If it were said that "aliens" had visited our solar system three times, Earthlings would probably be incredibly excited, and it would be headline news every day. But if it were said that interstellar objects had already visited our solar system three times, people might not be so excited. Indeed, in 2017, the first interstellar object, named "Oumuamua", visited our solar system; it wasn't very big, only about 400 meters long. In 2019, the second interstellar object, named "Borisov," visited our solar system; it was about 1 kilometer in size. This year (2025), on July 1st, the third interstellar object, named "ATLAS," also came to join the fun, and was first caught at a location between Mars and Earth in our solar system; it was about 10 kilometers in size. It's so fast that it could travel from New York City to Princeton, NJ, in just one second. The term "interstellar" refers to stars in the sky other than our Sun. The nearest star to us is 4.2 light-years away; even with the fastest spacecraft we currently possess, it would take tens of thousands of years to reach it. This "ATLAS/3I" doesn't come from the nearest star, but from the much more distant central part of the Milky Way. Don't underestimate this "ATLAS/3I"; although it's only 10 kilometers in size, in terms of age, our Sun has to bow down to it; calling it "Grandpa" wouldn't be an exaggeration, because it has existed for 7 billion years, much older than our Sun's 4.6 billion years. Some people might ask, could "aliens" live on this "interstellar object"? Huh? A big question!

(2025-07-10)