Royston

It's quite simple, if I'm dead there's no room for something good happening...it's impossible to make a change if you're inanimate, change could lead to something good, (depending on what your Son considers good).

It's a little tricky fitting an AGN into your garage.

Just to echo IA and Severian, but what a complete mess of an election. I naively thought, that 'this time', we had a three party system, obviously not. I promised myself I would leave the country if the Tories won the most seats, so possibly looking forward to booking my visa once my degree is finished i.e if I can finish it, funding has already stifled my Uni, (which I won't get into right now) but funding for science under a conservative government, is enough to bunk the country on it's own. If there's anything to perpetuate the political apathy in the UK, it's a shoddy election.

My mate Dave managed to remove his underpants whilst his trousers are still up...there's no excuse. EDIT: I don't actually have a mate Dave, but I distinctly remember a girl managing to do it, when I was on holiday. Albeit her knickers were a long saggy mess after completing the feat. Congratulations.

I realize this is an old thread, and three pages long, (so sorry if this has already been covered) but there's only a paradox if you ignore one of the main tenets of general relativity i.e coordinates do not have an immediate metrical significance. IOW, there is nothing physical about a coordinate singularity, which is what you get for a stationery observer, who's radial distance is [math]O_d>>R_s[/math]. Where [math]R_s[/math] is the Schwarzschild radius. A transformation of coordinates can eliminate infinite redshift et.c. I think confusion arises when special relativity is applied to general relativistic situations, there's bound to be inconsistencies as SR doesn't cope with gravity.

I'm currently bogged down with three assignments (two on extreme environment astrophysics, the other is more basic astronomy), I need to cram two weeks work into one, as I'm off on holiday next week. Incidentally, the comic strip in the OP seems particularly apt. I went to vote today (election day in the UK) and after cramming my brain with the physics of accretion discs, I found great difficulty putting some paper into a slot. I was told to fold it twice EDIT: Good luck ajb

I would imagine people who experiment with so-called hard drugs, are predisposed to experiment, it's just cannabis is more readily available, and is considered softer, so it stands to reason this will be the first drug they try. I agree with Padren, in that some people who supply cannabis, also supply other drugs, if the customer fancies a change, (or even talked into it) it's available, and this could be another reason for this 'gateway' label. As for stats, well they're a bit sketchy (but better than a survey of anecdotes.) There is a difficulty in getting the data, which is explained near the beginning, and although this article is talking about drug problems, the same difficulty extends to people who use drugs, and don't have any problems i.e getting stats on the number of cannabis users, or amphetamine users for example. http://www.drugscope.org.uk/resources/faqs/faqpages/how-many-people-are-addicted However, cannabis does seem to be a lot more popular, and figures for people with problems is really quite low, so it appears that many are using cannabis but not experimenting with harder substances.

I realise this is an old thread, but thought some of you may be interested, I'll post more updates as and when they happen... Merged post follows: Consecutive posts merged I didn't mean to sound like a TV news ad Good news though...

There's no spacetime beyond the event horizon using an unmodified Schwarzschild metric, there is if you use advanced Eddington-Finkelstein coordinates, where the t and r (distance) coordinates are related by... [math]ct'=ct+R_sln\left(\frac{r}{R_s}-1\right)[/math] You're talking about a coordinate singularity, which is what the paper you cited is discussing, (which is flawed reasoning to your argument) in a limited way, what you said is right i.e 'there is no spacetime inside the event horizon', but only when using an unmodified Schwarzschild metric, and that's because it's ill equipped to deal with events at and past the event horizon...time like, becomes space like.

