Text 20

dyav a-prithivyor idam antaram hi
vyaptam tvayaikena disas ca sarvah
drishtvadbhutam rupam ugram tavedam
loka-trayam pravyathitam mahatman

Translation

Although You are one, You spread throughout the sky and the planets and all space between. O great one, seeing this wondrous and terrible form, all the planetary systems are perturbed. 

Commentary by Srila Prabhupada 

Dyav a-prithivyoh (“the space between heaven and earth”) and loka-trayam (“the three worlds”) are significant words in this verse because it appears that not only did Arjuna see this universal form of the Lord, but others in other planetary systems saw it also. Arjuna’s seeing of the universal form was not a dream. All whom the Lord endowed with divine vision saw that universal form on the battlefield.

Commentary by Sri Visvanatha Cakravarti Thakur

Now that Arjuna had the proper qualification, the Lord shows him his form as time. This is described in ten verses.