Summary of “Have Aliens Found Us? An Interview with the Harvard Astronomer Avi Loeb About the Mysterious Interstellar Object ‘Oumuamua”

On October 19, 2017, astronomers at the University of Hawaii spotted a strange object travelling through our solar system, which they later described as “a red and extremely elongated asteroid.” It was the first interstellar object to be detected within our solar system; the scientists named it ‘Oumuamua, the Hawaiian word for a scout or messenger.
The first one is that we didn’t expect this object to exist in the first place.
If we assume all planetary systems around other stars are doing the same thing, we can figure out what the population of interstellar objects should be.
So we checked that and found that you need the thickness of the object to be less than a millimetre in order for that to work.
The point is that this is the very first object we found from outside the solar system.
My motivation, in part, is to motivate the scientific community to collect more data on the next object rather than argue a priori that they know the answer.
We have seen an object from outside the solar system, and we are trying to figure what it is made of and where it came from.
If you put the probability at zero per cent of an object coming into the solar system, you would never find it!

The orginal article.