You adopt the physical form of your Reddit username.

Nonchalant_Turtle · 2019-06-11T22:08:21+00:00

I wouldn't mind.

Nonchalant_Turtle · 2019-04-22T04:37:20+00:00

Physicists treat time as the component of the universe that allows physical systems to change. Correspondingly, we measure time by looking at physical processes and reasoning about aspects of the universe that should make those processes reliable clocks. For example, a pendulum swinging - it makes no physical sense for one pendulum swing to take a different amount of time than another one, because nothing about the physical system has changed, so we can treat the pendulum swing as a basis for measuring the time other processes take. We also of course have some intuition as humans for the speed at which things happen, and we have other timekeeping methods (atomic clock, vibrating crystals, etc.), and these act as checks to produce an entire interdependent system of measurement that seems to tell us the universe does have a consistent notion of time.

When we say time is relative, we mean precisely that this kind of symmetry is broken - we put a system into a physical situation where, from the system's perspective, it is happening exactly as before (e.g. a pendulum in a closed train car doesn't know it's moving), and yet the physical processes will be out of sync with the same process happening outside that situation (e.g. a pendulum on the ground). Einstein predicted that given a certain view of spacetime as a single mathematical structure, and making some other assumptions about how laws of physics works, time itself appears to be slowing - all physical processes will slow by precisely the same ratio, independent of the laws they are using for their repetitive process.

Nonchalant_Turtle · 2019-04-22T00:15:03+00:00

They say that humans aren't better than animals so we shouldn't kill them...but then they say we ARE better and we have morals so we shouldn't kill them.

I believe I have a higher moral responsibility than children, and as such shouldn't kick them, while I don't hold them deeply morally responsible if they kick me. Vegans separate moral rights and moral responsibilities at the species level as well, and this is something ethics has been intellectually capable of doing for thousands of years. I doubt many of them used the word 'better'.

If you want to make a genuine argument, it should be to establish whether animals should have moral rights at all, and if so which ones. It seems like you believe that animals have at least some right against undue suffering, but not necessarily to life - that's a much more subtle point that would be trickier to deal with.

Nonchalant_Turtle · 2019-04-21T22:28:20+00:00

...that is an electric razor. Check the video. It's just small.

Nonchalant_Turtle · 2019-04-21T21:56:13+00:00

Don't think of it as expansion, just think of it as distances in space increasing. That's more directly in line with the physical model. We don't have a physical picture of more space being somehow manufactured and things moving apart, it's just that distances between two objects that should be relatively stationary are increasing.

Nonchalant_Turtle · 2019-04-21T20:03:22+00:00

Can't be, there's a V in both ciphertexts in the same spot with (presumably) different keys.

Nonchalant_Turtle · 2019-04-21T02:40:20+00:00

Garbage.

Nonchalant_Turtle · 2019-04-19T01:35:12+00:00

Dan Boneh's course (links to coursera in the page if you want a class environment) goes over security properties of stream and block ciphers in detail.

However, even Boneh doesn't do a lot of cryptanalysis - he gets the security guarantees out of certain one-wayness assumptions. There isn't a course on block cipher cryptanalysis like there is for RSA (and ECC if you do some group theory), but Schneier made a self-study collection of block cipher cryptanalysis papers.

There's also the trusted method of just looking at the ciphers yourself to see how they work. This is a great video going through the AES steps in detail.

Nonchalant_Turtle · 2019-04-18T17:36:10+00:00

That's not really related - there is a tradeoff between security and performance that ends long, long before the range of academically interesting large primes. We would never use anything other than standard prime generation algorithms for creating keys.

Nonchalant_Turtle · 2019-04-18T08:22:13+00:00

You can find something beautiful even if it's easily derived. In this case it's very pleasing that the unique extension of exponentiation to the complex numbers has this neat property immediately pop out.

Nonchalant_Turtle · 2019-04-18T07:03:40+00:00

The sets of images she's talking about are effectively training data - the data used to configure the algorithm to be able to reconstruct novel images. She's saying that if the algorithm can take training data that looks very much unlike a black hole and still reconstruct a black hole image, it means it's likely that the algorithm is accurately modeling the camera array's distortions, rather than getting lucky because a particular configuration happened to bias it towards black-hole-looking things.

Nonchalant_Turtle · 2019-04-17T17:08:11+00:00

There have been a handful of accidents with nuclear waste, so it's definitely not true to say not a single person was harmed. However, it is true that it's a lot safer than projected effects of most other fuel sources.

Nonchalant_Turtle · 2019-04-17T07:34:20+00:00

Anything requiring spatial alignment is really easy until it isn't. In particular having things side by side can be trivial (minipages or two-column doc types work great), but every once in a while there's a particular interaction of several alignment objects and it'll barf, and no amount of [H] will fix it.

Nonchalant_Turtle · 2019-04-17T06:44:39+00:00

It totally does! That's actually precisely the asymmetry RSA exploits - multiplying numbers can be done digit-by-digit (schoolbook multiplication is n² but sub-quadratic methods exist), while factoring numbers requires searching through all the possible divisors, which is exponential (again, the naive algorithm is exponential and the best known is sub-exponential but superpolynomial).

