Super-Earths: New Planets Found!

Super-Earths: New Planets Found!


If we’re learning one thing in this golden
age of planet hunting, it’s that our galaxy is home to a wide diversity of other worlds. We’ve yet to find another earth, but we’re
getting closer. That’s because of a growing class of planet detections known as “super
earths.” These planets have a mass higher than that
of Earth, but substantially lower than our Neptune, at around ten times the mass of earth. At the higher end of the mass scale, these
planets are often referred to as mini-Neptunes or gas dwarfs. It’s those at the lower end of the scale that
have sparked our imaginations. Take the star system called Gliese 667, 22
light years from Earth. The central point in this image is actually two stars, A and
B. There’s also a third, Gliese 667C. It’s the
bright finger that juts out to the lower left of the two main stars. That’s where astronomers have found a solar
system. If you could visit one of the planets there,
you’d experience the curious spectacle of three suns rising. They are part of an elaborate sky dance of
stars and planets. Planet E, pictured here as a crescent, is one of at least seven planets. They were recently discovered by astronomers
at the European Southern Observatory, on the mountaintops of Chile. By unraveling the pattern of wobbles in the
star’s light, they have determined that three out of seven planets lie within the habitable
zone, the range of distances in which there is enough heat from the star to allow liquid
water to flow, but not so much that it would boil it off. Sentient beings in residence here might consider
the sight of just one sun rising to be boring. Certainly their world is anything but. Their parent star is slightly fainter and
cooler than our sun. That means that the habitable zone is closer and narrower than in our solar
system. In fact, it would fit entirely within the
orbit of our Mercury. Remarkably, the three worlds that are crammed
into this zone are all considered to be rocky super earths. This is the first time that three such planets
have been spotted within the same habitable zone. Of course, that does necessarily mean they
are earth-like. Our planet shows that it may take a range
of specific characteristics to nurture life, a magnetic field to deflect solar outbursts,
a stable rotation, an active geology, and just the right amount of water vapor and carbon
dioxide in the atmosphere to regulate surface temperatures. There is one other solar system that may well
have what it takes. The Kepler space telescope has a star in its
sights that is well beyond our solar neighborhood. Kepler 62 is considered to be “sun-like.”
It weighs in at 69% the mass of our sun, with a radius of 64%. Astronomers have discovered five planets orbiting
the star, based on subtle dips in its light as the planets pass between the star and earth.
Two of them, planets E and F are likely solid planets that lie within the star’s habitable
zone. The size of these planets is still uncertain.
They could be several tens of times the mass of Earth. And the larger they are, the less
likely they are to be life bearing. Still, these Super Earth discoveries are part
of an ever-growing diversity of planets known to grace our galaxy. No doubt there are planets,
somewhere out there, that have the right characteristics to be called “Earth-like.”

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