Top 10 Scary Facts About Earth

Earth is great. Its our home. A big bluey green dot in the scary vastness of space. Its chill. Unfortunately, even Earth has some pretty scary aspects to it. But unless youre watching this video hundreds of years in the future, Earth is still the only place we can go right now. So were just going to have to face these fears Im afraid. My name is Danny Burke and this is the Top 10 Scary Facts About Earth. Coming in at number 10 we have The Overdue Asteroid. 65 million years ago, a 15km wide asteroid slammed into modern day Mexico, starting a chain of events that led to the extinction of the dinosaurs. An asteroid of this size hitting Earth is, luckily, an extremely rare occurrence. Scientists estimate it happens once every 50 to 60 million years. But if youll remember though, the last one which wiped out the dinosaurs was 65 million years ago. Some people say that we are at least 5 million years overdue for another huge asteroid like that. Lets just hope it doesnt arrive in the next few years because theres almost nothing we could do to stop it. At the number 9 spot now we have Orbiting a Black Hole. Yes, its true. The Earth is technically orbiting a black hole. Not just the Earth though. The sun and all of our solar system, in fact, every solar system in the Milky Way galaxy is thought to be orbiting a giant black hole. Its about 4.3 million times the mass of our sun. Sometimes astronomers see it flare up, possibly after devouring an asteroid that got a bit too close. Thats essentially what were orbiting round on a very big scale. Good news is that its over 25,000 light years away from us, meaning the light we see from it now, left there when humans were still hunting woolly mammoths and didnt know how to grow crops. So its pretty far away. Were gonna stay with space now for our number 8 with How Near Space Is. It doesnt really matter where youre watching this video, it applies to pretty much everyone the same way. way up. If you think about it, thats not really very far. Theres 62 miles of atmosphere that slowly gets thinner and thinner and thinner until it reaches space and then its just space. Forever. In every direction. Just icy darkness, lethal radiation and no air. If you ever want to truly appreciate just how thin our bubble of atmosphere is, NASA has a lot of cool but slightly unsettling pictures of it. Coming back down to Earth now for our moment with our number 7 we have Global Warming. I know that you know that we all know global warming is possibly the biggest threat to life on Earth at the moment. Human activity has led to a 0.8 degree increase in the average global temperature. 16 out of the 17 warmest years ever recorded have happened since 2001. Weve seen an increase in extreme weather events and polar ice is melting at an alarming rate. Flooding and heatwaves are now ruining agriculture too in some parts of the world. And no food could destabilise international peace and cause instability. Theres no denying Earth is changing, its about what we can do to soften the blow … Next up at number 6 we have The Ticking Clock. Earth is 4.5 billion years old. Thats pretty old. Every billion years or so, the suns brightness increases by about 10% as it burns through its hydrogen. If another 10% increase were to happen, Earth would no longer be in the habitable zone that has allowed life like us to flourish. Oceans would start to evaporate, creating a greenhouse gas that would trap heat and speed up the whole process even more. As far as we can tell, thats going to happen within a billion years. Obviously, that is a long way away. Humans may be long extinct or just out there in space by then but still, its disconcerting to think that the definite end is slowly approaching our planet, one second at a time … Moving on to number 5 we have The Super Volcanoes. There have been a number of supervolcanoes throughout Earths history, cataclysmic events that have brought all life on the planet to its knees, sometimes almost ending it all together. The most likely candidate for the next supervolcano eruption is Yellowstone USA. The whole national park there is sitting on top of one massive reservoir of magma. Scientists say it erupts every 600,000 years without fail. Something must be up because its been 640,000 years since the last eruption. That doesnt mean its gone dormant. The ground at Yellowstone is 74cm higher than it was in 1923, indicating a massive swelling of magma down below. The effects of an eruption this size would probably need a whole video to explain but trust me, it wouldnt be pretty for life on Earth. Not at all. Moving on to number 4 we have Earth Speed. If you stand at the equator, youll be spinning with the Earth at over 1,000 miles per hour. At the same time, the Earth is also orbiting the Sun at about 67,000 miles per hour. Thats right, as you watch this video, you are moving around the Sun at about 87 times the speed of sound. The reason you dont go flying off is because, well, everything on Earth is moving together at this constant rate. Its kind of like when youre in a car, nothing seems like its moving inside because its all moving at the same rate. If the car stopped suddenly though, your drink would go flying. Its the same with the Earth. If the Earth suddenly stopped spinning, we would then go all flying. So lets hope it doesnt. It hasnt so far. Next up at number 3 we have Extinction. There have been 5 major mass extinction events in Earths history where more than 75% of species disappeared. Scientists think that we are currently living in the 6th. Its called the Holocene Extinction. It started at the end of the last ice age with the disappearance of large land animals like the mammoth. It continues today with species dying out at over 100 times the normally expected rate. In fact, its thought we lose 150 species of plants, insects, birds and mammals every day. Of course, species dying out is natural but scientists think that humans are a major contributor to whats happening right now. Meat consumption, overfishing and overpopulation are just some of the possible causes. At number 2 now we have Moving On. If humans were to die out, Earth wouldnt care if we disappeared today. There would be almost no record that we were ever here in the first place in just a few hundred million years. The Earth would look completely natural. A handful of human fossils may remain but every city, every bridge, every piece of art, everything you have ever seen or used will have been broken down in time. In fact, aliens visiting Earth in the future may only know we were here at all because of what we left on the moon. Those objects up there will still be there because there is no natural erosion on the moon. Its a pretty intense and scary thought. Does anything matter? And finally at number 1 we have 8 Minutes. Earth is about 8 light minutes from the sun. That means light from it takes about 8 minutes to reach us. When you look up at the sun, which you shouldnt, youre actually seeing how it was about 8 minutes ago. Thats cool but theres another disturbing thought that comes with that. If the sun exploded or disappeared, we wouldnt know anything bad had happened for another 8 minutes. Even if we looked up at the sky, the sun would still appear to be fine because the light wouldnt have reached us yet. The effects of an explosion would hit us soon after. Its a scary thought to think that as youve been watching this video, the sun could have imploded and everything seems fine right now. Maybe you should go and check. Well, I like to think that video was a healthy mix of scary and interesting. Like I said at the start of the video though, I think theres a lot more good things than scary things about the Earth. Its hard to get too scared about your own home, but I hope you did, a little bit. My name is Danny Burke, thank you as always for watching and Ill see you all in the next video!