Our sun, being the closest star to planet Earth, has long served as key to helping us understand the universe and its mechanics. While ancient civilizations worshipped it for it's life-bringing light and heat, modern scientists study it to try to unlock secrets of the universe, learning things that might be applied to celestial bodies elsewhere in the cosmos.
It was recently announced that NASA's Parker Solar Probe (previously called the Solar Probe Plus) will be sent skyward on a course for our star, and "swoop to within 4 million miles of the sun's surface, facing heat and radiation like no spacecraft before it." The Parker Solar Probe will be launched in 2018, and will "provide new data on solar activity and make critical contributions to our ability to forecast major space-weather events that impact life on Earth."
We know a lot about the sun already, and of course, with the new information gained from the Parker Solar Probe's mission, we can expect to learn even more in the coming years. But perhaps there are still some solar phenomena observed here on Earth from time to time that remain unexplained.
For example, is it possible that there could be atmospheric conditions that would cause the sun to appear to flash, producing an odd-looking "blinking" effect?
Admittedly, this sounds a pretty unlikely (if not a bit crazy), although a number of videos appearing on sites like YouTube these days purport to show this occurring, such as this one:
In most cases, it seems that the "phenomenon" in these videos appears to be related with the camera, rather than the sun itself, and what may be the device's auto focus and exposure settings attempting to adjust when pointed directly at the sun while filming. Another, perhaps more likely explanation, is that when a camera focuses on the sun, what are often called "blown highlights" can occur, resulting from light being captured in a dynamic range that exceeds the range of the camera in question.
In the video below, one of the commenters makes a similar suggestion, noting that this footage which purports to show the sun "flashing" again might have resulted from someone adjusting the ISO settings on the camera, rather than an atmospheric strobing effect:
Apart from the "blown highlight" theory we've proposed, there is very little in the way of scientific information that describes flickering or flashing sunlight, nor anything that suggests what might cause something like this to happen, atmospheric or otherwise.
Despite the lack of scientific data, there are at least one or two articles and blogs that seem to reference this so-called "blinking sun" phenomenon. One interesting post, dated February 1, 2009, appeared at the blog of physicist Gordon Watts, appropriately titled, "The Sun Should Not Flicker!". As Watts recounts, while flying from Seattle to Geneva he described his observation of a mild "flickering", which had been visible on a portion of the aircraft for a short period. He also managed to film this mild strobing effect, which can be seen here, where the flickering appears on the aircraft itself, rather than as a result of focusing his camera on the sun.
"We were in very smooth air at the time," Watts wrote, "so it couldn’t have been the bouncing of the plane. The only thing I could think of was there were some clouds on the horizon that were blowing by and obscuring the sun briefly. Unfortunately, without opening the plane door, I couldn’t check! Is that it?"
"Whatever it was – it was very spooky," Watts concluded. "The sun is supposed to be rock solid!"
Commenters on Watt's post claimed to have observed similar things in the past. In a reply dated August 17, 2011, a commenter named "Bob" responded saying, "I have sungazed (sic) for years and noticed how the solar disc appears to not only flicker, but also gyrates. It is no optical illusion as I have seen it through reflections and between tree branches. No one has been able to confirm what I see much less why it does this."
The description of flickering observed "between tree branches" sounds a bit suspect. However, another comment, dated April 17, 2017, was shared by a Tennessee resident named George Walker, who described a group of people that claimed to witness this "flickering" around sunset.
"Saw it flickering and pulsating at sunset in Tn. on Easter Sunday April 2017," Walker wrote. "There was a smaller, reddish sun or planet, about half in size, directly below our Sun. Everything was clearly visible and witnessed by many in the neighborhood."
As for the "smaller, reddish sun or planet" Walker described seeing directly below the sun, who knows precisely what this was in reference to. Granted, a variety of atmospheric conditions can lead to similar, unusual looking manifestations, such as the "green flash", where prismatic effects in the atmosphere cause sudden "flashes" and changes of color just as the sun sets over the horizon.
We'd be interested in hearing from any readers that have observed this sort of "flashing", particularly if it was observed with the naked eye, rather than merely on camera (since the videos alleging to show this phenomena make it difficult to discern whether this is a lighting adjustment with the device, or the "blown highlights" we discussed earlier). Feel free to use the comments section below, or you can also send us an email with your report here.