What is the black thing that Mrs. Whatsit shows the children on Uriel?

What is
interesting about the "Black Thing" from is that it is up for
interpretation exactly what the black thing is. Is it alive? Is it a place? Does it represent
something else? When the children fly up into the clouds of Uriel and first see the black thing
creeping closer and blotting out the stars, they wonder if it's an actual "thing" or a
shadow cast by a "thing." Either way, all the childreneven young Charles Wallaceknow
instinctively that it is dreadful and powerful. After they descend back down to to the flower
field, they all feel relieved, but then Meg suddenly realizes that the darkness is where she can
find her father. Whatever the black thing is, she must have hope and be brave enough to fight
against it in order to save him. While darkness generally symbolizes evil, the author purposely
makes it unclear exactly what the black thing is, so the reader is free to ponder what it means
and what it represents for them in real life.