The act of responding to a message that was posted either way earlier in a conversation or an otherwise long
time ago.
Derived from the premise of watching
stars from very far away, where the
light you see from them is billions years old and far from when it was originally sent in your direction.
John: "had some hella good pizza the other night" — 4 hours ago
John: "btw how did your game this evening go" — 3 minutes ago
Bella: "omg what kinda pizza was it" — a minute ago
John: "stop stargazing, Bella" — Now