Estimated 100 Billion Planets in the Milky Way

The above video is from 2008.  We have discovered hundreds of planets since then and doubled the estimate.

So, when the PLANET collaboration detected 40 microlensing events, and noted that three contained exoplanets, they could do a statistical analysis to estimate the number of stars that have exoplanets in our galaxy.

From this analysis, the PLANET team made a rough estimate of 100 billion exoplanets living in our galaxy. Additionally, they found that one-in-six stars host a Jupiter-mass exoplanet, half the stars in the Milky Way have Neptune-mass exoplanets and two-thirds of the stars have Earth-mass worlds.

Interestingly, this result points to least 1,500 exoplanets within 50 light-years from the solar system.

As already uncovered by the Kepler science team, smaller worlds appear to dominate our galaxy -- the PLANET collaboration supports this idea. [1]