What could the word unearthly mean in this reading?

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 46 to 50.
A young woman without eyebrows is seated in front of a beautiful landscape. Does this sound familiar to you? This is one of the most famous works by Leonardo da Vinci. The Mona Lisa is a beautiful painting. However, it was the mystery behind the painting that intrigued people. Who was the woman and why did da Vinci paint her?
Different theories have been proposed about her identity. Many art and history buffs thought that it was a portrait of da Vinci himself, but as a woman. Others thought it was not any particular person, but the ideal of a woman. They say this is why she was painted with no eyebrows. This gave her face a more unearthly look. Still, others thought that it was a portrait of an actual woman of the time, the wife of Francesco del Giocondo.
In 2005, historian Armin Schlechter of Heidelberg discovered the answer. While looking through an old manuscript, he found a small note. In this, the woman in the Mona Lisa was positively identified as Lisa del Giocondo. The artist had been paid to do her portrait after the birth of her second child. “Mona”, in fact, means “madam” in Italian. As for her unearthly look? Historians say women of this time liked to remove their eyebrows. Apparently, they thought eyebrows were not attractive.