Since the first use of electric lamps in the 19th century, society hasn't looked back. Homes and streets are lit at all hours so that people can go about their business when they'd once have been asleep. Besides the obvious benefits to societies and the economy, there's growing awareness of the negative impact of artificial light.

Light pollution has been blamed for wasting energy, disrupting wildlife behaviour and harming mental health. One aspect has avoided the spotlight though. Namely, that light not only allows one to see, but also to be seen. This could well attract unwelcome attention - and not just from moths.

The innate curiosity of humans and our growing knowledge of the universe in which we live have led us inexorably to a question. Do civilisations exist on planets other than Earth? Scientists now believe that there are many places in the universe which might harbour simple lifeforms such as bacteria.

What is more speculative is the notion that such extraterrestrial life could have become technologically advanced, perhaps even well beyond our capacity. This idea has captured the imagination of the general public, giving birth to a rich collection of science fiction literature and blockbuster films. But it has also received serious attention from scientists, who have thought of ways to find and possibly contact these alien species.

In 1974, radio astronomer Frank Drake used the then most powerful radio transmitter, at Arecibo in Puerto Rico, to broadcast a message into space announcing our presence. The message will now be 45 light years away from us. While there are many stars and planets closer to us than that, they won't have been in the path of Drake's broadcast.

But impatient as scientists tend to be, more effort has gone into searching space for such signals transmitted by extraterrestrial civilisations. As more and more planets are discovered around other stars, the search for extraterrestrial intelligence - often abbreviated to SETI - is becoming more relevant, better informed and better resourced. In 2015, wealthy entrepreneurs Yuri and Julia Milner allocated US$100m to the Breakthrough Listen SETI project, which buys time at observatories to use their powerful telescopes to detect artificial signals from outer space.

But despite the vastness and emptiness of space, scientists have started to wonder why we haven't heard from aliens yet. This puzzle is known as the Fermi Paradox, named after the physicist Enrico Fermi. Among the many solutions proposed for this problem, one really brings us down to Earth: aliens might be scared of other aliens.

A smake-like UFO appears to have returned after a bizarre object was seen "emitting an energy beam" above the US state of Washington.

Alien enthusiasts were sent into a frenzy last month when a baffling UFO shaped like a snake appeared above the Mojave Desert in California.

Several weeks later, a similar object was spotted plunging from the sky before speeding off at breakneck speed over Colorado.

And now, a third "snake UFO" has been caught on camera.

The video shows a grey cylindrical shape hovering in the blue skies above Washington.

Passenger Lucas Kim recorded the bizarre encounter as he flew from South Korea to Thailand

Lucas Kim spotted what he thought was another flight from his window

This is the stunning moment a mysterious 'aircraft' splits into six pieces and vanishes in full view of a shocked passenger aboard a nearby plane.

Lucas Kim was jetting to Thailand from his home in Seoul, South Korea, when he spotted what he thought was another flight from his window.

You may have heard of the Phoenix Lights, mysterious lights in the sky that sparked speculation and even documentaries over the years. Now, Tucson may have had its own version of the phenomenon.

A video posted to Twitter and viewed more than 13,000 times shows mysterious lights in the night sky in an area just south of the Davis-Monthan Air Force Base.


The video, taken shortly before 10 p.m. Tuesday, shows a string of reddish lights in the sky move slightly before blinking out. Below, three evenly spaced lights shine in a horizontal line. Isaiah Alvarez, who shot the video, said these lights became very bright and left.

Alvarez said he often sees strange things in the sky in that area; this was just the first time he was able to catch it on video.

One of the biggest questions surrounding the most recent known spate of UFO encounters with U.S. Navy pilots - those that occurred off the southeastern seaboard of the United States between 2014 and early 2015 - pertains to how persistent they actually were. We know Super Hornet aircrews from Strike Fighter Squadron 11 (VFA-11), the Red Rippers, detected unknown objects multiple times on radar and one aircrew even had a close encounter visually with one of them, but what about the rest of the many Hornet squadrons based at Naval Air Station Oceana, not to mention the E-2 Hawkeye squadrons from nearby NAS Norfolk? We have the answer to this question and it is remarkable.

A source with knowledge of the events has made it clear to The War Zone that presence of the mysterious objects in the restricted training airspace off America's east coast was so pervasive that it was largely common knowledge among local flying units. They noted that the majority of the Super Hornet squadrons equipped with AN/APG-79 Active Electronically Scanned Array (AESA) radars - you can read all about this technology and how it was key in detecting these objects in our exclusive piece on the subject - at the time were having the same experiences, as well as the crews flying the new E-2D Hawkeye with its incredibly powerful AN/APY-9 radar suite. It literally became such a common and near everyday occurrence that Naval Aviators and Naval Flight Officers from the base would talk about it informally with regularity.

