Cassie's description was right at the end of the story. The planet was an ocean of possibilities and the crew could not have realized the truth about it before it landed.
We can arrive at this answer because:
However, her father couldn't possibly have known how dangerous the planet was before he landed on it, not even Cassie could have known, as she only relied on her intuition.
You can get more information about the importance of water at the link:
https://brainly.com/question/11640384