lakmilis

the one providing the modulus thing is right.. When starting off with a = b (it is more pertinent to state +-a = +-b) Else, you will need to use the law of modulus which will lead to the only positive values of a n b and hence one will get 1= 1. If one doesn't use modulus, then one starts with the premise as stated above (+-a = +- b) hence 1 = -1 is a valid answer as the preise states (+- 1) = (+-) (-1) For the poster who mentioned division.. yes , it is not* valid to divide by (a-b) with the premise a = b. And about the square roots LOLOL. same thing: [MATH] +-\sqrt{4} = +-2 [/MATH] principal square root implies the modulus of the principla root, hence the positive value.. thus one can really suppress the +- ahead of the square root sign. Ok my tex is rusty lol: cameron : to use math in symbolic form, there is a syntactical 'language' called (la)tex.. (look up tex). if you wish to use here for example, you would type : "MATH] equation(s) according to tex syntax [/MATH" (PS. YOu would have to add the square bracket in front of MATH anf after /MATH but if I would do it, the line would be parsed as a MATH segment. i.e. : [MATH] equation(s) - according - to - tex - syntax [/MATH] )

Ye norman.. I am not looking to see who has the strongest argument or anything but because I see that question you posed to counter as a very good one... and I know swansont to be the one i consider has the generally best answers to criticise a problem (popper style). Whilst you are more open to say but what if... and I just think that a reply there form swansont could help develop that investigation between those two arguments you both provided.

cheers Swans (ps. ye , had a look at some of the cartoons of yours the other day, not as sharp as Gary Larsson generally but some did indeed make me crack up )

I do like these who is GR? and circumference squared.. cameron Spend some time on wiki , before trying to figure out things from a concept you don't quite grasp. However, you do have a very keen explorative mind.. that is very good to have

Well.. This would be a so-called naked singularity and would be violating the cosmic censorship (which has been reopened for debate), but yet, doubt this could happen. A singularity in GR space-time typically is a function of mass so I can't really see this being a feasible thought experiment. Ok, so now we assume the associated mass is there (like a mini created black hole from the LHC let's say). In reality , any small black hole of these scales would most likely be so unstable , they would break down.. but more interestingly, most likely they would be so minute, they would interact less with atoms than even neutrinos (earth herself would be a 4 mm black hole .. [ok, an artificial black hole is the only time I will accept a S.R. hold, so ok maybe 8 mm then]). Any larger black hole which in fact interacted with mass, would probably be sustained yes, and would create such an enormous gravitational force, earth would just be ZWIP, sucked in. BHs as we know them, are stable bar Hawking radiation. There are no compressing factors in an already established BH. It generates it's own existence, so additional mass only makes it 'grow'. Stopping mass would not make it explode. Again, any BH of any size which is large enough to start interacting with baryons and leptons anywhere in the area of earth would most likely destroy Earth exponentially.. The time it would take to suck us in, would be according to initial size and placement. Earth would probably become an accretion disk but we are talking this happening on anything from t = 0 (interaction with baryons/leptons) till lol no, this would be pure guesswork from my side as we have no statistical data to play with in such a scenario (but it would nonetheless be exponential). {snowball effect}. Again, if that BH woulds first be large enough to interact with baryons/leptons, when it would first be large enough to start affecting the molecules, it would not take long before any larger constructs would all get sucked in. (If that guy would get sucked in, so would Earth pretty quickly thereafter).

It would be moving at c away from you... thats the great mindboggling part of relativity AND if there was an external reference point, they would also measure both to be travelling at c. The thing with those thought experiments is that an inertial reference point can't be travelling at c.. which kind of makes that thought experiment invalid... of course we can say well a photon which then emits another photon.. soo all fair. Whatever you do.. in reltivity , light will always from all valid reference frames be travelling at c, no matter how you are trying to bend this rule, it won't work. Merged post follows: Consecutive posts merged Thanks for saying this swansont, cos that is how my reality works.. and had you nto said this, I would seriously be going bleep bleep BSOD.... I would of course counter this stopping thing with something hypothetical like : If you hit a mirror with a light beam in space normal to the surface, and c is maintained.. how then can the beam change its direction 180 degrees without slowing down? (When I was young, this I posed to myself to look into refraction etc, if in fact absorption , emission etc, always creates another photon which has information passed on from the incoming photon to fire off at the appropriate direction and velocity.. eg. that mirror or light from space hitting another medium lets say, refracts and 'slows' down, for me was perhaps an indication oof a photon pair interaction... Anyway.. these were just things I was thinking about as a youngster.. standard physicist teachers just said w00t?

