The theme of time weaves the narrative in the novel "How to Live Safely in a Science Fictional Universe" by Charles Yu.

• The protagonist, also named Charles Yu, commands a time machine and hops across different time periods.
• This novel is not just a science fiction tale about time travel but an exploration of memories and storytelling.

• The protagonist's memory of learning grammar from his mother serves as a reflection of time.
• Understanding tenses introduced him to the concepts of present, past, and future. For instance, he describes how he learned to express future uncertainty with sentences like "I don't know what I will do without you."
• The protagonist's understanding of his mother's worry shows how emotion is tied to our perception of time.

The text suggests that our language encodes worry into our thoughts, suggesting our perception of the future can be anxious.