The Neapolitan Particle

“Welcome back, Jennie.  Why would anyone want to steer an ice cube?

“Thanks, Jeremy, it’s nice to be back..  And the subject’s not an ice cube, it’s IceCube, the big neutrino observatory in the Antarctic.”

“Then I’m with Al’s question.  Observatories have this big dome that rotates and inside there’s a lens or mirror or whatever that goes up and down to sight on the night’s target.  OK, the Hubble doesn’t have a dome and it uses gyros but even there you’ve got to point it.  How does IceCube point?”

“It doesn’t.  The targets point themselves.”


“Ever relayed a Web-page?”


“Guess what?  You don’t know where the page came from, you don’t know where it’s going to end up.  But it could carry a tracking bug to tell someone at some call-home server when and where the page had been opened.  IceCube works the same way, sort of.  It has a huge 3D array of detectors to record particles coming in from any direction.  A neutrino can come from above, below, any side, no problem — the detectors it touches will signal its path.”

IceCube architecture

Adapted from a work by Francis Halzen, Department of Physics, University of Wisconsin

“How huge?”

“Vastly huge.  The instrument is basically a cubic kilometer of ultra-clear Antarctic ice that’s ages old.  The equivalent of the tracking bugs is 5000 sensors in a honeycomb array more than a kilometer wide.  Every hexagon vertex marks a vertical string of sensors going down 2½ kilometers into the ice.  Each string has a couple of sensors near the surface but the rest of them are deeper than 1½ kilometers.  The sensors are looking for flashes of light.  Keep track of which sensor registered a flash when and you know the path a particle took through the array.”

icecube event 3“Why should there be flashes? I thought neutrinos didn’t interact with matter.”

“Make that, they rarely interact with matter.  Even that depends on what particle the neutrino encounters and what flavor neutrino it happens to be at the moment.”

That gets both Al and me interested.  His “Neutrinos come in flavors?” overlaps my “At the moment?”

“I thought that would get you into this, Sy.  Early experiments detected only 1/3 of the neutrinos we expected to come from the Sun.  Unwinding all that was worth four Nobel prizes and counting.  The upshot’s that there are three different neutrino flavors and they mutate.  The experiments caught only one.”

Vinnie’s standing behind us.  “You’re going to tell us the flavors, right?”

“Hoy, Vinnie, Jeremy’s question was first, and it bears on the others.  Jeremy, you know that blue glow you see around water-cooled nuclear fuel rods?”

“Yeah, looks spooky.  That’s neutrinos?”

“No, that’s mostly electrons, but it could be other charged particles.  It has to do with exceeding the speed of light in the medium.”

“Hey, me and Sy talked about that.  A lightwave makes local electrons wiggle, and how fast the wiggles move forward can be different from how fast the wave group moves.  Einstein’s speed-of-light thing was about the wave group’s speed, right, Sy?”

“That’s right, Vinnie.”

“So anyhow, Jeremy, a moving charged particle affects the local electromagnetic field.  If the particle moves faster than the surrounding atoms can adjust, that generates light, a conical electromagnetic wave with a continuous spectrum.  The light’s called Cherenkov radiation and it’s mostly in the ultra-violet, but enough leaks down to the visible range that we see it as blue.”

“But you said it takes a charged particle.  Neutrinos aren’t charged.  So how do the flashes happen in IceCube?”

“Suppose an incoming high-energy neutrino transfers some of its momentum to a charged particle in the ice — flash!  Even better, the flash pattern provides information for distinguishing between the neutrino flavors.  Muon neutrinos generate a more sharp-edged Cherenkov cone than electron neutrinos do.  Taus are so short-lived that IceCube doesn’t even see them.”Leptons

“I suppose muon and tau are flavors?”

“Indeed, Vinnie.  Any subatomic reaction that releases an electron also emits an electron-flavored neutrino.  If the reaction releases the electron’s heavier cousin, a muon, then you get a muon-flavored neutrino.  Taus are even heavier  and they’ve got their own associated neutrino.”

