Nasa has discovered an eighth planet circling Kepler-90, a Sun-like star 2,545 light-years from Earth.

Discovered using machine learning from Google, the new Kepler-90i planet orbits its star once every 14.4 days.

Nasa astrophysics director Paul Hertz said: “Just as we expected, there are exciting discoveries lurking in our archived Kepler data, waiting for the right tool or technology to unearth them.

“This finding shows that our data will be a treasure trove available to innovative researchers for years to come.”

The planet was discovered after researchers Christopher Shallue and Andrew Vanderburg trained a computer to learn the method of identifying exoplanets in the light readings recorded by Kepler.

“This finding shows that our data will be a treasure trove available to innovative researchers for years to come.”

The artificial ‘neural network’ was inspired by the way neurons connect in the human brain, sifted through Kepler data and found weak transit signals from a previously-missed eighth planet orbiting Kepler-90, in the constellation Draco.

Kepler-90i is said to be about 30% larger than Earth and is close to its star. Its outermost planet, Kepler-90h, orbits at a similar distance to its star as Earth does to the Sun.

Shallue and Vanderburg also found a sixth planet in the Kepler-80 system, the Earth-sized Kepler-80g.

The researchers plan to apply their neural network to Kepler’s full set of more than 150,000 stars.

The Kepler and K2 missions for Nasa’s Science Mission Directorate in Washington are managed by Ames.

The latest work was performed through the Carl Sagan Postdoctoral Fellowship Program executed by the Nasa Exoplanet Science Institute.