## Search found 196 matches

Mon May 04, 2015 6:33 pm UTC
Forum: Mathematics
Topic: Can anyone solve this probability problem?
Replies: 15
Views: 2968

### Re: Can anyone solve this probability problem?

>-) wrote:to be clear, the k crucibles are created each with an k-sided dice if the prime dice rolls k?

I thought the first step was the number of iterations. Otherwise the center one is just like the others.
Mon May 04, 2015 5:35 pm UTC
Forum: Science
Topic: Constants and physical significance
Replies: 12
Views: 3459

### Re: Constants and physical significance

Also, Wikipedia disagrees with the neutron decay time I quoted earlier - but it's still a human timescale, around 15 minutes instead of 10. The half-life of a free neutron is around 10 minutes, but its mean lifetime is around 15 minutes. Ah! I know the difference, but it didn't even occur to me tha...
Mon May 04, 2015 5:33 pm UTC
Forum: Mathematics
Topic: Lowest Common Multiple - LCM
Replies: 6
Views: 2074

### Re: Lowest Common Multiple - LCM

Another example would be when things with different periods interact, what the overall resulting period is. I'm having a bit of trouble finding examples that are neither trivial (weeks being 7 days long makes this too easy) or too messy (months and even years are erratic).
Mon May 04, 2015 4:47 pm UTC
Forum: Mathematics
Topic: Time/energy required to cool tool steel
Replies: 5
Views: 2993

### Re: Time/energy required to cool tool steel

37C is rather conservative for 'safe to touch'. Even with a metal, 45C should be safe to touch. It may not seem like that big a deal, but with exponential slowdown in cooling rates it could shave off a noticeable amount of time. Also, the outer surface will be cooler than the average, and that's wha...
Sat May 02, 2015 10:59 pm UTC
Forum: Science
Topic: Constants and physical significance
Replies: 12
Views: 3459

### Re: Constants and physical significance

Well, 'spading' is gaming parlance (some games, anyway) for doing SCIENCE and figuring out the rules without being told. -- back on-topic -- The Lambda, Sigma, and Xi have finger-scale lengths. The charged pion is 2.6*10^-8 seconds, so that's around a meter. The longer Kaon lifetime is similar. Muon...
Fri May 01, 2015 5:38 pm UTC
Forum: Mathematics
Topic: What are monster groups and why do they exist?
Replies: 7
Views: 3092

### Re: What are monster groups and why do they exist?

I think the more interesting question is why there isn't an infinite number of sporadic groups, or an infinite number of infinite families of groups. Firstly, their are a countable infinite number of finite simple groups. This is essentially a consequence of the fact that the theorem is specificall...
Fri May 01, 2015 5:22 pm UTC
Forum: Science
Topic: Constants and physical significance
Replies: 12
Views: 3459

### Re: Constants and physical significance

The half-life of a free neutron is 10.2 minutes, which is on a human time-scale, and that seems pretty close to fundamental.
Wed Apr 29, 2015 6:31 pm UTC
Forum: Science
Topic: Earth's trajectory if the sun disappeared...?
Replies: 48
Views: 11174

### Re: Earth's trajectory if the sun disappeared...?

douglasm wrote:The geocentric model is not inertial, so it is actually not as valid as the solar one by relativity. Relativity states that all inertial reference frames are equally valid, not absolutely all reference frames.

