The last guy on Putin’s naughty list to fly into Moscow got an AA missile up the tail. Put me down for that.

In practice, PGP signatures/keys usually work using the “trust on first use” model. The web-of-trust/physical verification of ID documents is a fun idea, but I’ve never met anyone who has used that method in the wild.

The difference between publishing hashes and signatures/keys vs. publishing hashes-only, is that you only need to trust the published keys the first time. They don’t change from year to year. If one year someone hacks ubuntu.com and changes the image files and hashes AND uploads fake keys with signatures, you will notice that the signatures fail to match your saved keys and suspect something fishy.

This will not save you if this is your first time visiting ubuntu.com that happens to be the same day that it has been hacked, but it will protect everyone who has ever visited before and saved the keys. But if the releases were published with hashes-only, every year would be a new hash and a hack would easier slip through.

You can also try to verify the Ubuntu key out-of-band in places other than ubuntu.com, such as in blog posts, old forum/twitter/reddit posts, etc. In principle, hashes could be published on 3rd-party blog posts too, but again they change every year so not as interesting and you won’t find them in as many random places as the pubkeys.

That’s how they got Kim Jong-nam (Kim Jong Un’s brother) in 2017. A syringe filled with nerve gas (in liquid form) sprayed in the face while he was walking through a Malaysian airport. 30 minutes later - dead. The airport staff were confused at first as to what even happened, and assassins were on a flight to Pyongyang before anyone even realized this was an attack.

Not the only time nerve gas sprays to the face have been used for assassination either. Russian agents have killed several people in England in 2018 in an assassination attempt using a spray bottle of nerve gas perfume.

physicists are quite confident only blackholes can Hawking radiate

Good to know! I was starting to get worried :D

you absolutely need a horizon to get radiation

Does the particle need to travel all the way from the horizon to reach you? How long does that take? The horizon still exists on the centrifuge, if only for a moment, shifting slightly from one instant to the next. In principle, at any moment you could detach from the centrifuge and fire 10g rocket thrusters in a straight line instead. In that first instant there is no way to tell the difference between the two.

I say this because in the linked paper, the “acceleration” experienced by the positrons was the bouncing off the atomic nuclei in the silicon crystal, which takes place over the space of a few angstroms, or at most within the 3.5mm size of the crystal, in the time given by the speed of 178GeV positrons (+Lorenz contraction). This instant was sufficient to claim Unruh effects were occurring.

Another complication is that even if the centrifuge slows down as it gets heavier, you can recover most of that mechanical energy when you hop off the centrifuge with your now full jar. Then you can boost it back up almost up to full speed. So I’m not sure exactly at what point you input energy into the system to instantiate the particles. When they hit the belljar bottom transversely maybe? Is this some kind of Maxwell’s Demon situation where you need to close the jar before the particles fall back out?

Also good to mention Earth! Logically, if Hawking radiation works for black holes it seems as if it would also work for any star or planet! But I’ve never seen this mentioned anywhere.

Oh for sure, science is never boring :D but compare the intense situation in the troll science pic to the displayable results from the actual experiment (fig. 1c):

Tip: evidence for the Unruh effect you are looking for is this 2mm difference right here:

The teal dashed line is the power spectrum predicted from theory including the Unruh effect, and violet dashed line is without it. The data points match the teal line better. But you can’t even see that by eye from the noisy dots! You need to do chi-square statistics to even prove it. (The dots below 30GeV - outside the “accelerated thermality” region - are not included in the analysis because they are guaranteed to be incorrect, as the experiment wasn’t sensitive in that range.) Boooring!

What the authors of the paper glance over in a single sentence before moving on to better things is that they had to shoot a FRICKING POSITRON DEATH BEAM FROM THE MFKING LHC through a crystal target and watch the resulting Bremsstrahlung gamma rays that would melt your bones off to obtain these datapoints. Talk about intense!

Like many other popular weird physics effects, it has been accepted non-controversially by scientists and then popularized for decades in fun thought experiments and pop-sci videos, all of which neglecting to mention that no actual experiments have yet been performed. This lack of grounding leads to spread of confusing statements like “the Unruh particles exist in the accelerated frame but not in the lab frame”, which make no sense, for how can there be two separate realities that coexist? Luckily we now do have a first Unruh experiment from 2019 https://arxiv.org/abs/1903.00043v7 and the temperature did rise and reality did not split apart. So no longer hypothetical, just routine and boring.

