NASA's Kepler Space Telescope data used to discover Multi-Planet System

Abundant evidence in the solar system suggests that Jupiter and Saturn disrupted our systems early structure, resulting in the four widely-spaced terrestrial planets we have today, researchers said.

For the first time ever, citizen scientists have successfully discovered a new planetary system, located outside our solar system, around 620 light years away within the Aquarius constellation.

They found that planets in the same planetary system have correlated sizes.

All of its five confirmed planets are packed into a tight orbit in close proximity to the star, featuring orbital periods between 2.35 days to 12.76 days. They pored through publicly available data from K2, a follow-on to NASA's Kepler Space Telescope mission, which since 2009 has observed the sky for signs of Earth-like planets orbiting Sun-like stars.

While the fact that citizen scientists were the main discoverers of these exoplanets is exciting, and perhaps a harbinger of other similar finds in the future, the discovery itself also has some value for astrophysics. Kepler works by measuring the brightness of stars. If there was a dip in the intensity, it could indicate a possible transit across the star's face by a planet or some other object. In the past three years, Kepler has logged data from 287,309 stars - a number that climbs another 10,000 every few months. And that's where Exoplanet Explorers - and the assistance of citizen scientists - comes in.

The team used a popular citizen-scientist platform called Zooniverse to create its own project, dubbed Exoplanet Explorers.

"People anywhere can log on and learn what real signals from exoplanets look like, and then look through actual data collected from the Kepler telescope to vote on whether or not to classify a given signal as a transit, or just noise", said Christiansen in a Caltech news release.

At least 10 users would have to look at a potential signal, and 90 per cent of these users would have to vote "yes", for researchers to consider the signal for further analysis.

It was featured on a program called Stargazing Live on the Australia Broadcasting Corporation (ABC). These were examined for high resolution spectra that allowed the researchers to make precise measurements of the stars and their planets.

"That's a really tantalising clue that we may be missing more planets in this system".

"We wanted to find a new classification that would be exciting to announce on the final night, so we were originally combing through the planet candidates to find a planet in the habitable zone - the region around a star where liquid water could exist", said Christiansen.

Published in The Astronomical Journal, the study led by astrophysicist Lauren Weiss from University of Montral in Canada focused on 909 planets belonging to 355 multi-planet systems. A fifth planet was also discovered on the same chain, with hints of a sixth as well.

Citizen scientists have struck again.

"If we are making trying to find life on a world like ours, first we need to find other worlds like Earth".