Exoplanetology, or exoplanetary science, is an integrated science related to the study of exoplanets (extrasolar planets). It employs an interdisciplinary approach which includes astrobiology, astrophysics, astronomy, planetary science (planetology), geochemistry, astrochemistry and astrogeology. Exoplanetology deals with the study of extrasolar planets in terms of their physics, theoretical biology and geochemistry. The discovery of exoplanets in transit in front of their parent star has led to the birth of this burgeoning new field in science. Through May 2015, varying techniques have been used to discover 1,924 planets outside the Solar System. Being a new field, exoplanetology currently focuses upon the detection of exoplanets via the "planet-hunting" techniques (See methods of detecting extrasolar planets). However, as more and more planets are discovered, the field of exoplanetology continues to grow into a deeper study of extrasolar worlds, and will ultimately tackle the prospect of life on planets beyond the Solar System.