I understand the relief to be a depiction of creation: the lotus flower, according to the AEs, was the first thing to spring from the primordial sea of nothingness.
The lotus flower then brings about the creation of Atum Re, depicted as the snake (and not a light bulb filament!)
The god Atum creates the universe as a bubble of air in the waters of Nun that existed before creation. This is the 'bulb' you claim to see.
It is the bubble of air that is depicted around Atum.
Proponents of the light bulb theory need, in my opinion, to do two things:
* learn a little about the Ancient culture and its mythology before espousing baseless, controversial ideas
* support such claims with physical archaeological evidence from ANYWHERE other than this temple relief from Dendera (you can not include the misinterpretation of a relief based on complete lack of understanding with respect to the AE creation myth it so obviously depicts!)
Funnily enough, there are NO other depictions of "light bulbs" anywhere else in Ancient Egypt; yet one would expect evidence to be abundant if the technology had been harnessed.
Like the relief, there are none!
Steps off soapbox ... and turns out the light on way out!