Calcutta, Jan. 16: The predicted solar flares over sunspot 720 did occur late yesterday.

The sunspot group, which is as big as Jupiter, produced three major flares, which can have a lasting impact on earth. Of the three, two were M-class or medium-sized flares, capable of causing brief radio blackouts in the polar regions. One was an X-class flare, big in size and capable of causing radio blackouts across the earth and long-lasting radiation storms.

One of the M-class flares, labelled M8, lasted the longest, resulting in intense radio emissions and radio sweeps, with rising energetic protons. Satellite pictures have revealed a fast full-halo coronal mass ejection.

The sunspot, first sighted from the earth on Friday, is nearly seven times the size of our planet. It is a rare phenomenon. The spot hasn?t changed in shape or size since Friday but has shifted, moving towards the centre of the sun, as seen from the earth.

?Despite its duration, the M-class flare shouldn?t affect us but the X-class flare may have some reaction here,? said Debiprosad Duari, director of research and academics at the MP Birla Planetarium.

?But it will take time for the flowing particles to come in contact with the earth?s magnetosphere. Only then can one expect radio communications and high-altitude flights to get affected.?

What the flares also mean is the possible sighting of auroras by tomorrow. An aurora is a glow in the earth?s ionosphere caused by the interaction between the planet?s magnetic field and charged particles from the sun. The phenomenon is known as Aurora Borealis in the northern hemisphere and Aurora Australis in the southern hemisphere.

?Usually, the auroras are seen only from the polar regions. But due to these flares from the sunspot, the auroras can be sighted from downward latitudes,? added Duari.