An unearthly time is not at all convenient because it is too early in the morning or too late at night.

I was woken up at some unearthly hour of the morning by someone knocking on my door. 我一大清早就被敲门声吵醒了。

strange in a mysterious and sometimes frightening way

Cats' cries have an unearthly quality. 猫的叫声令人毛骨悚然。