I could well be totally wrong here, but I think it's a referance to blueshift, as Bloc Party are a pretty intelligent band. Blue has the longest (it could also be shortest though) wavelength in a beam of light, and when galaxies are moving away from us they seem red because of how fast they're moving. However, when they're coming towards us they look blue, because the light refacts that way (I can't remember why, and GCSE physics was only last year...). So it could be saying that this person's coming back to them.
While I'm at it - you and the taste of cigerettes, miss either really badly when they're gone.
I could well be totally wrong here, but I think it's a referance to blueshift, as Bloc Party are a pretty intelligent band. Blue has the longest (it could also be shortest though) wavelength in a beam of light, and when galaxies are moving away from us they seem red because of how fast they're moving. However, when they're coming towards us they look blue, because the light refacts that way (I can't remember why, and GCSE physics was only last year...). So it could be saying that this person's coming back to them.
While I'm at it - you and the taste of cigerettes, miss either really badly when they're gone.