“And they mutate?”

“In a particularly weird way.”

~~ Rich Olcott


Bigger than you’d think

Al’s coffee shop, the usual mid-afternoon crowd of chatterers and laptop-tappers.  Al’s walking his refill rounds, but I notice he’s carrying a pitcher rather than his usual coffee pot.  “Hey, Al, what’s with the hardware?”

“Got iced coffee here, Sy.  It’s hot out, people want to cool down.  Besides, this is in honor of IceCube.”

“Didn’t realize you’re gangsta fan.”

“Nah, not the rapper, the cool experiment down in the Antarctic.  It was just in the news.”

“Oh?  What did they say about it?”

“It’s the biggest observatory in the world, set up to look for the tiniest particles we know of, and it uses a cubic mile of ice which I can’t think how you’d steer it.”

A new voice, or rather, a familiar one. “One doesn’t, Al.”
Neutrino swirl 1“Hello, Jennie.  Haven’t seen you for a while.”

“I flew home to England to see my folks.  Now I’m back here for the start of the Fall term.  I’ve already picked a research topic — neutrinos.  They’re weird.”

“Hey, Jennie, why are they so tiny?”

“It’s the other way to, Al.  They’re neutrinos because they’re so tiny.  Sy would say that for a long time they were simply an accounting gimmick to preserve the conservation laws.”

“I would?”

“Indeed.  People had noticed that when uranium atoms give off alpha particles to become thorium, the alpha particles always have about the same amount of energy.  The researchers accounted for that by supposing that each kind of nucleus has some certain quantized amount of internal energy.  When one kind downsizes to another, the alpha particle carries off the difference.”

“That worked well, did it?”

“Oh, yes, there are whole tables of nuclear binding energy for alpha radiation.  But when a carbon-14 atom emits a beta particle to become nitrogen-14, the particle can have pretty much any amount of energy up to a maximum.  It’s as though the nuclear quantum levels don’t exist for beta decay.  Physicists called it the continuous beta-spectrum problem and people brought out all sorts of bizarre theories to try to explain it.  Finally Pauli suggested maybe something we can’t see carries off energy and leaves less for the beta.  Something with no charge and undetectable mass and the opposite spin from what the beta has.”

“Yeah, that’d be an accounting gimmick, alright.  The mass disappears into the rounding error.”

“It might have done, but twenty years later they found a real particle.  Oh, I should mention that after Pauli made the suggestion Fermi came up with a serious theory to support it.  Being Italian, he gave the particle its neutrino name because it was neutral and small.”

“But how small?”

“We don’t really know, Al.  We know the neutrino’s mass has to be greater than zero because it doesn’t travel quite as fast as light does.  On the topside, though, it has to be lighter than than a hydrogen atom by at least a factor of a milliard.”


“Oh, sorry, I’m stateside, aren’t I?  I should have said a billion.  Ten-to-the-ninth, anyway.”

“That’s small.  I guess that’s why they can sneak past all the matter in Earth like the TV program said and never even notice.”

This gives me an idea.  I unholster Old Reliable and start to work.

“Be right with you… <pause> … Jennie, I noticed that you were being careful to say that neutrinos are light, rather than small.  Good careful, ’cause ‘size’ can get tricky at this scale.  In the early 1920s de Broglie wrote that every particle is associated with a wave whose wavelength depends on the particle’s momentum.  I used his formula, together with Jennie’s upper bound for the neutrino’s mass, to calculate a few wavelength lower bounds.Neutrino wavelength calcMomentum is velocity times mass.  These guys fly so close to lightspeed that for a long time scientists thought that neutrinos are massless like photons.  They’re not, so I used several different v/c ratios to see what the relativistic correction does.  Slow neutrinos are huge, by atom standards.  Even the fastest ones are hundreds of times wider than a nucleus.”

