask upon learning of this, let me not act like I know any better at all about it, whatsoever.  But then, none amongst us does, so I can't feel very ignorant, in this regard.

I mean, once you start learning science, taking things apart and understanding them bit by bit, you eventually, either rapidly or more slowly, get to this question, in some guise or another.  You start asking how the Earth formed, how old it is, how life evolved, how atoms work - any of it, and you're led to this:  but why is any of it here?  And there *is no answer to this question*.   That is, we really don't even know if there is any *in principle* answer to this.  Or if the question has any real meaning, as we humans understand meaning.  But somehow, on the small scale of the Earth, when I generally thought on a daily basis about little atoms and leptons and quarks (and even about intermediate vector bosons) right in the present moment, it never kind of overwhelmed me as much.

But -- now.  Now: as I look up at the big black night sky, or look across to my monitor showing plots of various galaxies scattered throughout, or sit and listen to a prosaic everyday discussion amongst astronomers of the redshift-supernova distance calibration relation out to a few hundred megaparsecs (a megaparsec = 3.3 million light years) - I'm left just kind of feeling a bit mixed up inside.  I don't know how to describe it exactly, maybe because I don't know my exact feelings, because maybe it's a mix of so many things.  Awe, wonder, minuteness, confusion, happiness to be alive.  And others.  But definitely this weird sense of:  what are all those galaxies *for*?  Why are they there?  How did this happen?

Et cetera --  you get the idea.  It's just strange to me.

But you know - I have a job to do.  The government doesn't pay me to sit around and gibber like a child at how weird my job is, and that of all cosmologists.  No, they're paying me *to* do it, to get that little bit of data that extends our knowledge that little bit, shines a light on one more piece of the puzzle, so more of its beauty can be unveiled.  Yes, I suppose that really is as good an analogy as any: we are each of us scientists shining lights on different pieces of a vast, 3 dimensional puzzle. We all stumbled upon it, and we're each given lights of varying intensities with a highly focused beam that doesn't go too far, and it's also a climbing puzzle so you have to understand and know where the steps are below, which have now had floodlights set on them by your previous antecedents to show the way.   But you just keep climbing, because it's a thing of beauty this puzzle, every little speck of it, each bit that's been uncovered and the every single bit that is further uncovered as well.  And that's all we're here to do, is shine that light onto some further bit, while we can, as we can.

And, very importantly - we don't know if there's a top or edge in any direction.  We don't know if there's an  end at ALL.

I suppose I could work on this analogy more, as it does help me to think about what we're doing a little better, and I heard that somewhere, that the only way we really understand things is by analogies.  I don't know what it means..  But it seems the case, at times.

I'm not sure where all this came from, it's not like I'm having a mid-life crisis about what I do.  In fact, I still feel darn lucky and blessed and amazed that I'm paid to do what I can do.  I guess it was just coming for a while, after looking at all these danged breathtakingly beautiful galaxy images all the time.  I probably would *not* have gotten to this level of internal "weirdness" had I not turned to cosmology, with its assumed premise of understanding the *entire Universe*, on a "cosmic scale" (i.e. the biggest scales we know of).   I mean, the fundamental questions of HEP, as it is currently construed in our time (which obviously may be very different from what it may be many centuries hence, if anyone is reading these words then!) are not really to me any different: they're about the basics of what our Universe is made of and why, and these two are not really separable questions, as both these camps have come to realize more and more in recent years - but: HEP seems kind of more mentally "manageable" on a daily basis, containable, normally.  You're dealing with some big huge detector usually that is taking data from some particles you're smashing together, or watching come in from space, in which case you don't usually know the source.  So you do these things, and you have some beautiful equations that through a lot of painstaking work by physicists over many decades (and centuries, really) have been written down and they just *check* with the data, and check damn well.  You predict something, you go measure it.  Boom, it's right on, excellent, build a bigger machine to hit things harder together and see what you get. That's really the essentials of what HEP folk have been doing since oh.. the late 19th century I guess, really.  You don't necessarily think too much about the past history of the Universe, how it came to be and all that.

But cosmology?  Now that's different - way different.  You're sitting around with a big ole telescope, looking way way up into the night sky, at these galaxies that can be several *billion* light years away.   If you step away from your pressing data analysis for just a few *minutes* and start thinking about it, man - you may want to have some Tylenol handy.

Because this stuff can *blow your mind* man.  

Like in all the ways I've described above.

But -- we press onwards!

-M

(November 2006)