Kepler orbit led to Johannes Kepler working on his celestial mechanics. He later became known as the father of calculus. In 1601, Johannes Kepler acquired the extensive, meticulous observations of the planets made by Tycho Brahe. Kepler would spend the next five years trying to fit the observations of the planet Mars to various curves. In 1609, Kepler published the first two of his three laws of planetary motion. The first law states: More generally, the path of an object undergoing Keplerian motion may also follow a parabola or a hyperbola, which, along with ellipses, belong to a group of curves known
Stellar halo be investigated in much more detail; this data has been used to postulate a triaxial or oblate halo. More recent studies have found the halo to be flattened with a broken power law radius dependence; evidence for triaxiality is unclear. As a result of their faint brightness, observations of stellar halos in distant galaxies have required very long exposure times, the stacking of data from numerous galaxies to obtain averaged properties, or observing only the resolved stellar populations. Individual resolved stars in stellar halos can only be measured in the Milky Way and Andromeda. The furthest stellar halos detected are