NASA’s Spitzer Space Telescope has made a stunning discovery on the first known system of seven Earth-size planets orbiting around a single star in our galaxy. The discovery may well proved to be one of the most promising hunting grounds so far for life beyond the Solar System.
Three of these seven planets are firmly located in the ‘habitable’ zone – the area around the parent star where a rocky planet is most likely to have liquid water. The US space agency hold a news conference to present the findings at the agency’s headquarters in Washington on Wednesday.
According to the NASA, the discovery has set a new record for greatest number of habitable-zone planets found around a single star outside our solar system. And all of these seven planets could have liquid water – key to life as we know it – under the right atmospheric conditions, but the chances are highest with the three in the habitable zone.
All seven roughly match the size and mass of our own planet and are almost certainly rocky, and three are perfectly perched to harbour life-nurturing oceans of water, as reported in the journal Nature.
Most critically, their proximity to Earth and the dimness of their red dwarf star, called Trappist-1, will allow astronomers to parse each one’s atmosphere in search of chemical signatures of biological activity.
“We have made a crucial step towards finding life out there,” said co-author Amaury Triaud, a scientist at the University of Cambridge.
“Up to now, I don’t think we have had the right planets to find out,” he said in a press briefing.
“Now we have the right target.”
The Trappist-1 system, a mere 39 light years distant, has the largest number of Earth-sized planets known to orbit a single star. It also has the most within the so-called ‘temperate zone’ – not so hot that water evaporates, nor so cold that it freezes rock-solid. The discovery adds to growing evidence that our home galaxy, the Milky Way, may be populated with tens of billions of worlds not unlike our own — far more than previously suspected.