Over at Curious Wavefunction, Ashutosh Jogalekar offers a list of great surprising results in physics. This is fairly comprehensive, but leaves out one of my favorites, which is the discovery of the muon. Muons are particles like electrons, but a couple hundred times heavier. When they were first detected in cosmic ray traces in 1936, physicists briefly thought they were the mesons that Hideki Yukawa had predicted as the carriers of the strong nuclear force. It quickly became clear, though, that while the mass was about right to be Yukawa’s particle, the muon didn’t have anything to do with the strong force.
The existence of a heavy version of an electron was a complete surprise. The eminently quotable I.I. Rabi famously responded to the news by asking “Who ordered that?”
It’s interesting to look down Jogalekar’s list of “surprises,” though, and think a bit about what surprise really means in a physics context. Some of these are theoretical developments that people were led to by mathematical logic– like the Dirac equation, or asymptotic freedom– but other theoretical steps are desperate tricks– like Planck’s quantum hypothesis to get the black-body radiation formula, or Bohr’s quantum model of hydrogen, or Pauli’s proposal of the neutrino (which isn’t on the list). I would argue that the latter are more surprising than the former, in the conventional sense of the word. I would also disagree with Jogalekar about which of Einstein’s 1905 papers was genuinely “surprising”– special relativity is weird, but follows naturally from a rigorous consideration of the foundations of physics. Henri Poincaré and Hendrik Lorentz very nearly had special relativity before Einstein. Einstein’s photoelectric effect paper, on the other hand, was genuinely revolutionary, discarding classical ideas altogether, and that makes it the more surprising, to my mind.
It’s also interesting to look at surprises on the experimental side, where you have a similar split between discoveries that genuinely come out of nowhere– superconductivity, or the Marsden-Geiger experiment that discovered the atomic nucleus– and ones that were anticipated, just not by the people who actually made them. The latter category would include Penzias and Wilson discovering the cosmic microwave background: they didn’t set out after what they found, they were just trying to debug their big antenna. But just down the road in Princeton, Robert Dicke was setting up an experiment to deliberately seek exactly the background radiation that Penzias and Wilson found by accident (it had been predicted in the 40’s by Ralph Alpher). When they called him to ask if their weird static might be related to the cosmic background, Dicke took the call, and when he hung up, turned to his team and said “We’ve been scooped.”
There are also interesting cases of discoveries that were missed because they were too surprising, like the two Nobels the Joliot-Curies just missed. They might’ve discovered the neutron and the positron, but they weren’t prepared to think about massive neutral particles or positively charged electrons, and so ceded those discoveries to others. Others were almost missed, like the Davisson-Germer experiment, which was a puzzling curiosity until Davisson ran into Max Born, who recognized what was happening in their experiment.
(This sort of thing, of course, serves as evidence for the Kuhnian “paradigm shift” picture of science, or maybe a “steam engine time” kind of view, where discoveries can’t be made until the wider community is ready for them to be made. There’s something to that, but it’s often taken a good deal too far.)
I’ve never been part of any really world-changing surprises, but I did have one experience in grad school where a puzzling initial result turned out to be something really cool, when we started looking at time-resolved ionizing collisions. What I initially took to be a puzzling electrical problem turned out to be a rich source of data, and kicked off one of the best research experiences I ever had.
That kind of surprise, when something weird suddenly comes clear, and everything clicks into place, is the best feeling in science. Every odd result that comes out of an experiment or simulation creates a brief flash of hope that this is one of those surprises. The vast majority of these turn out to be boring results of loose cables or misplaced semicolons in computer code, but there’s always hope…
(I.I. Rabi photo at the top of this post from this page.)
from ScienceBlogs http://ift.tt/1zbAqJv
Over at Curious Wavefunction, Ashutosh Jogalekar offers a list of great surprising results in physics. This is fairly comprehensive, but leaves out one of my favorites, which is the discovery of the muon. Muons are particles like electrons, but a couple hundred times heavier. When they were first detected in cosmic ray traces in 1936, physicists briefly thought they were the mesons that Hideki Yukawa had predicted as the carriers of the strong nuclear force. It quickly became clear, though, that while the mass was about right to be Yukawa’s particle, the muon didn’t have anything to do with the strong force.
The existence of a heavy version of an electron was a complete surprise. The eminently quotable I.I. Rabi famously responded to the news by asking “Who ordered that?”
It’s interesting to look down Jogalekar’s list of “surprises,” though, and think a bit about what surprise really means in a physics context. Some of these are theoretical developments that people were led to by mathematical logic– like the Dirac equation, or asymptotic freedom– but other theoretical steps are desperate tricks– like Planck’s quantum hypothesis to get the black-body radiation formula, or Bohr’s quantum model of hydrogen, or Pauli’s proposal of the neutrino (which isn’t on the list). I would argue that the latter are more surprising than the former, in the conventional sense of the word. I would also disagree with Jogalekar about which of Einstein’s 1905 papers was genuinely “surprising”– special relativity is weird, but follows naturally from a rigorous consideration of the foundations of physics. Henri Poincaré and Hendrik Lorentz very nearly had special relativity before Einstein. Einstein’s photoelectric effect paper, on the other hand, was genuinely revolutionary, discarding classical ideas altogether, and that makes it the more surprising, to my mind.
It’s also interesting to look at surprises on the experimental side, where you have a similar split between discoveries that genuinely come out of nowhere– superconductivity, or the Marsden-Geiger experiment that discovered the atomic nucleus– and ones that were anticipated, just not by the people who actually made them. The latter category would include Penzias and Wilson discovering the cosmic microwave background: they didn’t set out after what they found, they were just trying to debug their big antenna. But just down the road in Princeton, Robert Dicke was setting up an experiment to deliberately seek exactly the background radiation that Penzias and Wilson found by accident (it had been predicted in the 40’s by Ralph Alpher). When they called him to ask if their weird static might be related to the cosmic background, Dicke took the call, and when he hung up, turned to his team and said “We’ve been scooped.”
There are also interesting cases of discoveries that were missed because they were too surprising, like the two Nobels the Joliot-Curies just missed. They might’ve discovered the neutron and the positron, but they weren’t prepared to think about massive neutral particles or positively charged electrons, and so ceded those discoveries to others. Others were almost missed, like the Davisson-Germer experiment, which was a puzzling curiosity until Davisson ran into Max Born, who recognized what was happening in their experiment.
(This sort of thing, of course, serves as evidence for the Kuhnian “paradigm shift” picture of science, or maybe a “steam engine time” kind of view, where discoveries can’t be made until the wider community is ready for them to be made. There’s something to that, but it’s often taken a good deal too far.)
I’ve never been part of any really world-changing surprises, but I did have one experience in grad school where a puzzling initial result turned out to be something really cool, when we started looking at time-resolved ionizing collisions. What I initially took to be a puzzling electrical problem turned out to be a rich source of data, and kicked off one of the best research experiences I ever had.
That kind of surprise, when something weird suddenly comes clear, and everything clicks into place, is the best feeling in science. Every odd result that comes out of an experiment or simulation creates a brief flash of hope that this is one of those surprises. The vast majority of these turn out to be boring results of loose cables or misplaced semicolons in computer code, but there’s always hope…
(I.I. Rabi photo at the top of this post from this page.)
from ScienceBlogs http://ift.tt/1zbAqJv
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