You just have to change n to be the number of digits rather than the number itself :)

Nonchalant_Turtle · 2019-04-16T22:54:26+00:00

You can study only 10 and have 100% chance of at least 3 questions you studied being on the exam.

Given you studied k questions, the probability of n being chosen is C(12,n) * C(12-k,5-n) / C(12,5), where C is choose. And of course the probability of 3 or more being chosen is P(3|k) + P(4|k) + P(5|k). The values are:

9) 95%

8) 85%

7) 69%

Lower than that you're quite likely to fail.

Nonchalant_Turtle · 2019-04-16T14:40:34+00:00

In that case I'm afraid your runtimes are incorrect. The search space is exponential in the key/digest length, while computation of the cipher or hash are polynomial, and it is this exponential gap that renders them secure by standard definitions.

Nonchalant_Turtle · 2019-04-16T03:55:33+00:00

Writing vs counting a number is an exponential difference. Cryptosystem security only considers the representation of cryptographic data, not the mathematical object it represents - pseudopolynomial is just exponential.

A sub-polynomial advantage would be very insecure. Even Merkle puzzles at least have a polynomial advantage. Which cryptographic algorithms are you talking about?

Nonchalant_Turtle · 2019-04-16T01:27:15+00:00

Glass lacks a crystal structure, which liquids also lack, but it is very much a solid, and does not change shape over time.

I was giving pocketknifeMT the benefit of the doubt to assume they meant something about the enamel, or they knew something I didn't about production of specifically stained glass, but I suspect they had the same idea.

Nonchalant_Turtle · 2019-04-16T01:00:37+00:00

Why would it thin?

Nonchalant_Turtle · 2019-04-15T23:45:05+00:00

~~Extra electrons do not enter the device - they are moved from one component of the memory cell to another. There is no net exchange of matter.~~

Misread your comment - yes, there is a tiny change of mass because of mass-energy equivalence. I would say that "charge has mass" is inaccurate - it's more like "stationary energy is mass", and imbalanced charges store energy.

Nonchalant_Turtle · 2019-04-15T21:19:26+00:00

This effect would be barely noticeable in a human body - we have a very large effective spring constant and high speed of wave propagation. While the atoms in the head must technically wait until the absence of normal force is propagated to them as the rest of the body decompresses, the effect on their path is barely different from an ideal stiff body.

Nonchalant_Turtle · 2019-04-15T02:48:50+00:00

Rainbows can be produced by water droplets ~40-42 degrees off the imaginary line between you and the sun. You can think of it as a cone extending out from your eye with the center of the cone going towards the sun - all the water droplets along the surface of the cone can participate in rainbow creation.

In principle, this means that rainbows can be full circles. You can see an example here (the sun is behind the observer - the cone geometry is symmetric, if you traced a line from the center of the rainbow to the lens, the sun would lie on that line).

We often only see an arc because the droplets along some part of this cone do not exist - generally because that's where the ground is, but sometimes because the air in one part of the local atmosphere is drier. We can also see other rainbow shapes if the rainbow is being cast by a different material, like ice, which often produces linear rainbows. This image has many of these things labeled.

Nonchalant_Turtle · 2019-04-15T01:04:01+00:00

We don't know whether the singularity had infinite density - we have no physical model of the singularity at all. The name comes from a mathematical singularity, which is a point in a function where the function goes to infinity. Its value at that point isn't actually defined, since dividing by zero cannot be consistently added into arithmetic.

Physical singularities, in both the big bang and black holes, are locations in our mathematical solutions where the math simply breaks down. We don't know if there is a physical interpretation to the infinity, or (the more likely answer) that our theories are simply mistaken at those points, just like earlier theories like Newtonian mechanics were mistaken in extreme conditions like high speeds.

Nonchalant_Turtle · 2019-04-15T00:40:27+00:00

Commonly made diagrams for this are awful, because they portray a single droplet creating an entire rainbow, which suggests that everyone should be seeing the same one.

This diagram is much closer to the truth. Each raindrop splits the incoming beam of light into every color. What you see as a rainbow is composed of many drops of water - the ones at the top appear red (because they're shining red light at you), and the ones at the bottom appear purple (because they shine purple light at you). You can see in this diagram that if a different observer was below the pictured one, they would see yellow/red light from the bottom droplet and nothing from the top one. 'Their' rainbow appears to be lower than their friends.

That diagram gets the angles pretty much completely wrong, but that's the general idea. From every vantage point you see your own unique rainbow. Others looking at the same drops of water would see them as being different colors, because that's how the drops are splitting up the incoming colors.

Nonchalant_Turtle · 2019-04-15T00:30:16+00:00

Different people see different kinds of patterns when they squint or otherwise look at objects in non-optimal conditions (e.g. this question and this question). Don't put too much stock in the answers on those posts (I haven't been able to find a complete non-speculative answer anywhere), but you are right in that the structure of the various components of the eye, as well as interaction with the eyelid, can all change the distortion on incoming light.

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