Royston

Not that I know enough particle physics to give an informed response, but I voted yes.

I smoke roughly 10 rollies a day, more at the weekend. I only drink on nights off study, science is keeping me healthy I rarely eat junk food, I despise McDonalds or anything similar, I like to eat food, not crap. I do sometimes binge on fatty food, but it's home cooked e.g a whopping huge plate of bolognese for example. I do (ahem) dabble in other recreational activities, but not nearly as much as when I was younger, I think like a balanced diet, work and play should be well balanced too.

Depending on the area, and if they get caught, they'd be arrested for vandalism. Like I said, the graffiti culture is ingrained into the culture of the city where I live, so there are areas where graffiti has become part of the city, rather than something that's deemed as defacing it. As CDarwin points out, these areas have now segregated from property, to public space over a period of time. I welcome that personally. Some examples...http://www.google.com/imgres?imgurl=http://bp1.blogger.com/_JTHkIoacY6Q/RncRZF9sHZI/AAAAAAAAAIE/kbo40LsvktE/s400/DSCF20661.JPG&imgrefurl=http://stellastarguitar.blogspot.com/2007/06/brighton-graffiti.html&h=400&w=292&sz=34&tbnid=r0tjLSGULIwJ::&tbnh=124&tbnw=91&prev=/images%3Fq%3Dbrighton%2Bgraffiti&hl=en&usg=__TtzxBmgBN_HuJn0MaWDuQQSFdOA=&sa=X&oi=image_result&resnum=2&ct=image&cd=1 However, as I said (and I'll run you through an example in a bit) there is, what could be deemed as appropriate artwork, and just scrawling 'f*ck the police' on the side of a law courts is purely to illicit a response, and get people's anger up. I get your point, but as photography and filming is permitted in public areas, then no. Ok, suppose I went to my local Baptist church (in England they have the highest percentage of believers in YEC) and scrawled on the side, 'YEC's are f*ck wits !' All I'm doing is trying to anger the members of that church, with a cheap shot. However, if I painted a huge elaborate mural, stating 'Young Earth Creationism is a Belief, not a Science.' and below 'You're welcome to your belief, but please keep it out of the science classroom.' I'm merely using the Church as an anchor to bolster a legitimate point. I could throw in a picture of a microscope, perhaps a fractal et.c. Yes, it would probably make the members of the Church angry, but they should only be angry that I've invaded their property, not the message that underlies the graffiti. Perhaps we're talking about two different things, but that's what I gathered from Pangloss's point. Back to the property side of things, and as an aside, (slightly different argument) but this thread reminded of this. When I visited the Grand Canyon there was a sign stating 'This is our Grand Canyon, look after it' or words to that effect, the Grand Canyon doesn't belong to anyone, and that to me is an example (although different context to CDarwins point) of public property over public space.

ajb, you're more than welcome to visit, and I'll happily give you a crash course in the art of shredding. If you could send us a PM nearer the time, I'll give you directions et.c

I'm a firm believer in that you're never too old to learn anything. Although I've played the guitar most my life, it's incredibly easy to pick up (no pun intended) Which is a passion of mine, along with anything electronic...feel free to PM me if you need any advice...you're a bit too far away for private tuition. Paranoia is quite a dab hand on the guitar as well, so he's somebody else you could ask. I could quite easily spend all day playing as loud and fast as possible, in fact I'm having a night off study tonight, so I may just do that.

That's certainly the case in England, there's quite a distinct divide between tagging the side of somebody's home (or just scrawling some hum drum activist message), and the areas around my city where certain hot spots for graffiti have become accepted as adding to the area, rather than taking away. This has happened over time, where artists have been left to their own devices to make certain areas a lot more interesting to look at...this is privately owned and council owned property. Not just skate parks, but the back of shops, alley ways, lamp posts et.c There's an etiquette involved, where I'm sure it was frowned upon when certain areas were subject to graffiti, but over time it has become part of that area, and accepted. People are free to express their art, be it political in content or not in these areas, providing it has content and flare, not just some childish scribbling. The area I live has attracted many artists, and their work is generally of a high caliber, and unique in style. So I think a distinction on what we're discussing is important.

I searched for a similar thread, but couldn't find anything. I have my first exam (in 14 years ) which covers physics i.e kinematics to basic QM and practically everything in between...so a lot to go over. This course consisted of 7 books roughly 250 pages each. I've worked out a revision strategy, such as going over chapter summaries and refreshing my memory on information, which I've forgotten or had trouble with. Setting aside a day each week to practice the math, as well as collating the main principles. I'm also going to answer as many questions from each category for practice, which are on a DVD I get with the course, as well as tackling a specimen exam paper. I also have revision notes courtesy of my Uni, where the course materials are condensed into a few pages, outlining the main points and equations et.c.All easier said than done, as I'm sure I'll end up spending too much time on one thing, or panicking about another. TBH I'm pooing my pants over sitting an exam after so long. Looking over the specimen exam paper last night, I've forgotten quite a bit. This of course can be rectified, providing my strategy is a sound one. So, does this seem to be a good revision plan ? Do any of you smart cookies have some revision tactics they'd like to share. Any help or advice would be really appreciated.

