These seven Earth-sized planets were seen by NASA Spitzer telescope.
New Delhi:
US space agency NASA has announced that scientists researching outer space have found the existence of another 'solar system' - seven Earth-like planets orbiting a small star in galaxy 40 light years away - opening up the most promising hunting ground so far for life beyond. A press release from the space agency said the Spitzer Space Telescope has found that the planets are as large as Earth and at least three of them are in a "habitable zone". Almost all of them are rocky and three are likely to have water. Because they are located outside of our solar system, these planets are scientifically known as exoplanets.
Here are the developments in the story:
- "New record! We've found 7 Earth-sized planets in the habitable zone around a single star outside our solar system," NASA tweeted.
- The system is around 40 light-years, which is 235 trillion miles, away from Earth, in a constellation called Aquarius. Because they are located outside of our solar system, these planets are scientifically known as exoplanets.
- The exoplanet system is called TRAPPIST-1, named after the Transiting Planets and Planetesimals Small Telescope in Chile.
- The scientists have measured the density of six of the planets and say further research will show if they have water on their surface.
- It is possible that all seven planets have water, "the key to life as we know it, under the right atmospheric conditions, but the chances are highest with the three in the habitable zone," NASA said.
- The mass of the seventh planet is yet to be measured. But scientists say it is possible that it would be covered in ice.
- Spitzer, an infrared telescope that trails Earth, was well-suited for studying TRAPPIST-1 because the star glows brightest in infrared light. Further studies involved the Hubble Space Telescope. In future the James Webb Space Telescope is expected to be used.
- For decades, there have been speculations about the existence of alien life forms - one of the biggest questions facing astronomers.
- The search for life had started in 1995 after NASA's Kepler Space Telescope found signs of the first alternative solar system. Called Kepler 10b, it also signaled what NASA said could be a "small planet orbiting a star about 540 light years away".
- "This discovery could be a significant piece in the puzzle of finding habitable environments, places that are conducive to life," said Thomas Zurbuchen of NASA. "Answering the question 'are we alone' is a top science priority and finding so many planets like these for the first time in the habitable zone is a remarkable step forward toward that goal."
