Why study astrobiology? Because it gives us a critical and unique perspective on the resilience and yet fragility of the only planet in the Universe that we know for certain harbours life. Are we alone in the Universe? The discovery of many extra-solar planets suggests not, and yet … we still don’t know. Even in the immediate neighbourhood of our own Solar System, there are (and were in the past) habitable worlds. But did life ever take hold elsewhere? Moreover, most of Earth’s big problems are caused by the biosphere’s pinnacle (us) taking over the planet – by studying astrobiology and planetary science we determine we are One Humanity on One Planet. The urgency of the need for stewardship over exploitation of Earth becomes apparent when we see ourselves whole, a blue marble in the blackness and emptiness of space.