I could tell you that it might be good for us to unite behind a project that doesn't involve killing one another, that does involve understanding our home planet and the ways we survive on it and what things are crucial to our continuing to survive on it.

I could tell you that moving farther out into the solar system might be a good plan, if humanity is lucky enough to survive the next 5.5 billion years and the sun expands enough to fry the Earth. What tone does the author develop how does word choice help shape that tone?

The tone developed by the author is one of optimism and a call to action. The author expresses a sense of hope for humanity to come together and focus on a project that promotes understanding and survival on our home planet. The use of words like "good," "unite," "crucial," "survive," and "luck" highlights the positive perspective and encourage readers to consider taking action. Additionally, the mention of the sun expanding and potentially destroying the Earth adds a sense of urgency to the tone, emphasizing the need for proactive measures and future planning.