 and really seven ways to destroy. This just seemed like a nice book to drift off to, to let our imaginations... I guess that's partially what I get out of ASMR. An asteroid hit, all the different. The asteroid hit, a comet, swarm, collision, and then we could get thrown out of the solar system. Supernova could start a sentence with, what if this book is for us in the vast realm of outer space. Space rockets the size of the soccer fields. We go through possible, probable, directly in terms of the species, but if you believe in the scientific line of thumb of these people and not wasting their time making up all these things that they're studying, make us up, have adapted, and evolved cognitive structures, things that have helped our ancestors all the way back to amoebas, we could be directly connect different sized planets, orbiting distant stars by seeing the stars wobble as the orbiting planets pull by watching light from a distant star dim, it passes by. But we already talked about that in the Dabby's Stars, two part episode again. We've recently become, come to understand that the universe is, is, it's very prolific, spinning out large numbers of planets, including ones like our, ones like our, in the Milky Way galaxy alone, there may be more than 20 billion Earths, and the Milky Way is just one of 200, more than 225 teachers out there. We have the art of holding a book like this for 20 minutes, so this is a really cool part, I like. So not only is the universe big, it's a marvelously chaotic place, full of collisions, explosions, and searing blasts of radiation from dying stars. New stars and planets are born, as older ones cease and slip. Wherever astronomers look, with their telescopes, chaos reigns, life, death, and change. What happens to planets like Earth is subject to chance and numeracy. Some are favorable to life, and others are not so much. Big changes occur over extremely long periods of time, and others like that. The Earth is unlike any other planet in our solar system. It's a world rich with independent, interdependent in every imaginable place. Single-celled organisms can be found inside rocks bearing 12 miles underground forms of life, and bizarre forms of life and habit, the seas and the oceans, lakes and rivers, or surrogate continents, or vibrant with life. And so it's atmospheres too. Five miles above the surface, bacteria, life appeared after it cooled down enough for oceans. Life began with simple forms, and then moved on to more complex, of course. It's very hard to imagine our world looking very much different than it is today, but if you go back in time millions of years ago, or in the future, maybe, the geological and biological landscape would appear almost alien to our eyes. These mass extinctions that have happened was a Permian extinction 252 million years ago, and then wiped out 96% of all life. So we, slowly changing environmental conditions as well, such as ice and massive volcanic eruptions, or explosive events such as asteroids, cannot devastate the world like ours. What might some of these startling dramatic events look like if they happen today? We're 13th, 2014. The people of, the people of Chelyazm, Chelyabinsk, Oblast, in the southern Ural region of Russia, were just starting their morning drinking coffee, driving to work, getting ready for a new school day, and suddenly a brilliant fireball streaked across the sky. It shone 30 times brighter than the sun, and left a long trail of smoke and dust behind it. Then there was a deafening, a shockwave smashed into the ground, injuring close to 1,500 people. I remember this off the dash cam. You could see, that was pretty amazing. Imaging some 7,000 buildings, got it almost resembled a war zone. You know, if we hadn't of caught this on camera, people even said, it smelled like gunpowder. So they think that the Chelyabinsk, Oblast, about 65 feet wide. This was the crux. This is the crucial point, is that it was traveling 40,000 miles an hour, or 64,000 kilometers an hour, but not like it really matters to the conversion at this point, at that speed. It released the explosive equivalent of 500,000 tons, the Hiroshima. The idea that rock from outer space is nothing new. Every day, 300 tons of space rocks hit our atmosphere, leaving white streaking trails. The result is that Earth continually gets heavier, about 40,000 tons heavier, or the equivalent of two aircraft carriers every year. Every year, wow, that's, want to see some of the debris. Next time you're away from the city lights at night, lie back on the ground, and just look up. Your eyes get adjusted to the darkness. You may suddenly see a flash of light, space rock hitting the Earth's upper atmosphere and flaming across the sky as a meteorite. And the spectacular is these are not objects. These aren't the ones we need to worry about. The space rocks that do real damage, called asteroids, are the leftover building materials in an area between Mars and Jupiter called the asteroid belt. However, thousands of rogue asteroids called near-Earth objects pass the Earth all the time. Some even pass between the Earth and the Moon. I know one did. The realization that large asteroids may have affected life on Earth is relatively new years ago. This sounds like a really long time, but in the history of Earth geologically, it's not that. Sea creatures that we study as fossils today. The Earth was wiped clean of 70% of its life and Italy discovered something quite remarkable. Digging along a rocky hillside, they realized that all the dinosaur fossils then stopped when it reached a one inch thick layer and revealed the layer mostly was made up of called iridium, same layer found. Iridium is extremely rare and this layer found in Italy came from a mountainside striking Earth 66 million years. They had discovered it underwater, greater than 110 miles wide, 12 times deeper than the ground impact greater on Earth. This is where the asteroid that ended the age of dinosaurs hit, blocking sunlight, it threw dust into the atmosphere, changed. Today we call it the KT event, named for the Cretaceous tertiary period that marks the disappearance of the dinosaurs and the emergence of large animals. Scientists labeled the Cretaceous period K because of its German spelling. Now you're probably wondering, what are the chances an asteroid this size or bigger could hit Earth again? If it did, what the asteroid that said the dinosaurs on their way measured three to 10 miles in diameter and this may seem large, but comparison to other asteroids in the belt, it's not when an asteroid collision occurs, it's not the explosion that creates all the damage, it's the fires, the dust, the burning debris raining down after, imagine a scene, maybe it's early morning in a prehistoric neighborhood, on the banks of a shallow lake, a small herd of ap majestically dipped their heads and up tasty plant morsels from the muddy bottom of the shoreline, but suddenly up sky, the sky flashes blank seconds, the sky turns an eerie glowing red, a shockwave traveling more than 300 miles an hour or 480 kilometers, rocks and soil ejected by the blast fallback, anything living caught above ground is incinerated, tidal waves 150 feet tall, 46 flood the landscape, sweeping rocks, boulders, trees, smoke and dust, joke, bright sunlight does not reach the ground again for months, so plants using photosynthesis, acid rain falls silently to the majestic dinosaur monsters of the seas and featherless flying reptiles, remains is a slowly recovering world that soon will have different life on it. What are the chances this could happen to us? Luckily, there are slim on average, big asteroids like the one that wiped out every once in a while to say that something couldn't suddenly surprise us, a critical role some astronomers played today is the detection of asteroids long before they get here, so that something might be done to prevent any collision. For example, if we had a few years to respond, we might send a robotic spacecraft to gently nudge the asteroid on another course. So it would miss Earth, it potentially has the capability of wiping out if it hits on March 16th. We have about 800 years to go. The chances are right, the chances right now by 864 years from now, we should have technologies to protect. However, the Earth has been hit many times in the past, we'll get hit in the future. So if a rogue asteroid approaching Earth from the direction of the sun catches us by surprise, that's it.