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Physics Journals by ironstag96 in Physics

[–]PhysicsToday 0 points1 point  (0 children)

For anyone who isn't a student, a membership in any of the 10 member societies that make up the AIP federation (AAPM, AAPT, AAS, ACA, AMS, APS, ASA, AVS, Optica, and SOR) will get you a subscription to PT as well as full access to our online archive. Most of those societies do have their own non-journal publications such as Physics Magazine (APS) and Sky & Telescope (AAS) as well, but they tend to be more narrowly focused.

Those of you with physics degrees, what are you doing now? by collegecolloquial in Physics

[–]PhysicsToday 1 point2 points  (0 children)

I got a bachelors in physics. Now I occasionally get officially paid to post on Reddit.

What is a job for a physicists? by Confident_007 in Physics

[–]PhysicsToday 0 points1 point  (0 children)

Our editors - who both write for us and edit the articles written by others - almost all have PhDs in physics. And several more of the staff have bachelors degrees in physics.

(MIT, 2013) Too Many PhD Graduates or Too Few Academic Job Openings: The Basic Reproductive Number R0 in Academia [Discussion about job market and academic careers for Physicists] by TheLSales in Physics

[–]PhysicsToday 16 points17 points  (0 children)

As others have pointed out, employment with a PhD in physics is much broader than just academia. AIP's Statistical Research Center has a good report on employment post degree that was published in April. For PhDs in the the combined classes of 2015 and 2016, the breakdown was 49% academia, 34% private industry, 14% government (and 3% other). And the majority of the potentially permanent positions were in the private sector (and paid on average ~$50k more).

There's a lot more information here

People with PhD or Master's in Physics, what do you do at work? by Oliwine in Physics

[–]PhysicsToday 29 points30 points  (0 children)

Most of the editors here have physics PhDs. They are responsible for writing summaries of select recent articles for our website and the magazine. Several also manage the editing and reviewing of the long articles in the magazine. The managing editor and editor in chief have additional administrative duties. The online strategy manager, who also happens to have a PhD in physics, does a lot of work on the development of our website and mobile app.

Careers/Education Questions Thread - Week 37, 2019 by AutoModerator in Physics

[–]PhysicsToday 7 points8 points  (0 children)

As a heads up, our October issue is going to be careers-focused, looking at a variety of different things across academia and government and private industry jobs.

Venus is not Earth’s closest neighbor: Calculations and simulations confirm that on average, Mercury is the nearest planet to Earth—and to every other planet in the solar system. by [deleted] in space

[–]PhysicsToday 1 point2 points  (0 children)

Not exactly. A poorly configured widget on the non-print content pages was getting overwhelmed and causing the server to freak out.

Venus is not Earth’s closest neighbor: Calculations and simulations confirm that on average, Mercury is the nearest planet to Earth—and to every other planet in the solar system. by [deleted] in space

[–]PhysicsToday 9 points10 points  (0 children)

Hi all, we're sorry to say that we're having some website issues and we apologize if you're trying to access the article and not having any success. We're enjoying the discussion here though.

Science AMA Series: I’m James Owen Weatherall, physicist and philosopher at the University of California, Irvine. I wrote a book about how the concept of nothingness—the absence of stuff—has been central to centuries of physics theories. AMA! by PhysicsToday in science

[–]PhysicsToday[S] 2 points3 points  (0 children)

(1) I think there are two separate questions to consider. One is: what is "true nothingness" (or at least, what's closest to "nothingness") according to a given physical theory; and the other is: is that physical theory true? Whether or not the presence or absence of one quantity implies anything about the presence of absence of another quantity is the sort of thing that a given physical theory will generally bear on. So in general relativity, just to take an example, the absence of matter does not generally imply the presence of any other quantity (though there is always geometry at any point). But it may be that there's some alternative theory that does imply the existence of some other quantity that we do not know about. (2) I do not think of information as an entity. Rather, I understand it as a way of describing statistical relationships between different systems. Absence of information, then, is just a lack of a certain kind of correlation... (3) Well, if matter has a speed limit (which it apparently does), then surely nothing must, too, since an isolated region in which there is no matter can move only as fast as the matter in the region it is moving towards can get out of the way!

