|A 1537 rendition of Thule|
On New Year's Eve 2018, a NASA probe transmitted pictures of Ultima Thule, an object 4 billion miles from Earth. "Ultima Thule" is not your typical astronomical naming convention.
Ultima Thule, or the "ultimate Thule," was first described about 300BCE by a Greek explorer named Pytheas. It was supposedly about six days north of Britain, a place so far from the natural world that land and sea and air were no longer separate substances, but instead formed a strange mixture in which one could not survive.
A thousand years after Pytheas, Isidore of Seville (mentioned here, also involving astronomy) explained Ultima Thule as being so far north that there was no daylight beyond it, making the sea cold and sluggish.
As stories of explorers (verified or not) appeared, Thule was identified and re-identified with lands farther and farther from mainland Europe. St. Brendan's voyages suggested new lands that historians thought might refer to Thule. The later Middle Ages decided it must refer to Iceland or Greenland. In early modern times, Norway became the candidate to explain early stories of a land that far north.
In the 20th century, the idea of Thule was co-opted by certain German writers and politicians as the legendary origin of the Aryan race. Fortunately, the 21st century has given it a new connotation.