On a very fine morning of the 30th of June 1908, in the middle of the Siberian Taiga, at about seven o’clock, we observed a strange star in the sky. Right now, we are towards the end of what was Imperial Russia, and the current head of state is Tzar Nicolai II, who’s been crown Emperor of All the Russia now more than ten years now. Things were slowly starting to decline in Russia back in the days, as it was a country globally poor, inequalities were quite important, and, of course, outside of the main cities such as Moscow and St Petersburg, it was all rural and, let’s face it, quite under-developed. It was not everyone who could be able to go to school, and, despite the fact that Nicholai II tried to implement reforms to modernise his empire, he faced some oppositions that would, ultimately, lead to his own downfall.

But we were far from Moscow, and, very early in the morning, something very suddenly popped out from the sky. Out of a cloudless sky. It was massive, so big that it made some sort of tremendous trail in the sky, very, very fast. The noise was deafening, and everybody, in the small village of Vanavara, close to where this strange object was about to crash, had their eyes on it. No-one could imagine what it could have been, because, no-one really have seen such a thing before! Oh my god, is the heaven falling on us? As the object, that was massive, kept its growing and growing, very far away, everybody comes to the same speculation: this could only be coming from the God! People may have heard about comets, but… One, coming so close? Is it even possible?

One of the eyewitnesses of the event was Mister Semenov, who gave a testimony of his event days after. (Remember that this is a close translation of what has actually been said, since it were translated to Russian from local languages and then from Russian to English, so it may not be as close as what has actually been said but the idea stands there). So Mr Semenov said:

At breakfast time I was sitting by the house at Vanavara Trading Post, facing north. I suddenly saw that directly to the north, over Onkoul's Tunguska Road, the sky split in two and fire appeared high and wide over the forest. The split in the sky grew larger, and the entire northern side was covered with fire. At that moment I became so hot that I couldn't bear it as if my shirt was on fire; from the northern side, where the fire was, came strong heat. I wanted to tear off my shirt and throw it down, but then the sky shut closed, and a strong thump sounded, and I was thrown a few metres. I lost my senses for a moment, but then my wife ran out and led me to the house. After that such noise came, as if rocks were falling or cannons were firing, the Earth shook, and when I was on the ground, I pressed my head down, fearing rocks would smash it. When the sky opened up, hot wind raced between the houses, like from cannons, which left traces in the ground like pathways, and it damaged some crops. Later we saw that many windows were shattered, and in the barn, a part of the iron lock snapped.

And, of course, right at the moment of the impact of this strange object from the sky, an intense noise of explosion was heard. Vanavara Trading Post was about 65 kilometres, or 40 miles away from the zone of the impact, in the south. Below the horizon, a light, so high, and so bright, that no-one could have been able to look at it straight, immediately surprised everyone who followed the path of this mysterious object coming from the sky. This was immediately followed by a noise, so deafening that everybody got caught by surprise. The sound was shortly followed by an intense shockwave that knocked people off their feet and broke windows hundreds of kilometres away. The explosion was evaluated as being so intense at the place the mysterious object crashed, ranging somewhere between 3 to 30 megatons of TNT. If you don’t know what it could represent, the strength is similar to about two hundred Hiroshima bombs or, similar to the 2004 Indian Ocean Earthquake that devastated Indonesia. So, in the grand scheme of things, something really, really nasty.

Another eyewitness, named Chuchan, who was near where the incident happened, will say about the incident:

We had a hut by the river with my brother Chekaren. We were sleeping. Suddenly we both woke up at the same time. Somebody shoved us. We heard whistling and felt strong wind. Chekaren said "Can you hear all those birds flying overhead?" We were both in the hut, couldn't see what was going on outside. Suddenly, I got shoved again, this time so hard I fell into the fire. I got scared. Chekaren got scared too. We started crying out for father, mother, brother, but no one answered. There was noise beyond the hut, we could hear trees falling down. Chekaren and I got out of our sleeping bags and wanted to run out, but then the thunder struck. This was the first thunder. The Earth began to move and rock, the wind hit our hut and knocked it over. My body was pushed down by sticks, but my head was in the clear. Then I saw a wonder: trees were falling, the branches were on fire, it became mighty bright, how can I say this, as if there was a second sun, my eyes were hurting, I even closed them. It was like what the Russians call lightning. And immediately there was a loud thunderclap. This was the second thunder. The morning was sunny, there were no clouds, our Sun was shining brightly as usual, and suddenly there came a second one!

