The field of exoplanet research has recently had a big breakthrough. The transit method, which detects exoplanets by measuring the drop in flux from the star which it orbits, is now able to detect multiple planet systems by studying the transit timing variations (delays in expected transit times). This is the first time this has been done. Before only non-transiting multiple planet system where only detected by the radial velocity method.

Photo: David A. Aguilar (CfA)

To read the paper check out: The Kepler-19 System: A Transiting 2.2 R_Earth Planet and a Second Planet Detected via Transit Timing Variations