One of the biggest unsolved mysteries of nature is the mystery of matter/antimatter asymmetry. Scientists believe that when two very high-energy photons collide, they produce equal amounts of matter and antimatter, and that when matter collides with antimatter, it is converted into high-energy photons. Such beliefs are based on what scientists have observed in particle accelerators such as the Large Hadron Collider, where particles are accelerated to near the speed of light before they collide with each other. But such conclusions about matter, antimatter and photons leads to a great mystery as to why there is any matter at all in the universe.
Let us imagine the first minute of the Big Bang about 13 billion years ago, when the density of the universe was incredibly great. At that time the universe should have consisted of a tightly packed density of energy, matter and antimatter. The energy should have been in the form of very high energy photons that were frequently colliding with each other. All such collisions should have produced equal amounts of matter and antimatter. So the amount of antimatter should have been exactly the same as the amount of matter. As a CERN page on this topic says, "The Big Bang should have created equal amounts of matter and antimatter in the early universe." But whenever a matter particle touched an antimatter particle, both would have been converted into photons. The eventual result should have been a universe consisting either of nothing but photons, or some matter but an equal amount of antimatter. But instead we have a universe with lots of matter and only trace amounts of antimatter.
It would be incredibly inconvenient if matter and antimatter were equally distributed. So much energy is released when matter makes contact with antimatter that if there were large amounts of antimatter lying about, you'd have “oops, someone blew up Europe because he stepped on a tiny piece of antimatter” situations all over the place.
Scientists have made no progress in resolving this mystery of why we live in a universe in which matter is 1,000,000,000,000,000 times more common than antimatter. But you'd never know this from reading recent press accounts. Such accounts have discussed futile dead-ends pursued by scientists looking for answers about why we don't live in a universe that is all photons or half antimatter. But such dead-ends have been hailed as explanatory progress.
An example is the recent misleading headline in Scientific American, a headline of "Physicists Come Closer to Answering Question of Antimatter’s Scarcity." No real progress was made in resolving the issue. The physicists merely found that an antihydrogen atom (a hydrogen atom consisting of antimatter) behaves the same way as a hydrogen atom, which is what was expected. We read this:
"Doing so allowed them to observe that in antihydrogen—which is composed of an antiproton and a positron, the electron’s antiparticle—jumps in energy levels known as the Lamb shift were identical to those seen in hydrogen. This symmetry rules out one of the possible answers to the matter-antimatter discrepancy."
There is nothing else of substance reported in the article. No real progress was made in resolving the question of why we live in a universe that isn't all photons or half antimatter, neither of which would be habitable. You do not make progress in resolving some problem with limitless potential answers when you merely rule out one answer. If I spend a weekend pondering whether the meaning of life is crucially related to potato chips, and finally decide after 48 hours of deliberation that the meaning of life is not related to potato chips, I have ruled out one possible answer; but this does not mean I have actually made progress in figuring out the meaning of life. And, similarly, if you spend six months trying to create a high-voltage time machine, and finally conclude after six months that high voltage is not useful in making time machines, you are not entitled to claim that you have made any progress in making a time machine.
A similar example of misleading spin is an article on the Science Daily web site. The title of the article is "Why is there any matter in the universe at all? New study sheds light." Below this headline we have a subtitle of "Scientists one step closer to understanding the mystery of matter in the universe." Below is a quote:
"After more than two decades of work by researchers at the University of Sussex and elsewhere, a final result has emerged from an experiment designed to address one of the most profound problems in cosmology for the last fifty years: namely, the question of why the Universe contains so much more matter than antimatter, and, indeed, why it now contains any matter at all. Why didn’t the antimatter cancel out all the matter? Why is there any matter left? ...The answer relates to a structural asymmetry that should appear in fundamental particles like neutrons. This is what we’ve been looking for. We’ve found that the 'electric dipole moment' is smaller than previously believed. This helps us to rule out theories about why there is matter left over – because the theories governing the two things are linked."
Of course, you have not made any actual progress in resolving some question with a near-infinite number of possible solutions when you merely exclude one or a few of those possible solutions. So scientists have not actually "shed light" on the mystery of matter's existence, or moved "a step closer" to solving such a mystery. Science Daily's unwarranted spin on this topic was repeated by other science web sites such as this one. What's going on is that the science news web sites are all just uncritically parroting the spin from a university press release. So the groundless claim of that press release ("Scientists one step closer to understanding the mystery of matter in the Universe" ) was mindlessly parroted all over the science news media. This kind of thing goes on almost every day. University press releases very often make claims about research that are not warranted. A scientific study found that 33% of university press releases contain "exaggerated causal claims."
No comments:
Post a Comment