Context: Meanwhile, Le Verrier by letter urged Berlin Observatory astronomer Johann Gottfried Galle to search with the observatory's refractor. Heinrich d'Arrest, a student at the observatory, suggested to Galle that they could compare a recently drawn chart of the sky in the region of Le Verrier's predicted location with the current sky to seek the displacement characteristic of a planet, as opposed to a fixed star. On the evening of 23 September 1846, the day Galle received the letter, he discovered Neptune within 1° of where Le Verrier had predicted it to be, about 12° from Adams' prediction. Challis later realised that he had observed the planet twice, on 4 and 12 August, but did not recognise it as a planet because he lacked an up-to-date star map and was distracted by his concurrent work on comet observations.

Question: Who was Henrich d'Arrest? 
Answer: student at the observatory

Question: What did Henrich d'Arrest seek to find? 
Answer: the displacement characteristic of a planet

Question: When did Galle discover Neptune? 
Answer: 23 September 1846

Question: How many degrees off was Adams' prediction?
Answer: 12°

Question: What was Challis looking for when he saw Neptune the first two times? 
Answer: comet observations

Question: Who urged Le Verrier to search with the observatory refractor?
Answer: Unanswerable

Question: What did Galle suggest to Heinrich d'Arrest?
Answer: Unanswerable

Question: Who discovered Nepptune in the 18th century?
Answer: Unanswerable

Question: What was within 10 degrees of where Le Verrier predicted it would be?
Answer: Unanswerable

Question: When was Le Verrier born?
Answer: Unanswerable

Question: When did Le Verrier die?
Answer: Unanswerable

Question:  What didn't Henrich d'Arrest seek to find?
Answer: Unanswerable

Question: What was 15 degrees away?
Answer: Unanswerable

Question: What was Challis looking for when he saw Uranus the first two times?
Answer: Unanswerable