When the Dragon Swallowed the Sun: A Brief Review of Eclipses

By Ashfaq Ali

Cosmofluencer (Season 2)

When the three heavenly bodies we are most familiar with, the Sun, the Moon and the Earth, floating in their orbit form a particular arrangement, a phenomenon called the eclipse occurs. 

Derived from ancient Greek ‘ekleípō’, meaning to vanish or to abandon, an eclipse is a phenomenon which has been a source of knowledge, and intrigue and has awakened fear and superstitions among various human communities through time. 

A sight that might seem like the dawn of doomsday for people who don’t have correct knowledge of why and how the eclipse happens, it can be easily explained by observing the Sun, Moon and the Earth and applying the basic laws of nature.

As the name suggests, an eclipse seems like the Sun is ‘vanishing’ from the sky. But what actually happens is that the Moon comes in between the Sun and the Earth, blocking the light we get from the Sun. This kind of eclipse is called the solar eclipse. When these three heavenly bodies are aligned while they go about their orbits, in such a way that the Moon is in between the Sun and the Earth, the Moon blocks most of the light from the Sun, thus the Earth is left behind in sheer darkness. 

A lunar eclipse is when the Earth is in between the Moon and the Sun, thus blocking the light from the Sun that was supposed to fall on the Moon. This creates an illusion that the Moon is ‘vanishing’ from the sky.

The Moon giveth, and the Moon taketh

The fact that three individual bodies, each undergoing a continuous fall due to the gravity of the other, can come together to form such a breathtaking phenomenon, is itself very hard to imagine

A ball of fire is blocked by a humble, small and dull Moon. The Moon, beautifully defined by Parmenides, a Greek philosopher is ‘a lamp by night, wandering around the Earth with borrowed light’. This definition of the Moon is apt considering that it reflects the Sun’s light to Earth.

The Moon, which illuminates the dark of the night with its lamp-like brightness, is the same heavenly body that causes a sudden ‘death’ of the daylight, leaving the residents of Earth awe-struck and contemplating.

Coronation: The Crown of the King

The total eclipse of the Sun happens when the centre of the Moon perfectly aligns with the centre of the Sun, and the distance between the Sun and the Moon is just right so that the Moon blocks the Sun’s entire light. The distance between the Sun and Moon keeps changing as the Moon does not orbit the Earth in a perfect circle, but rather in an elliptical fashion. This total eclipse brings out aspects of the Sun we previously could not observe. 

The outermost part of the Sun’s atmosphere, the Corona, is a thousand times dimmer than the Sun’s ‘disk’. When the centre light is blocked due to the eclipse, and when the scattering of light due to Earth’s atmosphere is minimal, the corona reveals itself in its beauty.

When one is lucky enough to observe a total eclipse, one has an opportunity to experience the sight of the Sun’s atmosphere without leaving Earth. Like a heavenly glow behind a dark circular disk, the Corona seems as if the Sun is emanating swirls of hot gases, while sharp rays of light stand straight behind it. When it seems that the Sun is ‘smoking’, it is! The corona is nothing but super-hot ionized gas known as Plasma. The swirls of this gas formed around the Sun keep changing their shape and size because of the Sun’s magnetic field.

Helios and his Chariot of Fire

The eclipse whose shadow or the path of totality fell on India in the year 1868 was used to discover a new element. When the French Astronomer Pierre Janssen observed the spectrum of the solar prominence, the plasma in the Corona, he came across a bright yellow line in it. This yellow line in the spectrum did not match with the colour of the spectrums of the known elements(a unique wavelength of light). It was thus concluded that the spectrum was from an entirely new element. The British astronomer Joseph Norman Lockyer named this element Helium.

Helium was the Greek word for Sun, as it was thought to be the chariot of the Sun Titan Helios. In Greek mythology, Helios was the Sun’s titan, while Artemis, the hunter goddess, was linked with the Moon. 

To approach an ancient Greek man and to say to him, “When the Sun disappears in broad daylight, it is because Artemis fights and defeats Helios until he reappears with his chariot.” would be a feat I can only dream of doing. 

There is no escaping the Fabric

While eclipses tell us a lot about the Sun and the Moon and their trajectories with respect to the Earth, they can also be used to understand the Universe and how its fabric works.

When I say, ‘The Fabric of the Universe’, what I mean is the 3-dimensional space of the universe that we observe (or 4-dimensional, if you consider time as a coordinate). The Fabric of the Universe, simply put, is the ‘reality’ in which we exist. Anything outside of this fabric, by the definition of the Universe, should not exist (or is it that our 3-dimensional brains cannot comprehend it?).

What Albert Einstein proposed in his general theory of relativity was that gravity was not just an attractive force due to mass, but it was a result of distortion of space (the fabric) due to the mass of the object (Sun, planets, black hole etc). When you stretch a piece of rubber and put a heavy object on it, say a metal ball, you observe that the rubber sheet ‘curves’ around the ball. In the same way, the fabric of space between two objects (for example the Sun and Earth) is distorted due to the mass of the Sun and the Earth. The mass of the Sun is far greater than the mass of the Earth hence resulting in the orbit of Earth around the Sun. This is general relativity.

Coming back to eclipses, Einstein asked astronomers to observe the stars around the Sun during a total eclipse. If the theory of general relativity were to be true, the light from these stars should be deflected because of the presence of the Sun as compared to the light from these stars in the absence of the Sun.

 It was observed that the light from these stars in a total eclipse (in the presence of the Sun) was deflected by 1.98 arc seconds from the light from these stars when the Sun was absent (nighttime).

Hence, the theory of general relativity was backed by observation, making it a very accurate definition of our Universe

The Human World and Eclipses

The Solar and lunar eclipses have impacted various aspects of human life and society. Whether it is science, mythology, theology, literature, art, or philosophy, eclipses have helped shape the human belief system and the human society. It was a phenomenon that fueled human curiosity and led to the development of various scientific theories and philosophies and helped artists get inspired.

Each human civilization viewed eclipses in their own way:

• The Native Americans inferred it to be a bad omen, so they performed human sacrifices to please their gods.
• The ancient Chinese believed that the Sun was eaten by a dragon every time there was an eclipse of the Sun.
• The Babylonians looked at it as an empirical observation, and even if they couldn’t figure out the cause for it, they recorded most of their occurrences, as they connected astronomy to astrology.
• In the world of the Abrahamic religions, the Eclipse was seen as a sign of the almighty God.

The Islamic prophet Muhammed (صلاله عليه وسلم) was recorded to have said:

“The Sun and the Moon do not eclipse because of the death of someone from the people but, they are two signs amongst the signs of Allah. When you see them, stand up and pray.” (Hadith 2:168)

The Bible states the following:

‘”It will come about in that day,” declares the Lord God, “That I will make the Sun go down at noon, And make the Earth dark in broad daylight.’ – (Amos 8:9)

The Abrahamic religions did not observe eclipses as a superstition, but rather as a sign of the Almighty God.

The Astronomer and Eclipses

While different people from different times viewed eclipses in different ways, we as Astronomers observe it to be one of the greatest astronomical events that can be seen on Earth. It should inspire ecstasy in us when we are lucky enough to observe an Eclipse.

When we observe an eclipse, we should realize that it is one of the rarest natural phenomena that connects something happening in outer space to Earth and our lives directly. Three heavenly bodies floating in space in their own orbits somehow came in such an arrangement, that a big shadow is cast, either on the Earth or on the Moon. Such a big phenomenon occurs, only for us to be there and observe it. This should be considered the biggest gift for a space enthusiast and an astronomer.