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Dark Matter, Ozone, Proton Therapy, and Web3
🕑 Added 2023-09-13 16:01:00 +0000 UTCPhysicists Look for Dark Matter with Atomic Clocks (And Don’t Find It)
Theoretical physicists from the University of Sussex and the U.K.’s National Physical Laboratory have proposed a method of using atomic clocks to look for certain types of dark matter particles (ultralight particles that include axions). According to the idea, if we pass through clouds of dark matter particles, the frequencies of atomic clocks might subtly shift. The proposal itself is not new, but in the new paper, the authors have put forward a more sophisticated analysis for atomic clock data that allows them to look for a broader class of particles. Their data analysis didn’t reveal the presence of any dark matter particles. Press release here, paper here.
New Chinese Satellite Delivers Ozone Data With Unprecedented Accuracy
Scientists at the University of Science and Technology of China used a spectrometer onboard the Gaofen-5 satellite to measure the ozone layer, and they have been able to resolve it in remarkable detail. Using a combination of ultraviolet measurements and clever algorithms, they could infer the vertical distribution of ozone and could even see recent stratospheric intrusion events, which happen when air from the stratosphere pushes down where it normally doesn’t belong.
Ozone (O3) in the stratosphere protects life on Earth by absorbing harmful ultraviolet UV-B radiation. As climate change affects global wind patterns, ozone might redistribute, so we need to keep an eye on that. It won’t help us solve any problems, but at least we will know how badly we’ve messed up. Press release here, paper here.
Proton Beam Therapy Works Well to Treat Breast Cancer
Proton beam treatment apparatus. Image: Llorenzi/Wikimedia Commons
Scientists at the Mayo Clinic Comprehensive Cancer Center have recently completed a randomised trial comparing a condensed 15-day course of proton beam therapy for breast cancer with a traditional 25- to 30-day course of the same treatment. They found that both conventional and condensed proton therapy regimens resulted in excellent control of the cancer, but the condensed course of therapy was associated with lower risk of skin side effects.
Proton beams deposit energy into tissue in very narrowly-focused regions, and can therefore be applied very precisely, reducing unwanted damage to the surrounding tissue. This type of therapy is currently very rare because it requires a proton accelerator, which is a big and quite expensive machine. Press release here, full paper here.
Comments
'The Mouth of Hell' would be a great name for one of those big, expensive physics experiments that are buried in a mine somewhere I reckon.
Colleen Thompson: Indeed. On the other hand, at least this is pretty cheap compared with all the other ways of attempting to find Dark Matter. But maybe something like this could be said of all searches for it: "Rabbit holes to the right of them, Rabbit holes to the left of them/ .../ Into the Mouth of Hell/ Rode the Dark Matter Seekers." (With apologies to Lord Tennyson for taking this liberty with his poem "The Charge of the Light Brigade .")
Searching for Dark Matter with clocks sounds like something Lewis Carroll could've written about.
Still on the topic of Dark Matter and how to find it: According to repeated comments that have intrigued me considerably, made by Albert Giese now here and earlier on in another thread in Sabine's Channel, the gravitational effects attributed to Dark Matter can be explained by a new, modified theory of gravitation that, if I have understood this correctly, assumes that the Weak Equivalence Principle that is at the core of General Relativity needs to be replaced by a different concept. In other words, that Einstein's Theory of General Relativity is incorrect in one of its basic assumptions. Well that is possible and, if true, eventually it would be most welcome, as it would open the way to a new and better understanding of how the Universe works and also it may even solve the Dark Matter mystery without any invisible matter needed. But where is the beef? As it happens, a recent mission known as MICROSCOPE seems to have provided it, but the news are good for General Relativity and not so good for the idea that General Relativity needs a do-over. (Something that, in general terms, I would like to see as the answer to the Dark Matter mystery: It's time to move on, Albert! But ...) The French MICROSCOPE space mission to test the weak equivalence principle of General Relativity has found agreement between inertial and gravitational mass at the level of 10^15, or one part in 10 followed by 14 zeroes. https://ioppublishing.org/news/most-precise-test-of-general-relativitys-weak-equivalence-principle-published/ "The team found that the accelerations of pairs of objects differed by no more than about one part in 10^15 ruling out any violations of the Weak Equivalence Principle or deviations from the current understanding of general relativity at that level." There are plans to improve the equipment for a follow-on mission intended to test the principe at the 10^17 level. https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.129.121102
For detection, probably requires a dark matter clock...
About the use of atomic clocks to try to detect signs of dark matter: the general idea, as I just stated it is, indeed as Sabine has said, by no means new: An old friend of mine, a Brit, some 15 years ago, if memory serves, at his UK university, with his group there and other interested parties, tried to use the atomic clocks in the GPS satellites to detect a different type of Dark Mater made, not of particles, but of "space-time topological anomalies" (something akin to cosmic strings). As one of these passed by, crossing the different satellites in their orbits, over the fraction of a second that it would take to go from one to the next, such an anomaly would make their atomic clocks either go faster or slower, not sure of which and it does not matter, because the effect would be observable with ground-stationed GPS receivers, with the occurrences precisely timed with their own clocks, so the speed and direction of these anomalies could be found. There were some correlations calculated and sundry other details, but this was the idea in a nutshell. He presented this idea at that year's annual International Conference on GPS of the Institute of Navigation (ION) that I also attended. When we were saying goodby to each other at the end of the conference, because he was going back to the UK while I was staying to spend the weekend sightseeing before going home, he asked me what I thought of his talk. My answer: "At first I thought "this is going to be embarrassing!", but then, as you explained the idea, I corrected that to "maybe this just could work ... if those anomalies were real."" He laughed, we parted friends, and we still are. Clearly, they did not find any topological anomalies in space-time, because none was reported, and they were not the kind to hide their bushel under the bed. So people continued, and still are, trying to find any indication, however slight, of one kind or another of the stuff Dark Matter is supposed to be made of, but so far without reported success.
I get it... Web3 is nowhere.
The search for particles of the dark matter in the experimental environment here will deliver the same result as all previous experiments, namely NOTHING. The phenomenon of the dark matter is caused by a wrong understanding of the gravity: gravity is not dependent on mass (=inertia).
