"Astronomul nu este fizician."

Translation: The astronomer is not a physicist.

[Hatch-Slack]

As a matter of fact, this affirmation is not entirely correct.
Astronomers have to know and understand lots of physics in order to be classified or qualified as ”astronomers”.

[LeeDonovan]

As an astronomer, I object! My undergraduate and master's degrees are in physics and astrophysics, respectively. My PhD is also in astrophysics.

[lulubeck]

To "the" or not to "the," that is the question. Apparently in Romanian a (or the) definite article is correct here, but in English we would probably say "an astronomer," if I understand this correctly. The astronomer spoken of is not actually a certain person, but one that represents all. Correct me if I am wrong.

[crbratu]

You are right. If you want to say "all astronomers" you can either say "astronomii sunt oameni deştepți" or "astronomul este un om deştept". A famous Romanian idiom "codrul e frate cu românul" can be translated by "romanians are brothers to the woods" because from ancient times, if in trouble, the only solution was to go there: -)

[Renardo_11]

The use of the definite article "-ul" here means that we are talking about a certain astronomer (who has been mentioned before). "An astronomer" would be "un astronom" in Romanian.

[asd83]

But without the indefinite article it's not a correct sentence in English.

[crbratu]

This is correct but if no astronomer was mentioned before it could mean the whole category (all astronomers in this case)

[MysterMDD]

"The astronomer isn't" is somehow different than "The astronomer is not"?

[Mejjnor]

Actually, he is. Astronomy is a branch of physics.