Rise skywards bearing light, initially like the sun (5)
I believe the answer is:
solar
'sun' is the definition.
(I've seen this before)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for solar that I've seen before include "type of radiation" , "Pertaining to the sun" , "revolutionary system" , "Coming from the sun" , "Using the energy of the sun" .)