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* Posts by Chemist

1913 posts • joined 24 Mar 2010

Is lightspeed really a limit?

Chemist
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Re: Am I On Youtube?

"everyone has an opinion that "speculates" one way or another."

So why waste your time posting here - your speculation is obviously as good as anyone's .

I can understand it if you have no interest in this but simply to spout uninformed guff and then claim it's all too boring and anyway 'nobody knows' is juvenile in the extreme. It's clear from your posts that you've never tried to educate yourself about this other than by asking naive questions here and then complaining when you didn't understand the answers

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Chemist
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Re: Limits.

" drawing a comparison with a value which BY DEFINITION "

Here's an experiment, you don' know anything about absolute zero, you have a good thermometer reading to low temperatures - doesn't matter what the scale reads in. You build various kinds of kit to produce lower and lower temps. At a certain point, to your amazement, the temperature doesn't go down anymore.

You have reached a limit - the same throughout the universe - we merely define that as 0 K.

In another universe with different parameters the limit will likely be different.

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Chemist
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Re: @Destroy All Monsters - "humans limited forever"

"you can get anywhere you like as fast as you want"

Assuming you have a means of generating the vast amount of energy required. - otherwise I agree

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Chemist
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Re: Slow

Why assume light moves at 1 million m/s - it's KNOWN to move at ~3E8 m/s in a vacuum=c

If you or anyone else set up to measure it, no matter how you or they are moving it will still be measured at c.

You can't just travel at c+ or even c as the energy necessary to accelerate you becomes infinite. I've written the equation for relativistic kinetic energy in a post on this topic

If you are really interested the net is full of information about special and general relativity.

.

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Chemist
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Re: @Chemist

I was actually replying to a comment by outinoregan who suggested that I didn't without giving any evidence.

As for the negative temperature as you say that's rather esoteric and not directly related to my point. I apologise if I assumed that you had no understanding of the area but on these forums many people know enough to search/quote from the web but have no real knowledge of the subject.

My comment about "science education being rubbish" was due to several comments recently in the media where several pronouncements were made along the lines of "of course everything is possible" when clearly the history of the world, let alone science shows that there are almost certainly limits in certain directions.

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Chemist
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Re: @Chemist

Well I am really a chemist (retired) but I've spent a lot of my time writing scientific software, protein modelling and utilising quantum mechanics. All these things have required rather a good knowledge of physics..

Your evidence ?? and indeed provenance as you only joined today so we've not had the benefit of your wisdom before.

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Chemist
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Re: But Why?

Apologies - I didn't read the original post accurately - let's say classical kinetic energy is proportional to the velocity squared.

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Chemist
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Re: But Why?

"You might as well ask why energy increases with the square of velocity in classical mechanics?"

It doesn't - the classical equation for kinetic energy is 0.5mv^2

The equation for relativistic kinetic energy is :-

E=(mc2/sqrt(1-((v/c)2)))-mc2

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Chemist
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Re: Light or Gravity?

"time slows down closer to a bigger mass"

Mass alters spacetime and seriously affects time near large masses, but c is c

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Chemist
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Re: It's my understanding.....@Chemist

I don't think anyone can give you a 'simple' explanation for this. Many topics are rather inaccessible to analogy - the theory and the mathematics give certain predictions and measurements agree.

It's not the only theory to be 'difficult' - the predictions of quantum physics are equally difficult to rationalize.

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Chemist
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Re: FTL - easy-peasy...

"is perfectly possible "

Well potentially possible as you need to go moderately close to c, say 0.95c, but where is the energy to get there coming from ? An (unrealistically ) modest 1000 tonnes ship would need 2E23 J to reach 0.95c - if the propulsion 'fuel' had to be carried on board that would add to the initial mass.

2E23 J is a LOT of energy. It's roughly 400 times the annual energy production of Earth.

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Chemist
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Re: Light or Gravity?

"does light move faster when closer to a bigger object"

No. Worst than that you are now edging dangerously close to General Relativity

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Chemist
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Re: Slow

AFAIK and this is where it gets weirder.

If you fire a gun, in your local frame of reference ( the ship ) the bullet will exit at it's normal muzzle velocity as far as you are concerned.

HOWEVER an stationary observer relative to you will still only see a slightly increased speed of bullet. This is the same kind of thing as 2 observers approaching each other at 0.55c only being seen to close at ~0.84c relative to a 'stationary' observer.

