by Cecilie Wettre (EUMETSAT)
Jump to imagesOn 29 March, the shadow of the moon crossed the Earth, resulting in a partial eclipse for most parts of Northern Europe, and a total eclipse over Turkey and parts of North Africa (see images below).
A total solar eclipse occurs only at new Moon, when the Moon passes directly between the Sun and the Earth. The Moon’s complete shadow (the umbra) sweeps across the Earth in a narrow path called the path of totality. To see a total solar eclipse, you have to be in the path of totality. Outside the path of totality, in the Moon’s partial shadow (the penumbra), some portion of the Sun’s bright disk remains visible.
Below are animations showing the shadow of the moon moving across the Earth disk as seen by Meteosat-8. We see how the shadow of the Moon sweeps over the Atlantic Ocean, crosses the Sahara and passes over Turkey.
A total solar eclipse is a quite rare event. Since the orbit of the Moon is tilted by about five degrees with respect to the Earth’s orbit, the Moon usually passes slightly above or below the line between the Sun and the Earth. Only about every six months, during an eclipse season, are the conditions right for a lunar or solar eclipse (see link below: Total and annular solar eclipse paths: 2001 - 2020).
In the pictures below from the Turkish State Meteorological Service, we see some interesting phenomena. When the Moon occludes the Sun almost completely, and the narrow crescent of the Sun begins to disappear, tiny specks of light remain visible for a few seconds more. These points of light are spaced irregularly around the disappearing edge of the Sun, forming the appearance of a string of beads around the dark disk of the Moon. These lights are known as Baily's beads, named after Francis Baily, the British astronomer who was the first to draw attention to them. The beads are actually the last few rays of sunlight shining through valleys on the edge of the Moon. Baily's beads make their brief appearance up to 15 seconds before totality. When a single point of sunlight remains, a "diamond ring" effect is created against the outline of the Moon.
In the brief period of a total eclipse one sees the corona of the Sun. A million times fainter than the Sun itself, the corona is visible only during a total solar eclipse. Wispy plumes and streamers of coronal light reach out with distances of up to several diameters of the Sun. Against the backdrop of the white corona and the black disk of the Moon, it is possible to see the light from the Sun's lower atmosphere, the chromosphere. For a few seconds both after the beginning and before the end of totality, this pinkish glow appears at the edge of the Moon.
On the Earth, the darkness of totality resembles nighttime, and plants and animals react accordingly. Birds stop singing and may go to roost, bees become disoriented and stop flying, and daytime flower blossoms begin to close as if for the night. The temperature drops in the coolness of the Moon's shadow, as is shown in the graph of the temperature measured in Manavgat, Turkey (see link below). Also, of interest is the photograph of the Campbell-Stokes sunshine recorder at the Turkish State Meteorological Service, where sunlight is focussed through a water-filled glass sphere, burning a line on a paper strip as the sun moves over the sky, in order to record sunshine hours every day. In this picture from 29 March we see a gap exactly at the time of the eclipse.
If you have any questions or queries about EUMETSAT, its products and services, please . | |||||||||||||||||||||
