Pay taxes, get a job to stimulate the economy, becoming part of ones community.
Main sequence stars burn through hydrogen
The sky is pale blue in higher altitudes while it is deeper blue in lower altitudes. This is because there is more air molecule closer to earth surface (as a result of higher air pressure) than higher altitudes. The air molecules are responsible for scattering of sunlight hence giving the sky its blue hue. The more the air molecules the more the scattering.
Because it is a habitable planet that is capable of supporting living creatures