7 facts about solar eclipses

Total eclipses of the Sun are rare and have huge scientific value. To mark the March 20 eclipse, visible in Europe, here are seven facts that may be new to you.

1. Earth is the only planet in the solar system subject to total solar eclipses

Ours is the only planet in the solar system whose moon appears from the surface to have the same angular size in the sky as that of the sun. This allows the moon to block out the sun completely to reveal the corona — its outer atmosphere.

2. This is the first time since 1662 that a total solar eclipse has coincided with the March Equinox

A total solar eclipse coinciding with Northern Spring Equinox (when night and day are the same length) and Southern Autumn or Fall Equinox hasn’t happened since 1662. This won’t happen again until March 20, 2034

3. The element helium was discovered as a result of solar eclipse observations

French astronomer Pierre Janssen observed the eclipse from India in 1868 and, using a spectroscope, spotted light from a new element — helium — decades before it was found on earth.

4.  A total solar eclipse proved Einstein’s theory of general relativity

According to Einstein, light from a star should appear to bend as it passes the edge of the sun. Observations during a 1919 total solar eclipse showed a star appear to shift in the sky due to the sun’s gravitational influence, so confirming the theory.

5. Europe gets 3% of its energy from the sun 

Solar panels provide roughly 3% of Europe’s electricity supply, up from nearly zero a decade ago, with Friday’s eclipse potentially causing a drop of up to 35,000 megawatts of generation capacity – the equivalent of about 20 large coal-fired power plants coming off the grid at the same time.

6. Solar eclipses and lunar eclipses come in pairs

A solar eclipse always takes place about a fortnight before or after a lunar eclipse. There’ll be a lunar eclipse on April 4.

7. Solar eclipses are associated with disaster

The Greeks thought they represented the anger of the gods, the Vikings thought they were the fault of wolves and a common superstition is that they are dangerous for pregnant women.

Image: The new Moon blocks out the sun, producing a partial eclipse in the sky over Reykjavik on March 20, 2015.  REUTERS/Sigtryggur Ari

Author: Mark Jones is Commissioning Editor for the World Economic Forum’s Agenda