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Comment: Re:Who will get (Score 5, Interesting) 359

by Roger W Moore (#48655009) Attached to: North Korean Internet Is Down

The U.S. by the look of things. I think it'd be a bit heavy-handed to call it a proportional response though as Sony is a lot smaller than a country.

Physically perhaps but in terms of internet presence I would doubt it. As a non-American I'd think this was an entirely appropriate response if it were the US. It has the beauty of being non-violent, extremely humiliating and very effective at preventing them from engaging in further cyberattacks. This should send such a clear message that hopefully even their insane government can understand it. Indeed if anything it seems so well thought out and proportionate that it seems unlikely to be the US government given their previous record.

Comment: Re:Stone Age diet ? he wants to live all 20 years? (Score 1) 430

by Roger W Moore (#48654833) Attached to: How Venture Capitalist Peter Thiel Plans To Live 120 Years

30 years was about right for the paleolithic. Neolithic though, our best guess is around 20.

Really? Since the neolithic was later than the paleolithic what did people do that dropped the life expectancy so much? I realize that the number is heavily skewed by a large infant mortality rate and that those surviving to adulthood lived a lot longer than the average but still to drop 10 years while technology was improving seems very strange - how robust is the data supporting this huge drop?

Comment: Re:Wildly premature question (Score 1) 81

by Bruce Perens (#48620117) Attached to: SpaceX To Attempt Falcon 9 Landing On Autonomous Spaceport Drone Ship

If we look at jet aircraft, wear depends on the airframe and the engines, and the airframe seems to be the number of pressurize/depressurize cycles as well as the running hours. Engines get swapped out routinely but when the airframe has enough stress it's time to retire the aircraft lest it suffer catastrophic failure. Rockets are different in scale (much greater stresses) but we can expect the failure points due to age to be those two, with the addition of one main rocket-specific failure point: cryogenic tanks.

How long each will be reliable can be established using ground-based environmental testing. Nobody has the numbers for Falcon 9R yet.

Weight vs. reusable life will become a design decision in rocket design.

Comment: Credit Card Charge (Score 1) 138

by Roger W Moore (#48603505) Attached to: Amazon UK Glitch Sells Thousands of Products For a Penny

So, once the order has been placed, haven't you effectively entered into a contract for sale or something?

No, not until your credit card has been charged. If they have done that then you have them under the credit card agreement but before that they can wriggle out of it as a mistake under their own terms.

Comment: Re:Entropy (Score 1) 107

by Roger W Moore (#48598793) Attached to: 2 Futures Can Explain Time's Mysterious Past
Given the context - which is a post of Slashdot and not a paper - I'd stick with countless as in "too many to be counted" or "very many" given that I'm not willing to put in the large amount of effort that would be required to actually count them. Rather than the hugely overly technical considerations you are engaging in there is a very easy way to simplify this.

If I start with the glass on the table then there are is a very large range of momenta I can give the glass to arrive at the state where it is shards on the floor so long as I don't care which particular set of shards it makes. To convert from any given set of shards on the floor back to a glass I have to give each shard a precise linear and angular momentum such that they will reassemble themselves into the glass. Hence in the phase space of all possible momenta for all the shards I have to hit a single point where as for the reverse just have to hit a large area in a far lower dimensional phase space. The same applies to glasses colliding in space.

In the high energy limit the same will apply. The nuclei of the glass will collide to produce hadronic showers, each particle of which will have its own 4-momentum. However in this case it is clear that you cannot reverse the system since some of the interactions and subsequent decays will involve the weak force which we know is not symmetric under time reversal.

Comment: Ever been to London? (Score 2) 295

by Roger W Moore (#48598705) Attached to: French Cabbies Say They'll Block Paris Roads On Monday Over Uber

As such, I take a lot of taxi rides each year. But it doesn't matter if I'm in NYC, London, Paris, Berlin, Toronto, LA....

