How many known planets are in the Milky Way?

1 Answer
Apr 15, 2017

About 3,500 exoplanets have been discovered as of April 2017.

Explanation:

As of April 2017, NASA has confirmed about 3,500 exoplanets. There are also over 4,000 candidate planets which hasn't yet been confirmed.

The web site zooniverse.org has started a Exoplanet Explorers project where volunteers look for patterns in light curves which indicate that a planet has transited its star. In a few days about 200 planets were discovered this way.