You know, I was beginning to second guess myself. Maybe the nimbys know something I don’t? After all, nimby rights matter too! I don’t live in Astoria or run a business, I only travel and shop there. Maybe their safety concerns have merit?

We had our group ride of support, and I have now personally seen the two-block section where the repainting work was already completed, before the court injunction took effect, (and where car parkers actually obey the new parking markings), and it is marvelous. The bike lane is comfortable and with great visibility of street and sidewalk, much better than the slalom course it was before. There are two parking spaces between each pair of columns that can fit two cars with ample room or an extra long delivery truck. With a couple extra physical improvements, like flying island bus stops and extra-wide sidewalk cutouts at intersections with ramps for curb-level bike path crossings, Astoria 31st Street redesign could become a reference model for all the other elevated track streets in the city. Having seen it, the design just makes sense and impossible to imagine going back the way it was.

As a person who spends inordinate amount of time thinking about street lane width allocation and reading DOT engineering proposals, I can now confidently say that the nimbys were complete shitheads all along, as they always are, all the time, and I should have never doubted myself. And if you had any doubts too - don’t.

It looks cool, I’d use it! When you start making fun of me I’d just shrug and carry on, because I don’t care what judgements some weirdo makes about my accessories.

The crazy thing to me is that as you look at galaxies further away, they become bigger in the sky. Obligatory xkcd: https://www.explainxkcd.com/wiki/index.php/2622:_Angular_Diameter_Turnaround There could be huge dragons out there occluding half the sky, but they’d be beyond the last scattering surface of the cosmic microwave background.

First thought was ISP intermittent packet loss, but

Ping is unaffected
no packet loss or jitter
Speedtests of any kind always return when problem is occurring / when problem is not occurring

Suggests otherwise. My second thought was DNS crashing, but

DNS seems irrelevant

You already got it covered.

Some websites like Facebook and Google work
VOIP does not seem to be affected

Really weird situation! Try using wireshark to listen on the interface and observe what’s happening. Are packets going out but none returning? Are they returning with errors? Retransmissions? Are some destinations fine but others get no reply?

Could you geographically locate the IPs that work vs. the IPs that don’t? My next suspicion is that there is some upstream backbone link that cuts out, so stuff with local CDNs like facebook continue to work, but a lemmy server on another continent is unreachable. Try traceroute.

it’s not geography aware, it’s network topology aware

Yes, I’m using “geographic awareness” here as shorthand for the same algorithm that BGP uses to calculate shortest route. As far as I know, BGP has no knowledge of “countries” or “continents”, it makes decisions purely on local policy and connectivity info available to it. However, the resulting topology map does greatly resemble the corresponding geographic map, a natural consequence of the internet being a physical engineering structure. I’m not sure how publicly available the global BGP data is. If you were designing a backbone-bandwidth-preserving P2P app you would either give it BGP data directly, or if that’s not available, give it the world map to get most of the same benefit.

topology that is often obscured by the ISPs for a variety of benign and malevolent reasons

The multicast proposal would need to be routed through the very same ISP-obscured topology, so there is no advantage over topology-aware P2P.

I’m not sure this math is mathing

As a graph problem, it does look to me within factor of 2 is practical.

First consider a hypothetical topology-aware “daisy chain” scheme, where every swarm user has upload ratio of exactly one. Then every backbone and last-mile connection gets used exactly twice. This is why I say factor of 2 is the upper limit. It’s like a maze problem where you can navigate an entire maze and only traverse each corridor twice. Then look at the more practical “pyramid” scheme where half the users have upload ratio of about 2. Some links get used twice but many get used only once! UK-UK1 link is the only one to be used 3 times. Notably observe that US-JP and US-UK transcontinental links only get used once, as you wanted! Overall this pyramid scheme looks to me to be within 20% efficiency of the optimal multicast scheme.

we’re still using “someone else’s computer” … at “we’re” using “our computer” and that’s the royal “we”. Multicast is all switch no server, all juice, no seed

What do you think backbone routers are? They are computers! Specialized for a particular task, but computers nonetheless. Owned by someone other than you. Your whole lament is that you can’t force those owners to implement multicast on their routers. I think using the royal “our” computer, something we can do right now without forcing anyone else, is much better by comparison. If you insist that P2P swarm members, they who actually want to see your livestream, are not good enough, that you only want to use “your” computer to broadcast and no one else’s, then you are left with no options other than bouncing HAM video signals off the ionosphere. And even the radio spectrum is claimed by governments.

