emeritus, I am also puzzled. This is a quotation from one of Auguste Comte's works, but it still doesn't fully explain the puzzle:
"I persist in the opinion that every notion of the true mean temperatures of the stars will necessarily always be concealed from us." Source: Cours de Philosophie Positive. 1835.
'T' is the temperature I am guessing 'maintained/in' Come(t)
He also...
//For instance, he had an acute feeling for the way humanity is dependent on astronomical conditions: assume small changes in the elliptical orbit of Earth, in the inclination of Ecliptic, and life, at least life as we know it, would have been impossible.//
Is these a themed crossword, where some answers that follow the theme are undefined? If not, unfortunately I can't add anything else to what has already been said.
I've just reached for my copy of The Oldie, which has this information which might be relevant:
"7 clues share an absent definition. One clue has a superfluous word which identifies where you might find these 7"
(Don't ask me though; I struggle to do the 'Moron crossword', as The Oldie cruelly names their easy one!)
Hi folks. yes, 7 clues share an absent definition. cheeses you can buy in a delicatessan. these are brie, manchego, gouda, yarg, saint agur, and stinking bishop which is 1 down and 15 across accounting for two...i think.