That's special relativity. General relativity eases that restriction.
Wed Apr 29, 2015 6:25 pm UTC
Forum: Mathematics
Topic: What are monster groups and why do they exist?
Replies: 7
Views: 3092

### Re: What are monster groups and why do they exist?

I think the more interesting question is why there isn't an infinite number of sporadic groups, or an infinite number of infinite families of groups. Why should there be one largest sporadic simple group? It's like - taking the primes analogy mentioned above - we discovered that every prime beyond s...
Mon Apr 27, 2015 5:09 pm UTC
Forum: Science
Topic: On friction
Replies: 17
Views: 4045

### Re: On friction

Also, when you set up equations like this in class, you will want to represent most quantities with letters, not words, and you can define your variables first. I find it helpful to use words while I'm figuring out what I'm doing. I can switch over to letters once I'm familiar with the meaning of e...
Mon Apr 27, 2015 5:05 pm UTC
Forum: Mathematics
Topic: how to maximize number of beard states?
Replies: 8
Views: 2623

### Re: how to maximize number of beard states?

I am very disappointed that 'beard' was literal and not jargon.
Thu Apr 16, 2015 5:54 pm UTC
Forum: Science
Topic: What would it be like to put a giant drop of water in a...
Replies: 15
Views: 5907

### Re: What would it be like to put a giant drop of water in a.

This also occurs in Endymion.
Thu Apr 16, 2015 5:52 pm UTC
Forum: Science
Topic: Schrodinger's Cat Satire
Replies: 8
Views: 3614

### Re: Schrodinger's Cat Satire

ahammel wrote:The cat is too warm to decohere, if memory serves.

Don't you mean, the cat is warm enough to decohere right away? Aside from that, what Mayor Mare Copper Bezel and quantropy said.
Thu Apr 16, 2015 5:51 pm UTC
Forum: Science
Topic: De Broglie Wavelength and humans
Replies: 13
Views: 5290

### Re: De Broglie Wavelength and humans

There are so many more reasons that humans can't diffract, don't get hung up on that one.
Thu Apr 16, 2015 5:49 pm UTC
Forum: Mathematics
Topic: function points
Replies: 35
Views: 6915

### Re: function points

f.point wrote:
drachefly wrote:If that's so, then the standard way of writing 5-sub-y would be "(0,5)". The standard way of writing 5-sub-x would be "(5,0)"

I see that you think my notation is not compatible with the classical mathematics !!!

No, I'm sure it is. I just don't know what you're talking about.
Wed Apr 15, 2015 5:05 pm UTC
Forum: Mathematics
Topic: Simple probability question - cards
Replies: 7
Views: 1967

### Re: Simple probability question - cards

Ordinarily, the probability P of drawing an ace on the first try would merely be P = k/n, but it is an unevenly-distributed deck and so the true probability is slightly lower...I'll call it P1. By unevenly distributed do you mean that it has been shuffled in some inhomogeneous fashion? What happens...
Wed Apr 15, 2015 4:51 pm UTC
Forum: Mathematics
Topic: function points
Replies: 35
Views: 6915

### Re: function points

If that's so, then the standard way of writing 5-sub-y would be "(0,5)". The standard way of writing 5-sub-x would be "(5,0)"

But what might X-sub-x mean?

Is Y-sub-x the line given by the following equation?

f(a) = a*(1,1)
Wed Apr 15, 2015 3:48 pm UTC
Forum: Science
Topic: Maxwell's demon -- consensus on disproofs?
Replies: 20
Views: 5202

### Re: Maxwell's demon -- consensus on disproofs?

This scheme dissipates energy in the form of setting up the sensor and letting it trigger, and regains some of the free energy lost by taking advantage of transient imbalances which will occur on thermodynamically long timescales. So it's a really, really, really slow and inefficient pump. Seems to ...
Wed Apr 15, 2015 3:29 pm UTC
Forum: Science
Topic: Carnot limit of a solar cell
Replies: 30
Views: 6150

### Re: Carnot limit of a solar cell

The two relevant temperatures are given by the energy distribution of the incoming photons and the energy distribution of the electrons in and around the junction. These latter are very close to the bulk temperature of the solar cell.
Thu Mar 05, 2015 12:11 pm UTC
Topic: 1489: "Fundamental Forces"
Replies: 93
Views: 27961

