3I/ATLAS is the third interstellar object confirmed passing through the Solar System, after 1I/ʻOumuamua (discovered in October 2017) and 2I/Borisov (discovered in August 2019).
And we all know that the Ramans do everything in threes!!!
-PJ
I read somewhere that the estimates are that there are about 10 interstellar objects greater than one kilometer diameter inside the solar system on average at any time. We only detect the bigger ones, occasionally.