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It's been pretty dull lately. This at least is moderately entertaining...
http://www.xkcd.com/505/
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Invisible wrote:
> It's been pretty dull lately. This at least is moderately entertaining...
This is Wolfram's turing-complete 1-dimensional CA, in case you didn't
recognise it.
--
Darren New / San Diego, CA, USA (PST)
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Darren New wrote:
> This is Wolfram's turing-complete 1-dimensional CA, in case you didn't
> recognise it.
Yes, I *own* the book. ;-)
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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Orchid XP v8 wrote:
> Darren New wrote:
>
>> This is Wolfram's turing-complete 1-dimensional CA, in case you didn't
>> recognise it.
>
> Yes, I *own* the book. ;-)
>
Strangely, I was just reading about this very CA the other day ...
--
~Mike
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>>> This is Wolfram's turing-complete 1-dimensional CA, in case you
>>> didn't recognise it.
>>
>> Yes, I *own* the book. ;-)
>
> Strangely, I was just reading about this very CA the other day ...
More specifically, I would imagine this is Wolfram's assertion that the
universe might be a giant CA, which would explain why certain physical
quantities have a discrete, "quantum" nature. (I believe he theorised
that different subatomic particules might be "tangles" in some kind of
hyper-dimensional network, which updates itself in a mannar similar to a
CA.)
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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Orchid XP v8 wrote:
> More specifically, I would imagine this is Wolfram's assertion that the
> universe might be a giant CA, which would explain why certain physical
> quantities have a discrete, "quantum" nature. (I believe he theorised
> that different subatomic particules might be "tangles" in some kind of
> hyper-dimensional network, which updates itself in a mannar similar to a
> CA.)
He really seems like a "man with only a hammer" in this regard.
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Orchid XP v8 wrote:
>
> More specifically, I would imagine this is Wolfram's assertion that the
> universe might be a giant CA, which would explain why certain physical
> quantities have a discrete, "quantum" nature. (I believe he theorised
> that different subatomic particules might be "tangles" in some kind of
> hyper-dimensional network, which updates itself in a mannar similar to a
> CA.)
>
Interesting.
Ever notice how when we start examining the very small scales or the
very large scale the theories get more and more bizarre? Especially when
we get to talking about what the universe is made of.
--
~Mike
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Mike Raiford wrote:
> Ever notice how when we start examining the very small scales or the
> very large scale the theories get more and more bizarre? Especially when
> we get to talking about what the universe is made of.
Perhaps these theories only seem "bizarre" to us because we're used to
things which aren't exceptionally small or large? ;-)
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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Orchid XP v8 wrote:
> More specifically, I would imagine this is Wolfram's assertion that the
> universe might be a giant CA, which would explain why certain physical
> quantities have a discrete, "quantum" nature.
There are a number of people who assert such a thing, actually. Wolfram
was more summarizing there than inventing, methinks.
Altho I thought his point that even if only one cell was updated at a
time, we still wouldn't know this, because we would only see updates
when we ourselves got updated. Freaky.
--
Darren New / San Diego, CA, USA (PST)
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Darren New wrote:
> Altho I thought his point that even if only one cell was updated at a
> time, we still wouldn't know this, because we would only see updates
> when we ourselves got updated. Freaky.
...hence one guy with an infinite plans moving rocks by hand, one at a
time. ;-)
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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Orchid XP v8 wrote:
> Perhaps these theories only seem "bizarre" to us because we're used to
> things which aren't exceptionally small or large? ;-)
I saw an interesting lecture (Carl Sagan, I think?) who pointed out that
if we were the size of insects, we'd barely notice gravity and we'd be
much more concerned about surface tension, for example.
--
Darren New / San Diego, CA, USA (PST)
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Darren New wrote:
> I saw an interesting lecture (Carl Sagan, I think?) who pointed out that
> if we were the size of insects, we'd barely notice gravity and we'd be
> much more concerned about surface tension, for example.
Or if we were radically larger/smaller, the concept of a "fixed point in
space" would seem incongruous.
(On a large scale, planets, stars and galaxies wander round all over the
place Similarly on a sufficiently small scale.)
Why no SciFi writers have caught on to this idea I don't know...
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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Orchid XP v8 wrote:
> Why no SciFi writers have caught on to this idea I don't know...
Greg Egan does a wonderful job with all these kinds of oddities. I'm
sure I've mentioned him before.
--
Darren New / San Diego, CA, USA (PST)
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Orchid XP v8 wrote:
> Or if we were radically larger/smaller, the concept of a "fixed point in
> space" would seem incongruous.