“With its neutrino-ness spread so thin, no wonder it’s so sneaky.”

“That may be part of it, Al.”

“But how do you steer IceCube?”

~~ Rich Olcott

Naming the place and placing the name

“By the way, Cathleen, is there any rhyme or reason to that three-object object‘s funky name?  I’ve still got it on Old Reliable here.”

PSR J0337+1715

“It’s nothing like funky, Sy, it’s perfectly reasonable and in fact it’s far more informative than a name like ‘Barnard’s Star.’  The ‘PSR‘ part says that the active object, the reason anyone even looked in that system’s direction, is a pulsar.”

“And the numbers?”

“Its location in two parts.  Imagine a 24-hour clockface in the Solar Plane.  The zero hour points to where the Sun is at the Spring equinox.  One o’clock is fifteen degrees east of that, two o’clock is another fifteen degrees eastward and so on until 24 o’clock is back pointing at the Springtime Sun.  Got that?”

“Mm, … yeah.  It’d be like longitudes around the Earth, except the Earth goes around in a day and this clock looks like it measures a year.”

“Careful there, it has nothing to do with time.  It’s just a measure of angle around the celestial equator.  It’s called right ascension.

“How about intermediate angles, like between two and three o’clock?”

“Sixty arc-minutes between hours, sixty arc-seconds between arc-minutes, just like with time.  If you need to you can even go to tenths or hundredths of an arc-second, which divide the circle into … 8,640,000 segments.”

“OK, so if that’s like longitudes, I suppose there’s something like latitudes to go with it?”

“Mm-hm, it’s called declination.  It runs perpendicular to ascension, from plus-90° up top down to 0° at the clockface to minus-90° at the bottom.  Vivian, show Sy Figure 3 from your paper.”Right ascension and declination“Wait, right ascension in hours-minute-seconds but declination in degrees?”

“Mm-hm.  Blame history.  People have been studying the stars and writing down their locations for a long time.  Some conventions were convenient back in the day and we’re not going to give them up.  So anyway, an object’s J designation with 4-digit numbers tells you which of 13 million directions to look to find it.  Roughly.”


“That’s what the ‘J‘ is about.  If the Earth’s rotation were absolutely steady and if the Sun weren’t careening about a moving galaxy, future astronomers could just look at an object’s angular designation and know exactly where to look to find it again.  But it’s not and it does and they won’t.  The Earth’s axis of rotation wobbles in at least three different ways, the Sun’s orbit around the galaxy is anything but regular and so on.  Specialists in astrometry, who measure things to fractions of an arc-second, keep track of time in more ways than you can imagine so we can calculate future positions.  The J-names at least refer back to a specific point in time.  Mostly.  You want your mind bent, look up epoch some day.”

“Plane and ship navigators care, too, right?”

“Not so much.  Earth’s major wobble, for instance, shifts our polar positions only about 40 parts per million per year.  A course you plotted last week from here to Easter Island will get you there next month no problem.”

Old Reliable judders in my hand.  Old Reliable isn’t supposed to have a vibration function, either.  Ask her about interstellar navigation.  “Um, how about interstellar navigation?”Skewed Big Dipper

“Oh, that’d be a challenge.  Once you get away from the Solar System you can’t use the Big Dipper to find the North Star, any of that stuff, because the constellations look different from a different angle.  Get a couple dozen lightyears out, you’ve got a whole different sky.”

“So what do you use instead?”

“I suppose you could use pulsars.  Each one pings at a unique repetition interval and duty cycle so you could recognize it from any angle.  The set of known pulsars would be like landmarks in the galaxy.  If you sent out survey ships, like the old-time navigators who mapped the New World, they could add new pulsars to the database.  When you go someplace, you just triangulate against the pulsars you see and you know where you are.”

If they happen to point towards you! You only ever see 20% of them.  Starquakes and glitches and relativistic distortions mess up the timings.  Poor Xian-sheng goes nuts each time we drop out of warp.

