I believe you misinterpret the article. Physicists on earth are using small timing fluctuations in the radiation arriving from multiple far-flung pulsars to try and detect gravitational waves. This is what is meant by a galaxy-sized gravitational wave detector.

It was a joke.

Yes, it was. And that is a reason to downvote.

People aren't on Hacker News for the jokes, and a significant fraction don't like seeing threads hijacked by silliness. We've all seen Reddit, and are choosing not to be there for a reason.

That's not to say that you can't get away with jokes here. But the bar for them to work is very high.

You are correct, and this is important. The flood of 2020 newcomers have not acculturated, creating frequent misapprehensions.

We are not amused.

The detector could just be the entire galaxy, it doesn't have to be an artificial construct. To your question, you have already seen it, hiding in plain sight.

Writing copy in the English language is a dying art.

Similarly to a Sun-sized lens, which is... the Sun (and the lensing is gravitational).

Personally, i found this hilarious, so I don't understand why you're being downvoted

Didn't downvote so can't be 100% certain, but it may be related to the fact that this isn't Reddit.

Because that's how websites die

They don't all land, I guess.

We do get people that stupid here occasionally, so I didn't read it as a joke. Poe's law, etc. Ed: FWIW, I didn't downvote.

Space is awfully big though - the actual structure presumably would be detectable with hindsight but these galaxies are an unbelievably long way away and a detector would presumably be thin on that scale.