When the alien ship screamed through the solar system, it disrupted communications between the far-flung human mining ships and supply stations, and between them and Earth. So Earth and Luna were unaware that they had been invaded until the ship pulled into Earth orbit, and began landing terra-forming crews in China. Politics and pride slowed the response on Earth, and on Luna, corporate power struggles seemed more urgent than distant deaths. But there are a few men and women who see that if Earth doesn't wake up and pull together, the planet could be lost.
Look again at that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there--on a mote of dust suspended in a sunbeam.