There are a number of versions of Mach's principle depending on how it's applied, none of them have anything to do with the 'origin' of mass. More they're statements on inertia, or how you measure relative motion e.g inertia of a body can be influenced by a distant object such as a star.

I'm pretty sure Smolin raises the point in 'Three Roads', but my ex is sleeping in my bed at the moment, and I don't want to disturb her to find out (the book is in my bedroom). Martin is right, in fact I remember discussing this definition with Bascule on chat, and he said the same thing i.e it's a tautology. Nothing can exist outside of everything...well thanks for that. What Arch is arguing is that the Universe is all we can currently measure, but that to me is the 'know Universe.' For instance, if we can detect higher dimensions via experiment, then they instantly become part of the definition of know Universe, they were always there, correct ? Therefore they're a part of the Universe, it's just we have yet to find the means of proving their existence through experiment. I was gullible enough back in my layman days, to think that Smolin's statement is a physical principle, it's not, for the reasons already raised. I'm sure we can labour the point till we're blue in the face, but we're discussing a definition, not physics, so if somebody wants to argue the Universe is this, that, or the other we probably won't get very far. It's really a silly word, that's limitless in extent, and can be filled with whatever we care to choose, that we feel is part of the Universe, discovered or yet to be discovered.

That will always be something to consider, but this article highlights the situation in the UK recently... http://www.guardian.co.uk/society/2008/mar/23/drugsandalcohol.health1 The impact of the smoking ban on pubs... http://www.guardian.co.uk/business/2008/jan/04/business.smokingban The point is, these two factors only confound the issue, of people choosing to buy cheap alcohol (which obviously means more), sit at home i.e no waiting times at the bar, as well as not being in public (although many people couldn't careless how they conduct themselves...just walk through my neighboring city on a Friday night.) I'm not saying bring back smoking in public places et.c, just highlighting the situation in the UK, and the so-called booze Britain that's been coined by the media. The area where I live at least, has always been renowned for people going out to get very drunk, but it's a seaside town that attracts people from across the country...so not the best comparison. 24hr licensing has also caused a rise in more rowdiness in the city. I'm certainly not adversed to people enjoying themselves, by any stretch of the imagination, but binge-drinking (that is to get drunk, not just a few pints) is definitely a real thing in the UK, but I feel it has been for some time. However, the recent changes in policy on licensing and smoking et.c, really doesn't help matters. I'm sure there's more to add, but I'm off down the pub

But then it just boils down again, to whether such ideas can be falsifiable by experiment. Whether an idea follows a mathematical formalism, isn't enough. This just opens up a number of possibilites of what reality 'could' be, I don't really class that as science, just a subset of. Meh, I missed this bit... Interesting.

Sorry if this has already been mentioned before, (I know this thread is primarily about the situation in the US) but the problem in the UK with so-called binge drinking (which to be classed as binge drinking, it's something silly like 4 pints) is purely the price. The age thing doesn't come into it, there are loads of bars closing across the UK due to large supermarkets competing on prices of alcohol, and along with the smoking ban, most people would rather get a cheap crate, and relax in with their mates playing playstation...you can get a lot more for your money if you buy lots of alcohol. The age groups of kids on the street, and in parks falling on their faces with a bottle of cheap cider in their hands, is around 13 to 17. If you're old enough to buy alcohol, then it's more than likely you'll 'get some in' before going to the pub i.e 18 onwards...purely because bar prices are ridiculous at least compared to shop prices.

M3 is a globular cluster, and is within our galaxy. I'm not sure what telescope you're using, I managed to find M13 the other night (but I'm on the Northern Hemisphere) and it wasn't twinkling per se, it looked more like a cloud of gas. I've only been using my scope for the last few months, and the weather has been rubbish, but it's the first globular cluster I've found, and it was very cool all the same. Pradeep, just asking, but why do you start all your threads with a thumbs down ? That indicates you're posting something you don't like, or don't agree with.

