Kepler Found Planets Better Than Earth

These question, and more like how Kepler found planets better than Earth. 

Kepler was a space telescope designed to survey a portion of the Milky Way galaxy in search of exoplanets, which are planets outside our solar system.

Using data from the Kepler mission and the extended K2 mission, scientists have identified more than 2,800 candidate planets and have confirmed more than 2,600 of these as bona fide exoplanets. A handful of planets are thought to be rocky like Earth (but a bit bigger), and orbit in the habitable zone of their stars, where liquid water - an essential ingredient of life as we know it - might exist. 

After nine years in deep space collecting data that indicate our sky to be filled with billions of hidden planets - more planets even than stars - NASA's Kepler space telescope has run out of fuel needed for further science operations. NASA has decided to retire the spacecraft within its current, safe orbit, away from Earth. Kepler leaves a legacy of more than 2,600 planet discoveries from outside our solar system, many of which could be promising places for life. They are the so-called “Earth-like” exoplanets.

NASA's Kepler mission revolutionised our scientific understanding of our place in the cosmos by a huge amount of discoveries. Before Kepler, we had just a few information about exoplanets. For example:

How many planets are out there?

Which planets are more common?

The big gaseous ones, as Jupiter?

The ring-giant planets like Saturn?

And what about Venus-like planets?

Do they exist just in our solar system?

And if so, why?

All of these were very interesting questions, that needed to be answered. 

But the universe is always a little bit more creative then we are. 

Here's what we know after Kepler.

Planets outnumber the stars. Kepler has proven there are more planets than stars in our galaxy - and knowing that revolutionises our scientific understanding of our place in the cosmos.

Small planets are common. Kepler has shown us our galaxy is teeming with terrestrial-size worlds; the most recent analysis of Kepler’s discoveries concludes that 20 to 50 per cent of the stars in the sky are likely to have small, possibly rocky planets similar in size to Earth within the habitable zone of their parent stars, where water could pool on the planet surface.

We still have much to learn about whether any of them could host life.

Planets are diverse. Kepler has discovered a diversity of planet types, opening our eyes to new possibilities. The most common size of planet Kepler found doesn’t exist in our solar system - a world between the size of Earth and Neptune - and we have much to learn about these planets.

Solar systems are diverse too! While our own inner solar system has four planets, Kepler found systems with considerably more planets - up to eight - orbiting close to their parent stars. The existence of these compact systems raises questions about how solar systems form: Are these planets “born” close to their parent star, or do they form farther out and migrate in?

New insights revealed about stars. Besides launching us into the golden age of exoplanets, Kepler has reinvigorated the study of stars. Kepler observed more than a half-million stars over the course of its nine years in operation.