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s never been proven we only know they exist because of their involvement in the weak nuclear force which governs some but not all radioactive decays the picture above is the earth as seen in neutrinos neutrinos are emitted by uranium products in the earth s crust but then pass pass through the earth as though it were a soap bubble the bright spots are new they are nuclear power plants to a weakly interacting being who only sees neutrinos nuclear reactors and atom smashers are the only evidence of life on earth read more spinning tops protons and planets when i was little i tried to make an electromagnet by winding a thin wire around a nail and connecting it to a battery i must have seen this on mr wizard s world but instead of magically picking up paper clips it just got hot and wasted the battery what i didn t understand is that the wire must be insulated not bare metal instead of flowing around the nail in many circular loops the electric current flowed through the whole thing as a bumpy metal blob this fact that circulating electric currents produce magnetic fields can be seen everywhere in nature electromagnets whether they flip bits in a hard drive or cars in a junkyard are essentially just insulated wires wound around nails neutron stars spin faster and faster as they collapse generating the strongest magnetic fields known in the universe elementary particles such as electrons are haloed by tiny magnetic fields due to their intrinsic spin a kind of internal rotation they can never stop even refrigerator magnets are not as stationary as they seem their magnetic fields are due to a partial alignment of electron spins sometimes though the flow can be so turbulent and complicated that its dynamics are a mystery the underlying equations are known but even supercomputers are not powerful enough to determine the implications of those equations only simplified versions of these systems can be calculated so the predictions don t exactly match the real systems in all their messy glory the two examples i have in mind are a proton s magnetic field and the earth s read more the discovery of rainbows i was stuck in traffic one day when a glorious double rainbow appeared over the highway it had been a drizzly day the whole sky was covered with clouds except for a little gap along the horizon and it was just about sunset as the sun slipped between the grey above and the ground below the chicago skyline was briefly golden with horizontal light and two concentric rainbow rings encircled i 290 like a kind of tunnel most of the rainbows i d ever seen were faint wisps this was an intense glow as bright as a flask of electrified mercury fortunately the cars weren t moving so i got a good long look rainbow like color separation happens a lot in physics classes and i thought i understood what caused the second rainbow i was wrong i was thinking about first order and second order rainbows from diffraction gratings if the rainbows in the sky were due to the same mechanism the second rainbow would have to be twice as big as the first it isn t and the colors would have to be in the same order they aren t i stared at that second rainbow until the car behind me started beeping were my eyes deceiving me did the colors really go in the opposite order when i got home i read all about rainbows and how they work it s fascinating the story of its discovery spans twenty centuries read more the crunchy star a voyage to the sun would not be a pleasant trip while still a million miles away the tungsten hull of our spacecraft would start to melt at half a million miles it evaporates a little farther and we d be nothing but swirling plasma mixing into a nuclear furnace so vast that oceans would be an understatement though we could never touch the sun there are stars that you can touch former stars anyway and one has recently been discovered link to paper it is only four thousand light years away 16 1 years traveler time see we can get there from here this star has been transformed by its neighbor into a husk of cold diamond since it s solid some astrophysicists are calling it a planet but it s not clear that the word applies to an object with such a bizarre history suppose that we take the 16 year trip to visit this world what would it look like could we really stand on the heart of a dead star read more we can get there from here have you heard about this opera says neutrinos travel faster than light i was in a conversation at fermilab yesterday when i first heard about it is that like one of those things where astrophysicists say that quasar jets travel faster than light but only because they re leaving out some projection effect i said no this is for real except i think so i can t really tell the article doesn t say very much i shrugged i have no nose for news it was only when my wife asked me about it that i knew it was a big story she usually hears too much physics from me so she doesn t actively seek it out by that point it was in all the newspapers the experimenters made their paper public and cern s director general sent out a general e mail if it s true that neutrinos travel faster than light it would be a huge upset some may take it to mean that relativity is overturned einstein rolls in his grave and there s no longer any limitation on the speed of future spaceships we can get to distant stars in weeks rather than decades however the implications run a lot deeper than that relativity is a fact of life as much as falling or heat and cold we may not experience relativity in everyday things but particle physicists encounter it daily it s not a small effect something that might be a mirage in fact in the conversation at fermilab i was learning about special techniques to measure particles that travel significantly slower than the speed of light those are the oddballs if this new observation about neutrinos is true then it would have to fit into the constant stream of other observations the new data would have to augment relativity they can t overturn it read more quirky science fiction i like old science fiction the stories from the first half of the twentieth century didn t always get the science right but they incorporated a lot of the latest ideas of their time for example when worlds collide a 1934 novel about the earth colliding with a roving exoplanet had this description of the rocket that would save a remnant of humanity each of these tubes generates the rays that split atoms of beryllium into their protons and nuclei the forces engendered in the process which is like a molecular explosion but vastly greater together with the disrupted matter is then discharged through this gun splitting atoms vast forces they re talking about nuclear energy ten years before the world knew about the atom bomb but more surprisingly the authors knew that beryllium might be a good atom to do it leó szilárd s secret patent two years later was based on the idea that beryllium or uranium might start a chain reaction beryllium didn t work but uranium did why did the authors balmer and wylie think that beryllium might be a good ingredient for a nuclear rocket at the time beryllium was used as a neutron source and neutrons were known to increase the radioactivity of normal matter but the neutron had only been discovered three years prior did they read scientific journals were these ideas in the air known to a literate public today s science fiction usually doesn t follow science