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Joined 4 months ago
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Cake day: October 19th, 2024

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  • Tbh I think flag hate or angst is about as useful/less as flag worship. If you need something to be preoccupied with, why not make it a problem you can put that energy into doing something about where you live - like homeless people or food aid.

    I might be reacting this way because I’ve been getting recent emails from my college about changing the school mascot, which is a “pioneer”. When I was there I don’t remember even being aware that there was a mascot. But apparently they think “pioneer” might be too closely associated with colonialism and they’ve decided this is an important issue. My attitude is create a Native American scholarship (or anything that actually does something) - don’t obsess on imagery.


  • LovableSidekick@lemmy.worldtoAsklemmy@lemmy.mlWhy would'nt this work?
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    14 hours ago

    There’s a thought experiment about this in most intro classes on relativity, talking about “length compression”. To a stationary observer a fast-moving object appears shorter in its direction of travel. For example, at about 87% of the speed of light, length compression is about 50%. If you are interested in the formula look up Relativistic Length Compression. Anyway, if you are carrying a pole 20 meters long and you run past someone at that speed, to them the pole will only look 10 meters long.

    In the thought experiment you run with this pole into a barn that’s only 10 meters long. What happens?

    The observer, seeing you bringing a 10-meter pole into a 10-meter barn, shuts the door behind you, closing it exactly at the point where you’re entirely in the barn. What happens when you stop, and how does a 20-meter pole fit in a 10-meter barn in the first place?

    First, when the pole gets in the barn and the door closes, the pole is no longer moving, so now to the observer it looks 20 meters long. As its speed drops to zero the pole appears to get longer, becoming 20 meters again. It either punches holes in the barn and sticks out, or it shatters if the barn is stronger.

    Looking at the situation from the runner’s point of view, since motion is relative you could say you’re stationary and the barn is moving toward you at 87% of the speed of light. So to you the 10-meter barn only looks 5 meters long. So how does a 20-meter pole fit in?

    The answer to both questions is compression - or saying it another way, information doesn’t travel instantly. When the front end of the pole hits the inside of the barn and stops, it takes some time for that information to travel through the pole to the other end. Meanwhile, the rest of the pole keeps moving. By the time the back end knows it’s supposed to stop, from the runner’s point of view the 20-ft pole has been compressed down to 5 meters. From the runner’s point of view the barn then stops moving, so it’s length returns to 10 meters, but since the pole still won’t fit it either punches holes in the barn or shatters.

    One of my physics profs had double-majored in theatre, and loved to perform this demo with a telescoping pole and a cardboard barn.
















  • Addendum: one that stands out was an in-house survey app that allowed you to create questionnaires and email them to people in the company. Responses were saved in a database and you could make complicated statistical inquiries like, show me how people answered questions 7 and 8 who said Yes to question 12, No to 13, and filled in the “Other” blank for 19.

    My job was to speed up the SQL queries, which were so complex and slow the max runtime had to be increased to like an hour to let them finish. This was because the original database of questions and multiple-choice answers had been modified in several stages, which ended up with response details in multiple fields in multiple tables depending on the type of question. After about a month I managed to streamline the queries so the longest one took less than 10 minutes, but this was still enormously slow because questionnaires had maybe 2000 responses max. The problem was the database structure relationships was too complex because things had been scabbed onto it.

    One day at lunch I spent about 20 minutes noodling a redesign with fewer tables. All user responses would be in one place, and the longest queries probably would have run in a second or two, plus maintenance and enhancements would be WAY easier. When I proposed actually doing this, management said they would think about it if they ever did a new version.

    At least I tried.



  • We would need enough advance notice to prepare for massively farming mushrooms or something underground to eat. Canned food will run out in a few years, even military MREs have a shelf life. A few lucky people might survive a generation, but there’s a minimal breeding stock requirement to avoid degeneration from inbreeding. Extremely long odds, I think the human race would only survive this event in a sci-fi fantasy story.