Kepler estimates there are at least 300 million potentially habitable planets within the Milky Way galaxy

• Data from the Kepler space telescope combined with the ‘Drake Equation’ has revealed that there are at least 300 million potentially habitable planets within the Milky Way galaxy, but outside of our Solar System.
• Some of these planets are within 30 light years of the Sun; Earth is just yet to find them.
• Unlike other estimation methods, which only account for the distance between a planet and its star, the Drake Equation takes into several factors that could impact the habitability of a planet.

The search for life beyond Earth and the scope of one day settling down on another planet is something that everyone has thought about at least once in their life. Now, the Kepler space telescope has finally quantified the odds of that dream becoming a reality.

It estimates that there are at least 300 million potentially habitable planets within the Milky Way system, and some of them are quite close — within a distance of 30 light-years from the Sun.

"This is the first time that all of the pieces have been put together to provide a reliable measurement of the number of potentially habitable planets in the galaxy," said co-author of the study, Jeff Coughlin — an exoplanet researcher at the SETI Institute and Director of Kepler's Science Office.

The ‘Drake Equation’

In order to estimate the number of habitable planets that could be discovered one day, researchers at SETI used something called the ‘Drake Equation.”

It is a probabilistic argument that takes into account the factors to consider when estimating the potential number of technologically advanced civilisations in the galaxy that could be detected.

Within the scientific community, the Drake Equation is often referred to as the ‘roadmap for astrobiology’. It is different from other estimates of habitable planets around the galaxy since they only consider the distance between the planet and its star.

Factors that go into the Drake Equation:

• Number of exoplanets similar in size to Earth — mostly likely to be rocky planets
  
• Number of Sun-like stars — around the same age and temperature
  
• How much light hits the planet — defines capacity to support liquid water
  

The Kepler mission, specifically designed to study the Milky Way for planets beyond our Solar System, stopped collecting data two years ago. However, using that data, scientists have been able to identify over 2,800 confirmed exoplanets so far — some of them even habitable.

While that’s a feat in itself, Kepler’s estimate shows that there are many planets out there that haven’t yet been identified — and one of them could be humanity’s next home.