MBGP table will be megabytes long and extremely dynamic

I think you underestimate the size. Imagine if multicast were ubiquitous, billions of internet-connected users each with dozens? hundreds? of multicast subscriptions. Each video content creator is a multicast, each blogpost you follow, each multi-twitter handle, each lemmy community you subscribe to. Hundreds easily. Thats many gigabytes, possibly hundreds of gigabytes, of state to fit into every router. BGP is simple because you care only about the physical links you actually have. You can stuff entire IP ranges into a single routing table entry. Your entire table could be a dozen entries. Fits inside the silicon. With multicast I don’t think you can fold it in, you must keep the entire many-to-many table on every single router^[1]. And consult the 100GB table to route every single packet, in case it needs to get split. As you said, impossible with 1990s technology, probably possible but contrary to business goals in 2020.

You are concerned about the battery life of your phone when you use the bandwidth of 2 video streams compared to watching just 1? Yet you expect every single router owner to plug in hundreds of gigabytes of extra RAM sticks and spend extra CPU power and electricity to look up routing tables to handle your multicast traffic for you. You are just offloading the resource usage onto other people’s computers! Not “our” computers - “theirs”. Remember how much criticism Bitcoin got for wasting resources? Not the proof of work, but the having to store a duplicate copy of 100GB’s of transactions blockchain on every single node? All that hard drive space wasted! When “Mastercard” and “Visa” can do it with only a single database on a mainframe. Yet now you want “them” to do the same and “waste” 100GB’s of RAM on every single router just so your battery life is a little better.

If everyone suddenly used the internet to this full potential, then we would get the screws turned on us. … Multicast would essentially fly under the radar.

This does not follow. Didn’t you say that multicast was already sabotaged by the very same cablo-distribution networks to maintain their send-monopoly? You expect to force the ISPs to turn multicast back on and somehow have it fly under the radar, but P2P would get the screws turned? It can’t be one and not the other! If you plan to have the governments force the ISPs to fall in line and implement multicast standards, then why couldn’t you have the same governments (driven by democratic pressure of billions of internet users demanding freedom, presumably) enshrine P2P rights? Again, remember that P2P is something we already have, something that already works and can be expanded with no additional cooperation from other players. Multicast is something that would need to be forced on others, on everyone, and require physical hardware updates. If there are future restrictions on P2P, they would be easier to defend against politically and technologically. If you cannot defend P2P, then you for sure do not have enough political power to force multicast.

[1]: Thinking about this, maybe you could roll it in a little. Given N internet users (~a billion), each with S subscriptions (say a hundred), C number of content feeds (a hundred million? 10% of users are also creators, 90% are pure consumers), and each router has P physical links (say ten), then instead of N*S amount of state (100GB’s), each router could fold it down into C*P amount of state (1GB’s). As in “If I receive a multicast packet from [source ip=US.5.6.7] to [destination ip=anyone], route copies of it out through phy04, phy07, and phy12”. You would still need a mechanism to propagate table changes pretty rapidly (full refresh about once every minute?). Your phone can be switching cells or powering on and off. You don’t want to multicast packets to a powered-off IP - that would be waste of resources!

And how do you detect oversubscribing? If a million watchers subcribe to 1 multicast livestream - it’s fine, but what happens when 1 troll subscribes to a million livestreams? If I subscribe to 1 million video streams, obviously my last-mile connection cannot fit them all. With TCP unicast, the senders would not receive TCP ACK replies from me and throttle down. But with multicast, the routers in between do not know about my last mile, or even if my phone is still powered on since later than a minute ago. All they know is “if receive multicast from IP1, send to phy04; if receive multicast from IP2, send to phy04;” etc. Would my upstream routers not get saturated trying to send a million video streams to a dead IP? Would we need to implement some sort of a reverse-multicast version of “TCP ACK”?

Ahh! Malicious compliance. Beautiful.

While I agree that P2P is the next best thing and torrents are pretty awesome, they are unicast and ultimately they waste far more resources, especially intercontinental bandwidth than multicast would.

