It's called the "overview effect*" a term coined by Frank White referring to the one of the "Four Epiphanies of Awareness" that overwhelm astronauts who venture into space for the first time:
1) The thinness of the atmosphere
2) The interactivity of the biosphere
3) *The smallness of earth in space, and
4) The roundness of the earth.
The Overview Institute was created "To get people on this planet to realize we’re all living on “spaceship Earth” together, and that we need to care for the planet before we all become homeless together."(Source here)
"Perhaps if our world leaders all took an orbit on the space station, the idea of world citizenship over national citizenship would take hold, and the only thing left to wonder would be why it took us so long to realize it in the first place."
- Astronaut Michael Lopez-Alegria,
Former President of Commercial SpaceFlight Federation
So until Mars becomes inhabited - Here's to all of us earthlings realizing we're on the same "spaceship Earth" together, same team, same human race.