~~ Rich Olcott

Rhythm Method

A warm Summer day.  I’m under a shady tree by the lake, watching the geese and doing some math on Old Reliable.  Suddenly a text-message window opens up on its screen.  The header bar says 710-555-1701.  Old Reliable has never held a messaging app, that’s not what I use it for.  The whole thing doesn’t add up.  I type in, Hello?

Hello, Mr Moire.  Remember me?

Suddenly I do.  That sultry knowing stare, those pointed ears.  It’s been a yearHello, Ms Baird.  What can I do for you?

Another tip for you, Mr Moire.  One of my favorite star systems — the view as you approach it at near-lightspeed is so ... meaningful.  Your astronomers call it PSR J0337+1715.

So of course I head over to Al’s coffee shop after erasing everything but that astronomical designation.  As I hoped, Cathleen and a few of her astronomy students are on their mid-morning break.  Cathleen winces a little when she sees me coming.  “Now what, Sy?  You’re going to ask about blazars and neutrinos?”

I show her Old Reliable’s screen.  “Afraid not, Cathleen, I’ll have to save that for later.  I just got a message about this star system.  Recognize it?”

“Why, Sy, is that a clue or something?  And why is the lettering in orange?”

“Long story.  But what can you tell me about this star system?”

“Well, it’s probably one of the most compact multi-component systems we’re ever going to run across.  You know what compact objects are?”

“Sure.  When a star the size of our Sun exhausts most of its hydrogen fuel, gravity wins its battle against heat.  The star collapses down to a white dwarf, a Sun-full of mass packed into a planet-size body.  If the star’s a bit bigger it collapses even further, down to a neutron star just a few miles across.  The next step would be a black hole, but that’s not really a star, is it?”

“No, it’s not.  Jim, why not?”

“Because by definition a black hole doesn’t emit light.  A black hole’s accretion disk or polar jets might, but not the object itself.”

“Mm-hm.  Sy, your ‘object’ is actually three compact objects orbiting  around each other.  There’s a neutron star with a white dwarf going around it, and another white dwarf swinging around the pair of them.  Vivian, does that sound familiar?”

“That’s a three-body system, like the Moon going around the Earth and both going around the Sun.  Mmm, except really both white dwarfs would go around the neutron star because it’s heaviest and we can calculate the motion like we do the Solar System.”

“Not quite.  We can treat the Sun as motionless because it has 99% of the mass.  J0337+1715’s neutron star doesn’t dominate its system as much as the Sun does ours.  That outermost dwarf has 20% of its system’s mass.  Phil, what does that suggest to you?”

“It’d be like Pluto and Charon.  Charon’s got 10% of their combined mass and so Pluto and Charon both orbit a point 10% of the way out from Pluto.  From Earth we see Pluto wobbling side to side around that point.  So the neutron star must wobble around the point 20% outward towards the heavy dwarf.  Hey, star-wobble is how we find exoplanets.  Is that what this is about, Mr Moire?  Did someone measure its red-shift behavior?”PSR J0337+1715Cathleen saves me from answering.  “Not quite.  The study Sy’s chasing is actually a cute variation on red-shift measurements.  That ‘PSR‘ designation means the neutron star is a pulsar.  Those things emit electromagnetic radiation pulses with astounding precision, generally regular within a few dozen nanoseconds.  If we receive slowed-down pulses then the object’s going away; sped-up and it’s approaching, just like with red-shifting.  The researchers  derived orbital parameters for all three bodies from the between-pulse durations.  The heavy dwarf is 200 times further out than the light one, for instance.  Not an easy experiment, but it yielded an important result.”

My ears perk up.  “Which was…?”

“The gravitational force between the pulsar and each dwarf was within six parts per million of what Newton’s Laws prescribe.  That observation rules out whole classes of theories that tried to explain galaxies and galaxy clusters without invoking dark matter.”

Cool, huh?


