Together throughout time and space (2,6)
I believe the answer is:
in tandem
'together' is the definition.
(working in tandem is working together)
'throughout time and space' is the wordplay.
'throughout' becomes 'in' (I can't justify this - if you can you should give a lot more credence to this answer).
'time' becomes 't' (abbreviation).
'space' becomes 'em' (in typography, a space as wide as a letter 'm').
'in'+'t'+'and'+'em'='IN TANDEM'
Can you help me to learn more?
(Other definitions for in tandem that I've seen before include "Manned it as twosome" , "Together - as on a bicycle made for two" , "Together (as a pair)" , "One behind the other or alongside" , "Working together" .)