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The theorized asteroid hits some land mass on Earth and the impact causes a column of dirt to rise into the atmosphere and ultimately out of the atmosphere, at least to some degree. (As I understand it, the effect is similar to a column of water which replaces the vacuum left by a dropped object; fill a bowl with water and drop a marble in it to see a small-scale version.)
The column of dirt doesn’t manage to escape Earth’s gravity so it starts to fall back. The dirt this entire time is colliding with a whole bunch of air particles causing a lot of heat to be generated. This heat becomes enough to temporarily (hours) turn the surface of the Earth into an oven, which kills most life. A distant human-evolutionary ancestor had been a mammal which liked to burrow and the insulation provided by the surrounding dirt protected such animals from the heat.
I’m not sure about some details like I’m pretty sure (as theorized) the dirt might turn to glass as it goes up but I’m not sure how much that matters. The important things are the oven-like heat and how our ancestors were spared.
The energy of the asteroid is effectively turned into heat by the planet, which eventually dissipates but hypothetically not before cooking a lot of things.
You at least tried to explain the scenario. However, I don't believe that the volume of dirt and rock expelled by the impact is enough to engulf the entire planet.
It could cause heavy local damage. But it can't cause global extinction, unless the volume of dirt is the size of a continent.
Have you done the math, or is this based on a gut feeling?
Because the people who have done the math disagree with you. Some of the ejecta would be thrown well out of the earth's gravitational pull, the other would end up various suborbital trajectories, coming down over the next day or so across the entire surface of the earth. Their re-entry heating will be enough to turn the entire sky incandescent, and the radiative heating will essentially barbecue the entire surface of the earth. Only swimming, burrowing or cave-dwelling animals would survive.
There is also the possibility of increased volcanic activity due to disruption of the crust, depending on where it occurs and how large the impacting object is. That can exacerbate and prolong the blanketing of the earth, and introduce severe air quality issues as well.
I’m sure there are other challenges to life as well. It sounds like misery for decades.
> It could cause heavy local damage. But it can't cause global extinction, unless the volume of dirt is the size of a continent.
If someone is going to make this claim academically, they will have calculated a whole bunch of things -- with perhaps some assumptions to numbers like mass, volume, velocity of the asteroid so they can play around with them as variables.
I will admit I have not dug deeper into this to find the numbers myself and do the relevant calculations. That is, in part, why I choose to be explicit about “theorized”. It’s what might have happened, given what we know, but it’s hard to be sure of what happened unless one studies the relevant ideas.
10 Km diameter, made of carbonaceous chondrite that has a density of 3g/cm^3, falling from sky at escape velocity of 11km/s https://www.wolframalpha.com/input?i=4%2F3*pi*%2810km%2F2%29... -> 9.5E22 J (Joules)
Total weight of atmosphere: 5.2 E18 Kg
Specific heat of air: 1.0E3 J/Kg°C
Assuming all energy went to the air, we get an increase of https://www.wolframalpha.com/input?i=9.5E22+J+%2F+5.2E18+Kg+... -> 18°C (32°F)
Assuming all energy went to the air, and you live in a nice place where the temperature is already 20°C(70°F) then the temperature increase to 40°C (100°F). That's bad, but you probably have time to jump into a lake if it's nearby (otherwise you are toasted).
This is mush less than an oven temperature like in the GP comment.
What happens is that the re-entry heating of the falling ejecta produces radiative heating, which directly heats the surface of the earth. And that gets cooked well past oven temperature.
The surface of the Earth is 5.1E14 m2, so it's 1.8E8 J/m2. I don't expect the fireworks to be synchronized so let's assume that they fall in an hour. That gets 50,000 W/m^2 For comparison, sunlight is 1,300 W/m^2 so it's almost like 40x sunlight. This bad, very bad.
I don't expect a 100% conversion of meteorite energy to fallout energy, but it's more dangerous that my initial calculation.
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I'm confused because the weight of the atmosphere is like the weight of 10m of water. So heating all the atmosphere is like heating a 10m layer of water. But actually water has a much bigger heat capacity, so the final temperature would be smaller. And dirt has an intermediate value. Also the radiation would not heat 10m of water or dirt, perhaps only the first meter.
So I expected that if my first calculation got a not dangerous temperature increase, I'd get in this second calculation a not dangerous result. So I guess I made a mistake in at least one of the calculations or my hand waving has a mistake.
What leads you to the beliefs that you have?
Do you have anything to support this hypothesis besides your reckons?
Which is exactly the worst-case with the current, human caused greenhouse effect.
Earth has only a core, and that is hundreds of kilometers below it's surface.
Ecosystems have "vital organs" as well. If you kill off enough key species they collapse. If you sufficiently change the environmental conditions to which all life is adapted, well then the majority of that life ceases to be able to live.
> For a while people thought this impact may have caused the Triassic-Jurassic mass extinction event. But now that the crater has been carefully dated, they don’t think that anymore. The extinction happened 12 million years later!