Search found 1094 matches

by tomandlu
Sat Oct 22, 2011 4:46 pm UTC
Forum: Science
Topic: Wait, can free will exist?
Replies: 247
Views: 25332

Re: Wait, can free will exist?

This really begs the question. We can't choose to act as if free will exists, unless it actually exists. If free will does not exist, then we have no choice in the choice we make. Therefore choosing to behave as if free will exists is not really a choice, so we may as well choose it, since, if free...
by tomandlu
Sat Oct 22, 2011 6:25 am UTC
Forum: Science
Topic: Wait, can free will exist?
Replies: 247
Views: 25332

Re: Wait, can free will exist?

Where secular morality is concerned however it's at best superfluous. ... and rather reductive. Would an archetypal brain in a vat have free will, despite being incapable of action? I would argue yes ("I could be bounded in a nutshell and count myself a king of infinite space" etc.), but ...
by tomandlu
Sat Oct 22, 2011 5:44 am UTC
Forum: Science
Topic: Is this real?
Replies: 25
Views: 5421

Re: Is this real?

So when the superconductor is exposed to a magnetic field at a particular distance these persistent currents act as a form of memory, forcing the superconductor to maintain that distance from a magnetic field of the same strength, although it can move sideways, as such translations don't change the...
by tomandlu
Fri Oct 21, 2011 4:46 pm UTC
Forum: Science
Topic: Is this real?
Replies: 25
Views: 5421

Re: Is this real?

Can anyone give me a simple explanation of what's happening here?

Not so much about super-conductors - I just don't understand what forces are keeping that thing where it is. Is it riding on the expelled flux? I don't understand why it stays at a particular height. Sorry.
by tomandlu
Fri Oct 21, 2011 4:14 pm UTC
Forum: Science
Topic: Wait, can free will exist?
Replies: 247
Views: 25332

Re: Wait, can free will exist?

free will is expressed not in the ability to confound causality, but in making conciousness part of causality. That's a fine way to understand the existing, physical thing we're "really" talking about most of the time when we say "free will". It is not, however, what philosophic...
by tomandlu
Fri Oct 21, 2011 1:56 pm UTC
Forum: Science
Topic: Wait, can free will exist?
Replies: 247
Views: 25332

Re: Wait, can free will exist?

Perhaps it's the wrong question. Try 'do we perceive ourselves as having free will?' Going further, I'm not even sure 'free will' is relevant - isn't it just an axiomatic consequence of conciousness? The awareness of 'I' and that 'I' have made choices in the past and will do so in the future? In oth...
by tomandlu
Fri Sep 30, 2011 1:00 pm UTC
Forum: Fictional Science
Topic: FTL in my book
Replies: 63
Views: 23763

Re: FTL in my book

I think it might be a good idea to have the time-shifting mechanism integral to the ship's drive, rather than having it as something that gets switched off & on (although that would mean getting rid of the scene quoted above). That way, your ship's world-line will always be a light-like geodesi...
by tomandlu
Wed Sep 28, 2011 10:46 am UTC
Forum: Fictional Science
Topic: FTL in my book
Replies: 63
Views: 23763

Re: FTL in my book

Robert'); DROP TABLE *; wrote:The twins paradox is resolved by considering that one of the twins must accelerate. It doesn't imply an absolute reference frame.


Ah, of course...

... okay, I think the solution is to say that the shift is relative to one's self at the time of turning on the shift... or something
by tomandlu
Mon Sep 26, 2011 9:33 am UTC
Forum: Fictional Science
Topic: FTL in my book
Replies: 63
Views: 23763

Re: FTL in my book

T(I suppose you could have some universal reference frame that your speed is compared against, although that's breaking relativity even further, which says that no such thing exists, and velocity (and thus rate of time passing) is all relative.) ... thinking about it, and a bit of a cheat, but ther...
by tomandlu
Sun Sep 25, 2011 8:02 am UTC
Forum: Fictional Science
Topic: FTL in my book
Replies: 63
Views: 23763

Re: FTL in my book

The tricky part is avoiding simply going back into your own past. I mean, how would you limit that? If you tried limiting it to your speed, the question becomes: your speed, relative to what? I mean, in the story section there, it says they're moving at half light-speed, but half-light speed relati...
by tomandlu
Sun Sep 25, 2011 5:39 am UTC
Forum: Fictional Science
Topic: FTL in my book
Replies: 63
Views: 23763

