Does the Sun rotate? Premium
The Hindu
The Sun rotates on its axis with varying speeds, creating a differential rotation phenomenon observed by solar physicists.
A: Yes. the Sun too rotates about its axis. But unlike the earth, which has a rotation period of one day, the sun has a differential rotation. That is, all parts of the sun do not have the same period of rotation.
The period of rotation near its equator is 26.5 days, at sun spot zone (16 degrees north) it is 27.3 days, and at the pole it is 31.1 days.
The Sun’s enormous core temperature of 15 million degrees K and a surface temperature of 6,000 degrees K leaves all its constituents in a high-pressure gaseous state called a plasma.
For the purpose of certain calculations, the top and the bottom ends of the visible sphere of the Sun are designated as north and south poles respectively.
Photographs are taken daily and the movements of the spots, filaments, and plages are observed for various latitudes and longitudes, for a long period of time. From this, the sidereal rotation period is calculated.
The reason behind this phenomenon is still a puzzle to solar physicists.
A great book written and illustrated by English polymath Robert Hooke, Micrographia appeared in bookshops in January 1665. The advance copy of this book, which details Hooke’s exploration into many things small, far, and sometimes elusive, is believed to have been shown to the Royal Society on November 3, 1664. A.S.Ganesh tries to hook you onto Hooke’s story…