Sun is the Devata (Deity/Surya Deva) of Air (Vayu) and Sun travels on Air (vayu) as its chariot (Vayu rupi rath). If there is no air can the sun rays have speed?
Sun is the Devata (Deity/Surya Deva) of Vayu as "Sun’s Chariot" travels in "Air" which symbolizes "Air" (Vayu) as "chariot" on which Sun (Surya Deva) travels.
The movement of the chariot of the sun: By the force of Air (Pravaha Vāyu), the Sun God, the Incarnate of the Vedas travels round the cities, the Zodiac, in one Samvatsara (year) The Devi Bhagavata Purana(book 8, chapter 15)
Sun-rays (Tej) is tangible. Earth, Water and Fire have a form. They are called Tangible. Air (Vayu) and Ether (Akash) do not have a tangible form that is why we feel Sun rays are faster. But the enabler of speed in Sunrays is Air (Vayu).
So if there is no air, can the sun rays have speed? If Air (Vayu) would not exist, if it does not combine with the Sunrays how would the rays come?
Answer what Scriptures say:
But before that we need to know that is there any place which is devoid of air? Or any place where absolute vacuum exist?
Wherever there is movement you have to accept the presence of Air (Vayu). Even if air is very subtle. And where there is Ether (Akash) there is Air (Vayu).
In 9th Chapter of Gita, “sarvagatah vayu” has been said. Where there is Akash there is Vayu.
यथाकाशस्थितो नित्यं वायुः सर्वत्रगो महान्।
तथा सर्वाणि भूतानि मत्स्थानीत्युपधारय।।9.6।।
Meaning Just as the extensive air, which is moving everywhere, (being born of ether) ever remains in ether, likewise, know that all beings, who have originated from My Sankalpa, abide in Me.
Hence when we go up (in space), where we say the place is devoid of air, Ether (Akash) is there, so air must be there.
But let me give some example. Have you seen Tortoise or Fish, when one has Toroise or Fish as pet, and put someone on duty for 24 hours, that how many hours the tortoise sleeps and how many hours the fishes sleep? In their movement itself they sleep. Like Horse does not lie down to sleep, lifting a leg - they sleep, so subtle is their sleep. Similarly, Tortoise and Fish while swimming the reduction in speed they rest in that only and get sleep during that only.
Similarly, the places which we call devoid of Air, whose divine movements are very caring, they can manage with that type subtle air.
In 9th Chapter of Gita,
मयाऽध्यक्षेण प्रकृतिः सूयते सचराचरम्।
हेतुनाऽनेन कौन्तेय जगद्विपरिवर्तते।।9.10।।
Meaning: Arjuna, under My aegis, Nature brings forth the whole creation, consisting of both sentient and insentient beings; it is due to this cause that the wheel of Samsara (Universe) is going round.
Param Brahman is the cause of Ether (Akash) and Param Brahman is the controller of all the energies.
Ether (Akash) is the cause of Air (Vayu) whereas Ether (Akash) is the source of all energies and there are four types.
Air is the cause of Fire whereas Energy emanating from Air would be stronger than the one emanating from Fire
Fire is the cause of water whereas Energy emanating from Fire would be stronger than the one emanating from water
Water is the cause of Earth whereas Energy emanating from Water would be stronger than the one emanating from Earth
Hence from the above points we can conclude that Air is cause of Fire hence the rays generated from fire needs a medium to travel which is Air (Vayu) and present everywhere as there is no absolute vacuum exist. As Air (Vayu) do not have a tangible form that is why we feel Sun rays are faster. But the enabler of speed in Sunrays is Air (Vayu).