
Physics: What We Do and Don’t Know - jonathansizz
http://www.nybooks.com/articles/archives/2013/nov/07/physics-what-we-do-and-dont-know/?pagination=false
======
acqq
The article author is Steven Weinberg:

[http://www.nobelprize.org/nobel_prizes/physics/laureates/197...](http://www.nobelprize.org/nobel_prizes/physics/laureates/1979/weinberg-
bio.html)

The Nobel Prize in Physics 1979 with Sheldon Glashow and Abdus Salam "for
their contributions to the theory of the unified weak and electromagnetic
interaction between elementary particles, including, inter alia, the
prediction of the weak neutral current".

The article is fantastically clear, with much less mystification than in
ordinary physics popularization articles.

~~~
mturmon
Weinberg has been writing for NYRB for a long time now. Several of his other
articles are not behind the paywall:

[http://www.nybooks.com/contributors/steven-
weinberg-2/](http://www.nybooks.com/contributors/steven-weinberg-2/)

~~~
cma
Some good NYRB reviews by Freeman Dyson were collected into a book too, I'm
sure some of his aren't paywalled:

[http://www.amazon.com/Scientist-Rebel-York-Review-
Books/dp/1...](http://www.amazon.com/Scientist-Rebel-York-Review-
Books/dp/1590172949)

------
innino
That photo of the Hubble Deep Field really messes with me... in fact any photo
like that. You have to realise: somewhere out there, in fact, most likely,
many, many places out there, are planets where everything we have and will
experience has already happened. Whatever end-point human evolution is driving
towards (massive environmental degradation, simulacrum-building, rise of a
superhuman elite, space-travel, true self-knowledge, total mastery over the
physical world, whatever) - its already happened. Over and over again. By
people/things we will never meet and never know about.

Feels very disheartening.

~~~
Udo
If it's uniqueness you're concerned about, there are _a lot_ of different
parameters that describe habitable worlds and even more to describe the
history of a civilization. Odds are, what most civilizations experience is
unique to them; but I too believe there are likely to be many similarities,
too.

Our inability to see and interact with other civilizations - even within the
relatively small neighborhood of our own galaxy - is frustrating, and somewhat
of a logical conundrum as described by the Fermi Paradox. Whatever the factors
preventing us and others from making contact are, and I think it's likely a
combination of several instead of one big filter, I hope we can leave them
behind at some point and join up with the other people out there.

When I look at bigger parts of the universe, I feel inspired. The universe is
_not_ small and limited, it's vast and full of possibilities. Odds are we're
not singular but in good company, and we have a _lot_ still to discover and
explore. What we do and know is unique and meaningful, yet at the same time
_it 's not all there is_.

~~~
innino
Thanks for that. I do hope you're right. The prospect of eternal isolation is
not a pretty one.

------
galaktor
the article seems to be dated "November 7 2013", nearly one month in the
future. Clearly the author knows something about physics that we don't.

~~~
andyjohnson0
[http://en.wikipedia.org/wiki/Cover_date#Magazines](http://en.wikipedia.org/wiki/Cover_date#Magazines)

------
sidcool
A very insightful article. Once I started reading it, I got hooked. I started
searching for references on Wikipedia etc. Now I want to become a Physicist.

~~~
Ygg2
It's funny, for each thousand miles of space explored, we explored a mm or
less of what is beneath us. We know what primal forces govern building blocks
of space and time but we don't know how bicycle works.

For every profound truth we discover, there is an inane mystery we are yet to
discover.

~~~
Luc
Commercial and military applications of rockets and satellites have always
been important in improving access to space. There's no comparable reason to
deliver a probe to the Mariana trench or to dig a few km into the surface.

And we do know exactly how bicycles work. EXACTLY. This one is up there with
the one about NASA spending millions on a space pen.

------
jheriko
"Oddly, little attention was given to an obvious conclusion: if the galaxies
are rushing apart, there would have been a time in the past when they were all
crunched together. "

I still find this hard to swallow - whilst its obvious as a conclusion, it
also feels like it has obvious flaws. Can we not get exactly the same effect
from a large universe in which new space and matter is formed in the voids?
and don't we need to understand the /actual/ creation of space and matter in
totality (v.s. eg creation and annihilation of particles and other 'bits of
universe) - its an enormous gap in our understanding and a vital feature of a
truly comprehensive theory...

