Photos showing a funnel cloud seen around sunset on February 7, 2017, from Rio de Janeiro, Brazil. No tornado, storm or even rain was reported.

Helio C. Vital in Rio de Janeiro, Brazil captured these photos last night (February 7, 2017). He wrote:

They show very interesting cloud formations that were part of an approaching storm cell at sunset. The threatening formations included a very interesting funnel cloud and also lenticular clouds

The photos were taken with my Canon PowerShot SX60 HS at high zoom amplifications and low ISO (100-250). Post-processing was either 5 to 1 or 3 to 1 stacking and the resulting image had its contrast improved with PhotoScape in order to make the structure of clouds over Rio more easily noticeable.

In spite of the menacing appearance of the clouds no tornado, storm or even rain was reported.

Thank you, Helio!

A rare "fire rainbow" was spotted in the sky over Humberston.

Formally known as a circumhorizontal arc or circumhorizon arc (CHA), it appeared horizontal in the sky, rather than making an arc towards the earth.

Spotted at lunchtime yesterday, the person who took it said she spotted it high up in the sky - and only just managed to capture what was left of it on her phone camera as it disappeared.

"I've never seen one like it before as it was horizontal rather than vertical and was a lot clearer before I managed to take a photograph," she said. Not wishing to be named, she said she had to tip her head right back to see it. "I just wish I had been able to get it on camera before it disappeared."

An international team led by researchers at Nagoya University, along with US and Swiss colleagues, has identified a new type of solar event and dated it to the year 5480 BC; they did this by measuring carbon-14 levels in tree rings, which reflect the effects of cosmic radiation on the atmosphere at the time. They have also proposed causes of this event, thereby extending knowledge of how the sun behaves.

When the activity of the sun changes, it has direct effects on the earth. For example, when the sun is relatively inactive, the amount of a type of carbon called carbon-14 increases in the earth's atmosphere. Because carbon in the air is absorbed by trees, carbon-14 levels in tree rings actually reflect solar activity and unusual solar events in the past. The team took advantage of such a phenomenon by analyzing a specimen from a bristlecone pine tree, a species that can live for thousands of years, to look back deep into the history of the sun.

"We measured the ¹⁴C levels in the pine sample at three different laboratories in Japan, the US, and Switzerland, to ensure the reliability of our results," A. J. Timothy Jull of the University of Arizona says. "We found a change in ¹⁴C that was more abrupt than any found previously, except for cosmic ray events in AD 775 and AD 994, and our use of annual data rather than data for each decade allowed us to pinpoint exactly when this occurred."

From as far back as 2008, video recordings of strange and eerie sounds have been appearing on the internet. They occasionally garner a mention in the media but are generally ignored or explained away as a 'hoax', the result of "secret government weapons", the "activation of HAARP" or "HAARP-like technologies", the by-product of "top secret construction work on underground bases", or "aliens", etc., etc.

Variously described as groaning, metallic, clashing, clanging and trumpet-like, these (usually loud and pronounced) noises seem to come from the sky but generally reverberate in such a way that listeners are unable to make out from which general direction they come.

These 'strange sky sounds' have been observed all over the globe and first really caught the public's attention in 2011, when a spate of events sparked such widespread interest that significant effort was made to discredit the phenomenon through the dissemination of fake recordings.

Some, certainly, are hoaxes. That's human nature; we mock that which we do not understand. But the sheer proliferation of 'strange sound events' in recent years, the similarities (with minor differences) between them, and the diversity of the locations they've been recorded in (sometimes more than once), speaks to there being a global reality to this phenomenon. In the course of tracking and reporting these events on SOTT, we've noticed that they tend to come in waves; there can be 'silence' for some time, then 4 or 5 'strange sounds' events occur in disparate locations (perhaps within the same region or continent) in the time span of a week or fortnight. And, as best we can tell, this trend seems to be increasing.

Here is our 'best of' strange sounds summary video, comprising some events from around the world in 2016. Please excuse the occasional foul language - muting or otherwise distorting it would have interfered with the strange sounds themselves. Besides, hearing them curse and swear, you get a real sense of the observers' astonishment!

Vivid iridescent clouds have been spotted over Cumbria sparked by bitter weather coming from the North Pole.

The multi-coloured clouds are sometimes known as 'mother-of-pearl' or nacreous clouds because of their shimmering pastel hues which resemble the inner surface of sea shells.

Usually the clouds only form over the poles during winter because the air in the upper stratosphere needs to be at least -78C.

A driver captured the creepy sight as the birds soared through a dark gray sky.

In the video, the birds appeared to be flying in a snake-like formation as they swarmed over cars entering and leaving the city.

This is the moment a mysterious orange mushroom cloud was spotted in the skies above Sheffield.

The photo, taken by a security guard on late night patrol, shows the skies over the east end of the city shrouded in a mushroom cloud orange glow.

Robert Barnes, who took the picture from Kettlebridge Road said: "I noticed a bright orange light in the clouds over Attercliffe. I am curious as to what it could be. Do any of your readers know?"

Mr Barnes says he spotted the glow shortly before midnight on Wednesday - and that the skies were dark before and after the picture was taken.

He said: "There was no movement. It was just static. I have seen it before but never thought anything of it."

The photo was taken between 11.40pm and around midnight and believes the lights were near the Outukumpu site near Shepcote Lane.

When the temperature dips below freezing, rainbows vanish, right? Rainbows require liquid raindrops, and frozen water doesn't do the trick. Yesterday in Alaska, however, a rainbow appeared that seemed to defy the simple laws of physics. John Dean photographed the pale arc over Nome:
"It was not raining," says Dean. "The temperature was 25 F and a light snow storm had just passed through about an hour before. This is a first for me, and it has me perplexed."

Atmospheric optics expert Les Cowley explains what happened: "This is definitely a rainbow made by water drops, even though it was so cold. Ice spheres, hail or snowflakes cannot make them because a rainbow needs almost perfectly spherical, smooth and transparent water drops. This bow is broad, telling us that the water drops were small. They were also probably quite high up, and might even have been supercooled below the normal freezing point of water."

Supercooled raindrops can form when droplets of water fall through layers of subfreezing air. Droplets containing specks of dust or even microbes readily freeze as ice crystals form around the impurities. But when rain droplets are especially pure, they can remain in a liquid state even when the temperature drops below freezing.

Hence -- the "supercooled rainbow." High latitude sky watchers should be alert for these rare rainbows as strange Arctic weather grips the North in winter 2017.

A number of Russian cities have been treated to an awe-inspiring sight of so-called light pillars seemingly shooting up from the ground all the way up to the horizon and beyond.

Vertical beams of bright light, reminiscent of columns, were captured by sleepless Russians over the past weeks, and the stunning images were quickly shared on social media.

'Light pillars' in the central city of Rostov stirred controversy with some people coming up with mystical explanations for the occurrence. Experts were quick enough to dispel those myths though, saying it's nothing but an atmospheric optical illusion.

A mysterious UFO-shaped cloud baffled skiers when it appeared in the sky over Sweden.

The bizarre cloud floated in the sky over ski resorts Åre and Duved on Thursday, prompting some to speculate that Martians had arrived for a day on the slopes.

Many rushed to take pictures of the unusual phenomenon and posted them on social media. "I thought it was pretty cool," one of them, Elvira Kuper, told broadcaster SVT.

Experts explained it was a so-called lenticular cloud, which forms over mountain peaks when the air is forced to rise as it hits the hillside. As it cools it condenses into a cloud.

Thanks to their peculiar shape, they are often mistaken for UFOs.