Saptasva Radhamaarudham Prachandam Kasyapaatmajam Sweta Padamdharam Devam tam Suryam Pranamamyaham!!ImageSource
The son of Rishi Kashyapa, rides on a chariot with seven horses while holding a white lotus in his hand. To that Surya, I offer my salutations! The mention of the seven horses here in fact, a metaphor to describe the seven colours he radiates through the White Light.
Long before the Western theories sprung up, the Vedas revealed that the Sunlight consists of seven colours. The seven colours of the Sun god are Violet, Indigo, Blue, Yellow, Orange and Red, commonly known as the VIBGYOR colours. It is a known fact that the sun god radiates millions of rays. The distinct feature is that each ray has the seven colours in it and this is signified as the Sun God riding the chariot driven by the seven horses. The Vedic meaning of Asva also translates as Light Rays. The Garud Puran mentions the names of the Asvas as Gayatri, Brihati, Ushnin, Jagati, Trishtubh, Anushtubh and Pankti, (which are used as the Sanskrit metres in poetry). This chariot of the Sun God is driven by Arun, brother of Garud.ImageSource
The Rig Veda mentions that the Sun God’s seven coloured rays make a day. The Vishnu Puran mentions that Lord Vishnu enters the Sun’s Solar Rays and emits his presence into the Universe through these seven rays.
The Vedas also mention the Sun god accompanied with his eleven brothers in form of Eleven Suns, and hence called also as Dwadasaditya (Dwadas means 12). Few texts ascribe it to the twelve months of the year according to which the span of the year was calculated on the basis of the Earth’s movement around the Sun.
Not only signifying the scientific calculations, each ray depicts a virtue. These rays are the symbols of Will power, Wisdom, Sincerity, Harmony, Perservance, Devotion and Courage. As every creation of the Universe depicts are inter relation with the human, the seven rays too describe the virtues to be possessed by mankind for the conduct of his/her Dharma.ImageSource
The Vedas have mentioned every aspect of the God‘s creation as an example of the way of life one has to lead and the Seven colours of the Sun God represent our knowledge and how it can be used to for the benefit of one self and also the entire mankind.