>
> (On a large scale, planets, stars and galaxies wander round all over the
> place Similarly on a sufficiently small scale.)
That's a problem for time traveling. You have to travel in time yet stay in
the same point in space. Oh wait, that would leave you in the middle of
nowhere without an atmosphere. You have to stay in the same point in space
*relative to your planet*!
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Orchid XP v8 wrote:
>> This is Wolfram's turing-complete 1-dimensional CA, in case you didn't
>> recognise it.
>
> Yes, I *own* the book. ;-)
Where I come from, it'd be embarrassing to admit to that.<G> I read
perhaps 30-40 pages before I tired of the Mathematica evangelism and
megalomania. Sure glad libraries exist.
--
Psychoceramics: The study of crackpots.
/\ /\ /\ /
/ \/ \ u e e n / \/ a w a z
>>>>>>mue### [at] nawaz org<<<<<<
anl
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Darren New wrote:
> Orchid XP v8 wrote:
>> More specifically, I would imagine this is Wolfram's assertion that
>> the universe might be a giant CA, which would explain why certain
>> physical quantities have a discrete, "quantum" nature.
>
> There are a number of people who assert such a thing, actually. Wolfram
> was more summarizing there than inventing, methinks.
If I recall correctly, the specifics of the possibilities he suggest for
how the current laws of physics can be computed by a CA are also
provably wrong under a rather reasonable set of assumptions. (note that
I might be getting the details on this wrong, since it was a while back
that I read about it). I can try to find the link again if anyone's
interested.
When I get some free time I'll still read the book though, since I'm
curious about it and I'm sure that it will still be interesting, I'm
just highly skeptical of his main thesis.
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Kevin Wampler wrote:
> If I recall correctly, the specifics of the possibilities he suggest for
> how the current laws of physics can be computed by a CA are also
> provably wrong under a rather reasonable set of assumptions.
I'd like to see that link. Sounds interesting.
But, yeah, I think the ones I've seen that are close to right are
networks with the distance between nodes being roughly plank length, and
the only important thing is the number of links coming from each node
and where they go. Not quite "cellular" as such, but similar.
--
Darren New / San Diego, CA, USA (PST)
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> -----Original Message-----
> From: Orchid XP v8 [mailto:voi### [at] devnull]
> Perhaps these theories only seem "bizarre" to us because we're used to
> things which aren't exceptionally small or large? ;-)
Or it could be that things get more and more complex to explain what
we're seeing, since you need all the rules we're familiar with to
explain things at our level, *plus* additional rules to explain things
at other levels.
...Ben Chambers
www.pacificwebguy.com
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Chambers wrote:
> Or it could be that things get more and more complex to explain what
> we're seeing, since you need all the rules we're familiar with to
> explain things at our level, *plus* additional rules to explain things
> at other levels.
The rules at other levels are actually pretty simple. It's understanding
1) how to actually calculate the values, and
2) what it means statistically when you add up huge numbers of
almost-zero values
that it gets tricky.
E=mc^2 - That's pretty much it. :-)
There's only something like ten numbers plugged into something like four
or five equations that essentially describe the entire universe (as far
as people understand it).
The problem is that the equations are an infinite number of
successively-smaller values for even something as simple as "an electron
goes from here to there", let alone to the complexity of the cultural
interactions between clusters of neurons leading to "some people believe
in a god."
And of course, there's *just* enough weird stuff going on that people
aren't quite sure what's happening. QED is pretty well figured out, and
relativity certainly seems to check out, but gravity is incompatible
with QED and every time someone figures out something cosmological,
something else crops up to add another free variable (hence, dark
matter, dark energy, dark force, dark gravity, etc).
--
Darren New / San Diego, CA, USA (PST)
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> I saw an interesting lecture (Carl Sagan, I think?) who pointed out that
> if we were the size of insects, we'd barely notice gravity and we'd be
> much more concerned about surface tension, for example.
Yeh, this comes about because gravity forces, mass and inertia etc all scale
with length cubed, but surface tension scales with length squared. This is
an important concept in Engineering when making very small things.
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> That's a problem for time traveling. You have to travel in time yet stay
> in
> the same point in space. Oh wait, that would leave you in the middle of
> nowhere without an atmosphere. You have to stay in the same point in space
> *relative to your planet*!
And rotate with the planet, otherwise you might end up inside some mountain
or falling 500 metres towards the sea!
