Physics: What We Do and Don’t Know(nybooks.com)
nybooks.com
Physics: What We Do and Don’t Know
http://www.nybooks.com/articles/archives/2013/nov/07/physics-what-we-do-and-dont-know/?pagination=false
14 comments
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/
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/1...
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.
Feels very disheartening.
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.
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.
Thanks for that. I do hope you're right. The prospect of eternal isolation is not a pretty one.
I have completely different feelings about this image, but I think you are correct in attaching a lot of meaning to it. We're very lucky to have been born at a time were we get to see it.
> We're very lucky to have been born at a time were we get to see it.
And yet utterly unable to conceive things being any other way!
And yet utterly unable to conceive things being any other way!
You're experiencing the effects of Douglas Adams' Total Perspective Vortex (from Hitchhiker's Guide to the Galaxy).
It was basically a torture chamber which inflicted the most horrific sort of torture imaginable upon its victims. How?
"For when you are put in the Vortex, you are given just one, momentary glimpse of the size of the entire unimaginable infinity of creation along with a tiny little marker saying, 'You are here'."
When the victim sees his complete and utter insignificance, his psyche is utterly destroyed beyond recovery.
It was basically a torture chamber which inflicted the most horrific sort of torture imaginable upon its victims. How?
"For when you are put in the Vortex, you are given just one, momentary glimpse of the size of the entire unimaginable infinity of creation along with a tiny little marker saying, 'You are here'."
When the victim sees his complete and utter insignificance, his psyche is utterly destroyed beyond recovery.
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.
Presumably it's dated by when the print version is released.
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.
Yeah physics departments should share this article with incoming students, to help them see where the field is going. Although one thing missing is that I would want to find another article that illustrates the ways that physics research is improving and helping our lives today.
I started out in physics, was interested in relativity and the like, but thought ahead to a career in physics and saw that folks were into string theory, which didn't really appeal to me, and I wasn't seeing how physics research was helping people today. I should have done more research into the field before leaving it, but, I went into physics and science education research and cognitive science. Ironically, a similar article like this one got me into cognitive science (before I even started college), an interview with Patricia Churchland by Bill Moyers.
I started out in physics, was interested in relativity and the like, but thought ahead to a career in physics and saw that folks were into string theory, which didn't really appeal to me, and I wasn't seeing how physics research was helping people today. I should have done more research into the field before leaving it, but, I went into physics and science education research and cognitive science. Ironically, a similar article like this one got me into cognitive science (before I even started college), an interview with Patricia Churchland by Bill Moyers.
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.
For every profound truth we discover, there is an inane mystery we are yet to discover.
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.
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.
"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...
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...
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
[1] http://en.wikipedia.org/wiki/Steady_State_theory
You are not the first that thought about that possibility, there's a lot that we observe that is expected result of the Big Bang and that wouldn't exist otherwise:
http://en.wikipedia.org/wiki/Big_Bang#Observational_evidence
http://en.wikipedia.org/wiki/Big_Bang#Observational_evidence
First, we would expect to see such matter production occuring today, not just in the past.
Second, and much more conclusively, we have specific predictions from Big Bang Nucleosynthesis (which was just 20 minutes after the big bang, when the entire universe was as hot and dense as the interior of a star) that match up to observations today with exquisite detail. BBN is perhaps the most stunning underappreciated fact about our world, even amongst physicists.
Second, and much more conclusively, we have specific predictions from Big Bang Nucleosynthesis (which was just 20 minutes after the big bang, when the entire universe was as hot and dense as the interior of a star) that match up to observations today with exquisite detail. BBN is perhaps the most stunning underappreciated fact about our world, even amongst physicists.
"don't we need to understand the /actual/ creation of space and matter in totality"
Well, there are some hypotheses on what caused the Big Bang in the first place (and as a result, all of space, time & matter) but they are currently relegated to thought experiments. We just don't have the technology yet to test them. There might be some things that could show up in more detailed observations of the cosmic microwave background, things which if found would be suggestive, but the evidence still wouldn't be conclusive.
You can google "what came before the big bang" to read up on those hypotheses. Keep in mind that they are thought experiments. Pop-scientists will often talk about those hypotheses like they're fact, but the truth is there's still a long way to go.
Well, there are some hypotheses on what caused the Big Bang in the first place (and as a result, all of space, time & matter) but they are currently relegated to thought experiments. We just don't have the technology yet to test them. There might be some things that could show up in more detailed observations of the cosmic microwave background, things which if found would be suggestive, but the evidence still wouldn't be conclusive.
You can google "what came before the big bang" to read up on those hypotheses. Keep in mind that they are thought experiments. Pop-scientists will often talk about those hypotheses like they're fact, but the truth is there's still a long way to go.
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.
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.
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...
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.
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
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
[1] http://en.wikipedia.org/wiki/Hubble_Extreme_Deep_Field
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.
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
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.
"...in the grim darkness of the far future there is only war."
How many neutrinos can you bench press?
What we don't know: shit.
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".
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.
Dude probably thinks he's scoring comment karma at Reddit with that gem.
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.
Down-votes without discussion strike me as being against the generally productive atmosphere this place usually has.
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.
That's fair.
I'll do better.
I'll do better.
http://www.nobelprize.org/nobel_prizes/physics/laureates/197...
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.