How to find a planet you can’t see

 A link to my answer on Quora

1. Focus onto one star within one filed of view and watch it for a long period continuously for any dip of its brightness due to obstacle rotating around that star. Field of view is shown below-

1. Measure the intensity of the brightness dip. By measuring the dip, scientist can determine the size and shape of the obstacle.

1. Measure the frequency of the dips, scientists can conclude the orbital radius and the speed of the obstacle. From the orbital size and the temperature of the star, the planet's characteristic temperature can be calculated. From this the question of whether or not the planet is habitable (not necessarily inhabited) can be answered.

Project- NASA deployed the Kepler space telescope in 2009 in search for new planets.

Observations-

1. Generally brightness spectrum of any star looks like as

As we know that dip in brightness depends on the size of the planet orbiting that star. By estimating the dip in Sun’s brightness due to earth and Jupiter we can set the base parameter to predict the size of exoplanets.

Kepler telescope on May 2009 observed some dip while looking towards Field of view (shown in image-1)

From the above picture, it is clear that the dip is more than Jupiter’s and the dip is asymmetrical too. It is concluded that the obstacle which is orbiting that star is massive than the Jupiter but not a round in shape. Sounds Strange ?

Then again in March 2011, a dip was observed and this time the dip is shorter and symmetrical in shape. But the scientist were surprised again when in 2013 several dips of different shape and different symmetries were observed.

Conclusion-

Several theories were circulated to support the multiple dips of different shape and different symmetries like as planet collision, comets approaching that star. But none of these seem satisfying the scientists. The scientist claim that the planet may be habitable by an advanced civilization which have exhausted all their planet energy resources. Hence now they are completely depend upon their star’s energy. To absorb more energy from their star they might have build up giant solar shields around their planet. Scientist think that due to theses giant structures around their planet, theses different shape and different symmetries dips are being observed.