Microlensing's New Frontier: Parallax

Microlensing was once thought to be a purely statistical technique,yielding only dimensionless numbers like the planet/host mass ratio,but no real masses, distances, or orbital parameters.  However,after 2 decades of theoretical and practical work, we haveentered a new era: the era of microlensing parallax, whichis starting to yield mass measurements and thus revealingunexpected systems that cannot be probed by other techniques.I discuss how these breakthroughs are being made today as wellas the prospects for radically augmenting them in thenear future using a combination of ground-based surveys, Spitzer,Kepler, and ultimately WFIRST.