For Earth Day on Saturday, many Twitter users wanted to say something festive. However this planet-size topic means that all the memes and jokes didn't exactly fall into one category.

Even saving the Earth can be funny.

You knew there would be political references.

Corporations and celebrities wanted to look engaged without being too controversial.

Even fictional characters weighed in.

But some of the best messages came from NASA along with current and former astronauts, who know what the Earth really looks like from a distance and how fragile it can be.

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