It is probable that Shakespeare observed, or at least heard about, many natural phenomena that occurred during his time, which may have influenced the many references to nature and science that he makes in his work. Although he was very young at the time, he may have witnessed the blazing Stella Nova in 1572, which could explain his reference to the “westward star” in Hamlet.

10

Sigh no more, ladies, sigh no more.
   Men were deceivers ever,
One foot in sea, and one on shore,
   To one thing constant never.
Then sigh not so, but let them go,
   And be you blithe and bonny,
Converting all your sounds of woe
   Into hey nonny, nonny.

(requested by @first-enchanter-surana)

“Infanta Isabella Clara Eugenia of Spain” (1598-1599) (detail) by Juan Pantoja de la Cruz (1553-1608).