This sentence describes the Cowherd and the Weaver Girl looking at each other across the Milky Way. Although they only meet each other on Chinese Valentine's Day every year and cannot be together day and night, their love is still stronger than gold.
In fact, there is a similar sentence in Su Shi's "Shui Tiao Ge Tou":
I hope that people will live forever, thousands of miles away, ***Chan Juan
It expresses that although Although we are thousands of miles apart, we can still look up at the same bright moon and express our sincere feelings to each other.