Astronomers have found the biggest cluster of exoplanets ever, the first in 15 years. The star at the center of the discovery is Sun-like, and there may even be an Earth-y planet still hiding in the data.
Over a six year period of observations at the European Southern Observatory astronomers watched the star HD 10180, 127 light years off in the Hydrus constellation, using the world’s most powerful spectrograph (an instrument which measures light over a specific wavelength). The sky watchers used the same method as used to discover many of the other exoplanets we now know about–by looking for “wobbles” in the light coming from the star, and then modeling these perturbations to work out what planets are in orbit. By clever maths, you can calculate the mass of the planets in question.
Accordingly the new discovery is of five giant planets, around the same mass as our gas giant Neptune, and they orbit at a distance that gives them a wide range of years, equivalent to six Earth days and 600 days. Within the data there’s also evidence that there are two more planets in orbit in this system, one around the same size as Saturn and one that’s only 1.4 times as big as Earth. Abandon any hope that this little planet is anything like Earth though–an M-class body orbiting at the right distance from the Sun to allow liquid, gas and solid water to exist: This extra-solar planet is so close to the star HD 10180 that it orbits in just 1.8 Earth days.
What does this all mean for you? It won’t touch your life very much, unless you’re a thinker: Next time you stare up at the sky, you can know that out there somewhere is a solar system that’s essentially very similar to our own. The very fact that it exists, and we’ve found one so very quickly now we’re able to look, increases the chance that there are many more out there. E.T. suddenly seems a more realistic prospect.
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