~~ Rich Olcott

Moby Divergence

Stepping into Pizza Eddie’s I see Jeremy at his post behind the gelato stand, an impressively thick book in front of him.  “Hi, Jeremy, one chocolate-hazelnut combo, please.  What’re you reading there?”

“Hi, Mr Moire.  It’s Moby Dick, for English class.”

“Ah, one of my favorites.  Melville was a 19th-century techie, did for whaling what Tom Clancy did for submarines.”

“You’re here at just the right time, Mr Moire.  I’m reading the part where something called ‘the corpusants’ are making lights glow around the Pequod.  Sometimes he calls them lightning, but they don’t seem to come down from the sky like real lightning.  Umm, here it is, he says. ‘All the yard-arms were tipped with pallid fire, and touched at each tri-pointed lightning-rod-end with three tapering white flames, each of the three tall masts was silently burning in that sulphurous air, like three gigantic wax tapers before an altar.’  What’s that about?”St Elmos fire

“That glow is also called ‘St Elmo’s Fire‘ among other things.  It’s often associated with a lightning storm but it’s a completely different phenomenon.  Strictly speaking it’s a concentrated coronal discharge.”

“That doesn’t explain much, sir.”

“Take it one word at a time.  If you pump a lot of electrons into a confined space, they repel each other and sooner or later they’ll find ways to leak away.  That’s literally dis-charging.”

“How do you ‘pump electrons’?”

“Oh, lots of ways.  The ancient Greeks did it by rubbing amber with fur, Volta did it chemically with metals and acid,  Van de Graaff did it with a conveyor belt, Earth does it with winds that transport air between atmospheric layers.  You do it every time you shuffle across a carpet and get shocked when you put your finger near a water pipe or a light switch.”

“That only happens in the wintertime.”

“Actually, carpet-shuffle electron-pumping happens all the time.  In the summer you discharge as quickly as you gain charge because the air’s humidity gives the electrons an easy pathway away from you.  In the winter you’re better insulated and retain the charge until it’s too late.”

“Hm.  Next word.”

Corona, like ‘halo.’  A coronal discharge is the glow you see around an object that gets charged-up past a certain threshold.  In air the glow can be blue or purple, but you can get different colors from other gases.  Basically, the electric field is so intense that it overwhelms the electronic structure of the surrounding atoms and molecules.  The glow is electrons radiating as they return to their normal confined chaos after having been pulled into some stretched-out configuration.”

“But this picture of the corpusants has them just at the mast-heads and yard-arms, not all over the boat.”

“That’s where the ‘concentrated’ word come in.  I puzzled over that, too, when I first looked into the phenomenon.  Made no sense.”

“Yeah.  If the electrons are repelling each other they ought to spread out as much as possible.  So why do they seem pour out of the pointy parts?”

“That was a mystery until the 1880s when Heaviside cleaned up Maxwell’s original set of equations.  The clarified math showed that the key is the electric field’s spread-out-ness, technically known as divergence.”

DivergenceWith my finger I draw in the frost on his gelato cabinet.  “Imagine this is a brass ball, except I’ve pulled one side of it out to a cone.  Someone’s loaded it up with extra electrons so it’s carrying a high negative charge.”

“The electrons have spread themselves evenly over the metal surface, right, including at the pointy part?”

“Yup, that’s why I’m doing my best to make all these electric field arrows the same distance apart at their base.  They’re also supposed to be perpendicular to the surface.  What part of that field will put the most rip-apart stress on the local air molecules?”

“Oh, at the tip, where the field spreads out most abruptly.”

“Bingo.  What makes the glow isn’t the average field strength, it’s how drastically the field varies from one side of a molecule to the other.  That’s what rips them apart.  And you get the greatest divergence at the pointy parts like at the Pequod’s mast-head.”

“And Ahab’s harpoon.”