this closely much of what i find in the modern stories is based on scientific ideas or discoveries that are at least fifty years old like wormholes antimatter and parallel universes if telepathy was ever considered scientific then it was in the hyper empirical environment of the 1920 s and 30 s yet mind readers are still ubiquitous in sci fi did the science in science fiction congeal half a century ago read more leprechauns and laser beams my fourth grade teacher was a child of irish immigrants and sometimes he told stories in class my favorite went like this leprechauns are bound by a law that obliges them to do whatever you say if you catch them one day a man caught a leprechaun and ordered him to reveal the location of his pot of gold the leprechaun was furious but he had no choice he led the man through the forest to an old tree and said there me treasure is under the roots of that tree and that was the truth the man needed an axe and a shovel to get at the gold so he tied a ribbon around the tree to mark it while he went back to town for some tools he commanded the leprechaun not to take down the ribbon or move his gold or anything like that the leprechaun still under obligation grumbled but agreed when the man returned with his tools the tree was still marked by its ribbon but so was every tree in the whole forest he never found that treasure the beauty of the leprechaun s trick is that a completely ribboned forest has exactly as much information as an unribboned forest a ribbon on every tree except one would convey as much as a ribbon on one tree this amount of information is called entropy and it is as much a physical quantity as length voltage and temperature in fact i think that entropy is a more fundamental concept than temperature knowing about entropy makes it easier to understand what temperature is read more a stitch in time i never really understood general relativity until i learned to sew just as i never really understood thermodynamics until i learned to cook as with cooking i was driven to sewing by necessity my jeans didn t fit the first modifications were small ones darts here and there to pull in material later i added elastic waistbands then suspenders eventually i got so fed up with the bad fit that i decided to make my own jeans from scratch i bought a few yards of fabric wrapped it around myself and started cutting mistakes weren t a problem i knew how to patch and i figured i would just keep cutting and patching until the thing fit around my body it took about a week for the carpet to slowly evolve into pantaloons i finished them just in time to wear them when my wife came home from a conference whereupon she exclaimed they re purple pants 1 0 have been described as part joker part catwoman and they lasted about a year spending all that time with fabric forced me to think a lot about topology and curvature i had to somehow reproduce my own curvature in cloth too much curvature and it would bulge too little and it would be tight the most difficult part is the crotch which bends upward in the front and back but downward toward the legs oh i realized that s what it means to be negatively curved zero and positive curvature are easy to understand from textbooks but negative curvature is always drawn as a twisted bit of graph paper mysteriously called a saddle point of course it s a saddle i said to myself what else are saddles meant to fit read more what is the sound of two electrons clapping paszenko the cat is a music critic i don t say that just because he looks for a better place to nap whenever i play my cello i wouldn t blame any creature for that it s because he seeks out good music he sits attentively ears forward whenever the music is harmonious and full of pentatonic intervals but he has no patience for anything as modern as a diminished fifth my cat made his tastes obvious one day when a tutor came to give me cello lessons the cellos came out of their boxes and paszenko casually left the room but when my teacher began to play he came back he got closer sniffed the strange cello and hopped into the teacher s lap while he was still playing and purred what colors a sound most is the path that it takes to get into our ears from cello string to bridge to chamber to cat s body sounds different than it would if it had bounced around the room before reaching paszenko s eardrums as the waves flow from one object to another they excite resonances whose frequencies depend on the shapes of those objects the fancy curves in a cello s body are not merely decorative remote as it may seem the creation and destruction of subatomic particles works the same way this is more than an analogy it is one of the ways nature repeats herself at vastly different scales read more to see the world in a cup of coffee and eternity in an hour this was the original about page but i have converted it into a full length article i used to hate coffee though i knew that it s an acquired taste i couldn t understand why anyone would want to acquire that taste it was like drinking ink my wife tried to introduce me to the joys of coffee the way she had been raised creamer first when she was young she sipped the little cups of creamer with one drop of coffee added to each then gradually increased the ratio i tried some coffee ice cream but it seemed like a waste of good vanilla my conversion however was inevitable i m a particle physicist and the two things that particle physicists do socially are drinking coffee and skiing many important physics conversations happen over coffee the way that tobacco presided over native american covenants one day at cern a swiss colleague offered me a cup while we worked out the details of some project and i said sure thank you to be polite he hesitated for a moment then asked do you take it with or without pollutants read more nukes booze the burning of uranium in an atomic furnace is so strange an affair that to get a picture of it at all we must overturn our familiar ideas about the behavior of fuel this is the beginning of a 1952 scientific american article on nuclear chemistry by john f flagg and edwin l zebrowski imagine a lump of coal in which only a tiny proportion of the lump one part in 140 is combustible the combustible atoms are scattered all through the lump as each burns it gives off sparks that ignite the others and the burning proceeds by a chain reaction but the ashes of the burned atoms deposited throughout the lump soon begin to absorb some of the sparks and smother the fire something about this metaphor seemed wrong to me when i read it perhaps i should call it an anti metaphor because the point is how uranium is unlike coal i later came across the following quote from ernst rutherford interviewed a year before nuclear chain reactions were first proposed he said anyone who expects a source of power from the transformation of these atoms is talking moonshine that s exactly it nuclear energy is just like moonshine read more talking to physicists at parties so what do you do me i m a physicist hey isn t that a coincidence i hated physics really wow i was so terrible at it in school and my teachers were simply awful but you must be a genius um actually oh hi nice to meet you a mathematician i was so bad at math that exact conversation is more common than you might think i m sure that lawyers get evil lawyer jokes and accountants get some variant of gee that s boring but physicists are told that their passion is dreadful in a way that s suppos...