~~~
Sharlin
As the _article itself mentions_ , the Big Bang hypothesis did not become an
accepted theory just based on the single piece of evidence that other galaxies
seem to be receding from ours. Indeed, the term "Big Bang" was originally
coined as derogatory by the famous astronomer Sir Fred Hoyle, a steadfast
supporter of the competing Steady State hypothesis [1]. Many in the astronomer
community found the idea of the universe having a beginning simply
preposterous. However, in the end, it was the model that best matched
observations, and thus became (perhaps reluctantly on some people's part)
accepted. This is how science is supposed to work.

[1]
[http://en.wikipedia.org/wiki/Steady_State_theory](http://en.wikipedia.org/wiki/Steady_State_theory)

------
bfe
So we've hit a wall in trying to understand how dark energy works or how its
parameters arise. But I don't think it's logical or helpful to conclude that
an anthropic explanation is the only option we have left. Maybe we just
haven't yet figured out the right questions to ask, that might open up a new
field of investigation that could lead to new physics that provides a
mechanism for how it works.

For example, we also still don't understand the nature of dark matter. Even
more fundamentally, we still don't have a solid understanding of time, and why
there is an apparent flow of time in one direction from the past to the
future, or whether spacetime curvature induces quantum state collapse, or how
the universe began with such low initial entropy.

Maybe discovering a deeper understanding of the foundations of the physics
we're already familiar with will open a way forward with understanding how
dark energy works.

~~~
lamontcg
Yes, there is basically no real evidence for any of the multiverse hypothesis.
If they're right then physics and cosmology has nearly ended in its reach of
what is knowable. It feels so much like this is premature surrender and
physicists are turning themselves into religious philosophers just because
they can't think of anything better. If we had been backed into this wall for
hundreds of years with nothing better, then I might agree that the program was
over, but I think the whole anthropic/multiverse idea is a condemnation of how
sold physicists and cosmologists have gotten on one possible solution, and
indicative of the fossilization of some of their ideas. We need a new Einstein
to do away with the modern-day aethers...

------
geuis
I found the article to be a good summation of work done over the last few
hundred years.

~~~
marai2
I thought that article was a great read, combining historical perspective with
technical detail that wasn't glossed over.

------
DavidWanjiru
I don't like thinking about space too much; I mildly worry that if I get too
much into it, something might snap in my head, and that can't be a good thing.

------
redwood
great article but interesting to see it on the same day as the article about
science moving sometimes in the wrong direction. for example string theory no:
critical results. why string effort and not others? well a lot of people and a
lot of effort went down that path it's a simple as that: people. maybe there
are other approaches, no doubt there are and that's where the future will be

------
leeoniya
btw, Hubble Extreme Deep Field (2012) is deepest optical to date. "The
exposure time was two million seconds, or approximately 23 days" [1] -- that's
insane stability!

[1]
[http://en.wikipedia.org/wiki/Hubble_Extreme_Deep_Field](http://en.wikipedia.org/wiki/Hubble_Extreme_Deep_Field)

~~~
splat
Keep in mind that the 2 megasecond exposure was not done all at once. It
consists of many shorter exposures (probably about 10-20 minutes apiece) added
together. If the exposure had been done all at once, it would have saturated.
Moreover, cosmic rays would ruin large regions of a single long-exposure
image.

------
jimgardener
why does he say this >> "early universe must have been very hot, or else all
the hydrogen in the universe would have combined into heavier
elements"?.Hydrogen is still present and it is not so hot nowadays

~~~
GuerraEarth
They mean that when hydrogen gas is highly energized/ionized, the (hot)
hydrogen electrons exist ripped out of the atom and this state prevents
hydrogen from collapsing on itself to form stars and stuff.

------
TausAmmer
"...in the grim darkness of the far future there is only war."

------
WhitneyLand
How many neutrinos can you bench press?

------
_-_-_-
What we don't know: shit.

~~~
geuis
Really? That's what you have to contribute in conversation to a discussion
about thousands of years of discovery about the nature of reality itself? We
know a lot more than "shit".

~~~
CrankyPants
He's like the drunk neighbor who tries to break into your home, thinking he's
locked himself out of his.

Dude probably thinks he's scoring comment karma at Reddit with that gem.

~~~
CrankyPants
I'm curious to know just how the original comment didn't reek of Reddit's
culture of vacuous pithiness.

Down-votes without discussion strike me as being against the generally
productive atmosphere this place usually has.

~~~
ordinary
I imagine it was because your comment added no more to the discussion than his
did. When the standard response to bad comments becomes posting more bad
comments, any community with a productive athmosphere quickly goes down the
drain.

~~~
CrankyPants
That's fair.

I'll do better.