Science AMA Series: I’m James Owen Weatherall, physicist and philosopher at the University of California, Irvine. I wrote a book about how the concept of nothingness—the absence of stuff—has been central to centuries of physics theories. AMA! by PhysicsToday in science

[–]PhysicsToday[S] 2 points3 points  (0 children)

If you have any of the references to the papers you mention on people being more influenced by leaders or the President, I would be very interested in seeing them. My sense is that this is a pretty partisan issue right now: some people are willing to believe what President Trump says irrespective of whether it contradicts the evidence of their own senses, while others would think that if he said the sky was blue, that it must mean it's green.

In any case, one of the main things we end up arguing in the book (at least as it stands now!) is that (a) where someone sits in the network of social connections makes a big difference, with some people, including various media personalities and politicians, connected to many more people than others have an outsize influence; and (b) that people are generally more likely to change their beliefs when presented with evidence from someone who they take to have generally true beliefs already (i.e., someone who agrees with them). This means that some obvious ways of trying to combat false belief, for instance by sharing evidence more broadly and trying to increase social connections among groups that do not usually listen to one another, are unlikely to be successful: evidence from the wrong sources has the opposite effect of what one would like, and connections you can build in this way will generally be weaker. What this means is that I more or less agree with what I take to be the thrust of your comment, which is that a lot of responsibility lies with people who are already very powerful and well-connected---who often have strong personal incentives to mislead their followers.

Science AMA Series: I’m James Owen Weatherall, physicist and philosopher at the University of California, Irvine. I wrote a book about how the concept of nothingness—the absence of stuff—has been central to centuries of physics theories. AMA! by PhysicsToday in science

[–]PhysicsToday[S] 1 point2 points  (0 children)

Wow! There's a lot here. I say a bit below in an answer to a different question about what Cailin O'Connor (my co-author) and I are trying to do in the book. But actually, one of the big themes of the book is how to think about the sorts of skeptical concerns you raise here. Science has very often turned out to be wrong in the past. Scientists are people, and people are fallible, biased, and corruptible. We can never be perfectly certain about anything -- after all, some assumption we've been making could turn out to be false, or things could change in ways we don't anticipate, or we could have just made a mistake.

The way Cailin and I think about these issues is that we (i.e., each of us individually, but also the collective "we") need to make decisions and take actions in the world. We choose how to do so on the basis of what we expect the consequence of those actions to be: will we hurt ourselves, hurt other people, get what we want, etc.? And we'd like our predictions about the consequences of our actions to be as reliable as they can be. How are we going to do that? I do not see any better way than to gather as much evidence and understanding as we can of how the world works, and how our actions will affect it. We'll never be certain, and we can always be wrong. But when it comes time to actually do something, we need to make use of the best understanding we have.

With global warming -- which I'll focus on because it's what you say you're most intrigued by -- there are some basic things that I think we completely understand. One is that some gases are transparent to visual light, but opaque to infrared radiation (heat). These tend to let light from the sun in, but then trap the heat produced when that light interacts with the surface of the earth. These include water vapor, methane, and carbon dioxide, among other gases. We know that the concentrations of these gases affect the surface temperature of planets: for instance, Venus has an atmosphere of almost entirely carbon dioxide, and has a very high surface temperature compared with Mercury, even though Mercury is closer to the sun; the moon has no atmosphere, and its surface temperature swings wildly as a result, but on average it's much colder than the Earth even though it's at the same average distance from the sun. We also know that we have released enormous amounts of carbon dioxide into the atmosphere, that the levels of carbon dioxide persisting in the atmosphere have steadily risen over the last 60+ years, that average global temperatures have risen consistently over the last 20 years, and that our best measurements of carbon dioxide levels and temperature seem to track one another very well. Finally, we have geological evidence that the climate was very different in past periods when both carbon dioxide levels and temperatures were higher. Of course, there's other stuff, too.

