As societies from centuries back were slow to understand that our home planet is only a small part of the subsuming Solar System, today people are only slowly realizing what it means to live in the Galaxy. This latter, larger reality determines more about your day to day life than you probably realize (as discussed in the September 7 New Paradigm show, “Your Life in Our Solar-Galactic Climate“).
Today marks the first, preliminary release of a new map of our Galaxy by the European Space Agency’s Gaia star mapping satellite (launched in 2013). When its mission is completed in the early 2020s, Gaia will provide a 3D map of the positions and motions of one billion stars in our Galaxy — creating the greatest Galaxy map mankind has ever made. To understand how this is done see the written pedagogy, “The Solar System’s Motion Through the Galaxy” and the video presentation, “Galaxy Project Part II, Wandering Stars.”
While we’ll have to wait for the fully completed map, today’s preliminary release provides the positions (but not distances or motions) of the one billion stars targeted by Gaia — plus one additional surprise treat. After the Gaia satellite was launched it was determined that Gaia’s observations could be combined with the observations made by its precursor mission (the Hipparcos satellite), allowing for a much earlier determination of the distances and motions of the 2.5 million stars observed by both Gaia and Hipparcos. While this is far from the full one billion, our new 2.5 million star map is a significant intermediate step (prior to this the largest map including distances and motions was of 100,000 stars).
As Tycho Brahe’s (1546-1601) precise measurements of planetary motions provided the data Johannes Kepler (1571-1630) needed to make his revolutionary discovery of the principle of universal gravitation, the Gaia data provides the basis for an entirely new wave of scientific investigations. We can expect significant improvements in understanding how the Solar System moves through the Galaxy, how our position in the Galaxy determines conditions here on Earth, and how our Galaxy is organized as a whole.
But the data alone is just the start. Gaia will tell us how the stars are moving, but not why. There are fundamental paradoxes in our understanding of the dynamics of galaxies (as discussed in the video presentations, “Galaxy Project III: Our Galactic Year & Dynamics” and “Galaxy Project VI: Singularities and Anti-Entropy“). How they are created? How are they organized? How do they develop?
Actual scientific discoveries of new physical principles will require more than the data of a Brahe, it will require the genius of a Kepler.