In this verse the word yatharkah indicates that the sun is not fixed but is rotating in its orbit, which is set by the Supreme Personality of Godhead. This is confirmed in the Brahma-samhita and also in other parts of Srimad-Bhagavatam. In the Fifth Canto of Srimad-Bhagavatam it is stated that the sun rotates in its own orbit at the rate of sixteen thousand miles per second. Similarly, Brahma-samhita states, yasyajnaya bhramati sambhrta-kala-cakrah: the sun rotates in its own orbit according to the order of the Supreme Personality of Godhead. The conclusion is that the sun is not fixed in one place. As far as Prthu Maharaja is concerned, it is indicated that his ruling power would extend all over the world. The Himalaya Mountains, from which the sunrise is first seen, are called udayacala or udayadri. It is herein indicated that Prthu Maharajas reign over the world would cover even the Himalaya Mountains and extend to the borders of all oceans and seas. In other words, his reign would cover the entire planet.