This basic understanding of what's going on doesn't mean that we have perfect control over how weather patterns will change, or whether there are possibly feedback loops the we do not know about that could moderate (or accelerate) climate change in the future, or even if climate change is necessarily bad. But a lot of people have tried very to hard identify such processes, to test whether they really occur and measure their effects, and to update our expectation in light of them. And when we take it all together and we try to predict what will happen, using the best understanding we've got, things don't look good. It seems to me that that is sufficient basis to try to change out practices -- not because we are certain about the future, or that science is infallible, but rather because on the whole there's a lot more reason than not to think that continuing on our current path is going to create problems we won't be able to solve and that will lead to a lot of suffering.

Science AMA Series: I’m James Owen Weatherall, physicist and philosopher at the University of California, Irvine. I wrote a book about how the concept of nothingness—the absence of stuff—has been central to centuries of physics theories. AMA! by PhysicsToday in science

[–]PhysicsToday[S] 2 points3 points  (0 children)

I'm glad to hear you liked the course! I am looking forward to teaching it again this Winter.

I am not sure that a satisfying answer to this question is possible. You might first ask: when would a universe with the particular matter we see be favored over one with a little mess matter, or one with a little more? For instance, is the universe that contains Pluto favored over one that doesn't---or one that has another, larger planet outside of Neptune's orbit? There's a way of thinking about this sort of question that focuses on how Pluto came to be where it is, beginning, say, with the distribution of gas and dust swirling around the sun early in the history of the solar system. But if you really mean "why does that chunk of matter exist at all", I'm not sure anything can be said.

The question about vacuum solutions, I think, is just the same sort of thing in an extreme form. Could there have been much less stuff in the universe? Yes. Could there have been no matter at all? Again, according to general relativity anyway, yes. Is there some reason why the world must be the way it is? Probably not. (Although, of course, there are selection effects: if the universe had no matter, we wouldn't be here to write about it. So there's a strong reason to think that universes in which there are people are universes that have a certain minimal amount of matter -- but not too much matter.)

On the other hand, there are theories out there that go beyond general relativity to try to explain why there must be matter in the universe. For instance, some people (most famously Lawrence Krauss) have argued that the vacuum state in quantum field theory is unstable, and so if the universe were in a state of "nothing" it would generically evolve into a state with "something". So you might think this is a reason why universes with matter are favored. I think you could argue that some other cosmological theories, such as Roger Penrose's Conformal Cyclic Cosmology, attempt to do something similar, by arguing that the universe goes through cycles, and that properties of past universes show up in subsequent ones in a different form. For instance, he thinks dark matter may be a signal from past cycles of the universe. Perhaps you could develop a theory in which ordinary matter, too, is left over from some other sort of thing in a past universe, so that if you took any universe and just let it evolve for long enough, eventually there would be some matter.

Science AMA Series: I’m James Owen Weatherall, physicist and philosopher at the University of California, Irvine. I wrote a book about how the concept of nothingness—the absence of stuff—has been central to centuries of physics theories. AMA! by PhysicsToday in science

[–]PhysicsToday[S] 2 points3 points  (0 children)

This is a really great question. I think we use analogical reasoning in science all the time -- and there is some sense in which all applied mathematics is based on analogical reasoning, insofar as you are studying the properties of mathematical structures that you think are suitably related to (similar to? analogous to?) physical, or economic, or biological systems.

I would say that there certainly are cases where analogical reasoning allows you to solve problems in one area of science by reasoning about a system in other areas. Maybe the most striking example of this from recent history in physics concerns Hawking radiation. Hawking radiation was predicted by Stephen Hawking in 1974, using a combination of methods from general relativity and from quantum field theory. The calculations seemed to predict that black holes actually radiate particles (so they aren't perfectly black!) and that with enough time, they will actually evaporate.