Chekaren and I had some difficulty getting out from under the remains of our hut. Then we saw that above, but in a different place, there was another flash, and loud thunder came. This was the third thunder strike. Wind came again, knocked us off our feet, struck the fallen trees. We looked at the fallen trees, watched the treetops get snapped off, watched the fires. Suddenly Chekaren yelled "Look up" and pointed with his hand. I looked there and saw another flash, and it made another thunder. But the noise was less than before. This was the fourth strike, like normal thunder. Now I remember well there was also one more thunder strike, but it was small, and somewhere far away, where the Sun goes to sleep.

The explosion knocked some people off at Vanavara Trading Post, destroyed a few windows because of the shock wave. At Irkutsk, about a thousand kilometres away from the site, it is estimated that, on that day, a seismic activity of magnitude 5.0 on the Richter scale had been logged. The explosion was also logged in various sismic stations in the UK, Germany, France, Croatia… but also in Washington D.C. So, of course, said like this, it may be looking like something very dramatic, but let me explain here something quite important so you guys can understand: the Richter magnitude scale is logarithmic so that means that the higher you go, and the more intense the activity is. Example, a sismic activity between 5 to 5.9 is considered as moderate, and it can cause damage of various severity to buildings that have been poorly built, but, this sort of event is very common, and, according to some estimations, it is logged about a thousand to a thousand and five hundred times a year. What was felt in Washington were just the waves of the impact. But no-one felt a difference in their everyday life. The most powerful one was the Great Chilean Earthquake in 1960, which reached a magnitude of 9.5.

Anyway, back to Vanavara, and Irkutsk? What happened? Well, probably in Vanavara, start repairing a few windows. In Irkutsk? Nothing really exceptional on that day. Life resumed. As if nothing happened.

So, I’m sure you guys wonder what was this thing coming from the sky, even though, you certainly have an idea. Well, turns out that they wondered the same thing. The difference between you and them was that, they completely had no idea of what was happening.

But for finding answers, it would take almost a decade: the political turmoil in Russia led to the October Revolution and Emperor Nikolai II being overthrown, and the fact that the event happened in a very remote place in Siberia made scientific investigations challenging, and, indeed, an explosion that happened in a forest decades ago was the very last concern of the newly communist government of Russia. The event was barely covered by Russian press back in the days, but, the ongoing political mess made everyone forget about this. The fact that the site where it happened was remote and nearly inaccessible, or at least would require people who know the region very well as well as people who are trained to carry out such expeditions, the Tunguska event remained in the drawers for a substantial amount of time, and, indeed, the political turmoil going on in Russia, which became the Soviet Union, ghosted the story and made everyone forget about this. But if everyone forgot the event, one guy did not, and he was named Leonid Kulik. Back in 1921, he led a team near the Podkamennaya Tunguska River, one of the closest point of where the explosion is now said to have occurred a years back.

Of course, from this expedition, he needed the help of villagers living nearby, but everyone refused to go there. The reason, everybody believed that the area was the residence of some nasty God haunting the forest, and, it is said that this god was badly upset not too long ago. Mister Kulik, understanding that he needed funds to carry out with his survey, and also he couldn’t do it without experienced people who know the region, went back to Moscow and managed to convince the Soviet Academy of Science, telling them that, there is in this region a potential meteor impact, and, they could use the remains of the meteor there to help extract the iron, much needed to develop industries in Russia, as industries were stating to bloom back there to cope with its industrial late development. On those grounds, the Academy granted him the fundings he needed, so he went back to explore the area in 1927. And when he arrived there, an unexpected spectacle came to him and his team.

