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Cake day: June 9th, 2023

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  • macarthur_park@lemmy.worldtoScience Memes@mander.xyzCat
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    6 months ago

    Actually we haven’t observed a difference between the speed of neutrinos and light, which sets an upper limit on their mass based on the precision of those measurements. The evidence of mass is much weirder, in the observation of neutrino flavor oscillation.

    Neutrinos come in 3 flavors: electron, tau, and muon. We’ve observed that the flavor oscillates as a function of time, or equivalently as a function of distance from the neutrino source. The data is quite precise, and is perfectly explained by there being 3 neutrino mass states that are distinct from the flavor state. So a neutrino with a well defined flavor will have a superposition of the 3 mass states, with each flavor corresponding to a different admixture of mass states.

    The flavor oscillations allow us to measure the difference in the mass values, but not the absolute masses. Technically it’s possible that the “lightest” neutrino is massless, and the other 2 mass states are nonzero. Without an absolute value for the masses we can’t rule this out.






  • I’m gonna echo what others have said here. The mastodon signup process is too complex, and searching for instructions just leads to “what is the fediverse and/or activitypub” explainers.

    I created a mastodon account a few years ago and it was my first introduction to the fediverse. It was frustrating and I only persevered because I REALLY wanted to replace twitter.

    Once I got it set up, I realized that no one who I followed on twitter was there. My feed is currently like 2 people, plus a bunch of dead accounts from people who dipped their toe in but didn’t stay.

    Joining Bluesky was simple, and there were already a bunch of accounts I wanted to follow. The recent influx has increased that, and it feels a lot like old school twitter without the nazis.

    People originally joined twitter (and stuck with it for so long) because that’s where everyone else is. Mastadon is too clunky join and use, so people aren’t.




  • macarthur_park@lemmy.worldtoScience Memes@mander.xyzJazz hands
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    10 months ago

    Fun fact: fiestaware plates (this was the company that made the uraranium glazed ceramics) are commonly used by radiation safety folks as check sources and for teaching how to use survey meters. This is because they usually aren’t considered a radioisotope source, so there’s less paperwork to keep them around.