"The university is near here."
Translation:La universidad está cerca de aquí.
"De" is needed because of the direct translation. It actually means "Close to here" but can be translated to near here and other. "A" would not be used before "aquí" in this case, because of grammar rules. One says that two words should not be able to easily be mistakenly connected in pronunciation. I.E.: "Del", not "de el". Saying "a aquí" could be mistaken easily for just "aquí" or as a stutter. So instead, it is "de aquí" or "of here".
A previous commentor (Marcy) gave this explanation:
The de is required here because cerca de = close to, near, when there is an object of the preposition or place mentioned after it: Examples: Cerca de mi casa = near my house, close to my house. Cerca de la escuela = near the school, close to the school. Cerca de aquí = near here, close to here.
Cerca can be used without the de when there is no object. Examples: Vivo cerca. I live nearby. El parque está cerca. = the park is close, nearby.
"estar" is also used for location.
As the sentence is describing where the station is situated, "estar" is used. Think of this sentence as answering the question "¿Dónde
está la universidad?" "Where is the university?".
For further info on "ser" and "estar" see this page on Spanishdict.com
I wrote, "La universidad esté cerca de aquí" I hit the wrong key. In haste, I moved the mouse over the é instead of the á. It was a typing error. Yet, I was marked wrong and was forced to redo something I had mastered. My only mistake was moving my mouse to the right key. The other language I studied here would have told me that I had committed a typing error and let me move on. Here I have to repeat it. Why?
Ron, usually, if your typo results in something that is an actual word in the language Duo considers it a mistake. In this case, "esté" exists as part of the present subjunctive conjugation of "estar" eg
En cuanto esté listo el contrato, Canales firmará por el Madrid" — As soon as the contract is ready, Canales will sign for Madrid
es and está are two different ways to say "is" in Spanish. Duolingo has some lessons on ser and estar, and there are various articles on the differential use of both verbs on the www. Read, for example, https://www.realfastspanish.com/vocabulary/ser-vs-estar .