SOHO spacecraft Current Affairs - 2019
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A team of researchers have discovered solar seismic waves which revealed that Sun’s core is rotating four times faster than its surface. Earlier it was assumed that sun’s core rotate at same speed as the surface.
The discovery was made using 16 years of observations from GOLF (Global Oscillations at Low Frequency) instrument on Solar and Heliospheric Observatory (SOHO) spacecraft, a joint project of ESA and NASA.
Researchers had use ‘Helioseismology’ to probe the solar interior by studying sound waves reverberating through it. They had studied surface acoustic waves in the Sun’s atmosphere, some of which penetrate to the Sun’s core, where they interact with low frequency gravity waves (g-waves) known as g-modes that have a sloshing motion.
From those observations, they detected the sloshing motions of the solar core. By carefully measuring the acoustic waves, the researchers precisely determined the time it takes an acoustic wave to travel from the surface to the centre of the Sun and back again.
On the basis of the signature of the g-waves, researchers determined that the g-waves are shaking the structure of the sun’s core. The signature of the imprinted g-waves suggested that the inner core of the Sun is rotating once every week, nearly four times faster than the observed surface and intermediate layers.
Significance of Discovery: The rotation of the Sun’s core may give a clue to how the Sun formed. It may also help to find linkages between the Sun’s core rotation and sunspots.