Jump to content

Royston

Senior Members
  • Posts

    2688
  • Joined

  • Last visited

Everything posted by Royston

  1. I had a quick look on google earth, and the socks are floating just off the coast of Iceland. I have no idea how they got there, or by what means (on the backs of turtles?) in any case, they are there for the taking !
  2. Royston

    GR question

    Stop, what do you mean by this ? What ? Not so much abstract, more failing massively to ask coherent questions about GR.
  3. No it isn't, quantum gravity is incredibly complicated....loosing socks is incredibly easy. Anyone in there right mind can loose a sock, but it takes years of dedication to come even close to slightly understanding QG. If genius was based on sock loss, then I am clearly a whopping genius, which I'm not !
  4. Oops, I meant line integral. IOW, you define the space before you imbed (for want of a better word) the Lorentz transformations, for instance you could start with Cartesian spherical coordinates [math]x^2 + y^2 + z^2 = c^2[/math] expanding the transformations when the space is already defined (and the fact there's nothing physical about doing so) doesn't make much sense. Albeit, you've decided not to go down this route.
  5. Lorentz transformations only make sense in local non-curved spacetime (i.e Euclidean), they are infintesimal sections on a manifold, where SR holds (part of the Lorentz group). It would make no physical sense to expand this set of linear equations into spherical coordinates...you really should start with a line element or path integral, then build a metric from that.
  6. Sorry Sisyphus, but this is wrong, a finite Universe is simply static, you can use a spherical metric to describe a finite Universe....(plus (and I know you know this) a sphere is 2D, perhaps you're referring to a 3 sphere, but I don't see the relevance) The topology of the Universe is around the Hubble volume, i.e there maybe clues to a wrap-around by probing the CMB, (there are no hints of a complex topology, so it's at or around the Hubble volume) so I have no idea what you mean by this. Source please. What do you mean by 'our' big bang, the rest appears to be unmitigated tripe.
  7. Royston

    Why The Anger?