I got a bit shocked, cos my whole knowledge of everything would just collapse like a probability wave collapsing had one stopped light entirely.. that would be the same efeect as if someone told me they had reached 0 Kelvin. Then I even saw this article was from 2001 or so.. then i really went nuts. Until I run the video, where the dane says ye so it ende dup being 1 m/s... REMOVED... have they really stopped light? Ok.. that's it.. im never ever gonna think again.. just gonna sing duppeyyydoooppooopppppp to myself and accept anything and everything... hell why not.. slowing it down to anything but 0 i could accept... I just can not accept yet.. that light can be stopped to 0 m/s. ddoooopppeeeeyyddddoooppppddddiiidddooopppppppppplllaallaaiillaaaaaaaaaaaaaa.breakdown.end of line

Martin.. I in some of my early metaphysical models (nevermind what they were), had postulates that 'tachyons' were not particles but a field. Anyway.. nevermind that.. I saw someone say run off and you went on about the misview of the big bang. sure.. but to their defence.. the universe is expanding faster than the visible universe, i.e. the very first photons. *If* tachyons would be particles, sure.. I agree with you they can be floating past us etc, no need to be ONLY ahead of the visible universe.. but it would also be tru to say.. that they indeed would be constituing or residing as well in the non visible part of the universe.. aslight has not reached there yet. Someone also said.. ye but what if we just can't observe them by nature.. ah yes.. skepticlance or so... well if absolutely no interaction.. why not? sure.. and why not pink elephants flying in yellow jaguars under bork , twelve degrees skewed towards dangdang? It is of no relevance, hence sure... why not....

we see mergers now going on in some binary systems.. ... these processes last thousands and millions of years. It tends to be not celestial events happening suddenly, but rather our equipment which gets better every year (and every half decade we get a new bling bling which helps us). Although of course , once in a while we get a nice flash of something which happened some odd million years ago Merged post follows: Consecutive posts mergedYe Martin.. Normally I feel things are pretty well guessed at or so, or deduced.. SagA* just seemed a bit weird to me (obviously know the wiki entry, wouldn't be asking about it , if I just needed the wiki thing Ye.. to be honest.. I don't have more specific queston on it right now.. just curious on the overall signature. You think its the whole thing hmmm... I think SagA seems to be more discrete than that... also moving at that speed and with thatsize.. I find it tantalising.. I gave up on where my philosohy was taking me , as my models were predicting quasars of ~5 kHz but till date the fastest we've found are what... 1.5 or so? 2? sigh.. just didn't cut it. So now I just look around the cosmological map in a very Socratean way :/ SagA has got me curious though (plus S2 sorry)

I'm sorry... it was so bad I kept falling asleep and never really could give you some detailed analysis of it... deleted it pretty fast! Didn't know this thread was based on a particular program viewing? Anyway.. Martin, I was about to start a thread when I saw your post about the cosmological expansion (or cosmological redshift etc.). (And hey, these questions are laymen , not technical as such). I am thinking.. we see light from for example andromeda.. no strike that for simplicity lets say a star in our galaxy.. 10 000 ly away. (and let us just say it is moving away from us, the principle is important, not the actual dynamics of the galaxy.. we could use a redshift galaxy as an example). Anyway.. light reaches us now, and so when we say.. hey this thing is 10 000 years away.. is that AFTER taking into account it was perhaps 7000 ly away when the light started reaching us or was it 10 000 at the time the light was emitted and so now would actuall be, lets say 11000 light years away?

Ok.. so what if they were more than 400 light seconds apart? (1 AE for example)? (sorry, I was reading the whole post but QM has long abandoned me , the little I knew. But was an interesting chat, then those few last posts really got me. (Hope me asking that, isn't entirely absurd)..as in I see your point swansont, but could* they be more than 400 lightseconds away in this example (assuming measurements took 400 seconds) and if so, would it indeed be superluminal then? OOps.. language mix-up.. I believe it is AU in English. (~480 light seconds).