Yeah, it's just the region bounded by the event horizon. Kerr black holes i.e mass and angular momentum (spin if you like), are the most likely, but that's not really relevant to the thread. IIRC the volume that's bounded by the event horizon, is just the surface area multiplied by ct, where t is the longevity of the black hole, so... [math]V_{bh}=4\pi r^2 ct[/math] Though we still have the problem of [math]V_{bh}\rightarrow\infty[/math] I actually lost sleep thinking about this last night, and wrote a lengthy reply earlier, and then decided to ditch it, so I may come back to this, here's a short version... I wondered if there was a way around [math]V_{bh}\rightarrow\infty[/math] using Kruskal coordinates, which copes with the problem of asymmetry using advanced Eddington-Finkelstein coordinates i.e the modified Schwarzschild solution. In principle, the point where a photon gets expelled (in the other domain), could be a cut off point for the volume, i.e there should be a change in curvature of the outgoing null geodesic (from a straight world line, to one curving outwards.) Although Kruskal coordiantes do away with coordinate singularities, AFAIK there's still a gravitational singularity to worry about, so I'm a bit confused on how this works. However, perhaps an expert could point out the flaw in this, or if it doesn't quite make sense et.c EDIT: Congrats on the promotion to mod Mr. Skeptic

I spotted this earlier, which seemed quite apt...

I don't understand your argument DH, I didn't mention the use of the word 'dark', and confirmation that dark energy is a real effect (in your words) is exactly that, it's been confirmed. I thought the article was interesting because of the methods used to conclude the fact of accelerated expansion...so I thought the title was appropriate i.e the measurement of expansion is a lot more refined than it was when it was first discovered, so surely it's a genuine addition to the Einstein equations ?

I suggest you do, you can derive the Newtonian limit via the Ricci tensor, it should reduce to Poisson's equation, from there you have gravitational potential. So (unless I'm missing something) your derivation is somewhat back to front, you certainly can't derive any constants (e.g cosmological) via Newtonian methods. You need the assumptions of SR and GR. EDIT: I'm a GR newb, so someone correct me if the above, isn't quite right.

I've always liked the idea of having a tail for some reason...and wings, as shakes has already mentioned. I have an issue with population, so any health benefits e.g limb regeneration like an axolotl, is a no no for me. Another aesthetic change, is that people are born with random coloured skin, and certain attributes, e.g bone structure (to an extent) et.c so the whole idea of race is obliterated. In short, I want to be a flying purple, greater spotted, monkey man.

This was posted by my tutor on our Uni forums, thought some of you may be interested.... http://www.spacetelescope.org/news/html/heic1005.html From the article...

Gravitational waves are certainly not derived from SR, the simple reason being, that SR is not a theory of gravity. For the equivalence principle to hold, spacetime needs to be curved aka a relativistic theory of gravity. Waves are produced via accelerated bodies in a curved spacetime. That's the raw basics, I, or someone with more expertise can go into more detail if you want. EDIT: Oops, ajb beat me to it.

Of course Cap'n is fully responsible for the below... Ulysses ryhmescheme, with the brains; bebsw

I agree with the second bullet point, in that all physics is theoretical (but that extends to every other branch of science.) I've never really given it much thought, to the meaning of the term. I've always stuck it in the category of 'what is yet to be tested', but that doesn't make sense with afterthought...I guess it's indicative about the perception of physics more than anything else, that such a category should exist, i.e over theoretical biology et.c

Oops...this year, I meant Crysis Warhead.

Leader Bee is right, Crysis / Crysis 2 is still the benchmark, because the Crytek engine is still the most background heavy graphics engine to date, despite it's age. I was looking for other things in my test, which I simply can't be bothered to explain right now.

Thanks ajb, this was what (in a clumsy way) I was alluding to...however, I'm having a real hard time trying to visualize what's going on, I guess I'm not content with just method. In any case, I'll post the results of the connection coefficients, and geodesics et.c tomorrow, it's good practice to tackle stuff outside the scope of what you're being taught...at least I think so.

1 and 2, amount to the same thing don't they ? I think the third is asking for trouble personally. I'd go for the first or second option (it doesn't matter which), ftl communication / travel, would manifest itself in technologies that would benefit us way beyond anything we use right now. However, it depends what point in history you're referring to jryan...or is that a free choice ?

By the time I got to answer the question, I was practically asleep, so sorry about that. Thanks, that's precisely what I was getting at, I just havn't come across an example yet (in my course) where the names of x, were switched, but that makes things a lot clearer.

You have to start the game over. I just double checked, and you're right, albeit it's a heavily modified version of the Dunia engine.

Well being a GR course, Einstein notation is used extensively, so I'm probably missing something obvious...or I worded my question poorly. Are my steps correct so far ? If so, then I know I'm on the right track at least.