- For the first time, astronomers have discovered seven Earth-size planets orbiting a single nearby star – and these new worlds could hold life.
- This cluster of planets is less than 40 light-years away in the constellation Aquarius, according to NASA and the Belgian-led research team who announced the discovery Wednesday.
- The planets circle tightly around a dim dwarf star called Trappist-1, barely the size of Jupiter.
- Three are in the so-called habitable zone, the area around a star where water and, possibly life, might exist.
- Scientists said they need to study the atmospheres before determining whether these rocky, terrestrial planets could support some sort of life.
- But it already shows just how many Earth-size planets could be out there – especially in a star ripe for extraterrestrial life.
- The more planets like this, the greater the potential of finding one that’s truly habitable. Until now, only two or three Earth-size planets had been spotted around a star.
- The potential for more Earth-size planets in the Milky Way galaxy is mind-boggling.
- The discovery gives us a hint that finding a second Earth is not just a matter of if, but when.
- University of Liege’s Michael Gillon and his team reported finding three planets around Trappist-1. Now the count is up to seven, and scientists said there could be more.
- This crowded yet compact solar system – 235 trillion miles away – is reminiscent of Jupiter and its Galilean moons, according to the researchers.
- Altogether, astronomers have confirmed close to 3,600 planets outside our solar system since the 1990s, but barely four dozen are in the potential habitable zone of their stars.
- Of those, just 18 are approximately the size of Earth.
- Both ground and space telescopes were used to identify and track the seven Trappist-1 planets, which they label simply by lowercase letters, “b” through “h.”
- As is typical in these cases, the letter “A” – in upper case – is reserved for the star.
- Planets cast shadows on their star as they pass in front of it; that’s how the scientists spotted them.
- Tiny, cold stars like Trappist-1 were long shunned by exoplanet-hunters (exoplanets are those outside our solar system).
- But the astronomers decided to seek them out, building a telescope in Chile to observe 60 of the closest ultracool dwarf stars.
- Their Trappist telescope lent its name to this star.
- While faint, the Trappist-1 star is close by cosmic standards, allowing astronomers to study the atmospheres of its seven temperate planets.
- All seven look to be solid like Earth – mostly rocky and possibly icy, too.
- They all appear to be tidally locked, which means the same side continually faces the star, just like the same side of our moon always faces us.
- Life could still exist at these places, the researchers explained.
- Chemical analyses should indicate life with perhaps 99 percent confidence.