This week we talk about DART, extinction events, and asteroid 2024 YR4.We also discuss Bruce Willis, Theia, and the Moon.Recommended Book: Exadelic by Jon EvansTranscriptIn the 1998 action flick Armageddon, an asteroid the size of Texas is nudged into a collision course with earth by a comet, and NASA only notices it 18 days before impact.The agency recruits a veteran oil driller, played by Bruce Willis, to fly out to the asteroid and drill a hole in it, and to detonate a nuke in that hole, which should destroy it before it hits earth, which undetonated, that rock not broken up ahead of time, would wipe out everything on the planet. It’s a fun late-90s flick loaded with some of the biggest names of the era, so I won’t ruin it for you if you haven’t seen it, but the crux of the plot is that there’s a lot going on in space, and at some point there’s a chance one of these big rocks hurling around in the void will line up just right with earth’s orbit, and that rock—because of how fast things move in space—would hit with enough force to wipe out a whole lot of living things; perhaps all living things.This film’s concept was predicated on historical events. Not the oilmen placing a nuke on a rogue asteroid, but the idea of an asteroid hitting earth and killing off pretty much everything.One theory as to how we got our Moon is that an object the size of Mars, called Theia, collided with Earth around 4.5 billion years ago. That collision, according to some versions of the so-called “giant impact hypothesis,” anyway, could have brought earth much of its water, as the constituent materials required for both water and carbon based life were seemingly most prevalent in the outer solar system back in those days, so this object would have slammed into early earth, created a disk of debris that combined that early earth’s materials with outer solar system materials, and that disk would have then reformed into a larger body, earth, and a smaller body, the moon.In far more recent history, though still unthinkably ancient by the measure of a human lifespan, an asteroid thought to be somewhere between 6 and 9 miles, which is about 10 to 15 km in diameter hit off the coast of what is today Mexico, along the Yucatan Peninsula, killing about 70% of all species on earth.This is called the Chicxulub Event, and it’s believed to be what killed the dinosaurs and all their peer species during that period, making way for, among other things, early mammals, and thus, eventually, humans.So that was an asteroid that, on the low end, was about as wide as Los Angeles. You can see why those in charge back in the 90s tapped Bruce Willis to help them handle an asteroid the size of Texas.Thankfully, most asteroid impacts aren’t as substantial, though they can still cause a lot of damage.What’s important to remember is that because these things are moving so fast, even though part of their material will be burnt up in the atmosphere, and even though they might not all be Texas-sized, they generate an absolutely boggling amount of energy upon impact.The exact amount of energy will vary based on all sorts of things, including the composition of the asteroid , the angle at which it hits, and where it hits; an oceanic impact will result in a whole lot of that energy just vaporizing water, for instance, while a land impact, which is less common because a little more than 70% of the planet is water, will result in more seismic consequences.That said, an asteroid that’s about 100 meters in diameter, so about 328 feet, which is a lot smaller than the aforementioned 6 to 9 mile asteroid—a 100 meter, 328 foot object hitting earth can result in a force equivalent to tens of megatons of TNT, each megaton equaling a million tons, and for comparison, the atomic bombs dropped on Hiroshima and Nagasaki at the end of WWII ranged from 15,000 to 21,000 tons of TNT, mere kilotons. So a 100 meter, 328 foot asteroid hitting earth could generate somewhere between a few hundred thousand and a few million atomic bombs’ worth of energy.None of which would be particularly devastating on a planetary scale, in the sense that the ground beneath out feet would barely register such an impact. But the thin layer of habitable surface where most or all of the world’s life exists, certainly does. And that’s the other issue here, is that on top of even a relatively small asteroid being a city-killer, wiping out everyone and everything in a large area around where it strikes, it can also cause longer-term devastation by hurling a bunch of water and soil and detritus and dust and ash into the atmosphere, acting as a cloak around the planet, messing with agriculture, messing with growth patterns and other cycles for plants and animals; the water and heat cycles completely thrown off. All of which can cause other knock-on effects, like more severe storms in unusual places, periods of famine, and even conflict over scarcer resources.What I...