Tell me if I understand the use case correctly here. I want to livestream to my 1000 viewers but don’t want to go through CDNs and gatekeepers like Twitch. I want to do it from my phone, as I am entitled to by the spirit of free internet and democratization of information, but I obviously do not have enough bandwidth for 1000 unicast video streams. If only I had ability to use multicast, I could send a single video stream with multicast up my cellular connection, and at each internet backbone router it would get duplicated and split as many times as necessary to reach all my 1000 subscribers. My 100 viewers in Japan are served by a single stream in the trans-Pacific backbone that gets split once it touches land, is that all correct?

In that case, torrent/peertube-like technology gets you almost all of the way there! As long as my upload ratio is greater than 1 (say I push the bandwidth equivalent of TWO video streams up my cellular), and each of my two initial viewers (using their own phones or tablets or whatever devices that can communicate with each other equally well across the global internet without any SERVERS, CDNS, or MIDDLEMEN in between, using IPv6 as God intended) pushes it to two more, and so on, then within 10 hops and 1 second of latency, all 1000 of my viewers can see my stream. Within 2 seconds, a million could see me in theory, with zero additional bandwidth required on my part, right? In terms of global bandwidth resource usage, we are already within a factor of two of the ideal case of working multicast!

It is true that my 100 peertube subscribers in Japan could be triggering my video stream to be sent through the intercontinental pipe multiple times (and even back again!), but this is only so because the peertube protocol is not yet geographic-aware! (Or maybe it already is?) Have you considered adding geographic awareness to peertube instead? Then only one viewer in Japan will receive my stream, and then pyramid-share it with all the other Japanese.

P2P, IPv6, and geographic awareness is something that you can pursue right now, and it gets you within better than a factor of 2 of the ideal multicast dream! Is factor of 2 an acceptable rate of waste of resource usage? And you can implement it all on your own, without requiring every single internet backbone provider and ISP to cooperate with you and upgrade their router hardware to support multicast. AND you get all the other features of peertube, like say being able to watch a video that is NOT a livestream. Or being able to read a comment that was posted when your device was powered off.

Also, I am intrigued by the great concern you give for intercontinental bandwidth usage, considering those pipes are owned by the same types of big for-profit companies as the walled-garden social networks and CDNs that are so distasteful. From the other end, the reason why geographic awareness has not already been implemented in bittorrent and most other P2P protocols is precisely because bandwidth has been so plentiful. I can easily go to any website in Japan, play video games with the Chinese, or upload Linux images to the Europeans, without worrying about all the peering arrangements in between. If you are Netflix you have to deal with it and pay for peerage and build out local CDN boxes, but as a P2P user I’ve never had to think about it. Maybe if 1-to-millions torrent-based server-less livestreaming from your phone were to become popular, the intercontinental pipe owners might start complaining, but for now the internet just works.

Agreed! That’s why I much prefer the “Is there any possible way you could be pregnant right now?” phrasing. Which is straight to the point of “we are about to operate on your abdominal section that could cause fetal loss if we are not aware of it, assuming you care about that sort of thing.” But if you are getting the period question, then it’s just a nurse checking off a box on an insurance checklist when you are there for an ear infection, and 100% of the time it is not relevant then.

Woops, sorry! I got immediately multiply downvoted 100%, I haven’t posted in this community before so not familiar with the culture, and even though I thought my response was relevant, it didn’t look like the community was interested in such an opinion, so I withdrew my post. I said something like that unless I am literally there do get tested for a suspected pregnancy, I would tell them it’s none of their business, or more politely, “given the current political climate, I do not answer questions like these”. Thanks for checking up on me!

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Yeah, I don’t think it’s possible for the concept to click until at least learning how to calculate Fourier transforms by hand. Before then all I could say when hearing about orthogonality was “Uh-huh, sure”, but you never really believe it. Only when you have calculated something like “what is the frequency of the delta function?” and seen the answer with your own eyes, not through someone’s interpretation, do you start believing it.

End of Eternity (1955) by Isaac Asimov (and its reimagining in Palimpsest (2009) by Charles Stross) involve a time-traveling secret organization that has its headquarters hidden away in time/outside of time. They don’t so much drain resources though as manipulate history to ensure a safe course.

The numbers in the meme are off. One sperm is 750MB, or about 1 CD, so full human is 2 CDs. Or a couple 1.4MB floppies if you only store the diff from the reference genome.