KOMPAS.com – On social media, photos are circulating showing the closed sky cloud and emitting rainbow colors, Saturday (10/4/2021).
The narrative written by the uploader, this celestial phenomenon occurs after earthquake earth.
Several other Twitter users also posted the same photo, showing clouds with light rays.
As of Sunday (11/4/2021), the photo has been re-shared 62 times and liked more than 565 times by other Twitter users.
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How do you explain this celestial phenomenon?
Head of Mitigation Division Earthquake Earth and Tsunami Agency for Meteorology, Climatology and Geophysics (BMKG) Daryono said the celestial phenomenon had nothing to do with the earthquake that occurred in Malang on last Saturday.
“There is no connection,” said Daryono when contacted Kompas.com, Sunday (11/4/2021).
According to him, the phenomenon of radiance on clouds after the earthquake was just a coincidence.
Phenomenon cloud irisdence
Meanwhile, when contacted separately, Indonesian amateur astronomer, Marufin Sudibyo, said that the cloudy sky phenomenon seen in the photo above and emitting rainbow light is called an irritating atmospheric phenomenon or cloud irisdence.
“This is a pure atmospheric phenomenon due to the presence of a strong light source (the Sun) and a cloud barrier whose edges are thinner,” said Marufin to Kompas.com, Sunday (11/4/2021).
He said that the light appeared considering the angular distance between the colors seen and the position of the Sun was relatively small (less than 45 degrees).
Marufin explained that this phenomenon is the same as when someone plays soap bubbles in a bright place during the day.
In the bubble, you will see rainbow colors glow caused by the diffraction of sunlight by nanoparticles that make up a thin layer of soap bubbles.
“Because sunlight is a combination of rainbow colors, when it is diffracted it will form rainbow colors as well. Not as dark and light patterns,” he continued.
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Related phenomena cloud irisdence which happened on Saturday (10/4/2021) afternoon, Marufin said, it happened when the sunlight was blocked by high clouds.
Then, the edges are quite thin and are composed of water droplets or micro ice crystals. At that time, light diffraction occurred.
Marufin explained that when the light from the diffraction products is transmitted to Earth until it reaches the observer’s eye, it will appear as rainbow colors.
The appearance of a rainbow of colors is determined by the size of the ice crystals.
“If the crystal grains are bigger, what will be formed is the halo (halo) phenomenon,” said Marufin.
In contrast to the fire rainbow
It is necessary to know, said Marufin, a phenomenon cloud irisdence different from the phenomenon of the rainbow fire.
He explained, fire rainbows are not a celestial phenomenon because actually fire rainbows occur in the Earth’s atmosphere.
“The fire rainbow occurs through a mechanism similar to that of the Halo Sun enomene, which is the refraction of the Sun’s light by micro-ice grains with a hexagonal plate structure in high clouds such as Cloud Cirrus, “ujar Marufin.
“So the formation process is similar to a rainbow. It’s just that in a rainbow, the position of the Sun is behind us while the raindrops are in front of us,” he continued.
Furthermore, the rays of the sun are refracted by the raindrops and then reflected perfectly so that the direction is the opposite of the direction of the sun’s light.
The process forms a semicircular arc of light equipped with a rainbow color component.
There is no factor from the earthquake
From this explanation, Marufin revealed, a phenomenon cloud irisdence does not occur because of the earthquake.
This sky phenomenon appears during the day and there are scattered clouds with high tops such as cumulus / altocumulus clouds in the central and eastern parts of Java.
“If this factor does not exist, then we think that it may be related to earthquakes. Because these factors exist and they occur more frequently, then the relationship with earthquakes cannot be withdrawn,” said Marufin.