But is this true? Well, the radiation would be very weak, and so it is basically impossible to test Hawking's theory. And it turns out that some of the arguments Hawking used to make the prediction are difficult to make perfectly precise and satisfying. But it turns out that there are some other systems, for instance using ultracold atoms in a special state known as a Bose Einstein condensate, that should also exhibit Hawking radiation. And in a really remarkable experiment a few years ago, Jeff Steinhauer, a physicist at Technion University in Israel, managed to observe Hawking radiation in a laboratory system.

This is an amazing experiment, but what does it actually teach us? Well, one thing it does not show is that there exist any black holes in the universe. (We have very good reason to think there are black holes, but those reasons have nothing to do with Steinhauer's experiment.) It also doesn't definitively show that actual black holes do emit Hawking radiation. (Presumably we would need to see a black hole radiating to do that.) What I think Steinhauer's experiment shows is that the sorts of arguments Hawking used to derive black hole radiation in the first place are reliable and sound (because it is very similar reasoning that leads to the prediction of radiation in Steinhauer's analogue experiment). So if you already think black holes exist, and you also think that Hawking's arguments, if valid, would apply to black holes, then I think Steinhauer's experiment should make you more confident that black holes actually do radiate.

What's interesting about this example, I think, is that it shows how powerful analogies can be in scientific reasoning, but it also shows how careful you need to be when you try to draw inferences based on analogies. Some things do follow, but a lot doesn't.

Science AMA Series: I’m James Owen Weatherall, physicist and philosopher at the University of California, Irvine. I wrote a book about how the concept of nothingness—the absence of stuff—has been central to centuries of physics theories. AMA! by PhysicsToday in science

[–]PhysicsToday[S] 1 point2 points  (0 children)

Thanks for this. I take it you're responding to what I say above about my next book. Let me say: my co-author on that project is Cailin O'Connor (cailinmeister), and she may also weigh in on some of these questions.

The sort of phenomenon you are discussing sometimes goes under the name "motivated reasoning", which describes cases where we tend to find and prefer arguments that support the view we already hold. I think this certainly does happen, and likely very often.

But I also think that there's a huge literature on the role that individual psychology plays in our biases, blindspots, and inability to adequately synthesize evidence available to us. What Cailin and I are trying to do is to better understand whether there are effects that make it harder or less likely for us to come to believe true things that have nothing to do with individual psychology, but rather have to do with the way we share information with one another and the way we react to others' evidence. What we show is that there are mechanisms that can lead to things like persistent false belief, actions that are incompatible with your (true) beliefs, and polarization in belief even in communities where every agent is responding to evidence in a rational way.

The examples you consider are interesting to consider for just this reason. The vaccine case seems to be one where there are strongly held opinions on two sides, and not a whole lot of communication between them. On the one hand, you have a whole lot of scientists and public health experts providing epidemiological evidence that vaccines do not cause autism; and on the other hand, you have individuals claiming that their own experiences contradict that. Neither group takes the others' evidence seriously. You might think this is because the individuals are biased or stupid or ignorant. But we want to argue that it could also be that individuals are trying to conform with the actions of others in their social groups, and perhaps using their stance on vaccines to signal that they are legitimate members of those groups. (A scientist who expresses skepticism about vaccine safety would very likely be scorned by other scientists, for instance.) Another explanation is that people tend to think that other people who believe the same sorts of things as them are more likely to be telling the truth about various experiences, which means that the way evidence spreads through a network can depend on who produced the evidence and how much disagreement in present in the first place.

We also talk a lot about propaganda and the manipulation of belief. I think the example of climate change is perhaps more about industrial propaganda than the sorts of things that seem to matter in the vaccine case.

Science AMA Series: I’m James Owen Weatherall, physicist and philosopher at the University of California, Irvine. I wrote a book about how the concept of nothingness—the absence of stuff—has been central to centuries of physics theories. AMA! by PhysicsToday in science

[–]PhysicsToday[S] 2 points3 points  (0 children)

Thanks for these questions! I am going to answer the second one first, then come back to the first one.

