RC Kapoor

The excitement about the total solar eclipse of 8 April 2024 in North America is unprecedented. Years before it was to pass, astronomers, educationists, students, the administrations and the local communities, and the shadow chasers from all over had begun to plan and prepare for the greatest show on Earth. While it is the corona of the Sun that is of greatest interest, visible for a very short duration of the totality, its fascination is multifaceted. The sensation caused by a total eclipse has a lasting impact on the viewers, and the anecdotes travel far and wide.

The solar corona is a highly rarefied atmosphere of hot ionized gases, visible up to a few solar radii during totality. Its density is ~10-16 g /cm3 or 4×108 atoms/cm3, 1013 times thinner than the atmosphere of Earth at sea. It is believed that magnetic energy heats the coronal plasma to two million degrees. However, the physical processes involved are not yet fully understood.

In a century, 238 solar eclipses occur; the maximum number in a year is five, whereas the minimum is two. A total eclipse occurs nearly every 18 months at some place on the Earth, but at any given place, it will repeat in 350–400 years only. The maximum theoretical duration for totality is 7 min 31 sec. The maximum width of the path of totality is about 250 km. The closer one is to the centre line of the path of totality the longer is the…read more on NOPR