Nasa has announced the discovery of a solar system which is home to not one, but two stars. The Kepler solar system, 4,900 light-years away from Earth, has two stars - called a binary system - orbiting each other in a cosmic dance. What makes this discovery exciting is the discovery of two planets circling the system - and one of them inhabits the so-called 'Goldilocks Zone', where the planet is the right distance ('not too hot, not too cold') to support liquid water and potentially support life. Before today, it was unknown whether planets could form around a two-star system. The discovery shows that more than one planet can form and persist in the stressful realm of a binary star, and also demonstrates the diversity of planetary systems in our galaxy. The two orbiting stars eclipse each other every 7.5 days from our vantage point on Earth. One star is similar to the sun in size, but only 84 percent as bright. The second star is diminutive, measuring only one-third the size of the sun and less than 1 percent as bright. Jerome Orosz, associate professor of astronomy at San Diego State University and lead author, said: 'In contrast to a single planet orbiting a single star, the planet in a "circumbinary" system must transit a "moving target". Source: The Coming Crisis
