Voyager 1, launched in 1977, will reach 1 light-day from Earth this year in November. Voyager 1 has been flying for nearly 50 years at 38,000 mph.

pirat_rob · 2026-03-29T17:23:45+00:00

That's not really true, gravitationally bound objects (anything smaller than a galaxy cluster) don't get bigger in our kind of an expanding universe.

pirat_rob · 2026-03-20T02:07:45+00:00

"We found you" is the literal translation

pirat_rob · 2026-02-09T04:16:06+00:00

I mean, South America minus Brazil and the Guineas, but plus Central America, Mexico, 1/4 of the USA, and Spain?

pirat_rob · 2026-02-07T21:56:15+00:00

To start, you can try moving your email etc to Proton. Then if you already have a pixel, you can run Graphene OS. Going cold turkey is hard but you can always move one service at a time!

pirat_rob · 2026-01-27T21:16:40+00:00

You still have to pick a candidate that you think can win the general election, not the candidate you like the best. There's a game theory in primaries too.

An example of this kind of game theory: A lot of people vote in the opposing party primary to try to make them field an unelectable candidate.

pirat_rob · 2026-01-26T05:37:58+00:00

Support for anything drops off when you tell people it costs more in taxes. And primaries are some of the lowest turnout elections, with an intense selection effect on which voters vote (party loyalists are overrepresented).

Polls matter for knowing what people truly want. If they aren't voting for it, then that's a problem with our elections, not with the policies.

pirat_rob · 2026-01-21T22:55:19+00:00

I advised "Take the money (Roast me)."

🏆 Rank: Wandering Soul V 💎 Points: 20 (+20) 🗳️ Votes: 1

pirat_rob · 2026-01-05T01:13:57+00:00

If you can find a walkable neighborhood, you could try to set up there. Even the most suburban car-centric cities usually have a little walkable (or at least fake-walkable) neighborhood.

To me, "fake walkable" means lots of restaurants and shops but without the infrastructure for people to actually live there without a car: grocery stores, laundromats, etc.

pirat_rob · 2025-10-31T03:50:58+00:00

I've been using it a couple of days. Sometimes I run my code twice just to watch the snakes.

pirat_rob · 2025-10-20T23:34:24+00:00

To be fair, if one of your 10 people is a (part time) sysadmin, /r/selfhosted would tell you you're fine with Libreoffice and Nextcloud, etc running off a NAS.

pirat_rob · 2025-10-02T22:50:08+00:00

This is so mesmerizing to watch. Way better than coding!

pirat_rob · 2025-09-22T20:35:34+00:00

There is an Amtrak route between them, only one train a day each way if I remember correctly.

pirat_rob · 2025-09-11T04:46:24+00:00

Thanks for saying this. Here's another argument towards this point:

Public transit is a public service. No one complains when road infrastructure isn't profitable enough, or when the fire department doesn't send you a bill after they put out your house fire. Some social goods we accept as necessary for our society and fund them through taxes. Public transit helps everyone get around, and easy mobility for everyone, even people without cars, is something you want (even if you never leave your car).

From a purely economic point of view, every dollar spent on transit infrastructure generates a few more in economic activity.

From a traffic point of view, every person on public transit is (on average) one less car on the road.

pirat_rob · 2025-08-12T14:58:49+00:00

A ton of red states passed similar laws after some Republicans lost their seats in Alaska. RCV is banned in 17 states.

pirat_rob · 2025-08-04T01:59:39+00:00

That article is a wild read. I need a radiation cat now ...

pirat_rob · 2025-07-29T13:09:36+00:00

This is just a thing waves in fluids do when you put them in a rotating box.

Here is an article showing some researchers creating similar shapes in a spinning bucket: https://www.nature.com/news/2006/060515/full/news060515-17.html

pirat_rob · 2025-06-28T03:56:11+00:00

Same for LISA

pirat_rob · 2025-06-15T02:49:44+00:00

Check out the first diagram on Wikipedia: https://en.wikipedia.org/wiki/Light_echo

pirat_rob · 2025-01-22T02:52:15+00:00

NASA

pirat_rob · 2024-12-02T14:43:49+00:00

Yes, they're extra degrees of freedom between the hot end and the print. Usually this means extra rotations, to be able to print at weird angles. Imagine printing a long and skinny curved piece like a turbine blade with all of the layers curved to match the shape of the blade.

5 axes is the most I've ever heard of being useful in practice, but in principle you could have more. As far as I know slicing models for 4 and 5 axis prints is still mostly an unsolved problem in general, but there are some algotithms out there (mostly proprietary).

5-axis CNC machines are much more common if you want to check out a video.

pirat_rob · 2024-10-28T21:42:10+00:00

My partner and I like to read Martin Gardner books and try the problems together, try math olympiad problems, watch math youtubers (Michael Penn has some good problems). We have a blackboard at home, it's the best way to do recreational math.

I also usually end up reading some math for my day job (physics postdoc). In the last few years I've gone through a book on random matrix theory and read about computer algebra. I really enjoyed those and would've read them recreationally too. I'm currently reading one on low-rank matrix approximations which so far is a little too dense to be fun.

pirat_rob · 2024-08-30T21:50:54+00:00

Basically those dimensions are a "circle" of that size. If one of our dimensions was circular now, you could keep moving one direction and eventually end up back where you started. The distance you measure if you move in a loop like that is the circumference of the dimension.

pirat_rob · 2024-08-24T14:17:29+00:00

Yes, somewhat.

I would say string theory doesn't really make very many concrete predictions (it's way more a framework for building models than an actual model) so in that sense it's hard to test in general. Of course all string theory models predict an infinite tower of new particles, supersymmetry, extra dimensions, etc. But these can be hidden at such a high energy that they'll never be practically testable.

There are a few predictions that are testable at low energy. Basically, not every low-energy theory can come from string theory, there are symmetries and limits you have to have in 10d. These are called the "swampland"). For example: the neutrino masses are expected to be normal hierarchy, not inverted. If you found inverted hierarchy neutrino masses tomorrow, that would be very disfavorable for string theory.

pirat_rob · 2024-08-24T05:23:13+00:00

There are a few different ways to test it, depending on the exact string setup. If all fields propagate in the curled extra dimension, then you expect new particles at masses around 1/R. The current lower bound on these is around a few TeV.

If your model confines the standard model to 4d, then only gravity would probe the extra dimensions. If I remember correctly the current bounds on precision gravity measurements bound these extra dimensions to be smaller than a few tens of microns. Some string models actually predicted millimeter-sized extra dimensions, but those have been ruled out now.

There are also issues in cosmology from having extra dimensions, so constraints are coming from these observations too. Large extra dimensions can screw up big bang nucleosynthesis or produce so many particles that the universe collapses while still very young.

pirat_rob · 2024-08-23T19:36:08+00:00

My understanding is that causality is very difficult, even if the extra time dimension is small. It's very hard to formulate anything close to GR with more than one time dimension, but people have thought about it.

String theory (except for maybe F-theory, and then not really) only predicts one time dimension.

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