A commemorative postage stamp on Centenary of the Discovery of the Evershed Effect (Radial Flow of Gas across the Photospheric Surface of Sunspots) :
Issued by India
Issued on Dec 2, 2008
Issued for : India Post is proud to issue commemorative postage stamp on centenary of the discovery of Evershed Effect.
Stamp & FDC : Suresh Kumar
Cancellation : Alka Sharma
Type : Stamp, Mint condition
Colour : Multicolour
Denomination : 500 Paise
Stamps Printed : 0.4 Million
Printing Process : Wet–offset
Printer : Security Printing Press, Hyderabad
- Earlier studies had concentrated on spots near the central meridian of the Sun. Evershed was the first to observe spots at various positions, up to 50 degrees, on either side of the central meridian. He found that the line displacements were more pronounced in the penumbral regions of the spots which are closer to the limb of the Sun. This clearly showed that the flow of the gases was radially outward parallel to the surface of the Sun. Evershed’s discovery is the forerunner of many important discoveries which connect the velocities and magnetic fields on the surface of the Sun, which has given rise to the entire field of solar magneto hydrodynamics. Evershed’s work established the reputation of Kodaikanal as one of the best solar observatories in the world. In 1913, Evershed visited Kashmir for three months and found the observing conditions in the Kashmir Valley excellent for solar work. He established a temporary observatory near Srinagar in 1915-16 obtaining very high-quality photographs of prominences and sunspots.
- During the hundred years since Evershed’s discovery, our understanding of the solar phenomena and the solar-terrestrial relations has grown enormously. It has profoundly influenced diverse fields of science and great benefits have been derived from these studies. Solar space missions have further enriched our knowledge of the complex processes taking place on the solar surface and their impact on the interplanetary space and our terrestrial environment.
- Text : As per the material provided by the proponent.