science

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Causality, relativity, uncertainty, and attractive versus repulsive gravity–these are worth celebrating

Okay, well, I’m writing this blog post from the office, because this is where I slept last night after the holiday party.  We did not have the party at the office, just to be clear.  We had it at a very decent restaurant called Maggiano’s, which may be part of a chain to some extent, I think.  It was a nice enough restaurant, food-wise, and the building and the outside lights were quite beautiful (see below).  However, inside, it was way too crowded and noisy, and we were seated at a very long, narrow table against a wall.

I felt incredibly stressed when we first arrived; I can hardly hear out of my right ear for one, and I have had tinnitus in it since about 2007 or so, and everything else was a tumult and commotion.  There was too much visual sensory overload also, and way too many people in too close quarters.  I miss the social mores of the pandemic, honestly.  I was barely able to endure long enough for our server to get me a drink so I could calm down a little.  I almost left and just walked back to the office.

My difficulties with such things have gotten worse over time, probably at least partly because I only ever used to go to restaurants and whatnot with people with whom I felt quite comfortable—my family, near and extended, then my wife, her family, our family, and so on—so there was always someone on whom I could focus, and with whom I could speak.

The drinks were rather weak, which may be good, since it was a work night, but I had to drink several to keep from tensing up.  Even so, at the end of the night, when they wanted to take a big group photo, I just walked away.  I had been dodging pictures all night already; there was a terribly annoying number of them, because everyone has their own little cameras in their smartphones, so instead of conversation—which was very difficult with anyone more than one seat away, and pretty hard even with those neighbors—people just took their little, instant, digital snaps, which I suspect will never really be used for recalling memories.

I’ve said it before, it’s not the case that things on the internet (or smartphones or whatever) are forever, as is sometimes claimed.  There is such a cacophony of data and images and whatnot, a good portion of it now not even being “real”, that most things will be swiftly lost like a drop of ink in a roiling, stormy ocean, or the quantum information of something that’s fallen in a black hole.  In principle it’s all there, but in practice it’s as lost as the echoes of Julius Caesar’s death rattle.

I guess it was a pretty nice evening, and the food was pretty good.  The salad was above average, and the broccoli I had on the side with my ziti dish was good.  It was all certainly well above the level of, for instance, the Olive Garden, but it was terribly noisy, literally and figuratively.  By the end, when we were the last party in the restaurant, it was still noisy, because our group was terribly noisy, and it was embarrassing and unpleasant.

I think I mostly at least prevented anyone from capturing my disgusting current face and form on camera in anything other than, perhaps, an oblique angle.  I really don’t like how I look, or how I feel, and certainly don’t want it memorialized, even if it’s evanescent and ephemeral*.

After the party, I was brought back to the office, which is only about four miles from the restaurant.  I could have walked, since the night was reasonably cool, but since I knew I wouldn’t be taking a shower, I decided not to do that.  I have washed up this morning and applied antiperspirant and aftershave (or whatever you call it when you haven’t actually shaved) and I brushed my teeth and everything.  I slept on the floor, with my backpack as my pillow, and it was about as comfortable as sleeping at the house, and I got about 3 hours of sleep.

This is the state in which my life is and has been for years now:  sleeping at the office and spending time here (by myself) is just as pleasant as being at the place where I nominally live.  That’s because I have no life, and I don’t expect one to occur again for me.  I’m really absolutely dismal and morose and unpleasant, even to myself.

I’ve hardly even read anything in over three weeks now, which is very weird and rare for me.  The single thing to which I’m now looking forward is the Doctor Who Christmas special, and that’s not a huge draw, just a pleasant one.  It’s not as though I’m actually watching it with anyone or can talk about it with a friend or anything.

I got out the hardcover books Spacetime and Geometry and Quantum Field Theory, As Simply as Possible at the office.  I have them resting on the desk, hoping to entice myself during any downtime I might have at work.  So far it hasn’t paid off, but I would like to master the mathematics of GR well enough that I can understand intuitively why a uniform energy field permeating space generates “repulsive gravity”.  I understand that it does, but I don’t have a good picture of it in my head, whereas I do have a much clearer intuitive sense of why the curvature of spacetime (especially the time part) leads to the apparent force of attractive gravity.

