Supercomputer simulation aims to resolve sun’s rotation mystery
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In a world first, Japanese researchers used the Fugaku supercomputer to reproduce imbalances in the sun’s rotation, a phenomenon that has puzzled astronomers for centuries.
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The scientists from Chiba University and Nagoya University simulated the inner workings of the ball of gas in an effort to determine why different areas rotate at different speeds.
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Their findings were published in the scientific journal Nature Astronomy at (https://doi.org/10.1038/s41550-021-01459-0).
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All areas on Earth complete one spin in 24 hours.
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But it takes about 25 days for zones near the sun’s equator to finish one rotation and about 30 days for those near the north and south poles.
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The phenomenon, known as solar differential rotation, was first observed around 1630, according to Chiba University. But there is still no definitive explanation for why this happens.
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Using around 5.4 billion points inside the sun, Fugaku calculated how energy from nuclear fusion inside the star is transferred to the surface by convection currents.
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The project simulated thermal migration and magnetic field changes based on observation data on the density, pressure and temperatures of the sun.
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The high-definition simulation successfully reproduced the equator rotating faster than the north and south poles, the scientists said.
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Fugaku’s predecessor, the K supercomputer, could do calculations using only around 100 million points, and it was unable to accurately reproduce the sun’s complicated internal workings.
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That experiment wrongly had the equator turning at a slower pace than the poles.
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The Fugaku supercomputer could help researchers shed light on another mystery.
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The difference in rotation speeds is said to play a key role in the emergence every 11 years of more sunspots and increased solar activity.
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“We will also work on figuring out the mechanism of the 11-year cycle–the biggest mystery in solar physics,” said Hideyuki Hotta, an associate professor of physics at Chiba University.
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