My experience has been mostly positive. When I reported a crash in gfortran it was fixed in the next version. The same happened when I reported a code generation error for the closed source competitor Ifort. When I reported a memory leak in the WCS library in Astropy, the bug was fixed within a few hours. When I requested support for a new site in youtube-dl that was added the same evening. But I've had less luck with projects like Firefox, though I don't remember exactly what the issue was there.

The thing that worries me the most about advertising is its psychological effects. The goal of advertising is to change your behavior so that you buy more products. And it is really quite effective, or 140 billion dollars wouldn't be spent on the digital part of it each year (for comparison, the entire Apollo program cost about 100 billion dollars in today's dollars).

But the main way they affect your behavior is not by giving you the information you need to make an informed decision. It is by using standard propaganda tecniques to as much as possible bypass your rational decision making process. They associate positive feelings with the product, and indicate that you will be popular and cool if you buy it, and lame if you don't. It is not uncommon to see advertising which is so uninformative that it is almost impossible to guess what product is being advertised until the logo appears, but because informing about the product is quite secondary, these ads are still very effective.

Most people think they aren't influenced by advertising (perhaps other people, but not oneself) because we tend to think that our decisions are rational, or at least that we are aware of what processes drive them. But psychological studies have shown that we basically have two decision-making modes: The fast and easy mode and the slow and tiring mode. The latter is quite rational but requires concentration and tires people out. So we usually use the other mode, which is very suceptible to manipulation.

I'm affected by advertising even when I think I'm ignoring it, and so are you. That's why using ad-blocking is a bit like wearing a condom - it protects you from both "mind viruses" and computer viruses (advertising networks are a major vector for malware) that the page you're interacting with might be spreading.

I agree.

And while it is true that one can opt out from the so-called "acceptable ads" (an oxymoron in my opinion, like "acceptable propaganda", "acceptable brainwashing"), I do not trust somebody who would take money from advertisers to maintain an advertisement-blocking extension. That's why I switched to Adblock Edge, a fork of Adblock Plus that hasn't sold out. Currently the only difference is that the "acceptable ads" "feature" is taken out, but I expect them to gradually diverge as Adblock Plus prostitutes itself further for the advertising industry.

Correct. Or to be more general, time passes more slowly deep down in a gravitational well

Yes. Every time a clock on earth ticks 1 time a (stationary) clock near a black hole will tick 1-R/r times. For example, a clock at a distance r=10/9*R will only tick 0.1 times every time a clock on earch ticks 1 time. The same applies to all other physical processes, not just clocks. So a person on Earch could wave their arms 10 times every time a person that close to the blck hole could wave them once. Or a person on earch could think 10 thoughts in the time a person close tot he black hole could think 1.

No. If time goes slowly for somebody they don't percieve themselves to be going slowly, they see everything else going very quickly. From the reference frame of an infalling object, their clocks are ticking at normal speed (by definition - a local clock measures how fast physical processes happen locally). But the far-away world seems to be sped up.

Time passes normally to everybody in their own frame of reference.

No. In our frame of reference, all physical processes near the black hole, be that clocks, falling people or light, are moving in slow motion. In the absene of red shifts and other optical phenomena, we would observe the object to inch closer and closer to the horizon ever more slowly until it's hardly moving. A photon next to them would similarly move extremely slowly (the speed of light as measured locally is constant, but not in other parts of spacetime).

I guess what you thought was something along the lines of "people in areas where time moves quickly will see everything move quickly, and people in areas where time moves slowly will see everything move slowly". To see why that doesn't make any sense, imagine if I had a slow-ray and shot it at you. It would slow you down, but not me. But because I'm not slowed down doesn't mean that I will see you moving at normal speed. Your time passes more slowly than mine, so I will see you move more slowly than me. And since your mind is also affected by the speed of time, you won't perceive yourself to be moving any slower than normal. But to you the rest of the world would look like a movie in fast-forward mode.

I hope this helps.

That's intereting. I didn't know that the EHT worked at SPT-relevant frequencies. I work on data analyis for the Atacama Cosmology Telescope, a very similar telescope to SPT, and a neighbor of ALMA. So I've seen the ALMA telescopes up close several times.

Isn't the weather often bad at the ALMA site in that period? In ACT we've used that period for maintenance.

That's a lot of hard drives! Is that the aggregate data rate for all the telescopes, or just for SPT?

That's a fascinating article, but you won't find many astrophysicists who would bet on it being correct (this probably includes the authors). Traversable wormholes are unstable without large amounts of negative mass, and we have no reason to believe that such exotic matter even exists. And if one is willing to assume that these wormholes have been there since the beginning of the universe in order to explain the presence of compact massive bodies in the center of every galaxy, then you might as well assume that black holes have been there since the beginning of the universe - that requires much less speculative new physics while solving the same problems. And those problems aren't that convincing in the first place - properly including baryons in cosmological simulations may well turn out to produce the right amount of large black holes when we get good enough computers to run them.

This is a typical case of somebody doing a fun "what if" or "devil's advocate" calculation, and the media turning it into something much more definite than it is.