~~ Rich Olcott

A Recourse to Pastry

There’s something wrong about the displays laid out on Al’s pastry counter — no symmetry.  One covered platter holds eight pinwheels in a ring about a central one, but the other platter’s central pinwheel has only a five-pinwheel ring around it.  I yell over to him.  “What’s with the pastries, Al?  You usually balance things up.”

“Ya noticed, hey, Sy?  It’s a tribute to the Juno spacecraft.  She went into orbit around Jupiter on the 5th of July 2016 so I’m celebrating her anniversary.”

“Well, that’s nice, but what do pinwheels have to do with the spacecraft?”

“Haven’t you seen the polar pictures she sent back?  Got a new poster behind the cash register.  Ain’t they gorgeous?”Jupiter both poles“They’re certainly eye-catching, but I thought Jupiter’s all baby-blue and salmon-colored.”

Astronomer Cathleen’s behind me in line.  “It is, Sy, but only in photographs using visible sunlight.  These are infrared images, right, Al?”

“Yeah, from … lemme look at the caption … Juno‘s JIRAM instrument.”

“Right, the infrared mapper.  It sees heat-generated light that comes from inside Jupiter.  It’s the same principle as using blackbody radiation to take a star’s temperature, but here we’re looking at a planet.  Jupiter’s way colder than a star so the wavelengths are longer, but on the other hand it’s close-up so we don’t have to reckon with relativistic wavelength stretching.  At any rate, infrared wavelengths are too long for our eyes to see but they penetrate clouds of particulate matter like interstellar dust or the frigid clouds of Jupiter.”

Jupiter south pole 1

NASA mosaic view of Jupiter’s south pole by visible light

“So this red hell isn’t what the poles actually look like?”

“No, Al,  the visible light colors are in the tops of clouds and they’re all blues and white.  These infrared images show us temperature variation within the clouds.  Come to think of it, that Hell’s frozen over — if I recall correctly, the temperature range in those clouds runs from about –10°C to –80°C.  In Fahrenheit that’d be from near zero to crazy cold.”

“Those aren’t just photographs in Al’s poster?”

“Oh, no, Sy, there’s a lot of computer processing in between Juno‘s wavelength numbers and what the public sees.  The first step is to recode all the infrared wavelengths to visible colors.  In that north pole image I’d say that they coded red-to-black as warm down to white as cool.  The south pole image looks like warmest is yellow-to-white, coolest is red.”

“How’d you figure that?”

“The programs fake the apparent heights.  The warmest areas are where we can see most deeply into the atmosphere, which would be at the center or edge of a vortex.  The cooler areas would be upper-level material.  The techs use that logic to generate the perspective projection that we interpret as a 3-D view.”

Vinnie’s behind us in line and getting impatient.  “I suppose there’s Science in those pretty pictures?”

“Tons of it, and a few mysteries.  JIRAM by itself is telling the researchers a lot about where and how much water and other small molecules reside in Jupiter’s atmosphere.  But Juno has eight other sensors.  Scientists expect to harvest important information from each of them.  Correlations between the data streams will give us exponentially more.”

He’s still antsy.  “Such as?”

“Like how Jupiter’s off-axis magnetic field is related to its lumpy gravitational field.  When we figure that out we’ll know a lot more about how Jupiter works, and that’ll help us understand Saturn and gas-giant exoplanets.”GRS core

Al breaks in.  “What about the mysteries, Cathleen?”

“Those storms, for instance.  They look like Earth-style hurricanes, driven by upwelling warm air.  They even go in the right direction.  But why are they crammed together so and how can they stay stable like that?  Adjacent gears have to rotate in opposite directions, but these guys all go in the same direction.  I can’t imagine what the winds between them must be like.”

“And how come there’s eight in the north pole ring but only five at the other pole?”

“Who knows, Vinnie?  The only guess I have is that Jupiter’s so big that one end doesn’t know what the other end’s doing.”

“Someone’s gonna have to do better than that.”

“Give ’em time.”

