Astronomers have found at least seven Earth-like planets orbiting the same star 40 light-years away, according to a study published
Wednesday in the journal Nature. The findings were also announced at a news conference at NASA Headquarters in Washington.
This discovery outside of our solar system is rare because the planets have the winning combination of being similar in size to Earth
and being all temperate, meaning they could have water on their surfaces and potentially support life.
"This is the first time that so many planets of this kind are found around the same star," said Michaël Gillon, lead study author
and astronomer at the University of Liège in Belgium.
The seven exoplanets were all found in tight formation around an ultracool dwarf star called TRAPPIST-1. Estimates of their mass
also indicate that they are rocky planets, rather than being gaseous like Jupiter. Three planets are in the habitable zone of the
star, known as TRAPPIST-1e, f and g, and may even have oceans on the surface.
The researchers believe that TRAPPIST-1f in particular is the best candidate for supporting life. It's a bit cooler than Earth, but
could be suitable with the right atmosphere and enough greenhouse gases.
The planets are so close to each other and the star that there are seven of them within a space five times smaller than the distance
from Mercury to our sun. This proximity allows the researchers to study the planets in depth as well, gaining insight about
planetary systems other than our own.
JWST and Exoplanets
One of the main uses of the James Webb Space Telescope will be to study the atmospheres of exoplanets, to search for the building blocks of life elsewhere in the universe. But JWST is an infrared telescope. How is this good for studying exoplanets?
One method JWST will use for studying exoplanets is the transit method, which means it will look for dimming of the light from a star as its planet passes between us and the star. (Astronomers call this a "transit".) Collaboration with ground-based telescopes can help us measure the mass of the planets, via the radial velocity technique (i.e., measuring the stellar wobble produced by the gravitational tug of a planet), and then JWST will do spectroscopy of the planet's atmosphere.
JWST will also carry coronagraphs to enable direct imaging of exoplanets near bright stars. The image of an exoplanet would just be a spot, not a grand panorama, but by studying that spot, we can learn a great deal about it. That includes its color, differences between winter and summer, vegetation, rotation, weather...How is this done? The answer again is spectroscopy.
i'm guessing it's the real mccoy -- NASA spent a few days promoting it as a major discovery...
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