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scott wrote:
>> That's a problem for time traveling. You have to travel in time yet
>> stay in
>> the same point in space. Oh wait, that would leave you in the middle of
>> nowhere without an atmosphere. You have to stay in the same point in
>> space
>> *relative to your planet*!
>
> And rotate with the planet, otherwise you might end up inside some
> mountain or falling 500 metres towards the sea!
Hmm. But is your planet rotating? Or is your planet actually stationary
and the universe is rotating around it? ;-)
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>> Yes, I *own* the book. ;-)
>
> Where I come from, it'd be embarrassing to admit to that.<G> I read
> perhaps 30-40 pages before I tired of the Mathematica evangelism and
> megalomania. Sure glad libraries exist.
I don't recall much actually being mentioned about Mathematica. I do
recall thinking it was perhaps a tad arrogant to declare that all of
science and mathematics is wrong and that you are right.
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> Hmm. But is your planet rotating? Or is your planet actually stationary
> and the universe is rotating around it? ;-)
Does "stationary" actually mean anything in absolute terms?
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scott wrote:
>> Hmm. But is your planet rotating? Or is your planet actually
>> stationary and the universe is rotating around it? ;-)
>
> Does "stationary" actually mean anything in absolute terms?
That's kind of my point.
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>> Does "stationary" actually mean anything in absolute terms?
>
> That's kind of my point.
Actually for rotation, you should be able to define stationary. Because in
order to rotate you need some force to stop you flying off in a straight
line. On the surface of the Earth, the downwards force that you feel is
ever so slightly less than what it should be due to gravity, because the
Earth is rotating. If the Earth rotated at the right speed then there would
essentially be no downwards force (at least on the equator) and everything
would float.
So, assuming you can measure forces and calculate gravity accurately enough,
you should be able to determine if you are rotating or not, and how fast you
are rotating.
Another method might be to use a gyroscope, it will react differently if the
planet you are on is rotating or not.
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Invisible wrote:
> Hmm. But is your planet rotating? Or is your planet actually stationary
> and the universe is rotating around it? ;-)
The planet is rotating.
http://en.wikipedia.org/wiki/Foucault_pendulum
Didn't you ever go to a science museum? :-)
--
Darren New / San Diego, CA, USA (PST)
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Darren New wrote:
> The planet is rotating.
> http://en.wikipedia.org/wiki/Foucault_pendulum
> Didn't you ever go to a science museum? :-)
Sadly, the science museum near us doesn't even have one of these.
--
~Mike
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Darren New wrote:
> Kevin Wampler wrote:
>> If I recall correctly, the specifics of the possibilities he suggest
>> for how the current laws of physics can be computed by a CA are also
>> provably wrong under a rather reasonable set of assumptions.
>
> I'd like to see that link. Sounds interesting.
>
> But, yeah, I think the ones I've seen that are close to right are
> networks with the distance between nodes being roughly plank length, and
> the only important thing is the number of links coming from each node
> and where they go. Not quite "cellular" as such, but similar.
I'm not sure that this is the same paper I was thinking of, but if not
it seems to have more or less the same content. The interesting bit is
in section 3 and in particular subsection 3.2:
http://arxiv.org/abs/quant-ph/0206089
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Kevin Wampler wrote:
> http://arxiv.org/abs/quant-ph/0206089
Kewl. Rather over my head, methinks, but I think I got enough of it to
understand the points even if I couldn't tell you who was right. :-)
Thanks!
--
Darren New / San Diego, CA, USA (PST)
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Invisible wrote:
> I don't recall much actually being mentioned about Mathematica. I do
Are we discussing the same book? The pages I read were replete with
Mathematica code, with *very* frequent comments about how Mathematica's
language is quite "natural" for investigating these systems.
And no, from reading the code, it didn't seem natural at all.
--
Psychoceramics: The study of crackpots.
/\ /\ /\ /
/ \/ \ u e e n / \/ a w a z
>>>>>>mue### [at] nawazorg<<<<<<
anl
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Mike Raiford wrote:
> Darren New wrote:
>
>> The planet is rotating.
>> http://en.wikipedia.org/wiki/Foucault_pendulum
>> Didn't you ever go to a science museum? :-)
>
> Sadly, the science museum near us doesn't even have one of these.
Make one! :-D
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Mueen Nawaz wrote:
> Invisible wrote:
>> I don't recall much actually being mentioned about Mathematica. I do
>
> Are we discussing the same book? The pages I read were replete with
> Mathematica code, with *very* frequent comments about how Mathematica's
> language is quite "natural" for investigating these systems.