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Chemist
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Re: I don't get it ...

"lightbulb "radiates" light, thus using energy to "propel" something we can see?"

AFAWK the proton mass is zero - so it can travel at c, indeed in a vacuum it HAS to travel at c. VERY light mass particles like neutrinos can get very close to c which explains why there was so much confusion over the CERN/Grand Saaso experiment recently.

SR is a very well tested theory and physical measurements at close to light speeds on particles in accelerators match the theory.

I don't know why people EXPECT the universe to be set up to allow us to explore the stars - don't get me wrong I'd love it -but it doesn't mean it will happen

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Chemist
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Re: I don't get it ...

"can't I create a car that travels at 60mph if light travels at 50mph "

The normal, simple model for this is as the speed of light is approached the mass of the vehicle actual increases in a non-linear manner so that more and more energy is required to accelerate it. The mass becoming infinite at c unless the original rest mass was zero.

This might sound like madness but in particle accelerators that is precisely what is seen, furthermore time itself alters so that short-lived particles have a vastly increased lifetime. This all predicted by SR.

Reality is pretty weird

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Chemist
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Re: Limits.

"The drive works by using a wave to compress the spacetime"

Sorry this has nothing to do with it. The so-called warp drive even if it eventually proves feasible allows a ship moving less than c to travel large distances quickly by altering spacetime using exotic matter and a great deal of energy.

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Chemist
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Re: @Chemist

"but it may be possible to be beyond the speed of light, in which case the object in question would have to have negative mass/energy."

I point this out below somewhere although earlier in the day.

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Chemist
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Re: Limits.

@Androgynous Cupboard

I do appreciate a well-reasoned argument. How about you provide one

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Chemist
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Re: It's my understanding.....

That's because 'your' maths isn't valid. This isn't linear that's the whole point. I suggest you read a little SR

To get 1kg to 0.99c needs ~5E17 J

To get 1kg to 0.999c needs ~2E18J

To get 1kg to 0.99999c needs ~2E19J

as v->c , energy -> infinite

Even the LHC can't accelerate it's minute mass of protons to c and that uses a colossal amount of energy.

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Chemist
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Re: Limits.

"http://en.wikipedia.org/wiki/Negative_temperature"

Now that you've found it try reading it and understanding what it actually means - here's a snipette :-

"by contrast a system with a truly negative temperature in absolute terms on the kelvin scale is hotter than any system with a positive temperature. If a negative-temperature system and a positive-temperature system come in contact, heat will flow from the negative- to the positive-temperature system."

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Chemist
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Re: Limits.

I know it's by definition but it's amazing how many, otherwise intelligent well-educate people, think that it's just something that will be overcome as we learn more.

Incidently there may be a potentially max. temp. around 1E32K where physics breaks down so that all predictions fail.

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Chemist
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Re: Limits.

So several downvoters appear to believe that < absolute zero is a perfectly reasonable concept ?

Science education is appalling !

Absolute zero IS one of the limits - certainly in this universe

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Chemist
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Re: Limits.

"A shadow can travel (or be perceived to at any rate) faster than light. Not terribly functional mind."

As can the spot of light from a rotating laser at sufficient radius - but it's not the same as FTL

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Chemist
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Re: Limits.

Why not suggest going below absolute zero as well (Hint : below absolute zero doesn't mean anything )

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Chemist
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It's my understanding.....

that nothing in SR forbids FTL - just that approaching c from either direction requires infinite energy for anything with non-zero mass. It does, however, hint that anything that is traveling at c+ is a very strange beast indeed

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Skype worm chats up victims - then holds PCs to ransom

Chemist
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Re: Skype takes the user experience very seriously

"Who uses credit rather than a subscription?"

I do - mainly use it for calling my mother from our holiday home in Switzerland - so £10 lasts for ages. Most other calls are skype-skype.

If I don't use $9/month why would I have a subscription ?

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Chemist
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Re: Not surprsing

4.0.0.7 here mate, works fine

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US boffins get Nobel for work on cell receptors

Chemist
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Re: Applause!

"So well deserved, this one"

Agreed - spent a lot of my working life on these devils.

Interestingly the full horrendous complexity of how they operate still hasn't been elucidated

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British Library tracks rise and fall of file formats

Chemist
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Re: Data size

I remember getting my first 470MB drive. It was like opening the fridge and finding Wembley stadium there.