I wasn't too sure about Dr Jekyll's post, but not confident enough to comment, from what I understand of the Friedmann equations (which is nowhere near enough...*but there's some good news, which I'll explain about in a sec.) is that, as you said [math]\Omega[/math] is just the observed density over critical density, i.e [math]\frac {p}{p_c}[/math] IIRC a value for the critical density is found be setting [math]\Lambda[/math] to zero. There's the Hubble parameter [math]H[/math] in the equations which gives the rate of expansion. You can probably tell my knowledge is a little cursory, but the equations give an overall geometry of the universe...spatially flat, open et.c *However, I started a thread a while ago, as I was concerned about the depth in to Einsteins equations (which you need before moving on to the Friedmann equations) and cosmology in general that my degree would cover, and lo and behold two courses are being introduced in 2 years time, which cater for exactly that, which is great news for me, as I'm looking to do an MSc in the subject. EDIT: I just remembered there's a download available where you can tweak the values of the Friedmann equations, so you can get a graphical representation of what's going on. It was posted by a tutor on my Uni forums (different course), but sadly they get closed each year, but I'll try and find it nevertheless.

I'm very much the layman in this area, I won't be covering this formally for another few years, though I'm very interested in the subject all the same, despite my lack of technical knowledge...hopefully Martin will swing by and clear up any confusion.

Hence I voted 'depends.' Well, why wouldn't there be mistakes ?

Doh, not sure what I was thinking when I posted that (I've got tinnitus at the moment...excuses excuses.)

It might be spatially infinite, we simply don't know yet, hence the value associated with [math]\Omega[/math]. Less than 1, would be infinite.

I presume you're referring to the many worlds interpretation? I'm a bit tentative when it comes to this. Although it agrees with quantum formalism, and it does solve the problem of wavefunction collapse due to observation i.e if you think of the wavefunction before measurement as a number of probable eigenvalues, then the measurement causes the wavefunction to collapse to one eigenvalue. Or with your example, the cat is definitely alive. (It could be dead...not sure if you're a cat lover.) The many worlds interpretation does away with this, by saying there's a universe for each probable eigenvalue...so the act of measurement doesn't have the effect of forcing the outcome into one, definite value due to observation. However these universes branch off completely seperate from our own i.e there is no way we can test for their existence i.e (as already said) the Universe is by definition everything, and the same applies to these alternate Universes. You can't probe (tee hee) or test for something that's outside of everything, it doesn't make sense. It's worth noting that you can't consider these Universes next to each other, or collected in one Mother of all Universe's, because they, by definition would cease to be Universes. That would be a nice way of making the whole thing intuitive, but science isn't about making things intuitive, if the experiments and math say 'this is how it is', then you just have to deal with it. I personally don't like the many worlds interpretation, because you just can't test it's validity. It will always be a 'could be.' EDIT: Sorry if you already knew all this, I'm bored at work and just fancied rattling on about something. EDIT II: ack, not sure why I was typing Universes's I'm really not thinking straight today (corrected)

Hang on... north's conclusion to a non-expanding universe, has little or nothing to do with... then... Since when has space-time been two dimensional ? What precisely is 'the circle of movement of things, which of course leads to a sphere' ? I'm really struggling to understand what you're talking about. I just don't want to see people confusing ajb's rather neat explanation, (which, mind you, I feel can be easily misinterpreted) with whatever north is talking about. Just to make it perfectly clear, all current observational data, shows we're in an isotropic universe that is expanding at an accelerated rate, this data is becoming a lot more refined recently, so let's not confuse the issue, for casual readers.

Which begs me to ask the question...are you two sleeping together ?

I spent nearly half an hour constructing a post explaining the history, and evidence that modeled big bang cosmology, only to press the back arrow, realizing that it's pointless arguing with somebody who has clearly no knowledge in the subject...and who has already made their mind up. I'm not meaning to sound pompous, but your idea really doesn't hold up. Jeff, do yourself a favour and do some courses in astronomy, I guarantee you'll see your idea will break down. If you're so adamant that your idea is correct, then you need some mathematical rigor to back your idea up, not only that, but you'll have to find error in accepted principles (and that, I'm afraid is very hard indeed)...good luck.

It's likely you were walking on an equipotential, so the potential difference would be low. Radially outwards from the lightning strike i.e [math]\Delta V = -\xi_r \Delta r[/math] you can imagine circles that form the equipotential lines. If you had been lying with your head on one, and your feet on another, the potential difference would be high i.e [math]\Delta r[/math] so you would be more likely to get a nasty shock, rather than a mild one. The voltage does diminish with distance, as you said...it's hard to give any figures, because the intensity of lightning varies. It can be as intense as 30 million volts.

I was told off a few years ago, for overuse (heh, SFN addict), but I've moved desks and can get away with it now. Surely you can squeeze in the odd half an hour or so, when you're at home, or are you just too busy ? I'm surprised this site hasn't been blocked at work, I'll be mortified if that happened, because I'm just too busy in the evenings (my degree would suffer, albeit I'm on here to learn.) I hope you're not essentially 'outta here', surely it's not a be all, or end all.