A new study claims that
there could be at least four alien civilisations with hostile intentions in our world.
However, the researcher has
concluded that the probability of these civilisations invading Earth is very low.
Caballero, in his latest paper, says
as a human civilisation, we would invade once we become a Type-1 civilization capable of nearby interstellar travel.
He also maintains that there could be
fewer than one malicious extraterrestrial civilization in the Milky Way that has also mastered interstellar travel.
The astronomers question by saying
that only GJ 273 b, located 19 light-years away, remains considered to be potentially habitable.
Four hostile civilisation exists in
the Milky Way, Caballero based his estimation on the world's history of invasions in the last century.