0:00 On the morning of June thirtieth, 1908, an object fell out of the sky over Siberia and exploded with the force of up to twenty megatons of TNT.0:11 It was one of the most powerful explosions in recorded history, and it didn't leave a crater.0:18 Last time, we talked about Australia losing a war to a bunch of emus, which is just a monumentally ridiculous story.0:27 This is the opposite of that.0:29 This isn't funny.0:30 It's a profound and terrifying mystery, and it's a story about what happens when the universe decides to throw a rock at us.0:40 So, imagine you're a reindeer herder or a homesteader in a remote part of Siberia.0:47 It's just after seven in the morning.0:49 Suddenly, the sky splits open.0:52 A column of brilliant blue light, brighter than the sun, streaks across the horizon.0:58 Eyewitnesses reported seeing a fireball.1:01 Then comes a series of deafening explosions, a sound that carries for hundreds of miles.1:08 The shockwave hits a few minutes later.1:11 It’s powerful enough to knock people off their feet and shatter windows in a town more than sixty kilometers away.1:20 And in the forest, at the center of it all, eighty million trees are flattened instantly.1:27 They fall outwards from a central point, like spokes on a giant, terrifying wheel.1:34 The area of flattened forest is VAST.1:36 We're talking an area larger than a major modern city.1:41 But here’s the part that broke everyone’s brain for a century.1:45 When scientists finally reached the site years later, there was no hole.1:51 No impact crater.1:52 Nothing.1:53 How do you have the biggest impact event in modern history with no actual impact?1:59 That’s the question that turned Tunguska from a local disaster into a global scientific obsession.2:07 And the answer is both simple and deeply unsettling.2:11 The object, whatever it was—and we’ll get to that—didn't hit the ground.2:17 It detonated in the air.2:18 It was an AIRBURST.2:20 Current models say a stony asteroid, somewhere between fifty and eighty meters across, screamed into the atmosphere and then exploded about ten kilometers up.2:32 All that energy, all twenty megatons of it, was released in the sky.2:38 Think of it like a massive bomb going off directly above the forest.2:43 The downward blast of superheated air and the subsequent shockwave did all the damage.2:50 It’s the same principle as a strategic nuclear weapon, which is often detonated at altitude to maximize the area of destruction.2:59 And this is where we have seen this before, just on a much smaller scale.3:05 Remember the Chelyabinsk meteor in 2013?3:08 That was also an airburst over Russia.3:11 It was a much smaller rock, but the shockwave still blew out a million windows and injured over a thousand people.3:20 NASA says an object like Chelyabinsk might hit us every ten to one hundred years.3:26 The Tunguska object was an entirely different class of beast.3:31 It was a planetary-scale event that just happened to occur over one of the most empty places on Earth.3:39 If it had arrived just a few hours later, its path would have taken it over Europe.3:46 Imagine that explosion over London or Paris.3:49 The other part of the mystery is simply… time.3:53 This happened in 1908 in Tsarist Russia.3:56 The region was incredibly remote.3:58 There were no roads, just rivers and swamps.4:02 It took thirteen years before the first Soviet scientific expedition, led by Leonid Kulik, even reached the area.4:11 By then, the forest was already starting to grow back.4:15 Kulik was obsessed with finding meteorite fragments to prove it was an iron-rich asteroid, but he never found any.4:24 He conducted multiple expeditions, but the smoking gun—the impactor itself—was gone.4:30 It had completely disintegrated in the explosion.4:34 This delay is what allowed the story to become a legend.4:38 In the absence of hard data, you get all sorts of wild theories.4:43 But the core truth is that the mystery wasn't just about physics; it was about geography and timing.4:51 The evidence was there, but getting to it was almost impossible.4:56 So what you’re left with is this ghost of an event.5:00 A scar on the landscape with no weapon to be found.5:04 And it forces you to look at the sky a little differently.5:09 It’s a reminder that the solar system is still a work in progress, and sometimes, it throws things.5:16 We now have planetary defense programs specifically designed to find the next Tunguska before it finds us.5:24 And it’s all because of an explosion that was so powerful, the only thing it left behind was a warning.