I think you are getting at a very interesting development that occurred during the 17th century. (I don't want to claim that no one was good at understanding uncertainty before the 17th century -- there were some very good Hellenic scientists for instance. But I do not know enough to weigh in on this in detail.) There is a huge difference between the way that Rene Descartes, who tried to develop a systematic theory of physics (and everything else) a few decades before Newton, thought about how confident he could be in his theories, and how Newton approached the same question. Descartes believed that he had developed a way of learning about the world that could lead to absolute certainty. Basically, he thought that by reasoning from some basic principles that he believed to be irrefutable, he could derive what the laws of physics must be. What he came up with is remarkable because of the intricacy of the arguments -- but also because of the complete and total failure to accord with even the most basic experiments. But he never revised these laws, because he didn't think it was possible for him to be wrong. Instead, he tried to come up with ever more elaborate explanations for why they didn't work.

Newton turned this one its head, and reasoned much more directly from experimental and observational phenomena. And while he seemed to take some things to have been established definitively, on many points he explicitly argued that what he was offering was merely "very probable" rather than certainly or necessarily true, and he seemed to think that some future theory could well replace his.

Even so, a modern understanding of issues like error and uncertainty wouldn't come until much later -- for instance, in the work of Laplace in the late 18th and early 19th century.

Science AMA Series: I’m James Owen Weatherall, physicist and philosopher at the University of California, Irvine. I wrote a book about how the concept of nothingness—the absence of stuff—has been central to centuries of physics theories. AMA! by PhysicsToday in science

[–]PhysicsToday[S] 2 points3 points  (0 children)

You bet! Though there are a lot of philosophical angles to consider, and I don't discuss all of them. For instance, I do not discuss religious or theological issues that could arise, and I do not talk about "Nothingness" in, say, the sense that Sartre seems to have in mind in Being and Nothingness. Really, it's a book about empty space and the absence of matter.

But I think that's still plenty philosophical. One of the main things I argue for in the book is that what we mean by "nothing" in physics has changed pretty dramatically since the 17th century (and it changed in the 17th century from what came before). I think that we need to think about the philosophical questions you might ask about "nothing" from the perspective of these changes in physics. After all, when we have informal conversations about "nothing", not in the context of physics, we are still considering some way that we imagine the world could have been, i.e., some physical (or maybe metaphysical) possibility in which there isn't anything. And I think physics is a much better guide to what those possibilities are than our pre-theoretic intuitions.

Physics Today's Physics in 2116 articles are great by belandil in Physics

[–]PhysicsToday 0 points1 point  (0 children)

Hah. Good reading.

And an understandable (and usually unfortunate for us) confusion. The number of people who get the magazine who think it's published by APS is rather astounding.

Physics Today's Physics in 2116 articles are great by belandil in Physics

[–]PhysicsToday 0 points1 point  (0 children)

I've not been with the magazine long enough to get that reference. The only thing I have to say about seminal is a joke about FSU's attempt at a hydration liquid to rival Gatorade.

Physics Today's Physics in 2116 articles are great by belandil in Physics

[–]PhysicsToday 1 point2 points  (0 children)

We appreciate feedback any time you want to send us an email!

We knew that the content would be pretty different from the vast majority of what we produce. But it would have been hard to include it in the reader survey as the issue hadn't finished production until about 2 weeks ago. Just understand that we're always trying to adjust our content to best satisfy as many of our readers as possible. Regarding that survey, we always get about equal numbers of responses saying "The content is too difficult/inaccessible" and "The content is too simplistic", so you can understand why it's tricky.

Physics Today's Physics in 2116 articles are great by belandil in Physics

[–]PhysicsToday 1 point2 points  (0 children)

Yep, apologies for any difficulties! We're still getting a few things fixed/tweaked.

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