But that doesn't mean formal action wasn't taken. Beyond filing an official safety report after one of the jets almost hit one of the unidentified objects - described eerily as a translucent sphere with a cube structure suspended inside of it - Notices To Airman (NOTAMs) were posted regarding the dangers potentially posed by unknown aerial vehicles flying in the same military operating areas that aircraft from NAS Oceana frequented for training. This action was taken by the base's command leadership as they couldn't figure out how else to address the bizarre issue and its perceived threat to their aircrews' safety.

Two mysterious white orbs were spotted in the Kansas City sky Thursday night, prompting widespread speculation on their nature.

"We honestly have no explanation for the floating objects over Kansas City," The National Weather Service tweeted Thursday.

The terrifying creature rose above the horizon of Chernobyl and Pripyat, a hideous humanoid with giant wings, a black headless body and red glowing eyes sending a message of doom to all who gazed upon it.

In the days leading up to the Chernobyl disaster, several of the workers in the control room of the nuclear power plant in northern Ukraine claimed to have seen the creature that is known as the Blackbird of Chernobyl.

Those unlucky enough to see the creature were said to be plagued with terrifying dreams and threatening phone calls.

Still others believe the Black Bird of Chernobyl was a form of the creature known as Mothman whose presence only ever meant one thing: that a catastrophic event would soon follow.

Last month marked 33 years since the Chernobyl tragedy and it seems the further time moves away from the event, the stories, folklore and legends continue to captivate and grow. And, since the huge success of the TV series, Chernobyl, there's a seemingly endless desire for more knowledge about the disaster - the known as well as the unknown.

The Black Bird Rises In Chernobyl

Sydney archaeologist Robert Maxwell is the only archaeologist who has ever worked at Chernobyl, completing two field excursions at the exclusion zone in 2010 and 2012.

He is passionate about the place in both a historical and archaeological sense; there is little Maxwell doesn't know about Chernobyl, on matters of both the physical and supernatural world.

Maxwell told news.com.au that the legend of the Blackbird of Chernobyl was something he heard about when he was in the exclusion zone.

"The legend states that in the days leading up to April 26, 1986, that a supernatural creature was sighted in the sky over Chernobyl by many of the men in the control room. They also claimed to have seen this terrifying creature just before the explosion," Maxwell said.

Three more U.S. senators received a classified Pentagon briefing on Wednesday about a series of reported encounters by the Navy with unidentified aircraft, according to congressional and government officials - part of a growing number of requests from members of key oversight committees.

One of them was Sen. Mark Warner (D-Va.), the vice chairman of the Senate Intelligence Committee, whose office confirmed the briefing to POLITICO.

"If naval pilots are running into unexplained interference in the air, that's a safety concern Senator Warner believes we need to get to the bottom of," his spokesperson, Rachel Cohen, said in a statement.

From the official Coast to Coast AM channel on YouTube:

David Paulides also has documented cases of bow hunters' mysterious disappearances, in which they are either not found or found under very bizarre conditions.

An experienced hunter, Aaron Hedges, was hunting with friends in the 'Crazy Mountains' in Montana in 2014, and get separated from the group, but was in contact with them via radio, before he went missing. A week after his disappearance, they found his boots and camelback in the snow, but ground searchers and dogs yielded no further evidence in the area.

Nine months later, his backpack and vest were found, 15 miles away from the other location, yet it would seem impossible that he could have traveled that distance in the snow without shoes, Paulides noted.

The strange objects, one of them like a spinning top moving against the wind, appeared almost daily from the summer of 2014 to March 2015, high in the skies over the East Coast. Navy pilots reported to their superiors that the objects had no visible engine or infrared exhaust plumes, but that they could reach 30,000 feet and hypersonic speeds.

"These things would be out there all day," said Lt. Ryan Graves, an F/A-18 Super Hornet pilot who has been with the Navy for 10 years, and who reported his sightings to the Pentagon and Congress. "Keeping an aircraft in the air requires a significant amount of energy. With the speeds we observed, 12 hours in the air is 11 hours longer than we'd expect."

In late 2014, a Super Hornet pilot had a near collision with one of the objects, and an official mishap report was filed. Some of the incidents were videotaped, including one taken by a plane's camera in early 2015 that shows an object zooming over the ocean waves as pilots question what they are watching.