Have you actually ever taken a cab in London? The problem is the exact opposite of what you describe with only ~5% from minorities to the extent that they are trying to recruit more. As for "untrained hipster" they are required to pass The Knowledge before they get a license. They may have somewhat colourful characters but I've never had one who is not extremely competent, knowledgeable and driving a clear, well repaired cab.

Comment: Entropy (Score 1) 107

by Roger W Moore (#48559733) Attached to: 2 Futures Can Explain Time's Mysterious Past

Eggs turn into chickens at a different rate than chicken turns into eggs. This is proof either that A) time must go forwards, or B) my proof has a logic flaw in it.

....or C) that you forgot to account for entropy. To study time reversal violation you must have two states with identical entropy or you must account for the effects of entropy. The reason that a glass falling from a table and shatters is far more likely than all the pieces of glass coming together, leaping off the floor and forming a new glass is because of entropy. There are countless ways in which a glass on a table can be converted to broken shards on the floor but starting with the shards there is only one way that that process can be reversed.

Scale the system up, and they're just little birds that fly in boring ways, don't time travel, don't fly faster than light,...

Ummm...yes but the reason for that is because the fundamental physics governing the particles of which the starlings are made up prevent time travel and moving faster than light (which are actually one and the same). Assuming you are building a model out of simple, plastic lego bricks then regardless of what you are building we know that it will not be a conductor of electricity because the bricks you are building it from are all plastic insulators. Studying the fundamental physics of a system lets you know what is possible.

For example we know that there is a fundamental arrow of time despite the fact that at an everyday scale this is completely obscured by entropy. You could study all the flocks of starlings you like but it would be impossible to show that you have time reversal violations in it...and yet since the particles in that system are subject to the weak force we know that at some incredibly tiny, insignificant level it is there.

Comment: Simple Explanation (Score 1) 107

by Roger W Moore (#48559491) Attached to: 2 Futures Can Explain Time's Mysterious Past

Because GP (and some physicist) think that if particle physics correctly describes matter/anti-matter....

Whoa there it is a LOT simpler than that. If you have a system in state A and it changes into state B then your process is A-->B. If you reverse time then the process you have is B-->A. Now if both these states have identical entropy there are no phase space arguments to favour one state over the other and so both processes (A-->B and B-->A) should be equally likely if the laws of physics are the same with regard to the direction of time.

What these experiments showed are that for some systems A-->B is more likely than B-->A and so the laws of physics define an arrow of time. If time were reversed then A-->B would become less likely than B-->A which is how you could detect it. It's the temporal equivalent of looking in a mirror. If you have a perfect left-right symmetry you cannot tell wether the image you are looking at is the real object or the reflection. However if the object is not left-right symmetric it is easy to know which image you are seeing.

So it does prove that there is an arrow of time. Perhaps you ought to spend a little time understanding the physics before you start applying simple logic: it tends to lead to more accurate conclusions.

Comment: Arrow of Time (Score 5, Informative) 107

by Roger W Moore (#48553781) Attached to: 2 Futures Can Explain Time's Mysterious Past
Actually we can do better than that. The arrow of time is baked into fundamental particle physics and we have known this since the 1990's when an experiment, CPLEAR, showed that kaons turn into anti-kaons at a different rate than they switch back. This is completely independent of entropy and the result was further improved on by the Babar experiment only a few years ago showing that the 'T violation' occurs in B-mesons as well.

The article is wrong when it says that the laws of physics work the same going forwards or backwards in time. They do not and there is data to prove it. So the 'arrow of time' does not need any entropy to define it - it is baked into fundamental particle physics.

Comment: Re:What late afternoon sun? (Score 1) 327

by Roger W Moore (#48540239) Attached to: You're Doing It All Wrong: Solar Panels Should Face West, Not South

Pro tip: "afternoon" means before sunset, by definition.

Clearly you are not a pro at English and should not be giving tips. 'Afternoon' means, quite literally, after noon. Evening is usually taken as roughly from 6pm to ~10-11pm. Those living further north in the arctic circle still have a morning, afternoon and evening even if the sun does not rise at all.

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