Light from the Sun
Solar light and heat is essential for life at the Earth surface. But the sun can also emit damaging radiations for human activities and health.
To prevent or forecast these phenomena, solar activity is monitored by a network of ground based observatories, as well as satellites performing observations in wavelengths absorbed by the earth’s atmosphere, as Ultra Violet, X or Gamma rays.
Monitoring the solar radiance
Paris Observatory, at Meudon and Nançay, makes daily observations of the solar surface since one century. A unique collection of more than 100 000 images has been registered along ten activity cycles. Solar flares can affect electric distribution and plants, and are monitored in real time by the GOES satellite in X rays.
Preventing damages
We know that the sun is a variable star with a 11 year activity cycle. Solar maxima are characterized by the presence of a large number of magnetized areas, as sunspots.
Magnetic fields are deeply anchored below the solar surface, which is characterized by convective motions ; when magnetic configurations become unstable, dramatic phenomena as eruptions of plasma, flares, or mass ejections, can occur. They inject into the interplanetary medium fast particles.
On the Earth, energetic particles from the Sun can generate a lot of various perturbations which can interfere with human activities : interruption of radio transmissions, magnetic induction in long distance electric lines, breakout of electronic devices onboard artificial satellites, enhancement of the amount of cosmic rays absorbed by people onboard transatlantic aircrafts, pipe line corrosion,...
RSS flux of daily observations
Ephemeris and Sun live
Sun ephemeris
Sun live
- See also the ephemeris and images of the last observing day in Meudon.
Dernière modification le 1er août 2018