Kepler has identified thousands of planet candidates, some in the habitable zone of their star. One example is Kepler-22b
(Figure 7.25). The candidates must be confirmed by follow-up observations of more transits or of radial velocities before
they are officially announced as planet detections. Amateur astronomers can access the candidate lists online (at the
“Exoplanet Transit Database,” http://var2.astro.cz/ETD) and conduct their own observations. Anyone with Internet
access can go to PlanetHunters.org, examine some Kepler data, and contribute to the search.