At first, they found the ground zero, the centre of the blast, which is the theoretical place where the impact of the asteroid may have occurred with the ground, but there was absolutely no impact crater. Of course, he came nearly twelve years later, so nature had time to reclaim the territory. Instead, they found an immense zone of about eight kilometres all covered with trees that had no branches, even less leaves. These trees were however still standing upright, but were all scorched, and burned. And there were a few of these. The rest of the trees were all knocked down on an opposite direction to the centre of the impact. This confirmed that, something terrible has occurred in this place, and it’s there that they could assess the strength of the explosion. Nothing conclusive really came out of this apart from some pictures. But no evidence of any meteor. So, no iron for the Russian industry. But no groundbreaking clues to solve the mystery either.

In 1960, another expedition got carried out in the same zone, mostly to make further investigation of this mysterious incident. It was assessed that the zone of the damage caused by the explosion was big of 2,150 kilometres square around the zone of the impact, somewhat resembling to a butterfly from the sky, has been damaged. It was very likely that all life living within this perimeter has been lost, but since no human structure was there, no human life has been claimed. Still no trace of meteor or extraterrestrial debris of rock were found. We just found flattened trees. Oh, no, we also found something else: a lake. Lake Cheko. This lake has never been placed into any maps before, and… and perhaps that the meteor or some debris of what exploded was in the lakebed? Well, guess what: they went to investigate. And no. Nothing. The investigation was also inconclusive. We just know that something fell from the sky and exploded, but we didn’t know what.

So now you’re wondering: Taylor, okay, we understood that this thing coming from the sky was a big asteroid that destroyed a few trees in a forest. We get that. Now why are you saying that we didn’t find anything? Well, guys, I never said that this thing was an asteroid, actually! In fact, even today, we still have no formal evidence of what happened there. Apart from a lake. And you wanna know the reason why? Well, it’s because, we are not even sure as to whether it was an asteroid.

Those who were old enough in 1999 probably remembered this, as this made the headlines: The Hale-Bopp comet, recently discovered, was about to come really close from Earth. This comet has a big revolution, making it appearing in the sky once every thousand years. And, it’s easy to recognise a comet from its big tail, piercing the sky. The most famous being the Halley comet, coming once every seventy years. Now, why am I talking about Hale-Bopp? Precisely because this event also cleared our understanding of the things from the sky. But, while asteroids are quite frequent visitors, for the comets, it’s a bit different.

I’ll come in a future episode of a future series as to how the solar system was born but, to make it short, when the sun was formed, dust started spinning around it under the force of gravity, which was what we called a protoplanetary disk. In this cloud of dust, particles started merging, eventually making rocks, and those rocks eventually became bigger and bigger, and this was what we called “asteroids”. The thing was, on some regions of the protoplanetary disk that spinned around the sun, some asteroids started merging together and eventually formed the eight planets that we know. Today, in the solar system, there are still asteroids, whose, most of them are closely monitored, to make sure that they are not a threat, and they are mostly located in what is called the Asteroid Belt between Mars and Jupiter, separating what is called the Inner solar system (which is Mercury, Venus, Earth and Mars) from the Outer Solar system (composed of Jupiter, Saturn, Uranus, Neptune, and what’s beyond that) and, in some extends, the rocky planets from the gas planets.  So, this is why you guys hear quite frequently that an asteroid came close to Earth, and… this is also what caused the Chelyabinsk event. An asteroid that, as it entered the atmosphere, exploded because of the fact that air slowed it down and destroyed it. Pretty much, in a nutshell, an asteroid is mainly composed of rock and metal. And, in the case of the Chelyabinsk event, it’s an asteroid that escaped surveillance.

But, asteroids falling on Earth are far from an unusual event. It’s actually about the mass of 5 cars full of asteroids falling on Earth on a daily basis, which makes it a very common event. And considering that the surface of our planet is at 70 percent composed of water, so that makes it even less common for us. What’s uncommon, on the other hand, is when an asteroid of the size of the one that exploded over Chelyabinsk enters the atmosphere, but, hopefully, this doesn’t happen very often.