When will observations start? How long will they last? When can we expect to see results on arXiv? How well will the fourier plane be covered (will you still need telescopes in the middle of nowhere to join/be built)? What will the spatial and temporal resolution be? Are there any important astrophysical foregrounds that could mess things up (blurring by plasma sheaths is something I think I've heard mentioned)? How are they handled? Did you know from the beginning that ALMA would join? Can you expect any other big boosts? How wide a frequency range do you have? How large an area in the neighborhood of the black holes you target will you be able to see? Could you expect to discover any nearby stellar black holes or neutron stars (I think one would expect a population of these in the general area)?

What about this story makes you think Hawking radiation doesn't exist? We can't be completely sure it exists because we don't have any observations of it, but there are compelling theoretical reasons to believe it should exist. But for non-tiny black holes, it is extremely faint, so faint that we have no hope of observing it. For example, the supermassive black hole in the center of the milky way would be expected to radiate 3.6e-48 W. That's 1 with 50 zeros behind it times weaker than a light bulb!

It would be nice if science reported were color coded or something. Green for robust, independently verified and generally accepted stuff (general relativity, evolution, etc.), yellow for new stuff that's not yet independently verified but in line with well-tested models, and red for stuff that's exciting but very uncertain and/or likely to be wrong (faster-than-light neutrinos, string theory, dark matter annihilation observations in galaxies, etc). The sort of stuff you read about in the news is usually red or yellow, but is presented as if it were green. The article you quote falls squarely into the red category.

In general your model is broken because you're not considering the metric. The most important effect you are neglecting in this case is the time-time component of the metric, which indicates how quickly stationary local clocks tick compared to coordinate time (there is also the radius-radius component which tells you that the event horizon is much further away than you would naively think, but we'll ignore that here). It looks like this for the metric outside a nonrotating, uncharged, massive body: 1-R/r, where R is the Schwartzchild radius of that source, and r is a radial coordinate. At large distances this factor approaches 1, so coordinate time moves at the same speed as the time of a far-away observer, such as us here on earth. But as r approaches R, the factor goes to 0. So time close to the horizon moves ever more slowly as one gets closer to it, according to our far-away reference frame. That is why crossing the horizon takes an infinite amount of (our) time.

However, the frequency and intensity of light is multiplied by the same factor, and very quickly becomes almost zero. So you would not see the object hanging there forever. You would see it quickly fade to blackness, leaving an incredibly faint and ever fainter afterimage in far radio wavelengths.

The surface will get very close to the apparent horizon very quickly though, and after that it will be so redshifted that it looks just like one of the idealized black hole solutions, and will be indistinguishable from one to any observer. It will be just as black, just as compact and just attractive, and still deserves to be called a black hole. When people say "black hole" they don't necessarily mean "Schwartzchild black hole" or "Kerr black hole".

Even at its best, before it closed google.cn and started redirecting people to google.com.hk, Google only had half the number of users as Baidu in China. It never had the dominance we're used to in the USA and most of Europe, and it's not certain that it would have come to dominate in China anyway, considering the stable dominance of other search engines in other large countries. Your statement made it sound like Baidu only caught on once google was out of the picture.

I've thought a bit about this too, but I arrived at the opposite conclusion. I think the single most valuable thing one gets from being a programmer is debugging experience, which is actually quite similar to the scientific method: You start with a mental model of how your program works. You observe symptoms that indicate that that model is wrong - the program isn't behaving according to the model. You form a new model based on the observed behavior, and then modify the program to test the new model. And repeat until you have a model that correctly predicts the future behavior or the program.

I can't think of many better ways to teach yourself that your mental model of the world can be wrong and the importance of testing it. Lacking that insight seems to be one of the defining characteristics of crackpots. That's why I think it's surprising to hear all the anecdotes here of crackpot programmers. Based on the reasoning above I would have expected them to be among the more madness-resistant segments of the population.

I think they might do something like this: You run a program on your server. That program establishes an encrypted connection to the Let's Encrypt server (using normal SSL). The Let's Encrypt server sends a secret message over the encrypted channel. The program on your server sets up a web page with that secret on it and sends the URL back to over the encrypted connection. The Let's Encrypt server then accesses the given URL normally, and checks whether it contains the correct secret. If so, it issues a certificate for the host name contained in that URL, since you have proved that you were in control of that server.

This is immune to man-in-the-middle attacks on your side, but it would still be vulnerable to somebody who can intercept all of the traffic to the Let's Encrypt server. But perhaps they're doing something cleverer than what I describe here. (If you had multiple Let's Encrypt servers spread across the internet, then you could have multiple ones participate in the handshake. That would mean that somebody would have to intercept the traffic of all those servers in order to fool them.)

The size of the images also doesn't mesh with the size described in the article text. The figurines in the images are actually quite large, and should be clearly visible even with much less than 400x magnification. For example, the head of a small ant might be 0.5 mm wide. That would make the figurine about 0.1 mm long. With 400x magnification it would be like looking at an object 4 cm long, which would be quite visible. Yet the text claims these were only visible with electron microscopes.

But of course, none of that is as strong evidence as the parent's damning link to a the pre-photoshopped picture of the needle head, with all the little dust motes and imperfections in exactly the same location, but missing the figurine.