Mysteriboi.. to ask that is anyone's equal guess. It is not science, but science fiction. We could hypothesize.. I myself believe that theoretical physics will be working on 'modems' modulate, demodulate , objects (even living organisms?) so that we are deassembled, then reassebled somewhere else.. (like the star trek zappers kinda).. sometime int he future. The question is, can this be done with the 'mind/emotion' part of organisms as well bla bla. (I look at this as a possibility with roots inthe aspect principle, or the photon pair experiment as it's known as I guess). Anyway.. it's purely speculative your question and no matter which arguments, solid or not from physics/maths... it would be simply a hypothesis with little merit of understanding as wormholes per definition are beyond GR + QM for at least 2 centuries more I'd say (again.. that is just an arbitrary proposal). (i.e. stating that we know anythign about information inside a BH/wormhole)

I just downloaded some THC documentaries in cluding some on space... more amateur , crap documentaries I have never seen. Stay well clear of that channel!!! (don't know how it is on archaelogy and the like though but certainly is C R A P on anything in physics).

hihi.. I haven't been on the forum in agesssssss and am reading around a bit.. and I have to say.. I noticed this North's comments here and there... and I most probably would agree with you.

did you mean travelling whilst accelerating at g?

And Norman asked, hmm how can you say that, giving a counter argument. I really would like had you Swansont, given yoru reply.. either to refute the counter argument or not being able to do so.. as to see how you both are coming from on that question. (or ajb, another geometer hihi [internal joke there ajb might get] who has very good evaluations on these kind of questions). Hope to see at least... or as often can be the case.. Norman further answering his own posed questions ;p lak xx

bleep Merged post follows: Consecutive posts merged Oh dear.. it's a year on.. but of course it should of been 13/4 on the right.. .not -11/4 LOL .. jees.. how did I do that?

haha ajb.. so sorry.. almost a year on.. but thank you for the answer Geometer it is!

No , it is not. First of all, no inertial mass (hmm in another topic someone states photons have some inertial mass but ok, conventional mass then) can not achieve the speed of light (infinite kinetic energy). Again, as stated, classical kinetic formula works for v << c (less than 0.1 c lets say as some arbitrary boundary). Merged post follows: Consecutive posts mergedThis by the way one is taught in last year of highschool (well, at least in Europe). However, all A-level books from around the world, use the wrong way of deriving the Swharzchild radius for example.. and uses classical escape velocity which wouldn't be the case when of relativistic escape velocities. It just happens to be that using classical kinetic energy , yields 2GM/c^2 (whereas special relativity predicts GM/c^2 so half the product). In GR however, through proper tensors, one gets the 2GM/c^2 again. This is something I pointed out (the half product from SR) when I did highschool physics but only to my teacher. No books have changed it or commented on it as I know of they still do it sigh. However, I am also an opponent of the S.R. as no black holes (bar perhaps SMBHs? although pfff) have no momentum, hence extreme Kerr holes I think are the real natural ones... i.e. GM/c^2). This however will have little consequence for centuries probably till we actually might be able to interact with them somehow. but anyway, this was off-topic. Merged post follows: Consecutive posts mergedPS. I don't know why I get doubleposted... really sorry..I clicked on that apostrophe once, don't know how ot use it and this has been happening since :/

In all honesty, If we were to be wiped out a year on, I'd personally love some mayhem and anarchy before going down ;p Nothing worse than finally quitting smoking, deciding to change your life in an exciting way, then when you start seeing the atmosphere turning red, the telly going: ok, this burning rock in the sky is about to destroy us.. sorry, we couldn't tell you because we didn't want anarchy before extinction..... DOH No, more to the point. ethically , it's insane that such things aren't informed. I till this day, can not fathom this idea that people panic lol. When sh** hits the fan, do people nto help out others? They act in panic, not shrivel up. If we had one year to try and survive as a species we'd need to frikkin know. So we could start digging racoon holes right away ^^ Merged post follows: Consecutive posts merged I HAVE TO START LAUGHING... nice one.. one gets flooded with 12 meters of water above ya... ye.. get into an underground shelter... with a periscope to check when the water is gone.. PS... take a DEEEEP LOONG breath before going down Merged post follows: Consecutive posts merged Erm and so *would* a supervolcano eruption be, like Yellowstone or near Gibraltar ones. Merged post follows: Consecutive posts mergedlol ok airbrush.. I assume you are a high school pupil ye? Anyway.. now you know you yanks why the imperial system you use from the English just is useless. Why 0.5 ? Lol , it's called kinetic energy from Newtonian (classical mechanics kid): E = 1/2*m*v^2 . E = mc^2 is a measure of internal energy stored in mass (it is more a form of 'potential' energy than kinetic, loosely speaking). Anyway, about conversions. Stick to the base unit... So if something is given in g/cm^3 or so, to get it in kg/m^3 you would convert X g = X*E-03 kg / (10E-2 m)^3.. etc... when you finally get your unit in base values (m/kg^3) , you can then convert to other things... (when you get used to the units, you can save a lot of time by knowing which relationships algebraically are equivalent.. but it's a start).