Re: FTL in my book

This one... Yeah I'm not sure I understood this properly: are you suggesting that while traveling at whatever speed you're going at, you are also constantly shifting backwards in time by exactly the same amount you lose due to time dilation? Not this one... Or, are you suggesting you make a trip, an...
by tomandlu
Sat Sep 24, 2011 3:30 pm UTC
Forum: Fictional Science
Topic: FTL in my book
Replies: 63
Views: 23763

Re: FTL in my book

The obvious question is what happens when/if you make a return journey along the same path. Or what happens if someone in the new timeline affects the ship in transit/arrival prior to it's jump back in time. I'm not sure if either of those present a problem. You might 'see' yourself (since your ima...
by tomandlu
Sat Sep 24, 2011 3:17 pm UTC
Forum: Fictional Science
Topic: FTL in my book
Replies: 63
Views: 23763

Re: FTL in my book

I don't understand. Your doing something to the people on the ship, and this makes the folks at home age more slowly? As I understand it, the idea is that you go on your journey and come back, so you age 1 month and everybody else ages 100. Then you jump back in time by 99 months using handwavium s...
by tomandlu
Fri Sep 23, 2011 10:04 am UTC
Forum: Fictional Science
Topic: FTL in my book
Replies: 63
Views: 23763

FTL in my book

Hi, Apart from obviously being nonsense, does the following sort-of make sense (and, for bonus points, has anyone ever used this idea in fiction before): “Let us suppose you travel at a little below the speed of light, and that for every second of ship time, a hundred seconds would pass externally.”...
by tomandlu
Wed Aug 24, 2011 7:24 am UTC
Forum: Science
Topic: Why Are Space Elevators Always "100 Years Away"?
Replies: 32
Views: 6310

Re: Why Are Space Elevators Always "100 Years Away"?

The biggest problem, imho, are the practicalities of construction. You need to build down (and up) from space, so you either need a factory in space to produce the material or ship it up there. Add in weather considerations, etc., and you probably want to be able to perform the construction fairly q...
by tomandlu
Mon Aug 22, 2011 9:35 am UTC
Forum: Science
Topic: Two basic physics questions
Replies: 26
Views: 3149

Re: Two basic physics questions

I can see three possible reasons to the usefulness of spinning/twisting: -more efficient way to use your muscles. Something like a better position of your arms, to get the best efficiency of your muscles, maybe even use different muscles. Try to do pull-ups with your palms on way, then the other, a...
by tomandlu
Sun Aug 21, 2011 7:33 am UTC
Forum: Science
Topic: Wait, WHY don't heavier objects fall faster?
Replies: 76
Views: 14750

Re: Wait, WHY don't heavier objects fall faster?

Sorry - can I check... is the general consensus that heavier objects don't 'fall' faster? i.e. if you have the Earth and an ordinary tennis ball, the speed at which the two fall towards each other would be the same if you replaced the tennis ball with one that weighed the same as the Earth? Aren't b...
by tomandlu
Sun Aug 21, 2011 6:57 am UTC
Forum: Fictional Science
Topic: Sci-fi balistics
Replies: 9
Views: 2882

Re: Sci-fi balistics

Well the marble sized piece of Dwarf star would weigh a few hundred thousand tons and if it was moving at 20,000 miles/second it would utterly destroy the tank in much the same fashion as a modern "silver arrow" tankbuster round from an Abrams tank though even more so and it would keep go...
by tomandlu
Sun Aug 21, 2011 6:19 am UTC
Forum: Fictional Science
Topic: Sci-fi balistics
Replies: 9
Views: 2882

Re: Sci-fi balistics

Well, we're in a very odd bit of universe, so we'll just assume that makes the dwarf star matter stable. Speed - hard to say (see previous answer), but let's give it something silly like 20,000 miles / second... I guess it's primarily a choice between: ⋅ Small hole, little bigger than the ...
by tomandlu
Sun Aug 21, 2011 5:43 am UTC
Forum: Fictional Science
Topic: Sci-fi balistics
Replies: 9
Views: 2882

Sci-fi balistics

Hi,

Anyone got a rough idea about what would happen if you shot a marble-sized* bit of white dwarf matter at very high speed through a tank?