Mind now I come back from one holiday with 5GB of video.....

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Big Blue bigwig: Tiny processor knobs can't shrink forever

Chemist
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"even long enough for someone to figure out how to shrink atoms down to a more convenient size"

Sorry this universe's parameters are so inconvenient - but it's the only one we've got at the moment

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Linux on ARM breakthrough to take away Torvalds' arse pain

Chemist
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Re: But wait

"Please refrain from feeding the troll"

Well I know what you mean but some people are SO ignorant about Linux that it's quite hard sometimes to tell them apart from trolls

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Chemist
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Re: But wait

"and least used OS "

What !!

(Hint : 1% of the DESKTOP market )

(Hint: think phones, routers, video recorders, televisions and supercomputers, servers.....)

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Astroboffins to search for mega-massive alien power plants

Chemist
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Re: Congratulations

12v does NOT = 0.012kw and the rest of your absurd ramblings make even less sense.

Troll or fool - it's hard to say

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Politico's locked room mystery Linux install crime solved

Chemist
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Re: On the other hand ..

""corrupted and erased the hard-drive of the campaign computer server"

I quote The Register - who they quoted is anyone's guess.

In my amateur experience using Linux as a file/printer/compute/web server is easy.

( of course I'm not a politician )

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Chemist
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On the other hand ..

a Linux installation can only improve his server

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They said it wasn't right for biz - but Samsung unveils TLC SSD

Chemist
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Re: How I learned to stop worrying and love TLC

"When SSD's come along, guaranteeing data destruction isn't going to be as easy.

"

BLOWLAMP !

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Chemist
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Re: How I learned to stop worrying and love TLC

"from time to time, be spectacular data loss incidents."

And this differs from HDD how ?

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Microsoft Research man: It all starts with touch

Chemist
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"be a good idea that companies are not allowed to patent an idea "

Ideas are NOT patentable - at least in sensible countries- only implementations are patentable. I can't patent an idea for treating a disease for example but I can patent a chemical entity that has some effect that might be useful in treating that disease, even if it turns out to be not so useful in practice due to side-effects or unrealistic doses or whatever.

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Pirate Party takes Mayor's chair in Swiss city

Chemist
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" Pirate Party takes Mayor's chair in Swiss city"

City ? Population about 1500 !

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NASA working on faster-than-light drive capable of WARP TEN

Chemist
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"Add to that the fact radio transmissions travel a little slower than the speed of light"

I think I'd alert a physicist about that !

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The Jupiter Ace is 30

Chemist
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Re: Some Forth:

Sorry, should qualify, that's for indirect threaded code as per most early 8-bit Forths

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Chemist
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Re: Some Forth:

No, most 8 bit forths need to JSR which , of course, can be a variable length routine depending on processsor. With the 6809 the actual code to implement NEXT is 4 bytes and can be put in-line saving the sub-routine call at the expense of slightly longer code

LDX 0,Y++

JMP [0,X]

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Chemist
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Re: Some Forth:

I'm more impressed by NEXT in 6809 assembler - 4 bytes !

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Microsoft preparing for diskless Windows 8 PCs

Chemist
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Re: USB 2.0

"I get a desktop up very quickly."

Ditto

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Windows Server 2012: Fickle pricing smacks Europe, Oz, Japan

Chemist
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Re: "Can you think of a reason they [Microsoft] can get away with this?" ....

I've only use Linux but that's not the point at all.

If you've backed yourself into being dependent on Windows ( or anything else) that is a de facto monopoly, even if it's largely self-inflicted.

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Chemist
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"Can you think of a reason they [Microsoft] can get away with this?" ....

Simple - if you MUST buy Windows Server then it's a de facto monopoly - they could charge what they want

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Old men who use computers less likely to get dementia

Chemist
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Re: NOOooooooo!

Excellent - many thanks.

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Chemist
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Re: NOOooooooo!

I know what you mean - I was taught Physics by a guy who had worked on the Manchester "baby" - he had a photo showing him stripped to the waist working in a cellar surrounded by racks of valves.

I thin Douglas Adams sums it up very well in a passage that kind of parodies the "Seven Ages of Man" speech from "As You Like It" but I can't just put my hand on just now. It's along the lines of - a technology that's invented when you reach a certain age is new and exciting and you could possibly get a job working with it ..........

I'm sure someone will have the passage off by heart

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