>
> And no, from reading the code, it didn't seem natural at all.
Apparently not them. The book I have doesn't contain any actual code at all.
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>> Sadly, the science museum near us doesn't even have one of these.
>
> Make one! :-D
Meh. Maybe.
My statement was more of a commentary of the vapid nature of our local
"science" museum. All they had was a Tesla coil powered light show (you
know, a larger version of the plasma ball) as a demonstration of
"lightning" and a few optical illusions. Oh, yeah, and a playground for
the kids.
I want a *real* science museum, dammit. Like the one I went to as a kid.
Had several electrical things, science demonstrations involving many
facets of physics. Lots of interaction with sound waves, light, heat and
electricity. It made science interesting! Oh, yes, and as a centerpiece
it had the aforementioned pendulum. And plaques that explained what was
happening.
The one we went to that was nearby was dull and hollow. They were
setting up some "science of sports" exhibit, but the main exhibits were
a few things about meteorology (you see, I'm in the southernmost part of
Tornado Alley) which included a few yawn inducing demonstrations (I
can't even remember what they were but they didn't really do much, oh,
yeah one that showed that heat rises, and a few pictures of storm
damage), and a artificial tornado. The rest of the main room was nothing
but optical illusions. Then it was some farm exhibit, for the kiddies,
and a playground. That was IT.
--
~Mike
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Mike Raiford wrote:
> My statement was more of a commentary of the vapid nature of our local
> "science" museum. All they had was a Tesla coil powered light show (you
> know, a larger version of the plasma ball) as a demonstration of
> "lightning" and a few optical illusions. Oh, yeah, and a playground for
> the kids.
>
> I want a *real* science museum, dammit. Like the one I went to as a kid.
> Had several electrical things, science demonstrations involving many
> facets of physics. Lots of interaction with sound waves, light, heat and
> electricity. It made science interesting! Oh, yes, and as a centerpiece
> it had the aforementioned pendulum. And plaques that explained what was
> happening.
>
> The one we went to that was nearby was dull and hollow. They were
> setting up some "science of sports" exhibit, but the main exhibits were
> a few things about meteorology (you see, I'm in the southernmost part of
> Tornado Alley) which included a few yawn inducing demonstrations (I
> can't even remember what they were but they didn't really do much, oh,
> yeah one that showed that heat rises, and a few pictures of storm
> damage), and a artificial tornado. The rest of the main room was nothing
> but optical illusions. Then it was some farm exhibit, for the kiddies,
> and a playground. That was IT.
Science is seriously interesting stuff. However, making it *look*
interesting is quite hard.
The easiest way to do this is to splash something complicated and
technical-looking over it. For example, my sister's A-level physics
textbook had a large Mandelbrot set on the cover. Unfortunately, that
has almost *nothing* to do with the contents of the book! This is the
general problem with this approach.
The London Science Museum has a giant steam winding engine. It has a
24-foot flywheel that weighs multiple tonnes, and trust me, when this
whole crazy Victorian contraption starts moving, it looks *very*
impressive. Doesn't teach you *squat*, but it's pretty amazing to watch!
I used to like watching TV programs like Local Heroes and Rough Science.
(I say "used to" since these are no longer produced, sadly.) Rough
Science in particular was great in that it depicted people making all
sorts of improbable devices out of old junk.
It was also quite amusing that the physist always wanted coils of wire:
"A heater? OK, we'll need a coil of wire..."
"A radio? OK, we'll need a coil of wire..."
"A speaker? OK, we'll need a coil of wire..."
"A thermometer? OK, we'll need two coils of wire..."
"A generator? OK, we'll need a coil of wire..."
"A washing machine? OK, we'll need a coil of wire..."
OK, most of those are pretty self-explanatory. But a thermometer? Who'd
have thought of making *that* out of a coil of wire?
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Invisible wrote:
> I used to like watching TV programs like Local Heroes and Rough Science.
> (I say "used to" since these are no longer produced, sadly.) Rough
> Science in particular was great in that it depicted people making all
> sorts of improbable devices out of old junk.
Heh, I have fond memories of Mr Wizard as a child.
> OK, most of those are pretty self-explanatory. But a thermometer? Who'd
> have thought of making *that* out of a coil of wire?
Yeah, hmm. Some dial types use a bimetallic spring. Which I suppose is
essentially a coil of wire. :) sort of ... That's a stretch, though.
