Guest Paul L. James Posted January 23, 2004 Share Posted January 23, 2004 Where are the original photons after they exploded and where are they in the exspanding universe and how did the scientist rate the speed of the exspanding universe? Paul Link to comment Share on other sites More sharing options...
JaKiri Posted January 23, 2004 Share Posted January 23, 2004 What? Link to comment Share on other sites More sharing options...
Radical Edward Posted January 23, 2004 Share Posted January 23, 2004 north wales. Link to comment Share on other sites More sharing options...
Radical Edward Posted January 23, 2004 Share Posted January 23, 2004 well the closest we can get to "original photons" (since there is no such thing in a way, for a number of reasons) is probably the Cosmic Microwave Background, and they are pretty much everywhere and coming from all directions. we calculate the speed of expansion by either figuring it out from the CMB (because we know how old the universe would have been when energy and matter decoupled) or by looking at stars really far away, and calculating their blue shift. Link to comment Share on other sites More sharing options...
Guest Paul L. James Posted January 23, 2004 Share Posted January 23, 2004 Whats a blue shift? Who first caculated the exspanding universe? Paul Link to comment Share on other sites More sharing options...
fafalone Posted January 23, 2004 Share Posted January 23, 2004 See this thread for information about the most accurate measure of the Hubble constant (the rate at which the universe is expanding). Link to comment Share on other sites More sharing options...
JaKiri Posted January 23, 2004 Share Posted January 23, 2004 Radical Edward said in post # :we calculate the speed of expansion by either figuring it out from the CMB (because we know how old the universe would have been when energy and matter decoupled) or by looking at stars really far away, and calculating their blue shift. I think you mean 'red shift'. Link to comment Share on other sites More sharing options...
Guest Paul L. James Posted January 23, 2004 Share Posted January 23, 2004 Thanks Paul Link to comment Share on other sites More sharing options...
Radical Edward Posted January 23, 2004 Share Posted January 23, 2004 MrL_JaKiri said in post # : I think you mean 'red shift'. no, I mean blue shift, because, because... oh bollocks, yes I mean red shift. thanks dude dunno how I did that. too much chocolate probably. Link to comment Share on other sites More sharing options...
Radical Edward Posted January 23, 2004 Share Posted January 23, 2004 Paul L. James said in post # :Whats a blue shift? Who first caculated the exspanding universe? Paul ] firstly, I meant red shift, sorry about that basically the spectrum of an object which is moving away from you is shifted red a bit. It is the same effect as listening to an ambulance drive past. As it approaches you it sounds ligher pitched (blue shift) and as it drives away, it sounds lower pitched (red shift) Link to comment Share on other sites More sharing options...
JaKiri Posted January 23, 2004 Share Posted January 23, 2004 Radical Edward said in post # : no, I mean blue shift, because, because... oh bollocks, yes I mean red shift. thanks dude dunno how I did that. too much chocolate probably. You could argue that the motion of nearby galaxies could give you a value for expansion of the universe, by how much the expected blue shift (for the forces involved) deviates from the actual. But that's like building an entire test earth to see if people like a new caramel center. Link to comment Share on other sites More sharing options...
Sayonara Posted January 23, 2004 Share Posted January 23, 2004 Also known as the Slartibartfast Approach. Link to comment Share on other sites More sharing options...
JaKiri Posted January 23, 2004 Share Posted January 23, 2004 Sayonara³ said in post # :Also known as the Slartibartfast Approach. Does anyone else have a sexual attraction to fjords? Link to comment Share on other sites More sharing options...
Neurocomp2003 Posted January 23, 2004 Share Posted January 23, 2004 redshifts and blueshifts are opposites. But we use the term redshift for simplicity Link to comment Share on other sites More sharing options...
Cap'n Refsmmat Posted January 23, 2004 Share Posted January 23, 2004 Radical ++++++ said in post # : ] firstly, I meant red shift, sorry about that basically the spectrum of an object which is moving away from you is shifted red a bit. It is the same effect as listening to an ambulance drive past. As it approaches you it sounds ligher pitched (blue shift) and as it drives away, it sounds lower pitched (red shift) Or, even better, call it the Doppler effect. Link to comment Share on other sites More sharing options...
NSX Posted January 25, 2004 Share Posted January 25, 2004 Cap'n Refsmmat said in post # : Or, even better, call it the Doppler effect. Ahh...the doppler effect. THat's too general though. Link to comment Share on other sites More sharing options...
JaKiri Posted January 25, 2004 Share Posted January 25, 2004 NSX said in post # : Ahh...the doppler effect. THat's too general though. What do you mean, too general? Link to comment Share on other sites More sharing options...
Cap'n Refsmmat Posted January 25, 2004 Share Posted January 25, 2004 The doppler effect affects probably all electromagnetic radiation. It's not just light, so maybe that's why. Link to comment Share on other sites More sharing options...
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