In a way, that’s my only remaining unaccomplished (and reasonably achievable) goal.  Quantum field theory is interesting and all, but the basic concepts of it seem fairly straightforward to me**.  Contrary to what people often say, quantum mechanics (et al) are only really counter-intuitive if you insist upon trying to apply macroscopic and mesoscopic intuitions to phenomena that happen at much smaller scales.  It’s a bit like expecting one of your bathroom tiles to behave just like the Burj Khalifa, only the scale is much more disparate between the quantum and the macroscopic.

People seem somehow puzzled by the notion of how complementary pairs of one’s measurements of quantum “particles” can never be more accurate than a certain level, as if this is truly different from measurements of macroscopic phenomena.  I’m quite sure that the errors when measuring, say, the mass or velocity of something as large as an elephant, or a car, or what have you, are waaaaaay huger than the absolute uncertainty in measurement of the position and/or momentum of a particle.  They’re just not as noticeable because the thing itself is big, and so the percentage of the error might be smaller and less consequential.

But we know things change with scale, like surface to volume ratios and whatnot.  An uncertainty of a millimeter when measuring a blue whale is hardly relevant, but if you’re measuring an ant, it could easily be crucial, and if you’re measuring a dust mite that error would be larger than the organism.

I also don’t get the objection to the possible “many worlds” description of quantum mechanics that derives from the fact that we only ever see and experience one world.  I don’t know why that puzzles people.  It’s not as if you can see both the outside and the inside of all the solid objects around you.  If you touch the near surface of a basketball with one finger, you can’t feel the opposite side of the ball with the same finger at the same time.

Yet, there’s no real doubt that the inside and the other side of physical objects really exist.  We just can’t sense the whole of any given thing at once.  Any part of space that will never enter our future light cones is something we will never, ever see at all***, but we don’t have any good reason to doubt that far distant regions of spacetime exist.  Internal consistency of reality and logical coherence of the world seem to demand many things existing with which we will not, and sometimes cannot, ever interact.

Okay, that was a weird tangent.  My apologies.  Anyway, I doubt that I’m going to achieve my “dream” of getting an intuitive, mathematical understanding, something I can feel, about why spacetime expands in the presence of a uniform energy.  After all, it’s something about which I honestly care, and my track record with such things is abysmal.  I don’t expect to achieve anything else of value, even to me, in my life.

I’m tired, I’m sad, I’m depressed, I’m alone; the only person in whose presence I always find myself is a person I despise (me).  My catharsis via this blog isn’t working.  I’m getting no help, though I wish for it, but I’m not sure how well I would respond if some were to come.  Maybe, like the wonderful simile Sting used in Be Still My Beating Heart, I would wriggle like a fish caught on dry land, unable to tell the difference between help and danger, between an offer of comfort and a warning of pain.

Whatever.  Sorry, that’s all pathetic, isn’t it?

In closing, I wonder if anyone listened to my little audio snippet yesterday, and if anyone thought it was worth it for me to try to do such a thing more often.  Let me know in the comments (on WordPress) if you have any feedback to offer.  Thanks.

maggianos

*Performing together live, for the first time.

**Straightforward for quantum field theory type things, anyway, to be fair.  I don’t mean that it’s not complex (ha ha! it uses complex numbers all the time, get it?) but I have a sort of picture of how the processes work, and it makes sense.  The rest would just be building details and specifics on top of the basic framework, which is a lot, of course, but there’s no real intellectual hurdle to be cleared.

***Assuming we do not discover any exceptions or workarounds to special relativity and the speed-of-causality limit.  There could in principle be workarounds, but it seems unlikely that there are local exceptions to the cosmic speed limit.  In any case, even such exceptions shouldn’t violate chains of causality.

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Believing in “believing in” matters of empirical reality…or not

The other day, I was scrolling through The Website Formerly Known as Twitter—which I tend to do after sharing my blog posts there, since it seems the polite thing to do—and I saw a “tweet” or an “X-udate” or “X-cretion” or whatever one calls them now, that asked, “Do you believe in global warming?”