### Re: 1489: "Fundamental Forces"

A particular particle can have a much stronger charge than it can have gravitational force of its own. That's a meaningful statement. Even aside from trying to compare “charge” with “force”, I’m not convinced it’s a particularly useful statement. For example, another specific particle—the neutron—h...
Thu Mar 05, 2015 11:58 am UTC
Topic: 1478: "P-Values"
Replies: 34
Views: 12226

### Re: 1478: "P-Values"

What is the exact statistical software I can use to test whether family A of snakes has lower muscle mass than families B and C using Bayesian methods, where I can just plug in a list of measurements, hit "go", and get an answer? There is not a thing in the world that can tell you that. I...
Wed Feb 25, 2015 11:34 am UTC
Topic: 1491: "Stories of the Past and Future"
Replies: 99
Views: 35252

### Re: 1491: "Stories of the Past and Future"

Lest Darkness Fall was not set in 1435 (1936-500 as on the chart). It is set starting 535. Anathem would be set outside the plane of the chart. if there were a time-travel story set in 1885 wherein they go back in time to 1855... I don't think I'd be able to tell the difference in the eras at all, a...
Tue Feb 24, 2015 12:54 pm UTC
Forum: Science
Topic: Teleporting inside a wall
Replies: 16
Views: 5363

### Re: Teleporting inside a wall

In Stargate, ring teleporters swapped their contents.
Tue Feb 24, 2015 11:50 am UTC
Topic: 1489: "Fundamental Forces"
Replies: 93
Views: 27961

### Re: 1489: "Fundamental Forces"

I looked up just exactly how the weak force causes beta decay. Really, a down quark in a neutron decays into an up quark and a W boson. Then the W boson decays into an electron and an electron antineutrino. Because the W boson is the mediator of the weak force, you can kind of think of the weak for...
Fri Feb 20, 2015 3:25 pm UTC
Topic: 1489: "Fundamental Forces"
Replies: 93
Views: 27961

### Re: 1489: "Fundamental Forces"

The weak interaction describes how and when the fairly-rigidly-defined type boundaries that underlie the structure of matter leak.
Tue Feb 17, 2015 11:07 pm UTC
Forum: Science
Topic: Fuck Dark Matter; It's a sprinkler, not a whirlpool.
Replies: 135
Views: 27615

### Re: Fuck Dark Matter; It's a sprinkler, not a whirlpool.

In the example, 'Skolnick's lovely asistant Gmal' is not in a P orbit. You need a lot more spherical harmonics to describe the location of a human on the surface of the Earth than a lonely L=1 M = 0 mode.
Mon Feb 16, 2015 3:52 pm UTC
Topic: 0526: "Converting to Metric"
Replies: 429
Views: 92198

### Re: 0526: "Converting to Metric"

I had to choose between common sense and being exact at a couple of place so I choose exactitude.( ex : 110 kph is actually 68 mph)

yes, I found your round-trip converting 65 mph to 68 mph amusing.
Sat Feb 14, 2015 3:33 am UTC
Topic: 1486: "Vacuum"
Replies: 44
Views: 11705

### Re: 1486: "Vacuum"

For a fan, that's really high speed.
Fri Feb 13, 2015 9:36 pm UTC
Topic: 1486: "Vacuum"
Replies: 44
Views: 11705

### Re: 1486: "Vacuum"

Honestly, because it's the first one I clicked on on wikipedia. I knew about turbomolecular pumps, but that felt more pumpish and less cleanerish, so I had a quick skim of the ultra high vacuum article for inspiration. Ion Pumps and Turbo Molecular Pumps are two really, really different things. A T...
Wed Feb 04, 2015 7:28 pm UTC
Forum: Science
Topic: Slowing down earth rotation: would fixed rocket engine help?
Replies: 3
Views: 1930

### Re: Slowing down earth rotation: would fixed rocket engine h

Most of the bright light from the rocket escapes, so you'll have a little effect. A very little.
Tue Jan 27, 2015 12:44 pm UTC
Topic: 1478: "P-Values"
Replies: 34
Views: 12226

