Every May and October, a curious phenomenon occurs along a 160-mile-long stretch of the Mekong River in the Isaan region in northeast Thailand. For a few nights during these two months, one can see the eerie sight of numerous glowing balls that seem to erupt from the very river itself to fly high into the air and vanish. Descriptions for these luminous orbs vary, ranging from the size of tiny bubbles or sparklers to larger ones said to be around the size of a basketball, usually a reddish color, but sometimes a bluish or yellowish hue and sometimes white. These balls typically will launch themselves upwards several hundred meters into the air before suddenly blinking out of existence, never making a sound and emanating no smoke or plume. They will continue for a time before stopping just as suddenly as they appeared, and there can be tens to thousands of these lights seen throughout a given night, rain or shine, with the most intense activity occurring during the night of Wan Ok Phansa at the end of Buddhist Lent in late-October and the most lights seen in the vicinity of a small village called Phon Phisai. Formerly called simply the “ghost lights,” they are now officially called bung fai phaya nak, and more commonly referred to by outsiders as the “Naga fireballs,” and no one is quite sure just what they are.
According to local tradition, the Naga fireballs have their origins in a type of giant river serpent prevalent in Buddhist folklore, called a Naga, in this case specifically a Naga called the Phaya Nak, or “the king of nagas.” These are said to be enormous semi-divine serpents and servants of Buddha with supernatural powers that lurk within the Mekong river or its estuaries, and are not only responsible for strange wave formations and other phenomena, but also are known from time to time shoot blazing fireballs into the air. Far from merely myth and folklore, a great many people in the rural areas of Thailand sincerely believe the Phaya Nak exist. There have been numerous sightings of them, and there are even supposed bones, teeth, and the egg of a Naga kept at a temple in Phon Phisai, and so it therefore goes without saying that for the locals the fireballs are coming from these beasts, as a display of celebration for the end of Buddhist Lent. However, of course there are plenty of other theories from scientists skeptical that the fireballs are coming from magical giant river serpents.
One theory that has been thrown around is that it is merely people firing tracer rounds, flares, or even just fireworks, the sound deadened by the distance and the often very noisy crowds of people who pour into the region to see the lights every year. Indeed, the annual 4-day Phayanak Festival in October attracts tens of thousands of people, who come to see the lights and enjoy the many festivities and events, including food stalls, Naga legend information, fireball exhibitions, a night bazaar, light and sound shows, and long-boat races prior to the main event of the fireballs themselves. With all of this activity it would seem that many of the lights might just be a show put on to draw in visitors, as the festival brings in huge amounts of revenue for the tiny rural local economy. However, while some of the Naga fireballs might be this, it does not explain the fireballs that originally began the festival, why they seem to come directly out of the water, or why they will often pop out in various different areas along the river. There are also frequent Thai boat patrols through the area to deter people from doing dangerous things like firing into the air. There is also the fact that the fireballs have been seen at other times of the year, and are only really paid attention to at the end of Buddhist Lent. They are also frequently reported as coming from smaller tributaries of the Mekong and even ponds in other areas, as well as some claims that these things have been seen for centuries. One reporter Andrew Biggs has said of the hoax angle in an article in the Bangkok Post:
First of all, the lights have been around a long time. Fishermen have reported seeing what locals still call "ghost lights" in the darkness of the Mekong River way before local governments attached the myth of Phayanak to them. Also, these lights apparently don't just appear on the end of Buddhist Lent. It's just that we pay attention to them on that night, which isn't the same as saying they only pop up once a year. The biggest quandary of all is that we are living in the era of digital record. Everything is filmed, photographed and uploaded onto Instagram. People photograph their morning coffee, for god's sake -- what happens when it's an event like weird coloured balls in the river? And yet despite all this, nobody has captured any hoax perpetrators.
It is also the scale of the operation. Just say I wanted to play a prank on Northeast believers and shoot a couple of coloured lights off the Mekong River. Who knows the specifics of the operation, but let's say I do indeed do that. Last Sunday night, starting at 6.28pm, the first fireballs were spotted by those 300,000 visitors camped along the banks of the river at Ban Tha Muang, Rattanawapee district. Then, another one was spotted in a different district. And another. And another. All in all, a total of seventy fireballs shot up throughout the night, and that was in Rattanawapee alone. There were more in the districts of Sangkhom and Pone-pisai. By the end of the night, there were more than 300 fireballs. That's a really big, expensive hoax!
For these reasons, it seems that surely not all of them could be caused by hoaxes or partiers, so what else could they be? Another possibility put forward is that the fireballs are caused by plasma orbs formed by the release of surface electricity, or even the old standby for UFO sightings called swamp gas. This is basically methane gas produced by the decomposition of organic material igniting when exposed to oxygen, and it has been used by skeptics to explain away a variety of ghost light and UFO phenomena, but this would not explain why it only happens most prominently at specific times of the year like clockwork, and it has also been called out as an unsuitable explanation for this phenomenon in other ways. Skeptic Brian Dunning has given a thorough and amusing skeptical debunking of the typical skeptical argument of swamp gas causing the Naga fireballs, saying:
There are two fatal flaws with this hypothesis. First, methane can only burn in an oxygen environment within a specific range of concentrations. It can only spontaneously ignite within an even narrower range, and requires the presence of phosphine combined with phosphorous tetrahydride. The needed proportions of these gases are unlikely to be found in nature. Second, in laboratory experiments designed to replicate the conditions needed for spontaneous ignition, the combination of oxygen, methane, and phosphorus compounds burns bright bluish-green with a sudden pop, producing black smoke. Under no conditions does it burn slowly, or red, or rise up in the air as a fireball. So even if the improbable conditions did exist in the Mekong river, the resulting display would not look like the Naga Fireballs.
Whatever is shooting up into the air, you've got to figure that it has some solid mass. When you watch the videos you can see that the red-orange lights go up very fast, consistent with fireworks, small rockets, or even tracer rounds (very much like a 12-gauge shotgun tracer round, which is comparatively slow). How is it possible for any flaming object to move that quickly through the air without blowing out? That's not a problem for something like a firework or a tracer round, things designed for exactly such a purpose. But it's a major problem for a burning ball of gas, which has an insufficient mass to drag ratio to move that quickly through the air. Even a pyrotechnic explosion that billows into the sky rises at a slow rate consistent with hot air rising through cold air; it does not and cannot streak like a bullet at hundreds of feet per second. For the Naga Fireballs to move as they do, they must enclose an object significantly more massive than the air they're moving through. This necessarily means they're heavier than air. And since they're rocketing skyward, this means they must have been physically propelled.
So, from what we can observe, it's actually more plausible that a river dragon is spitting flaming balls of dragon-mucus skyward, than it is for the Naga Fireballs to be naturally produced burning gas bubbles.
The Naga Fireballs have as of yet remained unidentified. What are we looking at here? Is this some rational, explainable phenomenon? Is it gases, atmospheric phenomena, or merely fireworks and people firing tracers into the air? Or is it perhaps something else altogether? The festival at the river still goes on every year, and if you talk to any local they will say it is the doing of the mysterious Naga, with perhaps even some spite thrown your way if you should say otherwise. Whatever the explanation may be, the Naga fireballs continue on, and have evaded understanding to this day.