* R = 0.8cm, M = 4,000kg
by tomandlu
Sat Aug 20, 2011 9:47 pm UTC
Forum: Mathematics
Topic: Mass of pea-sized bit of white dwarf
Replies: 2
Views: 823

Re: Mass of pea-sized bit of white dwarf

gmalivuk wrote:1cm is not 10^-6 km, but 10^-5.

Since you then use this for volume, it looks like your answer is off by a factor of 1000.


Many, many thanks... needless to say I failed to look for an error in my constants... doh.
by tomandlu
Sat Aug 20, 2011 9:42 pm UTC
Forum: Mathematics
Topic: Weighted coin question and probability
Replies: 10
Views: 2033

Re: Weighted coin question and probability

Because probabilities are all we really have in the real world. You are right of course... Thinking about it in depth, my real concern is when statistics are used not just to prove guilt, but to prove the existence of a crime. The was a case here in the UK where a woman was convicted of murdering t...
by tomandlu
Sat Aug 20, 2011 6:46 pm UTC
Forum: Mathematics
Topic: Weighted coin question and probability
Replies: 10
Views: 2033

Re: Weighted coin question and probability

What am I missing here? It will happen 1 in 32 times (1 in 64 if you pre-specify heads rather than just sitting down and immediately throwing 6 of a kind in a row). Isn't it then just a question of whether that probability makes you suspicious or not? It would probably make me wary if I was gambling...
by tomandlu
Sat Aug 20, 2011 5:29 pm UTC
Forum: Mathematics
Topic: Mass of pea-sized bit of white dwarf
Replies: 2
Views: 823

Mass of pea-sized bit of white dwarf

Anyone feel like checking that my maths is (approximately) correct? Mass of sun = 2*10 30 kg Radius of sun = 695,500 km Radius of sun as white dwarf = 6,378 km Radius of X = 0.5 cm Therefore Mass of X-sized bit of white dwarf = 0.96 kg I dunno - I was expecting a more impressive number at the end th...
by tomandlu
Fri Aug 19, 2011 4:53 pm UTC
Forum: Science
Topic: The Double Slit Experiment
Replies: 7
Views: 1909

Re: The Double Slit Experiment

But where's the part of the experiment where they watch the chicken hitting the gate?
by tomandlu
Thu Aug 18, 2011 1:28 pm UTC
Forum: Books
Topic: Neal Stephenson: Where to start?
Replies: 33
Views: 42034

Re: Neal Stephenson: Where to start?

I feel like Stephenson botches the endings a bit Doesn't he sort of 'fess up to this at the end of Cryptonomicon? iirc the lead character is just sort of sitting on a rock while (avoiding spoilers) something fairly interesting is going on and mutters something about endings being boring... or somet...
by tomandlu
Thu Aug 18, 2011 10:23 am UTC
Forum: Science
Topic: Laplace's Demon?
Replies: 6
Views: 3187

Re: Laplace's Demon?

Now, this idea is discredited due to thermodynamics, chaos theory and quantum mechanics, because mainly of increasing entropy and the Heisenberg Uncertainty principle. BTW, and I could be wrong, but I think chaos theory is a red-herring in this case. It makes the problem worse, but the problem stil...
by tomandlu
Thu Aug 18, 2011 8:27 am UTC
Forum: Books
Topic: Recommend a book
Replies: 484
Views: 256017

Re: Recommend a book

"Soon I Will be Invincible" by Austin Grossman ‎I was building another science, my science, wild science, robots and lasers and disembodied brains. A science that buzzed and glowed; it wanted to do things. It could get up and walk, fly, fight, sprout garish glowing creations in the remotes...
by tomandlu
Wed Aug 17, 2011 5:12 pm UTC
Forum: Science
Topic: gee force
Replies: 6
Views: 875

Re: gee force

Many, many thanks - pretty much what I thought, but I was worried that the thinner/weaker support structures might offset the gain (i.e. small creatures develop support structures that are just good enough for 1g).