### Re: 1478: "P-Values"

This really missed the opportunity to consider numbers up closer to 1 and, as noted above, beyond. More seriously... Meanwhile, the Bayesian statisticians are laughing. Because they don't have anything more useful to add? :wink: Aside from providing an odds ratio by which you should update, which wi...
Tue Jan 13, 2015 3:09 pm UTC
Forum: Science
Replies: 13
Views: 4146

Hmm. Out of curiosity, can a planet of the right size continue to give off heat as a result of gravitational squeezing, but not be large enough to initiate fusion? Will such a planet stop giving off heat eventually? My hunch is that you can't get heat from nothing forever, so, yes? It will slow dow...
Tue Dec 30, 2014 3:12 pm UTC
Forum: Science
Topic: Vertical farm energy calculator
Replies: 27
Views: 10638

### Re: Vertical farm energy calculator

I wonder if you can use a color-splitting diffracting mirror to funnel just the sunlight that's at the right frequencies to the plants directly, thus avoiding the doubled conversion inefficiencies.

Since direct sunlight is collimated, it should be doable.
Tue Dec 30, 2014 3:09 pm UTC
Forum: Science
Topic: (New) Neutrinos = Tachyon?
Replies: 19
Views: 5558

### Re: (New) Neutrinos = Tachyon?

Meaning flavor oscillations would statistically smooth out the results, with a tachyon flavor assumedly going > C and a bradyon flavor going < C. So you're not only proposing something going faster than light, but something that can oscillate back and forth across the lightspeed barrier? And switch...
Wed Dec 17, 2014 12:21 pm UTC
Forum: Science
Topic: Fingers on Humans
Replies: 80
Views: 18525

### Re: Fingers on Humans

I can easily detect extra tension getting my thumb to touch my pinky, but it's nowhere near the limit. I max out abut two additional finger-widths over.
Thu Dec 04, 2014 7:22 pm UTC
Topic: 1455: "Trolley Problem"
Replies: 172
Views: 50885

### Re: 1455: "Trolley Problem"

Folks, you've got to work in the least convenient possible world. That means no, no nukes are available.
Thu Dec 04, 2014 6:49 pm UTC
Forum: Science
Topic: Tiny medieval units
Replies: 32
Views: 8538

### Re: Tiny medieval units

I have to say, this thread is absolutely fascinating from many perspectives, and yet every time I see the topic I imagine phalanxes of inch-high soldiers. Yeah, I went the other way and kept thinking odd groups of only two or three infantrymen. Every time I see the topic title. And similarly, I fin...
Thu Dec 04, 2014 5:15 pm UTC
Forum: Science
Topic: Schrodinger Cat Disproof (Samuel Jacobs)
Replies: 88
Views: 21291

### Re: Schrodinger Cat Disproof (Samuel Jacobs)

Paragraph 2: Yes, neutrinos present a non-fundamental limit on the size*duration of a coherent state. However, neutrinos do not interact rapidly with the cat (to put it mildly), so this degradation will not be very quick. Easily long enough to perform the experiment and run up against much more fund...
Sat Nov 22, 2014 1:18 am UTC
Topic: 1450: "AI-Box Experiment"
Replies: 200
Views: 67756

### Re: 1450: "AI-Box Experiment"

I was always left with the impression that the lesswrong community was secretly an apocalypse cult building the basilisk themselves. Most of their behavior makes sense in that light... :facepalm: It's no secret whatsoever that LW is broadly behind an effort to make a Friendly AI. Once you've done t...
Wed Nov 12, 2014 2:21 pm UTC
Forum: Science
Topic: Can protons be extracted from an acid solution?
Replies: 26
Views: 5575

### Re: Can protons be extracted from an acid solution?

And here we see someone who doesn't know how lmgtfy is supposed to work. If someone didn't already know about the Niven technology, how are they supposed to google that for themselves? I suppose I was a little lmgtfy happy. a little like the explosion from only a cubic millimeter of water minus the...