Such questions always seem bizarre to me.  It’s similar to the old, “Do you believe in UFOs?”  Though, with the latter, one can always snarkily reply, “Why, yes, I believe in unidentified flying objects.  I think people often see things in the sky that they cannot properly identify, especially if they are not experts and conditions are not ideal.”  But really, even that sarcastic response misses the point and can be misleading, so it’s best to be avoided.

The problem is, the question entails a kind of category error.  The reality of global warming—by which I assume the questioner means some form of anthropogenic climate change—is an empirical question.  It is a statement about reality itself, and is either true or false whether or not anyone even knows about it as a possibility, let alone “believes in it”.

It’s more reasonable to ask, “Do you believe that anthropogenic climate change—AKA global warming—is happening?”  That, at least, is a sensible question, when using the form of the word “belief” that means that, based on the evidence and reasoning one has available, one has arrived at the provisional conclusion that global warming is happening (or is not).

In using this term “belief”, one would usually imply that one is reasonably convinced, but open in principle to alternative explanations and counter arguments and new evidence—as one always should be in matters of empirical fact, at least if one is committed to always trying to make one’s map describe the territory as well as possible (to borrow a phrase from Eliezer Yudkowsky).

But when people say, “Do you believe in…” something, it doesn’t come across—to me at least—like a question about facts, but rather as a question about ideologies, about team membership, about religion, in a way.  It can be at least excusable and appropriate, if still rather nonsensical in my view, to ask someone if they believe in Santa Claus, or in Communism, or in God.  It doesn’t necessarily have anything to do with external reality other than the state of certain people’s minds, but at least it’s reasonably appropriate.

The absurdity of this conflation of “believing in” something with an assessment of a thing’s actual reality is pointed out well in Terry Pratchett’s delightful Discworld novels—in either Wyrd Sisters or Witches Abroad, if memory serves.  I don’t recall how the point comes up, but it relates to belief in the gods of Discworld.  The narration says that, of course, witches knew that the gods were real, they had dealings with them, they sometimes met them.  But that didn’t mean there was any call to go believing in them.  It would be like believing in the postman.

If someone were to ask me whether I think that climate change is real, and why I think whatever I think, I might reply that the general consensus of the world’s climate scientists—people who actually specialize in the area—seems to be that it is happening, and though their most specific predictions can be highly uncertain, as can all specific predictions in science beyond the realms of simple linear dynamics, most of them conclude that it is really happening.

I read a statement once that claimed that the percentage of climate scientists who are convinced that human-caused global warming is really happening is higher than the percentage of medical scientists who are convinced that smoking tobacco increases the risk of lung cancer.  I don’t know whether that statement is true, and I don’t recall the source—it sounds more like a rhetorical point than an actual argument, which makes me suspicious.  If it is true, it’s remarkable in more than one direction.

One can look up in journals the papers and the data that is being gathered and analyzed by climate scientists.  Google Scholar works nicely for searching out real, published scientific studies on almost any amendable topic.  One can also go to pre-print servers such as arXiv, to see papers that have not yet been peer reviewed.

If one is judicious, one can even find decent science news in less technical publications—phys.org seems to be pretty good—but mainstream reporting on such things is often unreliable and inconsistent, since after all mainstream media exist primarily to sell themselves, not necessarily to promulgate the most rigorous truth they can uncover.  Even Scientific American has turned into a twisted mockery of its former self.

I understand at least some of the physics behind the “greenhouse effect”, without which the Earth would be uninhabitably cold.  Visible light passes through the atmosphere without interacting much with the gases therein—which is why air is mostly transparent, other than the modest scattering of blue light that leads to the sky’s daytime color (and inversely to the color of sunsets).  But such relatively low-entropy, high frequency light is absorbed by the ground, then reemitted as higher entropy, lower frequency light, such as infrared, which is much more readily absorbed by molecules like CO2 and H2O and methane (CH4).  The reasons for this are quantum mechanical in nature, but the fact that it happens is basic physics that’s been well known since before anyone currently alive was born, as far as I know.

And so, these atmospheric gases heat up (and in turn heat up the other atmospheric gases) until the outer surface of the atmosphere is warm enough to radiate out as much energy as comes into the Earth.  Such is the nature of so-called black body radiation.

