Well the biggest grain of salt to swallow when it comes to the miracle at Fatima is the variance in reporting. An Italian priest by the name of
De Marchi made a collection of numerous reportings from people at the event writing about what they saw and collected them in his book (6) here are the reportings;
"The sun, at one moment surrounded with scarlet flame, at another aureoled in yellow and deep purple, seemed to be in an exceedingly swift and whirling movement, at times appearing to be loosened from the sky and to be approaching the earth, strongly radiating heat." — Domingos Pinto Coelho, writing for the Catholic newspaper Ordem. (1)
"The silver sun, enveloped in the same gauzy grey light, was seen to whirl and turn in the circle of broken clouds [.. The light turned a beautiful blue, as if it had come through the stained-glass windows of a cathedral, and spread itself over the people who knelt with outstretched hands [...] people wept and prayed with uncovered heads, in the presence of a miracle they had awaited. The seconds seemed like hours, so vivid were they." — Reporter for the Lisbon newspaper O Dia. (2)
"The sun's disc did not remain immobile. This was not the sparkling of a heavenly body, for it spun round on itself in a mad whirl when suddenly a clamor was heard from all the people. The sun, whirling, seemed to loosen itself from the firmament and advance threateningly upon the earth as if to crush us with its huge fiery weight. The sensation during those moments was terrible." — De Marchi attributes this description to Almeida Garrett, Professor of Natural Sciences at Coimbra University.(6) Theologian Father Stanley L. Jaki wrote that it was actually given by José Almeida Garrett, a young lawyer, and is often mistakenly attributed to his father, a professor of natural sciences at the University of Coimbra,[3] named Gonçalo de Almeida Garrett.[4] (would like to note that it is understood if you want to discredit this account due to the disputing of source)
"As if like a bolt from the blue, the clouds were wrenched apart, and the sun at its zenith appeared in all its splendor. It began to revolve vertiginously on its axis, like the most magnificent firewheel that could be imagined, taking on all the colors of the rainbow and sending forth multicolored flashes of light, producing the most astounding effect. This sublime and incomparable spectacle, which was repeated three distinct times, lasted for about ten minutes. The immense multitude, overcome by the evidence of such a tremendous prodigy, threw themselves on their knees." — Manuel Formigão, a professor at the seminary at Santarém, and a priest. (6)
"I feel incapable of describing what I saw. I looked fixedly at the sun, which seemed pale and did not hurt my eyes. Looking like a ball of snow, revolving on itself, it suddenly seemed to come down in a zig-zag, menacing the earth. Terrified, I ran and hid myself among the people, who were weeping and expecting the end of the world at any moment." — Rev. Joaquim Lourenço, describing his boyhood experience in Alburitel, 18 kilometres (11 mi) from Fátima.(5)
(should be noted I excluded an account from a Afonso Lopes Vieira since it didn’t give any details over the event)
Here we can see the eye witnesses disagree on numerous things including the color, the sound (some described a sound and others omitted it, although this is expected with eye-witnesses accounts) this seems to be a mass-hallucination to me
Work cited:
1 - De Marchi 1952b: 147
2 - De Marchi 1952b: 143
5 - De Marchi 1952b: 149
6- De Marchi 1952b: 143