beth1974uk Posted July 28, 2010 Report Posted July 28, 2010 if the speed of light is 299 792 458 m/s...... what is the speed of dark? Quote
heres jonny Posted July 28, 2010 Report Posted July 28, 2010 i dont think dark in a sense exists...its a lack of light... so it doesnt really move, more the light retreats...ish it makes sense in my head (or it did) i started typing and its kinda gone... Quote
Cyprino Posted July 28, 2010 Report Posted July 28, 2010 Exactly, darkness is our perception of lack of light. Even when it's dark, any light still travels at 299,792,458 m/s, there's just not a great deal of it about. Quote
The Geoff Posted July 28, 2010 Report Posted July 28, 2010 The speed of dark is the same as the speed of light, but the other way around. To put it another way, the speed of light is identical to the distance between you, what you're looking at and the light source, and the speed of dark is the same but the other way around. Plus or minus the Planck time, obviously. The only thing that travels faster than light is bad news, which is why Fox News do so well. On a related note, the speed of politically biased bullshit has not yet been measured. Quote
heres jonny Posted July 28, 2010 Report Posted July 28, 2010 didt understand a word of that but it was funny Quote
rob91193 Posted July 28, 2010 Report Posted July 28, 2010 the speed of dark is the same as the speed of light, but the other way around. To put it another way, the speed of light is identical to the distance between you, what you're looking at and the light source, and the speed of dark is the same but the other way around. Plus or minus the planck time, obviously. The only thing that travels faster than light is bad news, which is why fox news do so well. On a related note, the speed of politically biased bullshit has not yet been measured. what? Quote
The Geoff Posted July 28, 2010 Report Posted July 28, 2010 (edited) Exactly, darkness is our perception of lack of light. Even when it's dark, any light still travels at 299,792,458 m/s, there's just not a great deal of it about. This is technically far more accurate than my nonsense, and it's really interesting. The speed of light has virtually nothing to do with what you can see. Seriously, try this on for size... The light you can see is a tiny, tiny bit of a much bigger thing, the whole spectrum of light, the Electromagnetic (EM) spectrum if you to be fancy. In theory the whole spectrum, all of it, ranges from the Planck distance (which is so close to nothing as makes no odds) to the size of the entire universe. We can see a range of 300 nanometres (nm) to 650nm roughly, so the "bit" of the EM spectrum we can see is 350nm, or three and a half thousandths of a centimetre. Three and a half thousandths of a centimetre, compared to a line which is as big as our universe in one direction, and just about as big in the other ("small stuff") direction. In fact, what we can see is sort of less than that, because the EM spectrum is really just a list of random bits of the universe at any moment in time, the photons that happen to be connecting two random particles at any given moment. They can be understood with just a list of numbers really. Nine numbers: You've got the position of one end of the photon, in your everyday coordinates, up/down, left/right and forward/back, plus time, which is four numbers. Double that, because the photon has two ends, and also the wavelength of the photon. So where does the speed of light come into it? It's basically a correction for the fact that we measure things in terms of the distance from Paris to the North Pole. Spacetime is a bit bendy from our point of view, it warps a bit, and the speed of light is a measurement of how bendy it is. Even in the dark, with no photons at all, spacetime would still be as bendy as the speed of light. It's got very little to do with lightbulbs at the end of the day, no pun intended. Edited July 28, 2010 by The Geoff Quote
heres jonny Posted July 28, 2010 Report Posted July 28, 2010 that made absolutely no sense in any way shape or form... apart from Paris and the North Pole, as i know what they are oh and light bulbs...otherwise no... Quote
Cyprino Posted July 28, 2010 Report Posted July 28, 2010 *sigh* I understood it. Perhaps that's why I'm single? Anyway, further to my point earlier: Even when it's dark, any light still travels at 299,792,458 m/s, there's just not a great deal of it about There probably is a lot of light about. Because photons are feckin' tiny, the light from just a few is nowhere near bright enough for us to see. So there's an incomprehensibly large number of the little blighters zooming about allowing us to see things, even in the dark. So there's a mahusive amount of stuff making up the tiny amount of light we can see when it's dark. Quote
The Geoff Posted July 28, 2010 Report Posted July 28, 2010 Do we include Neutrinos? Technically they've got mass, so the can't travel at the speed of light...doesn't stop us using them to take photos... This is a picture of the sun taken by a neutrino telescope. There's a lot of background noise when it comes to taking neutrino photos, so you need a big filter. These guys used the whole planet Earth. The neutrinos that make up the picture are ones that travelled right through the Earth. This is, quite literally, a picture of the sun taken at night. http://blogs.discovermagazine.com/cosmicvariance/files/uploads/neutrinosun.jpg Quote
heres jonny Posted July 28, 2010 Report Posted July 28, 2010 oooh Neutrinos..apparently going to end the world in 2012, according to the film... so thats a picture taken through the earth? thats quite nifty i guess, takes some doing :L Quote
Cyprino Posted July 28, 2010 Report Posted July 28, 2010 Oooh, pretty. Oh, those neutrinos in the film 2012... Why did they only cause the earth's core to increase in temperature, but leave the surface fairly ok? The oceans should have heated up hugely before the core got affected. Quote
The Geoff Posted July 28, 2010 Report Posted July 28, 2010 oooh Neutrinos..apparently going to end the world in 2012, according to the film... so thats a picture taken through the earth? thats quite nifty i guess, takes some doing :L Not too much - either a huge freshwater lake in Siberia or a big chunk of Antarctic ice, plus several cubic kilometres worth of the most exquisitely fragile glass spheres you can imagine, on strings. This one covers it nicely: Cool Science Books: The Edge Of Physics Haven't seen 2012 - the big threat is dark matter poisoning the heart of the sun and bringing a premature end to fusion if you really want to worry Quote
Afro1599968737 Posted July 28, 2010 Report Posted July 28, 2010 Oooh, pretty. Oh, those neutrinos in the film 2012... Why did they only cause the earth's core to increase in temperature, but leave the surface fairly ok? The oceans should have heated up hugely before the core got affected. the surface is too thin; the neutrinos pass straight through it. Only with the much thicker core is there enough mass for some of the neutrinos to interact with it and raise its temperature. its like asking why a bullet doesnt heat up a fishnet, but does a swimming pool Quote
heres jonny Posted July 29, 2010 Report Posted July 29, 2010 but who would shoot a fishnet and a swimming pool? I'll go to bed now :L My brain doesn't function properly after this many hours awake ... Quote
Squarehead666 Posted July 29, 2010 Report Posted July 29, 2010 'Tis a silly film! All the best Andy S. Quote
Taunton Posted July 29, 2010 Report Posted July 29, 2010 The speed of dark is the same as the speed of light because you need the lack of light to travel that distance / speed to your eyes to be able to work out the darkness... I thought I could explain it easier than The Geoff, but Fail :-( Quote
gjpo1 Posted July 29, 2010 Report Posted July 29, 2010 I LOVE THIS THREAD Gonna show it to my 10 year old, he wants to be like The Geoff when he grows up, reckons he's going to crack cold fusion! Quote
The Geoff Posted July 29, 2010 Report Posted July 29, 2010 Eep. No. Bad role model, honestly. I reckon cold fusion is doable...not sure how, but I bet you it's something funky... Quote
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