MrBingley

Off the top of my head I don't really remember, though Brian Greene does devote a whole chapter to the question of detecting other universes in his book, so that might be a good place to look further. At the moment though, this doesn't really bother me. For example, Giordano Bruno suggested the existence of exoplanets in 1584, and certainly he could not have predicted the modern techniques the Kepler telescope uses to detect them! It may be centuries before we have the theory or technology to determine if other universes are detectable or if they exist. A long time to wait perhaps, but this should not be a reason for ruling them out (though of course, solid evidence would be required before a multiverse theory could be accepted).

I think one crucial difference is that this actually has scientific precedence. For example, the Earth lies in an incredible number of "Goldilocks zones", which have just the right conditions for life to develop. For example, the Earth lies at just the right distance from the Sun for water to be in liquid form. To close and it would all evaporate, too far and it would all freeze. Why is this? Early astronomers (Kepler, I think) spent many years trying to discover some physical reason for why the Earth should be at this particular distance. From what physical principles could the distance be deduced? As we know now, this search was in vain, because there was no fundamental reason. Turns out, it was just a coincidence! With the discoveries of the (appropriately) named Kepler telescope, we have discovered thousands of exoplanets in thousands of star systems. With the billions upon billions of stars in the universe, there are likely trillions of planets out there. With odds like that, it is almost certain that a planet with our properties would show up somewhere, which it did. As it turns out, astronomers do invoke an "infinity" of unseen planets to explain the unusual features of this one, and I doubt Paul Davies thinks that's a leap of faith!

Sure. For example, string theory posits the existence of an extra 6 dimensions of space, which need to be wrapped up in something called a Calabi-Yau manifold. The exact properties of this manifold determine some of the basic properties of the universe, such as the values of the fundamental constants and the number of elementary particles. The only problem: there are about 10^500 possible Calabi-Yau manifolds, each of which looks just as valid as another. Early string theorists had hoped all the extra manifolds would somehow be ruled out, leaving only one that would uniquely determine the properties of our universe. However, this avenue is now looking pretty hopeless; it seems we're stuck with all 10^500 possibilities. So, what does one do with all these manifolds?

Well, it turns out that the early universe went through a phase of incredible, extraordinary expansion called inflation. The inflation was boosted by something called an inflaton field, and due to quantum properties the inflaton field could spontaneously destabilize and spawn a bubble universe, each of which with a different Calabi-Yau manifold. It's possible that we are inside such a bubble universe, and outside of us the inflaton field is continuing to expand and producing more bubble universes. If this is the case, then it's not much of a surprise why our universe has the properties it does. Out of the 10^500 possibilities, a bubble universe spawned with the right Calabi-Yau manifold for life, and (unsurprisingly) we find ourselves living in that universe. This is the landscape multiverse theory. (I originally read about this theory in Brian Greene's excellent book The Hidden Reality, which describes many other multiverse theories too.)

Now, something important to note is that all this is still highly conjectural. String theory has many pleasing theoretical properties, but about zero physical evidence to support it. What then is the difference between string theory and deism? The difference is that for string theory (and more generally other multiverse theories) we actually have physical and mathematical theories that describe them. Deism doesn't. For string theory, we have papers, conferences, books, equations, and physicists and mathematicians who study this problem. We have something to work with. What do we have for deism? Well, pretty much nothing. No data, no theories, no anything. Deism is a fall-back theory when nothing else works out, and it has no theoretical roots and makes no predictions. This may change in the future, but as of now, deism is a scientific dead end. Of course, I don't know if string theory or another multiverse theory will pan out (indeed, the failure of the LHC to detect supersymmetry is raising some eyebrows), or even if deism actually turns out to be correct. However, on a scientific basis, string theory has more going for it now.

One difference is that the multiverse emerges as a natural extension of many existing physical theories (string theory, inflation, many-worlds, etc). The deist perspective is a more ad-hoc solution: it doesn't have any evidence that supports it directly, just that we currently don't know the answer to this problem.

I hope they fixed the awful coil whine. I had one so bad it was practically unusable.

Here's another question: should 0 be considered prime? The zero ideal is a prime ideal, but 0 is certainly a different sort of number than the rest of the primes.

I'm taking a class in coding theory right now, and I've been surprised by how naturally it can be described using abstract algebra. There are also many deep relationships to important results in group theory. For example, the automorphism group of the binary Golay code (which was used during the Voyager missions to transmit pictures back to earth) is the Mathieu group M24, one of the sporadic groups from the classification of finite simple groups!

https://en.wikipedia.org/wiki/Binary_Golay_code

> Later, the OG PoWHcoin smart contract — that immutable, incredible construction made out of memes and duct tape — was drained completely of its $2 million total, leaving Ponzibot with the loss of over $2.5 million on his hands.

> How?

> Because the developers of the OG contract had failed to use the safe math functions included in Solidity, the language of Ethereum’s smart contracts, this allowed an unknown hacker to make an unsigned integer underflow withdrawal — giving themselves an infinite number of PoWH’s tokens to withdraw, and draining the contract.

It is absurd that one needs to opt-in to unsigned integer underflow checking, especially in a language designed for writing financial contracts.

Another problem with the C code, which is perhaps even more subtle, is the usage of `int` for the length, capacity, and loop index. On 64-bit platforms these variables will overflow for very large arrays, which will likely break the entire implementation. The call to `malloc()` should give a signed-to-unsigned conversion warning which will hint about this, but unfortunately many people ignore integer warnings. Incidentally, this could also be caught by compiling with `-ftrapv` or `-fsanitize=undefined`, but this problem is only triggered in a rather extreme corner case that is unlikely to be exposed during testing. The correct integer type to use is `size_t`, which is guaranteed to be large enough to hold the size of any object in memory.