If in the inner solar system, because of its huge gravitational attraction, Jupiter shakes some asteroid of the asteroid belt all across the solar system and make them move, in the Outer Solar system, it’s another story. There are still some asteroids, indeed, but as this area is richer in gas and various molecules that do not agglomerate because what’s been agglomerating has already been captured by Jupiter or Saturn that have a MASSIVE gravitational field, it’s mostly water and random gas that agglomerates. Sometimes, there are also small rocks. As the Universe is, to say the least, quite a cold place, and it’s even colder passed the Asteroid Belt, and even colder and colder beyond the Kuiper Belt (another asteroid belt located beyond Neptune), so, it’s mostly ice agglomerating. And that’s precisely what we call comets: a ball of ice agglomerated. Comets are mostly droplets of ice, that travel fast.

Now, what happens when a comet or an asteroid enters Earth’s atmosphere? Towards the end of this season we’ll talk about it, but the atmosphere is a fluid that protects us. Long story short, it’s pretty much like you’d throw a metallic glass very forcefully in a swimming pool, eventually, at the moment it impacts the water, it’s gonna break into small pieces before sinking. In the case of a comet or a meteorite, it’s the same: the air in the atmosphere will cause friction, meaning that atmosphere will slow down the entry, and this will cause a frictional heating. The more the heating will become intense, the more the object will start to disintegrate, causing, first of all, an intense light in the sky, all the way until the moment the object impacts the ground. In addition to that, as the object falling from the sky will of course travel faster than the speed of sound, so beyond 1200 kilometres per hours, so it will produce the classic supersonic bang. And, of course, the pressure to make it through will quickly become unsustainable for the object that will, eventually, explode, depending on its size before hitting the ground.

Now when the Chelyabinsk meteor hit the ground, the remnants were quickly found and, analysed, and it quickly showed what the object was. Most of what was found ended up in the Lake Chebarkul, not far from Chelyabinsk. In the case of the Tunguska event, we only have for evidence the site where the explosion happened, as well as the Lake Cheko. This lake is at about eight kilometres away, to a north-northwest position of the hypocentre of the impact. According to the numerous analyses that have been carried out in this area, its creation was likely to be linked with the event, as the shape of the lake seemed to have been created by an powerful explosion. But this lake gave somewhat an explanation as to what the object was like. As the age of computing arrived, and having all the data, it has been concluded that the likeliest candidate for the Tunguska impactor was a stony body between 50 and 80 m in diameter, entering the atmosphere at roughly 55,000 km/h, exploding at 10 to 14 km altitude, and releasing a quite powerful explosive energy equivalent to between 10 and 30 megatons of TNT. That’s for the most recent simulations. And it’s quite big.

But all we know about the event was the seismic activity, the few damages building and, probably three people have died, even though we aren’t really sure if this was related to the event. We just know that trees have been flattened on an area of 2,150 kilometres square and of forest and, of course, the wildlife living in the area was instantly killed. But apart from that, what was the meteor, or the comet? And where was it coming from? The mystery remains.

And on those notes, dear listeners, we precisely find ourselves at the crossroads of scientific inquiry and enduring mystery. The Chelyabinsk meteor left us with tangible pieces to examine, yet the Tunguska event offers only the haunting landscape of its impact and the enigmatic waters of Lake Cheko. Despite the advances in technology, despite the simulations that offer us a glimpse of what might have been, the Tunguska Event remains a cosmic riddle, a burst of energy that left its mark not just on the Siberian wilderness but on the edges of human curiosity. In the grand scheme of things, what do we really know? With each answer, a new question emerges, lurking in the depths of our understanding, as elusive as the origins of Lake Cheko. As you sit back and ponder the mysteries that still roam our skies, I invite you to share your thoughts, theories, or even fantastical imaginings in the comment section. Don’t forget to subscribe if you like the series and visit my website for more content. Because, after all, isn’t it the unknown that makes life truly fascinating? Until our next rendezvous with the enigmatic and the inexplicable, keep your minds open and question everything around you. See you next week, fellow seekers of the unknown.