Once upon a time King Prthu initiated the performance of a very great sacrifice in which great saintly sages, brahmanas, demigods from higher planetary systems and great saintly kings known as rajarsis all assembled together

Expressions researched:
"Once upon a time King Prthu initiated the performance of a very great sacrifice in which great saintly sages, brahmanas, demigods from higher planetary systems and great saintly kings known as rajarsis all assembled together"

Srimad-Bhagavatam

SB Canto 4

Once upon a time King Prthu initiated the performance of a very great sacrifice in which great saintly sages, brahmanas, demigods from higher planetary systems and great saintly kings known as rajarsis all assembled together.

SB 4.21.13, Translation and Purport

Once upon a time King Prthu initiated the performance of a very great sacrifice in which great saintly sages, brahmanas, demigods from higher planetary systems and great saintly kings known as rajarsis all assembled together.

In this verse the most significant point is that although King Pṛthu's residential quarters were in India, between the rivers Ganges and Yamunā, the demigods also participated in the great sacrifice he performed. This indicates that formerly the demigods used to come to this planet. Similarly, great personalities like Arjuna, Yudhiṣṭhira and many others used to visit higher planetary systems. Thus there was interplanetary communication via suitable airplanes and space vehicles.