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

What?

north wales.

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.

Whats a blue shift? Who first caculated the exspanding universe?

Paul

See this thread for information about the most accurate measure of the Hubble constant (the rate at which the universe is expanding).

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'.

Thanks Paul

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.

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)

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.

Also known as the Slartibartfast Approach.

Sayonara³ said in post # :

Also known as the Slartibartfast Approach.

 

Does anyone else have a sexual attraction to fjords?

redshifts and blueshifts are opposites. But we use the term redshift for simplicity

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.

Cap'n Refsmmat said in post # :

Or, even better, call it the Doppler effect.

 

Ahh...the doppler effect.

 

THat's too general though.

NSX said in post # :

 

Ahh...the doppler effect.

 

THat's too general though.

 

What do you mean, too general?

The doppler effect affects probably all electromagnetic radiation. It's not just light, so maybe that's why.