Also.. just to put it in some perspective.. your 'doomsday equation' (god, it's fun to be stoned, innit ;p) basically is: -Hey, I am guessing somethign might happen when other effects affects us when it reaches us long after the light of that effect (ie. 166 times later as you say). Ok, Now, the centre is what, roughly 26000 light years away? Meaning it would take about 166 * 26 000 years for these effects to come about: ~ 4.3 million years from now lak

It is interesting.. Ok Could I inject two (sorry, pretty off topic questions somewhat, although they started with this): A. What REALLY is Sagittarius-A*? It's apparently at the edge of our SM-BH, but a star that big??? PLease.. It seems as we only know it more or less as a light source? and B. (ok, this is the off topic one, my apologies beforehand, maybe I should put it as an eternal topic starter which comes up).. Yup, the 'centre of the universe' question. We know that all motion (linear) taken some reference point in space, will be moving away and as such , any reference point taken, will be the centre of the universe seemingly (Doppler effects all that).. HOWEVER, what about rotational movement. Everything in the universe revolves around something... now , in the case of this binary black hole system you mention, the centre is somewhere between them.. they however probably revolve around some other greater system where one could place a new centre point. Now these points are more absolute. If we choose the reference point anywhere i that system, the rotational centre of the system we can observe will remain fixed to the system as such. So techincally speaking, if we could observe allrotation in the universe, we would indeed find a centre point, no? (Would seem as the gravitational centre of the universe). Again, sorry if it is digressing.. If so, I will edit it out and maybe punch up a topicstarter. (Or just disregard the two questions). Also... I am wondering.. S2, moving at around 18 million kilometers per hour... (abt 0.017c). Lets say had a planet system in place around it and there was an 'earth-like' planet there rotating around it such that it would have a g=10 like our Earth. Would the sheer inertial momentum of it's star affect it in any way? (I guess our foolish minds just can't get used to the fact that in space, "resistance is futile" ;p) (PS. This last one is implying your question about the gravitational waves.. as S2 is close to our SMBH in the centre of our galaxy).

Hehe.. whoever it was who said 'maybe''she's still in highschool is just ludicrous. In high-school , they certainly would not ask to construct or come up with ideas how to send a payload of bacteriae sampling to the stratosphere. This is more likely an assignment in year 2, maybe 1 (depending if the criterias were more conceptual) of an aerospace engineering undergraduate course. Anyway, In all agreement with the pro-positive attitude. The question was perfectly viable for these kind of things, and to put it in astronomy cosmology.. ok maybenot perfect, but viable enough.. I 've seen more comments and subjects totally idiotic than I have seen misplaced topics. Anyway, the last poster found another reference (perhaps so did the OP?). Shame no feedback frmo OP, then again was first post.. happens. PS. What I wanted to reply to just the post before last, to captian: About the pressure.. yes , I was also thinking using pressuredifferentials as a working mechanism (not just for piston operation.. as would be good for opening, but what about resealing?). Anyway, I was thinking pressure differentials would be useful as a way of starting the experiment. It is true many weather conditions would play in so it wouldn't be easy to get it accurate in height necessarily! However, with optimal conditions , it should be able ot place on within the stratospheric belt.

hmm. what about prolog.... ML ? (i was *very late* in my internet discovery and cs... so pascal won't count for me ,p) shouldn't assembly be mentioned even if it probably has in disguised form? PS. read the poll and maybe 1 or 3 posts down

Would geometer not be a geometrist? Is it really called geometer? (Sorry, moved away from UK at 7, so this is an honest question ) (Sorry, this of course is so off topic but I just got curious about the term)