I'd forgotten about ants - also I guess that's why elephants don't jump ;)
by tomandlu
Wed Aug 17, 2011 4:17 pm UTC
Forum: Science
Topic: gee force
Replies: 6
Views: 875

gee force

Hi,

All else being equal, is a small creature less or more likely to be adversely affected by g-force than a large creature? (I assume the former, but waddaiknow?)
by tomandlu
Mon Apr 25, 2011 5:55 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0890: "Etymology"
Replies: 170
Views: 27828

Re: 0890: Etymology

Strangely enough, and in a slightly different context, I hit this exact problem the other day in something I'm working on... it's not always easy. For instance, I wouldn't use 'falcon' or even 'bird', although I'm happy with 'plant' and 'animal', etc.
by tomandlu
Tue Apr 05, 2011 11:21 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0881: "Probability"
Replies: 326
Views: 102928

Re: 0881: "Probability"

Randall, probably teaching my grandmother to suck eggs here, but Stephen Gould's article on cancer and survival stats, the median is not the message, is worth a read... of course, it would have helped if he hadn't gone and died...

http://www.cancerguide.org/median_not_msg.html
by tomandlu
Sun Feb 27, 2011 5:26 pm UTC
Forum: Science
Topic: Powered Orbits and Gravity
Replies: 13
Views: 3123

Re: Powered Orbits and Gravity

Soralin wrote:You don't even have to apply the thrust straight down, which could allow you to do some more unusual things, like have a geosynchronous orbit that's always directly over a point that's not on the equator.


Ooh - a shiny.

And, once again, tnx all...
by tomandlu
Sun Feb 27, 2011 7:54 am UTC
Forum: Science
Topic: Powered Orbits and Gravity
Replies: 13
Views: 3123

Powered Orbits and Gravity

Hi, I'm trying to figure out whether an artificial satellite in a powered orbit would have any gravity on board or not. E.g. a satellite that's orbiting too low for its speed, but is kept from falling to earth by a downwards thrust. Would the occupants be in free fall or not? I'm thinking not, and t...
by tomandlu
Sun Feb 27, 2011 7:49 am UTC
Forum: Science
Topic: Transformers
Replies: 10
Views: 1319

Re: Transformers

big boss wrote:This is off topic, but was I the only one who clicked on this thread hoping for a discussion on how Transformers (as in the robots) work...


Actually, when I saw it, I thought "this is probably the only place on the internets where that won't be a conversation about giant robots..."
by tomandlu
Thu Feb 24, 2011 10:19 pm UTC
Forum: Mathematics
Topic: sphere - know distance and width, find angle
Replies: 8
Views: 714

Re: sphere - know distance and width, find angle

Got it - many thanks (although I think the distance/width are mixed up in the last post). I now get (and either let this be right or shoot me now): Radius Distance Degrees Approx Degrees Better 1,080 240,000 0.54 0.52 1 1 60.00 53.13 44,423 365,000,000 0.01 0.01 44,423 2,000,000 2.67 2.54
by tomandlu
Thu Feb 24, 2011 7:56 pm UTC
Forum: Mathematics
Topic: sphere - know distance and width, find angle
Replies: 8
Views: 714

Re: sphere - know distance and width, find angle

Well, I was either getting it right, and am now wrong, or visa-versa... (by 50% afaict) Here's what I get using in Excel =DEGREES(ATAN( 1,080 /(2* 240,000 ))*2) = 0.257830573 i.e the moon, radius 1080 miles and 240000 miles from earth has a viewing angle of .25 degrees? Seems a bit small... (that's ...
by tomandlu
Thu Feb 24, 2011 7:33 pm UTC
Forum: Mathematics
Topic: sphere - know distance and width, find angle
Replies: 8
Views: 714

sphere - know distance and width, find angle

Sorry, this is a really dumb question, but I'm old and my sight is dim, I remember the road warrior, but trig is kind of a blur. If a planet is x miles away, and its radius is r miles, am I correct that the viewing angle of the planet is Degrees(tan(r/x))*2 ? (i.e. the angle between your eye and the...
by tomandlu
Fri Feb 11, 2011 8:33 am UTC
Forum: Science
Topic: LaTeX and other markup!
Replies: 30
Views: 18482

Re: LaTeX and other markup!

gmalivuk wrote:Probably you're still using the old subsilver forum skin, which doesn't have support for jsMath. There are greasemonkey scripts you can use for that, or you can switch to one of the prosilver ones.


Thanks - that fixed it.
by tomandlu
Thu Feb 10, 2011 4:05 pm UTC
Forum: Science
Topic: How to effectively give a presentation on evolution
Replies: 36
Views: 4955

Re: How to effectively give a presentation on evolution

My classes and instructors there are a breath of fresh air, so I was *shocked* to see a sign on campus yesterday about a lecture reconciling evolution and creation. Le sigh....I feel your pain. Is that necessarily a bad thing? (and I write as an emotional atheist with logical agnostic tendencies). ...

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