DARK MATTER ACCOUNTED FOR! IT'S JUST GAS
A team of scientists have clocked a huge halo of gas surrounding the Andromeda Galaxy. The astrophysicists, whose research was published – naturally enough – in the Astrophysical Journal (PDF), reckoned the expansive globe of gas stretches about a million light-years from the nearest significant galaxy to Earth. They …
> was not Zaphod Beeblebrox shagging Trillian
Possibly not. Dialogue from Fit the Second at 21:47
Trillian: Zaphod, please take your hand off me. And the other one. Thank you. And the other one.
Zaphod: I grew that one specially for you, Trillian, you know that? Took me six months but it was worth every minute.
Doesn't sound too hopeful, does it?
I always wondered about the Trillian character; all the other elements of the story were woven into the fabric of the Universal Improbability, but Trillian just seemed to drift away, having contributed only the phone number of her Islington flat.
Captain Kirk, sir! How did your beam from your pilot episode from the 60's to our sad-arse 21st century??
It brings tears of melancholy to my eyes.
"... the halo appeared to be roughly 100 times the diameter of the moon."
On a galactic scale, that is incredibly thin, assuming that is an absolute size and assuming that it's 'our' moon they are referring to. Or, does that mean the observed area of our sky compared to our moon .....?
"Andromeda Galaxy's halo is the largest one ever to be eyeballed so near to Earth beyond the Milky Way."
Is there another, smaller halo, within the Milky Way?
" does that mean the observed area of our sky compared to our moon" - this was the only way I could make sense of that "100 times the size of the moon" comment. I struggled with the phrase, but decided that it was unlikely to mean our moon is 10,000 light-years across, so plumped for the explanation you suggested here.
There is another way to parse that sentence. "the expansive globe of gas stretches about a million light-years from (Andromeda), the nearest significant galaxy to Earth." The galaxy was already mentioned by name earlier, so omitting its name from this sentence did not compromise clarity.