Left: age distribution for APOGEE stars (grey shaded area) and the stellar mass-weighted age distributions for all stars in black and high- and low-α populations in blue and red, respectively. The age distributions for APOGEE and the orbit superposition solutions are normalised by the number of stars and total stellar mass, respectively. Right: cumulative mass distributions for the stellar mass-weighted components. The orbit superposition method results in the mass-weighted age distribution, which can be considered the star formation history of the entire Galaxy, as it gives direct information about the amount of stellar mass formed over time. Since we propagate the age uncertainties along the orbits, in some cases, we end up with ages that are larger than the overall age of the Universe.