During the reign of Maharaja Prthu, everything on the surface of this globe was sinless, and therefore the Kumaras decided to see the King. Ordinarily they do not go to any planet which is sinful
SB Canto 4
Seeing the glowing effulgence of the four Kumāras, the masters of all mystic Power, the King and his associates could recognize them as they descended from the sky.
The four Kumāras are described herein as siddheśvarān, which means "masters of all mystic power." One who has attained perfection in yoga practice immediately becomes master of the eight mystic perfections—to become smaller than the smallest, to become lighter than the lightest, to become bigger than the biggest, to achieve anything one desires, to control everything, etc. These four Kumāras, as siddheśvaras, had achieved all the yogic perfectional achievements, and as such they could travel in outer space without machines. While they were coming to Mahārāja Pṛthu from other planets, they did not come by airplane, but personally. In other words, these four Kumāras were also spacemen who could travel in space without machines. The residents of the planet known as Siddhaloka can travel in outer space from one planet to another without vehicles. However, the special power of the Kumāras mentioned herewith is that whatever place they went to would immediately become sinless. During the reign of Mahārāja Pṛthu, everything on the surface of this globe was sinless, and therefore the Kumāras decided to see the King. Ordinarily they do not go to any planet which is sinful.