~~ Rich Olcott

Zwicky Too Soon

Big Vinnie barrels into the office, again. “Hey, Sy, word is you been short-changing Fritz Zwicky. What’s the story?”

“Hey, I never even met the guy.  He died in 1974.  How could I do him a bad deal?”

“Not giving him full credit.  I read an article about him.  He talked about ‘dark matter’ almost fifty years before Vera Rubin.”

“You’ve got a point there.  Like Vera Rubin he had a political problem, but his was quite different than hers.”

“Political?  I thought all you had to do was be right.”

“No, you have to be right and you have to have people willing to spend time validating or refuting your claims.  Rubin wasn’t a self-advertiser, so it took a while for people to realize why her results were important.  They did look at them, though, and they did give her credit.  Zwicky’s was a different story.”

“Wasn’t he right?”

“Sometimes right, often wrong.  Thing was, he generated too many ideas for people to cope with.  Worse, he was one of those wide-ranging intellects who adds one plus one to make two.  Trouble was, Zwicky got his ones from different specialties that don’t normally interact.  When people didn’t immediately run with one of his claims he took it personally and lashed out, publicly called ’em fools or worse.  Never a good tactic.”

“Gimme a f’rinstance.”

“OK.  Early 1930’s, Zwicky’s out in the still-raw wilds of California, practically nothing out there but movie studios and oil wells, using a manual blink-comparator like the one Clyde Tombaugh used about the same time to find Pluto.  He’s scanning images taken with Palomar’s new wide-angle telescope to search out novae, stars that suddenly get brighter.  He’s finding dozens of them but a few somehow get orders of magnitude brighter than the rest.  He and his buddy Walter Baade call the special ones ‘supernovae.'”

“Ain’t that novas?”

“Novae — we’re being proper astronomers here and it’s a Latin word.  Anyway, Zwiky’s trying to figure out where a supernova’s enormous luminosity comes from.  He got his start in solid-state physics and he still keeps up on both Physics and Astronomy.  Just a year earlier, James Cavendish over in atomic physics had announced the discovery of the neutron.  Zwicky sees that neutrons are the solution to his problem — gravity can pack together no-charge neutrons to a much higher density than it can pack positive-charge protons.  He proposes that a supernova happens when a big-enough star uses up its fuel and collapses to the smallest possible object, a neutron star.  Furthermore, he says that the collapse releases so much gravitational energy that supernovae give off cosmic rays, the super-high-energy photons that were one of the Big Questions of the day.”

“Sounds reasonable, I suppose.”

“Well, yeah, now.  But back then most astronomers had never heard of neutrons.  To solve at a stroke both cosmic rays and supernovae, using this weird new thing called a neutron, and with the proposal coming from somewhere other than Europe or Ivy League academia — well, it was all too outlandish to take seriously.  No-one did, for decades.”

“He didn’t like that, huh?”Zwicky inspecting dark matter

“No, he did not.  And he railed about it, not only in private conversations but in papers and in the preface to one of the two galaxy catalogs he published.  Same thing with galaxy clusters.”

“Wait, you wrote that Rubin found clusters.”

“I did and she did.  Actually, I wrote that she confirmed clustering.  We knew for 150 years that galaxies bunch together in our 2-D sky, but it took Zwicky’s measurements to group the Coma Cluster galaxies in 3-D.  Problem was, they were moving too fast.  If star gravity were the only thing holding them together they should have scattered ages ago.”

“Dark matter, huh?”

“Yup, Zwicky claimed invisible extra mass bound the cluster together.  More Zwicky outlandishness and once again his work was ignored for years.”

“Even though he was right.”

“Mm-hm.  But he could be wrong, too.  He didn’t like Hubble’s expanding Universe idea so he came up with a ‘tired light’ theory to explain the red-shifts.  He touted that idea heavily but there was too much evidence against it.”

“One of those angry ‘lone wolf’ scientists.”

“And bitter.”

~~ Rich Olcott