    err, anyway... A little bit rich considering your language and feet stamping. It's disappointing that even from seasoned members of these boards, a level of maturity is severely lacking when it comes to this subject. I cannot see anything wrong in trying to strictly define your beliefs, (I think ydoaPs has done a sterling job personally) and agnosticism is atheistic...there is no difference in taking the stance of 'not knowing', as there is in 'there is no available evidence.' Further, Ignosticism is a statement on a set of all theistic beliefs, i.e it's an observation on subjectivity, not a belief in it's own right. So, just because you can't decide which belief is or is not correct, doesn't categorize you into theism or atheism, so you can't bolt it on, despite the subject it encompasses, happy to expand on that point if it's not clear. Personally I find the idea of creation (which may or may not be ascribed to Godhood) not only absurd, but damaging. If you wish to further your knowledge and believe in creation, then it's a case of shifting the goal posts to accommodate new knowledge, which is logically fallacious. If God is conceived as completely overarching, i.e whatever you throw at the concept, it remains intact, then it's a meaningless concept. If we discover something that fits a preconceived notion of God, then that discovery is shifted into that notion, it's not shifted into a body of study. I find the idea stifling, and unnecessary personally, but perhaps that's me getting old and less tolerant. EDIT: The above is a happy diversion from my cosmology coursework, which is driving me suitably insane
  8. First, there are two types of SZ effect, thermal is used for distance measurements whereas kinetic deals with bulk motion relative to the cosmic rest frame, so the latter, despite being weak, would give some information on rotation. Cluster rotation is very complicated, although they do rotate (to an extent.) There is generally an accretor, where we're concerned this is M31, however the Milky Way also acts as an accretor. There are star trails where our most closest galactic neighbours are spiralling in towards the Milky Way, and we in turn, are spiraling towards M31 (I'm using the term spiraling loosely BTW, huge distances and timescales et.c). The SZ effect will be used in the next gen of CMB maps, so it's early days. As for clumping and cluster structure, the general clumping of DM (in the early Universe) is outweighed by young galaxies and their DM halos (see Quasar distribution), I guess that stands to reason where gravity is involved, but I may be missing something. I realize this is a late reply, but I covered the SZ effect recently, so thought I'd add my, albeit, basic knowledge on the subject.
  9. Typo of the day... Found in the Ultra Pink region of the EM spectrum.
  10. I can't seem to find this, although I'm no longer Snail anymore. My new username has nothing to do with 'The League of Gentleman', if anyone asks or cares.
  11. The only reason I asked is more storage, generally means more power consumption, so I think we can rule that one out. Here's a way to create dump files, that you can send to microsoft support...dump files If you're system is not overheating, the random freezing could just be a driver conflict, you may have something lurking that's causing problems. You could try driver sweeper...Driver Sweeper reboot in safe mode (with internet access) and get everything you need, and reinstall your drivers. But your first port of call really should be with ms support, with your dump files. If they can't find anything, then at least the possibilities of the problem have been narrowed down.
  12. As the name suggests, it's likely to be a driver problem. How do you update your drivers ? If you let windows do it for you, where you've previously downloaded from a website (especially for display adapters) you'll run into problems. You're probably better off sending your dump files to microsoft support, who'll be able to locate the source of the problem. You've got a new system, with ample power, although you didn't give us your hdd details (unlikely it's a power issue though) and you've checked your ram...so it's probably not a hardware issue. I'm quite envious of your set up btw
  13. You'll be much better off asking here...Maya programming forum or somewhere similar. I'm pretty sure, but don't quote me on this, but most studios use a platform e.g 3ds Max, and design their own plug-ins depending on what they want. IIRC Pixar use Maya, along with a host of other packages such as Marionette. I doubt you'll get much help on a science / physics forum.
  14. I think you're referring to the radius, not the mass. However, we can do a quick calculation to get an approximate value for the radius of this beast... [math]L \approx 4\pi R^2 \sigma T^4[/math] so... [math]R \approx \sqrt\frac{L}{4\pi \sigma T^4}[/math] [math]R = \sqrt \frac{3.84 \times 10^{33} W}{4 \pi \times (5.67 \times 10^{-8} W m^{-2} K^{-4}) \times (4.0 \times 10^4 K)^4}[/math] = [math]4.055 \times 10^{10} m[/math] Apart from the scale (the radius will be huge when it reaches it's red hypergiant stage), I'm more interested in how it's formed, and unfortunately my astronomy module doesn't go into enough detail on cloud fragments for exceptional cases like this...so I'll have a look around. Also, I wasn't aware that at very high masses, the resulting supernova will not leave a stellar remnant, in this case you'd think it would form a BH. It's lifetime as a main sequence star is very short indeed, so this is quite the find. EDIT: Sisyphus replied while I was posting.
  15. This is the best overview of what tensors actually 'are' that I've found... http://www.grc.nasa.gov/WWW/k-12/Numbers/Math/documents/Tensors_TM2002211716.pdf Carroll's lecture notes are hardly an introduction to tensors. GR is one application of tensors, there's many more basic examples that require tensors.
  16. True, the evidence for neutron stars is very indirect, so it's more of an observational issue. However there is a wealth of information you can grab from light curves, and it's a case of back tracking i.e we have available solar models (a culmination of observation, lab experiments and maths) and the emission detected from these bodies. So certain systems will give a distinctive light curve, which agree with current models. There's always exceptions of course. Well, being a stellar remnant and due to the longevity of stellar objects, trying to pin down the death of a neutron star is very hard. I can expand on that if you want. Binary systems are common, so for a neutron star with a high mass donor (the donor being a higher mass orbiting star) i.e the neutron star is gaining mass due to the donor overfilling it's Roche lobe, it could in principle, gain enough mass to form a black hole, depending on the stability of the system. Any terms you're not sure of, just google or ask.
  17. From Dexter... 'Science is one cold hearted bitch with a 14 inch strap-on' Break a leg, perhaps we could merge the above with 'It's too big for my genes!' (titter)
  18. So sorry to hear that Paranoia, for what it's worth, I'd feel exactly the same way if my beloved studio equipment was stolen, albeit it will be a bit more drawn out than just shooting them I think I've found your next purchase, hopefully it'll put a smile on your face... http://www.smithsonianmag.com/travel/Colombia-Dispatch-7-Turning-Guns-into-Guitars.html
  19. Sorry Phi, it seems I was struck repeatedly by the stick of stupidity yesterday...too much study I guess https://www.scienceforums.net/forum/showthread.php?t=51749

  20. I appreciate the fact you took the time to reply to someone, who can't read a sentence correctly.
  21. Immortality was bolted on by Paranoia, the initial argument from his son was 'what's the point.'
  22. He wasn't talking about immortality, he was wondering what difference it makes 'ultimately', if he was alive or dead. Which entirely depends on the person asking the question.
  23. 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).
  24. It's a little tricky fitting an AGN into your garage.
  25. 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.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.