But for the outer atmosphere to be warm enough to do this, the middle atmosphere must be warmer, and the layer below warmer still, and so on, since outer layers radiate inward as well as outward.  The outer layer of the atmosphere will always be just warm enough to radiate out just as much energy as the Earth receives in light from the sun; if it were not, the Earth would rapidly get hotter until a new equilibrium was reached.  The final radiating surface might end up being higher in the atmosphere, which would mean that, closer to the surface, things would be warmer.

Anyone who has dressed in layers in cold weather should understand this intuitively.

[By the way, there may be some slight imprecisions in my very quick summary above of the thermodynamics of atmospheric gases, so if any experts in the matter would like to make any corrections—especially if such corrections are truly substantive—please feel free to do so in the comments.]

There are other atmospheric effects that are even easier to understand at basic chemical levels, such as the fact that increasing CO2  concentration leads to increasing acidification of the oceans.  This is fairly straightforward chemistry—carbon dioxide, when dissolved in water, partially reacts to form a weak acid—“weak” meaning just that the hydrogen ions do not completely dissociate from the molecule H2CO3*.  This can be demonstrated easily by getting some pH paper (readily available at all high street pH paper shops), testing some neutral water (to confirm its baseline neutral pH) and then blowing through a straw into the water for a few minutes.  You can then check if the pH has dropped, which—if you are a typical mammalian creature from Earth—it will have done.

I think this experiment can also be done with phenolphthalein, which is wine-red when in a basic (alkaline) solution and clear when in an acidic environment.  You can do a sort of magic trick, turning “wine” into “water” with just your breath through a straw bubbling in a glass.  Don’t drink it, though.  I don’t think phenolphthalein is particularly dangerous, but I wouldn’t want to endorse someone imbibing it.

I’m not going to tell you my conclusions about the empirical fact of whether or not “global warming” is happening and how and why and all that.  You can explore the subject as a homework assignment (but don’t hand it in to me).  But I will tell you my conclusion, which is probably obvious, about “believing in” things.  I don’t believe in “global warming” nor in the lack thereof.  I don’t believe in Santa Claus.  I don’t believe in Capitalism or Communism or Socialism or Fascism or Scientism** or Antidisestablishmentarianism.  I don’t believe in the Tooth Fairy, and I don’t believe in life after love.

And I really don’t believe it’s useful or good or anything but an irrationality to “believe in” matters that involve claims about the nature of reality itself.  Reality is that which exists whether or not anyone believes in it—indeed, whether or not anyone exists to be capable of believing in it.  That’s why it’s reality, as opposed to fictions and ideologies and other abstract concepts of various kinds.

I know*** that Amazon delivery people exist.  That doesn’t mean there’s any call to go believing in them.

* H2O + CO2 ⇌ H2CO3 ⇌ H+ + HCO3–.  Something like that, anyway.

** Though I have more sympathy for Scientism than most “isms”.

***Not to a mathematical certainty, but to such a high degree that there’s no clear point in considering other possibilities, pending new evidence and/or arguments.

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So What Is All This GeV Stuff, Anyway?

[This is a reprint of an article I wrote for my hubpage…but I want to focus here on my own page, now, so hopefully no one will be too upset by the re-use.]

Recent news about events at the Large Hadron Collider in Switzerland has brought particle physics more into the mainstream, as scientists have discussed hints that they’re getting closer to finding and defining the Higgs particle…the messenger particle of the Higgs field.

I’m not going to try to rehash the meaning and nature of the Higgs field here. Most of the articles I’ve looked at do at least a decent job with that subject. If you want an even better treatment–as well as a fantastic summary of the state of modern physics that is thorough but extremely understandable–I recommend getting a copy of “The Fabric of the Cosmos” by Brian Greene. He does a better job of explaining difficult subjects in easy-to-understand terms (that nevertheless don’t dumb down the material) than just about anyone else I’ve ever read.

No, what I’m going to talk about is a term that’s thrown around an awful lot in articles about particles: The GeV (and more generally, the eV). The term eV is shorthand for “electron volt,” and “GeV” is the notation for “giga-electron volt”…a billion electron volts, in other words (MeV, mega-electron volt would be a million electron volts).

