joigus

Just one tiny pet peeve of mine. Love & Bananas a tad over the top on the sentimental side. But that's just me.

Thanks for the tips. Love & Bananas is very moving and awareness-raising--I'll watch the other ones ASAP--. Very recently I had a sour argument on animals and compassion on social networks much less informed on average than this one. My point was that compassion does belong in the animal world, especially for humans, cetaceans, and elephants, all of which have special neurons devoted to feelings of justice and compassion apparently --Von Economo neurons--. This is in no detriment to the fact that wild life is cruel most times, even between elephants, particularly male African elephants, that sometimes fight to the death. I also had very rough treatment in the past from people who defend bullfighting in Spain and southern France. You wouldn't believe how contorted and ridiculous some of the arguments from people who defend the human right to exploit animals sometimes become. A documentary in a similar vein than the ones you've pointed to is this:

Because ancient Romans didn't quite know where the hell they were? LOL

In mathematics I know of two ways in which you can define something that merits the name and notion of space. One is that based on a metric. A metric allows you to define a distance, and from there a notion of open sets. This is called a metric space, which is the one @ahmet is talking about. Also in mathematics, you have the notion of a topological space. You give structure to this entity without even having a concept of distance, but only the notion of inclusion, intersection, etc. upon which you define the notion of base of open sets. I remember this definition, but I must confess I have no use for it, or know how to handle it efficiently. As to physics, I don't have a complete answer for you, but I think it is worth noting that some physicists today are wondering whether space is an emergent property, or epi-phenomenon; that quantum fields perhaps (the stuff), are the really basic concept, and space & time are some kind of derived property. That quantum fields somehow "generate" extension, would be a way to put it. I think Einstein had a very similar notion, and that he thought that space-time is derived from relationships between matter and radiation, which are the actual be-all, end-all of all that we perceive. But maybe I misunderstood. I think it's entirely possible that conscience produces some constriction that doesn't allow us to perceive the ultimate nature of space-time and their contents as they are, and we are cursed by our very own nature of physical systems that project the world around them in the way of a 3+1-dimensional map, but the real business of what's going on is hidden safely beyond what we perceive and, perhaps (I hope not), what we can perceive, as J. B. S. Haldane put it:

And I won't swallow it. It's a non-starter, rather than a tough pill to swallow. Exactly as @Ghideon says, that would imply that empty space has special places and special directions, and all the edifice of physics would be knocked down. Either that, or the Lagrangian formalism goes out the window; and the Lagrangian formalism works for all of physics: Classical mechanics, classical field theory, quantum mechanics, quantum field theory. I'd rather give up quantum mechanics or general relativity than conservation of momentum. And it's passed all experimental tests.

I'm glad @John Cuthber and @swansont took this thread in the right direction after my faltering start. Very interesting link from @studiot too. I agree it's all in the symmetry. You would have to have, e.g., non-spherical fluctuations in charge, to have any radiation at all.

There is a correspondence, but it's nothing very deep, I must warn you. GR is very ambiguous as to what is energy in the sense that there are different energy "components" and all can even be arranged to add up to zero. You can call the Einstein field tensor "geometric energy-momentum tensor" if you wish... Because the Schwarzschild radius depends on what kind of energy you consider as contained within your volume, you can add up all the terms (matter, radiation, dark matter, and vacuum energy) and your recalculated radius would coincide with the radius of the observable universe. Any horizon is characterised by the receding velocity being v=c, so it's more a dimensional question than anything else. Now, physicists do distinguish vacuum energy from all the rest because conceptually it's very different, thereby the mismatch. I hope that was helpful/clear. Maybe later I have more time to elaborate further. Dark energy is everywhere, and is constant. The value of the density is very low, but it fills even the largest intergalactic voids, so it contributes a lot in terms of cosmic parameters, very significantly affecting the receding velocity when you reach the cosmic horizon. In fact, it is thought to be the dominant effect at this point in the history of the universe.

Also, I don't see how you could have a sphere of charge change its radius while keeping it uniformly charged. Uniformly in space while the charge density changes with time? Any "realistic" model I can think of would produce radiation, as compressing the charge to a smaller volume would produce repulsion, and thereby, acceleration.

It's dark energy that pushes everything away, not dark matter. Dark matter does the opposite. Google for "dark matter caused the formation of galaxies". Dark matter is thought to be essential for structure formation in the very early universe.

I think you're probably right about this. Factoring in all that could be significant might be even impossible. Let's not forget that fiat money is no more than 3 % of the total amount of money in circulation. Of course, doing a 10-million-dollar transaction from A to B by sending datagrams over a network is much less energy-costly in terms of CO2 than having the same amount of money move in cash. But still, it only adds to all the factors that you've mentioned.