Actually, an amazingly simple piece of technology exists in your car:
the thermostat that controls the flow of water to the radiator. Purely
mechanical, no electronics, but works to maintain the temp of the
coolant in the engine within a certain range. Just a couple metal parts
and a chunk of wax.
--
~Mike
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>> OK, most of those are pretty self-explanatory. But a thermometer?
>> Who'd have thought of making *that* out of a coil of wire?
>
> Yeah, hmm. Some dial types use a bimetallic spring. Which I suppose is
> essentially a coil of wire. :) sort of ... That's a stretch, though.
Ah, now, you see... the electrical resistence of a wire is proportional
to its temperature. So by having a long *coil* of wire, you have enough
wire for the resistence to be large enough to be measurable, and because
it's a coil, it's all in "the same place" and should have uniform
temperature. Compare the resistence of the test coil to the reference
coil (constructed the same way and held at a known temperature) and
you've got yourself an electronic thermometer. QED.
> Actually, an amazingly simple piece of technology exists in your car:
> the thermostat that controls the flow of water to the radiator.
D. Attenborough pointed out that a large Oak tree sucks multiple tonnes
of water out of the ground and lifts it 40 or 50 feet into the air each
day - with no moving parts.
A fire engine does the same thing - but using a rawring diesel engine
running on purified hydrocarbon energy. And not terribly efficient either.
The way the Oak does it is quite ingenius: IT USES THE LAWS OF PHYSICS.
Specifically, as water evapourates out of th leaves, that sucks more
water out of the branches - which sucks water out of the thunk, whic
sucks water out of the ground. So it's a completely passive system, and
it always delivers exactly the right amount of water without needing any
control systems.
Mankind, you have been PWN3D.
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Invisible wrote:
> Science is seriously interesting stuff. However, making it *look*
> interesting is quite hard.
I can heartily recommend to anyone who comes to the New York City that
you visit the American Museum of Natural History. The lobby, for
example, has a herd of 13 full-grown elephants (stuffed, of course).
It's looks kind of lost and lonely in the middle of the lobby. The cafe
has a full-size model of a blue whale hanging from the ceiling. If you
actually see all of it, it takes several days. There's a subway stop in
the basement, and it's free-ish. (Donation requested, basically.)
> OK, most of those are pretty self-explanatory. But a thermometer? Who'd
> have thought of making *that* out of a coil of wire?
It's called a bimetalic strip. ;-) Hence the need for two coils.
--
Darren New / San Diego, CA, USA (PST)
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>> Science is seriously interesting stuff. However, making it *look*
>> interesting is quite hard.
>
> I can heartily recommend to anyone who comes to the New York City that
> you visit the American Museum of Natural History. The lobby, for
> example, has a herd of 13 full-grown elephants (stuffed, of course).
> It's looks kind of lost and lonely in the middle of the lobby. The cafe
> has a full-size model of a blue whale hanging from the ceiling. If you
> actually see all of it, it takes several days. There's a subway stop in
> the basement, and it's free-ish. (Donation requested, basically.)
The London Natural History Museum also has a full-size blue whale model.
And the lobby features a Diplodicus skeleton. Actually, the main hall
mostly features dinosur remains of some kind. And *lots* of children! o_O
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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Orchid XP v8 <voi### [at] devnull> wrote:
> Actually, the main hall
> mostly features dinosur remains of some kind. And *lots* of children! o_O
That could be understood funnily.
--
- Warp
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Orchid XP v8 wrote:
> The London Natural History Museum also has a full-size blue whale model.
> And the lobby features a Diplodicus skeleton.
Hmmm... I'm pretty sure I was there, along with the British museum. I
don't remember the whale, so maybe not.
Also, New York has the only *actual* complete T-Rex skeleton. All the
others are plaster casts.
--
Darren New / San Diego, CA, USA (PST)
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Darren New wrote:
> Orchid XP v8 wrote:
>> The London Natural History Museum also has a full-size blue whale
>> model. And the lobby features a Diplodicus skeleton.
>
> Hmmm... I'm pretty sure I was there, along with the British museum. I
> don't remember the whale, so maybe not.
The blue whale is in the mammals exhibit. If you didn't visit that
particular gallery, you wouldn't have seen it. (Also, I'm not sure
precisely how long it's been there, or when you visited.)
> Also, New York has the only *actual* complete T-Rex skeleton. All the
> others are plaster casts.
The London museum has a few actual skeletons. Usually it's almost
impossible to tell what the hell you're seeing. The bone casts that have
been assembled into a life-like pose are much more interesting,
visually. (Obviously to a scientist the real thing is far more important.)
