Gaia in the Sky
The first thing that is necessary when studying the sky is direct observation of it. In the past, throughout the world, the ancients began with our primary tools: the eyes. Then came astrolabes, lenses, and bigger and bigger telescopes, protected by even bigger domes, until the recent introduction of satellites, able to capture light in different bands of the electromagnetic spectrum, completing the present picture. In parallel with the technological development of the instrumentation, humanity has developed strategies and models for understanding what it observes.