Unity of developers is the power to advance the future

Nowadays humanity is not united as one.
What if astronauts attack Earth?
What will humanity do then?
Will the Earth still fight among itself then?
What if humanity becomes one only then...?
Is such a sacrifice really necessary for the unity of humanity?
I want to ask everyone in the world
Is it necessary for someone to sacrifice for unity?
Is there a need for common sorrow in order to unite?