Hint: nothing.
Why the need to bring aliens into it? I like how this isn't in the topic here, because it's really clickbait. I didn't find one mention of any talk about aliens in the whole thing. But it is a great article about radio astronomy.
That's the part about aliens. McVittie's perception that the popular understanding of radio astronomy (listening to Martians) influenced the FCC decision (which, at least officially as described in the next quote, was not the case).
If the cynic in me wants to assume the copy-editor who was tasked with coming up with the title skimmed the article, saw the phrase "and found it had an extraterrestrial source", and interpreted the wrong definition for "extraterrestrial".
Ok, since I constantly get downvotes for no reason. Vice, runs tons of stuff about aliens. They're a meme news outfit that runs shows such as "Fuck, that's delicious" and shows with Action Bronson and friends who get really high and do commentary on episodes of "Ancient Aliens." So again, you have to be totally unfamiliar with Vice, to say "Why aliens?"