Does this mean good things for RISC-V?

> Send the Barbarian in First

As the barbarian in my group, I can confirm. :)

I agree. This tradition of writing short overly-clever code in C needs to die off. Screens can display more than 80x24 characters these days; we should use them.

I was referring more to its use (abuse?) of the word "isomorphic", which already has a well-established meaning in mathematics.

Web dev, the beast that consumes all. Nothing is sacred.

> Tom Tromey and I have replaced the most performance-sensitive portions of the source-map JavaScript Library’s source map parser with Rust code that is compiled to WebAssembly. The WebAssembly is up to 5.89 times faster than the JavaScript implementation on realistic benchmarks operating on real world source maps.

Wow. Some people have been wondering if Rust has a "killer app", but this could be it. Right now WebAssembly only supports non-GC languages (so C, C++, and Rust), and of those three Rust is the easiest to get started with. It looks really appealing.

> Solidity reads a bit like Javascript. It has a lot of quirks and pitfalls, though, especially when it comes to moving money around.

But isn't that, like, the whole point of the language? It was literally written for moving money around. Cripes.

> Be very careful if writing real money-transfer code; do your security homework, get others to review your code, and seriously consider an official security audit or even formal verification.

Amen.

Lol, the terminal is for plebs. REAL programmers read it straight from the framebuffer.

Hmmm, I don't think converting a 500k codebase in C to C++ has a meaningful cost/benefit ratio, especially for security critical code like this. It might be justified to do in something like Rust, but at that point I think it's better to move on from GPG entirely. The OpenPGP standard itself is showing its age (eg. no perfect forward secrecy) and is extremely complicated. I think GPG should be left as-is, and the community gradually move to something simpler, like OpenBSD's signify[0].

[0] https://www.openbsd.org/papers/bsdcan-signify.html

Can someone explain to me how on earth Ethereum is still a thing? People have lost hundreds of millions of dollars in the Ethereum ecosystem, many due to basic flaws in the "Solidity" language. For example, last November $280 million was frozen in Parity wallets because function visibility defaults to external rather than internal (see the previous HN discussion here[0]). Just for fun, I was looking through the Security Considerations[1] in the Ethereum docs, and here are two so-called "minor details":

- In `for (var i = 0; i < arrayName.length; i++) { ... }`, the type of `i` will be `uint8`, because this is the smallest type that is required to hold the value `0`. If the array has more than 255 elements, the loop will not terminate.

- The `constant` keyword for functions is currently not enforced by the compiler. Furthermore, it is not enforced by the EVM, so a contract function that "claims" to be constant might still cause changes to the state.

WTF?! Trivial loops won't terminate to due (unchecked) integer overflow, and the `constant` keyword does nothing? It's a complete gong show. I'm not touching anything to do with this language with a 100 foot pool. Is the hype bubble just that big?

[0] https://news.ycombinator.com/item?id=14807779

[1] https://solidity.readthedocs.io/en/develop/security-consider...

Edit: Oops, it looks like I'm mixing up my multi-million dollar screw-ups. First in July $30 million was stolen due to the "public is default" debacle, and then the fix for that problem introduced another bug (the developers forget to call the `initWallet` function), which lead to the $280 million being frozen in November[2]. Holy crap.

[2] https://news.ycombinator.com/item?id=15642856

I think you misunderstand the nature of parenting pal.

Should be the name of a movie.

"How will the world's hackers react when their source code goes offline? GitHub Down, watch it now!"

You might want to flash a custom rom. LineageOS is quite popular these days.

Hehe, you'd be suprised. I took an honors linear algebra course in my first year of university, and abstraction was the word of the day. Everything we did was for abstract vector spaces over arbitrary fields. We didn't look at the determinant as the signed volume of an n-cube, for example, but rather as a homomorphism from the group of matrices to the base field under multiplication. The cross product was never mentioned because it didn't generalize to arbitrary dimensions. It was good preparation for further abstract algebra courses, but not so much for others, like differential geometry, which rely heavily on geometric intuition.

Yup. It was only about a year ago that the undefined behaviour sanitizer stopped segfaulting when I turned it on, despite it being clearly "documented" in the man page. I'm amazed that a company with the resources of Apple has such shoddy developer tools.

Never forget people, Apple's emphasis on privacy is only a means to an end, that end being "making money". If Apple needs to relax privacy to help its bottom line, it will, as this example so incisively demonstrates.

Yeah, this laptop was supposed to replace my old MacBook Air. I had that thing for five years, and not once had a problem with it, even after dropping it and damaging the shell. I wanted to get a linux-compatible laptop and switch to it full time, but I'm having serious second thoughts. The build quality of Macs is top-notch, and to use the old cliche, it "just works". Honestly. They're ridiculously expensive, but hey, you get what you pay for.

Coincidentally, I just got my new XPS 13 today. Took it out of the box, booted it up, and was greeted by ... coil whine. Friggin coil whine. I knew this had plagued previous models of the XPS 13, but I figured Dell would have gotten their act together by now. Nope. It sounds like a bowl of Rice Krispies. A high pitched squealing sound comes out of the laptop anytime you launch a program or do anything that even remotely uses the processor. I tried booting into a USB to reinstall windows to see if that would help, and it got worse. The whole laptop would start to buzz whenever I touched the trackpad, and I starting hearing the most wonderful chirps and squeaks coming from underneath keyboard. Wonderful. I paid $1600 for what I thought was a premium laptop. Based on the OP's experience with Dell tech support, I don't even want to mess with trying to have it fixed. Nope, this piece of crap is getting returned, and I'm getting a Thinkpad.

Ah, but you forget, then we can't browbeat the JavaScript-kiddies with our own seasoned superiority. (adjusts monocle)

What about the Panama Papers?

Do you, by chance, use Arch Linux?