Here's a Bill Maher video, totally unrigourous, humourous, on the problem. I don't think it's a particularly impressive analysis of the problem, but it highlights some of the central questions. The main points being: A) CCs are based on nothing of "real" value B) CCs exert a huge demand on energy resources I think the second point is more or less right, but the 1st one, IMO, is not. I think Warren Buffett --and Maher with him-- misses the point of what the real problem with crypto-currencies probably is. It's not that crypto-currencies have no "real" value behind them (whatever that means). I don't know what "real value" is supposed to mean: Whether the actual cost of making it, which is next to nothing; its face value, which depends on socio-economical convention; or perhaps its purchasing power, which depends on how much money is circulating, as well as on the whole amount of goods and services available. I'll try to explain what I mean: Seigniorage (difference between face value and production cost of a monetary unit) of 1-dollar bill is 95 cents, if we're talking about paper money, which is practically the whole dollar. If "real" value is seigniorage, then it's arbitrary; if it's cost, it's just 5 cents; if it's purchasing value, it's highly volatile. It is ridiculous to think that money holds an objective value based on something real, in the same sense that machines, raw materials, qualified professionals, or energy sources are real. For digital money the cost is even less, I suspect, as it implies practically no extra cost writing 1'000'000'000 (a billion) instead of writing 1. In fact, crypto-currencies have a far safer system of controlling how much money is in circulation (a priori, at least) than the present monetary system has, resulting in a practically watertight framework to avoid inflation by dishonestly flooding the market with currency at any point in the network. And they also have an intrinsic value at least comparable to digital debt money (money just issued by writing numbers on a computer whenever banks "lend" money). I think the real problem with CCs is: 1) It creates yet another "bag" for inflation, encouraging people to massively invest in assets that may or may not fulfil their expectations of future returns. 2) It does so at the expense of a huge demand of power due to computational needs. 3) It does not comply with the criteria for sound money: Reasonable degree of; 3a) Scarcity; 3b) Standardization (accepted by many) If you create arbitrarily many types of money, you lose point 3b); and point 3a) becomes moot. What was intended to be safe money becomes investment in stamps. IMO, it's not worth the carbon footprint that it costs at the scale and with the rules of the game under which it's running, and it is at least in that sense that we all pay the price. I'm sorry that half my arguments are economic --thereby off-topic strictly speaking--, but that aspect is very much linked to the roots of the problem, and needs attention.

I think this is an interesting question. Energy is scarce (or world population puts enormous pressure on any level of energy availability at current time). Introduction of technologies that enormously increase demand of energy create inflation by way of increasing price of scarce resource. Inflationary movements can be seen as resulting in all people in need of energy (everybody) ending up paying a much higher bill for same amount of real resource. Inflation hides this effect of paying more by distributing load on whole populations, rather than reflecting its effects on an individual-by-individual way.

I think I've seen one of those somewhere.

Just to add to the mountain of very sound objections. I'm curious: How do you explain muon decay as a property of chains of protons? What about mesons? What would Tesla have to say about that?

Doesn't look like a very functional clock, does it? But still, when in Rome do as the Romans do.

To think how many dogs have had to put up with this shit... Last joke for today...

Nice account, by a top man in the field.

Good point. I think before the universe was vacuum-dominated, the calculation with just energy density of matter and radiation works quite well, and you can actually do the calculation by Newton's gravitation, the result giving coincidence between Schwarzschild's radius and radius of observable universe. I suppose you could do the trick of including an additional term to the total content of the energy by adding vacuum energy, then you would have to recalculate Schwarzschild's radius and everything would check again.

I think this belongs in the Brain Teasers section.

Erm... EM waves have no De Broglie wavelength. Their EM wavelength would not make much more than a few meters? There goes your teleportation. Tunneling is not teleportation. It's about things getting past classically forbidden energy barriers. And it has attenuation: the probability amplitude at the other side is much weaker than in the classically allowed region.

Black holes do not exist. This must be a peanut:

Where there's a will, there's a way. And even where there isn't exactly a will, there may still be a way.

Quantum tunneling is not free from attenuation. Look at this Wikipedia animation, for example: Also, quantum tunneling happens just next to the barrier, not far away. It's a completely different effect. https://en.wikipedia.org/wiki/Quantum_tunnelling

I was referring to the usual, i.e., speaking over the phone. Correlations at a distance are not magical, or anything new. But these correlations have to travel from Alice to Bob. Quantum correlations in entangled states are of a different nature. First of all, and most important, the word that Alice sets in her system is random. It's not like she can decide to send the word "ALERT" to Bob. That would be a code in binary 0100101101... etc. that she chooses. But she can't do that. All she can do is pick a spin projection --that much she can choose-- and see what word her system produces, which sometimes will be 0101001101..., other times 1101001000..., etc. Then she knows that, provided Bob has his magnets oriented in the same direction, he will measure 1010110010..., 0010110111..., etc. (the "complementary" words). She gains knowledge about Bob's state automatically. But the salient state is random. And were Bob to measure a different projection of spin, their respective states would be as uncorrelated as if they had never been in contact. This is a bit like a system that scrambles random words, so that the other user has the key to unscramble the message --the key being the particular projection they're going to measure--, but the words being completely random sequences --non-messages. What the uses of this technology would be, I don't know. But it's not completely obvious to me how they would take advantage of this technology.