The International Flag of Planet Earth

I feel having a flag for "Planet Earth" is a really strange thing, particularly if you were to do something like plant it on Mars.

Flags more commonly represent groups defined by political or cultural boundaries, and planting one of those outside their territory makes sense in a way because their boundaries are malleable.

To me it'd make more sense calling it the "Flag of Humanity" or something along those lines.

Instead of that bird's nest, how about a blue marble on a field of black?

I would rather like a flag one could easily draw by hand (like most flags). Not too fond of the color neither; if we want it to represent Earth, maybe a blue/green blend?