But wait…the articles about the Higgs (and other writings about atom smashers) refer to measures such as 125GeV as being a measure of a particle’s mass! What does that have to do with volts!? Don’t volts have something to do with electricity? Isn’t household current measured in volts? Does that mean that it takes a Billion times as much voltage as in household current to find a Higgs particle?

Well…not exactly. In physics, the electron-volt is actually a measure of energy, not the voltage in a circuit. Specifically, it’s the amount of kinetic energy (the energy of motion) a free electron would accumulate after being accelerated through a potential difference of one volt. You see, voltage is to electrical fields a lot like what pressure is to water. Voltage differences push things that respond to electric fields…and electrons are one of the most well-known of things that respond to electrical fields, and have been since at least Benjamin Franklin’s time. In other words, falling through a “pressure” difference of one volt will accelerate an electron until it has a kinetic energy that is defined as one electron-volt.

So what the heck does the kinetic energy of an electron have to do with the mass of a Higgs particle? Well, as you probably know, energy can change its form, but it doesn’t disappear, and if need be can always be measured in the same units. At every day energy levels, physicists are more likely to use joules as a measure of energy…a joule is the amount of energy put out by something that has one watt of power in one second. So a one hundred watt bulb puts out 100 joules of energy every second.

Now, when you’re dealing with smaller scale things–like electrons and protons and Higgs particles (Oh my!)–it’s better to use a smaller unit of measure. The eV is a VERY small amount of energy, and can be excellent currency when describing what goes on in interactions between subatomic particles. Just as you wouldn’t use a brick of gold to try to buy a gumball out of the grocery store gum machine, but would instead use your pocket change, you don’t usually use joules in particle physics. You COULD, of course…but you’d be using REALLY small fractions of joules and it’s just easier to use the particle physics version of pocket-change, the electron-volt.

But still, what does this have to do with the mass of a particle? I’ve been talking about energy here!

Well, now we come to probably the most famous equation in all of physics, at least as far as the general public is concerned: E=mc2 (the two here means “squared”, or a number multiplied by itself). This equation explains that matter and energy are interchangeable. Matter and energy are just two forms of the same thing. So you can describe how much Stuff something is made of by describing it in ordinary terms of Mass (such as grams and kilograms), or, if you’re feeling like it and if it’s useful, you can describe it in terms of energy. Now, the “c” in that famous equation is the speed of light, which is mighty fast: about 300,000 kilometers a second (about 186,000 miles per second). It’s already a big number, but when you multiply it by itself, it’s MUCH BIGGER. So even a little mass converts into an awful lot of energy. That’s why nuclear reactions are so powerful: they convert a fraction of a percent of the matter involved in the reaction into energy, and you get all the glory of our sun and all the horror of nuclear weapons.

So finally we arrive at the reason for using eV’s and MeV’s and GeV’s in particle physics. It turns out that, like joules, working with ordinary mass units like grams gets very cumbersome when talking about really tiny things like subatomic particles. You have to use extremely small numbers with a lot of zeroes after the decimal point. If you’d rather not deal with all those zeroes, well, since matter and energy are interchangeable, you can instead describe very small masses in terms of a pretty fair number of a similarly small unit of energy. An electron-volt is just such a useful small unit.

In other words, when they say that the Higgs particle doesn’t look like it can be more than 125 GeV in mass, they mean that, if you took its mass and turned it into free energy, the amount of energy you’d get would not be more than 125 billion electron volts. That may sound like a lot, and on the scale of subatomic particles, it IS. However, it really is a very small amount of energy, and thus an exquisitely small amount of matter.

Of course, the Higgs fields is thought to permeate literally the ENTIRE universe, and the Higgs fields effects are all carried out by Higgs particles, so the mass equivalent of the field would add up to a pretty big amount in total. In fact, ALL the ordinary things with which we are familiar are made up of particles whose masses can be described in terms of electron volts, and most of those “weigh” a lot less than the Higgs appears to. So big things are made up of small things, just lots and lots of them. Like, lots and lots of electron volts of energy can equal the mass of one small but very important particle.