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
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> -----Original Message-----
> From: scott [mailto:sco### [at] scottcom]
> Earth is rotating. If the Earth rotated at the right speed then there
> would
> essentially be no downwards force (at least on the equator) and
> everything
> would float.
Question: Wouldn't it be more accurate to say that everything in
contact with the Earth's surface would float?
After all, after you lose contact with the Earth's surface, the Earth
should (theoretically) no longer be applying the centripetal force to
throw you out, meaning that Gravity would again take over.
The corollary to this is that rotating a space station for gravity only
works when you're standing on the floor; anytime you're floating in the
air, you can watch the whole station rotate past you as you just sit
there :)
...Ben Chambers
www.pacificwebguy.com
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>> Earth is rotating. If the Earth rotated at the right speed then there
>> would
>> essentially be no downwards force (at least on the equator) and
>> everything
>> would float.
>
> Question: Wouldn't it be more accurate to say that everything in
> contact with the Earth's surface would float?
No, even things in the air would appear to float because everything is going
at the right speed to essentially "orbit" the Earth (ok a few m/s difference
between 6400km and 6400.001km from the centre, but...).
Just like if you fire a rocket horizontally at the right speed (with no
drag, eg on the moon) it will stay at exactly that height and orbit the
moon. Spinning the Earth fast enough would essentially make everything
orbit the Earth around the equator, the force of gravity would be exactly
right to keep everything floating at that speed.
But also the air would be floating now, so who knows what would happen to
the atmosphere!
Oh and you might get a headache from the very fast day/night cycles ;-)
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Chambers wrote:
> The corollary to this is that rotating a space station for gravity only
> works when you're standing on the floor; anytime you're floating in the
> air, you can watch the whole station rotate past you as you just sit
> there :)
An interesting related aside: If you're in a rotating space station, it
seems like the "gravity" would appear stronger or weaker depending on
weather you were moving with or against the direction of rotation, so
you should be able to, for example, jump further in one direction than
another.
Assuming the radius is small enough for the effect to be obvious, that's
got to feel really odd.
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Kevin Wampler wrote:
> Assuming the radius is small enough for the effect to be obvious, that's
> got to feel really odd.
http://en.wikipedia.org/wiki/Coriolis_effect
--
Darren New / San Diego, CA, USA (PST)
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Darren New wrote:
> Kevin Wampler wrote:
>> Assuming the radius is small enough for the effect to be obvious,
>> that's got to feel really odd.
>
> http://en.wikipedia.org/wiki/Coriolis_effect
>
I had thought that the Coriolis effect only dealt with the "force"
resulting from an object changing it's distance form the axis of
rotation. Looking at the article, however, it appears that I was
entirely incorrect and that the definition covers what I described as
well. Good to know!
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Darren New <dne### [at] sanrrcom> wrote:
> Invisible wrote:
> > Hmm. But is your planet rotating? Or is your planet actually stationary
> > and the universe is rotating around it? ;-)
> The planet is rotating.
> http://en.wikipedia.org/wiki/Foucault_pendulum
Some people actually have misconceptions related to this, or more precisely,
related to inertial coordinate systems. Some people think that basically any
coordinate system, even a rotating one, is inertial, and can be used as the
basis of any inertial calculations.
Of course this is not so. A coordinate system which is not intertial is
an accelerating coordinate system, and a rotating coordinate system (such
as one fixed on Earth) is accelerating. The difference to a truely inertial
coordinate system is that this acceleration can be measured from within
the coordinate system itself. The focault pendulum is one example of how
this can be measured.
These people often also have the misconception that it's not possible
to say if you are in a truely inertial coordinate system or not. But of
course this is not so, as it can be trivially measured: If there is no
any kind of acceleration you are in a truely inertial system.
(If I'm not mistaken, the idea in general relativity that gravitation
is inertial movement and not an accelerating force, is related to this.)
--
- Warp
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> -----Original Message-----
> From: Invisible [mailto:voi### [at] devnull]
> The way the Oak does it is quite ingenius: IT USES THE LAWS OF
PHYSICS.
> Specifically, as water evapourates out of th leaves, that sucks more
> water out of the branches - which sucks water out of the thunk, whic
> sucks water out of the ground. So it's a completely passive system,
and
> it always delivers exactly the right amount of water without needing
> any
> control systems.
>
> Mankind, you have been PWN3D.
Rofl :)
...Ben Chambers
www.pacificwebguy.com
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