Astrophysicists can now explore weather systems on distant planets orbiting other suns.
Recent headlines about rubies and sapphires on a distant exoplanet have been full of exclamation marks, real or implied. That’s understandable; the hint of bling raining down from clouds in an otherworldly atmosphere is exciting.
The headlines are, however, detracting from what might be the most fascinating part of the story: evidence of weather patterns has been detected on a planet over 1000 light years away. No longer content with simply finding planets outside of our solar system, we are now at the point where we can question their atmospheric conditions and how they change over time.
The study—published Monday in Nature Astronomy—combined four years of cloud data from HAT-P-7b, an exoplanet about 16 times larger than Earth. The planet is a gas giant, similar to Jupiter but bigger, and like Jupiter, it has strong winds and violent storms.
The researchers used NASA’s Kepler satellite to track cloud formations in HAT-P-7b’s atmosphere. In a recent article, David Armstrong, University of Warwick, UK, provided a clear explanation of the process:
“To study weather patterns on an exoplanet, we can look at the light it reflects. Light from the parent star heats the planet, but some of it is reflected, either by the planet’s surface or its atmosphere – especially if the exoplanet is cloudy. On top of this, the planet emits its own light, getting brighter the hotter it is. By observing the planet as it orbits, we can see changes in the planet’s light and so create a map of the brightness of the planet’s surface. If we observe multiple orbits of the planet, we can see how that brightness changes each orbit, and so work out how the planet’s atmosphere changes over time.”
The temperature on HAT-P-7b ranges from a scorching 2,100 degrees Celsius (3812 degrees Fahrenheit) to a ‘cold’ 1,300 degrees Celsius (2372 degrees Fahrenheit), so clouds on the exoplanet are not at all like those in our atmosphere. The scientists admit that they don’t know for sure what the clouds are made of, but they suggest that one possible answer is corundum: the second hardest mineral (after diamond), best known for its gem varieties, Ruby and Sapphire.
Sparkling red rubies are not falling from the sky, however, nor are there surface streams or puddles on HAT-P-7b filled with blue sapphires. Astrophysicists can now explore changes in weather systems on distant planets orbiting other suns, though, and that’s still pretty extraordinary.
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