How do scientists know that a meteorite killed the dinosaurs?
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while they don’t KNOW it for sure what they know is that they haven’t found dinosaur fossils newer than about 65 million years old, and approximately 65 million years ago there was a massive meteroite impact in Chicxulub (they know when it was based off geological science that would be too complicated to explain to a 5 year old but basically meteors do special things to the surface when they hit and they can see when that happened by looking at rock layers) and we know that massive asteroid impacts disrupt the environment in certain ways so it stands to reason that the Chicxulub impact created an extinction event that “killed” the dinosaurs (although “killed” is a bit of a misnomer because a fair number of them evolved into modern day birds)
There is a distinct line in the layers of earth that can be found all over the planet called the KT boundary No dinosaur fossils have ever been found above this line. Another interesting thing about the KT boundary is it contains a very high concentration of a mineral called iridium, which is one of the rarest minerals on Earth. Where the element is rare on earth and its common in the KT boundary, it gave us the idea that Iridium came from space, turns out in asteroids and comets Iridium is quite common. The theory was an asteroid or comet filled with Iridium slammed into the earth and the resulting dust and debris spread this iridium all over the planet and settled down to form the KT Boundary. As with all past mass extinction events this planet has seen the smallest animals tend to survive and the larger animals do not, so the large dinosaurs died out the smaller ones survived and continued to evolve and those small dinosaurs turned into modern day birds.
So fossils (and other things) are found in layers according to how old they are. The older fossils are found deeper in the Earth. There’s a boundary above which no non-avian dinosaur fossils are found, at about 66 million years ago. This is called the K-Pg boundary, where the Cretaceous period ends and the Paleogene period begins.
At this boundary, they found way high concentrations of iridium, as high as 160 times normal. Iridium is rare in and above the crust–when the planet formed, it mostly sank into the core, being that it’s so heavy. But a meteor could have a lot of it. That was the first major proof of the impact event. Other evidence was also found, like shocked quartz, something that’s found at the site of meteor impacts and nuclear explosions.
Then the Chixulub crater was discovered, and this was tied to the evidence that had been found.
I think they set up trail cams to study the dinosaurs. Saw the meteorite in the footage, then no dinosaurs.
Pterodactyl semen embedded in the rock. As the meteorite fell to earth, the pterodactyl’s collectively got together and decided to say fuck it, literally. What a sight that would have been to behold. Science is incredible.
There’s a massive crater (most likely cause by a meteor big enough to nearly wipe out all life) near Mexico that dates to right around the time period when the freshest dino fossils are dated to.
“Hmmm we’ve never found a Dino fossil newer than 66 million years old. I wonder why that is?”
“Oh hey, look at this absolutely massive 66 million year old crater. Wow, something this size would definitely fuck up the planet and most of the life on it for a long time” 1+1= 2
It’s not recorded definitive proof, but it’s not a wild guess either
Others have explained the data, and the asteroid definitely played a huge role. But there was a second, potentially equally deadly and climate changing, effect: the Deccan traps erupted at around the same time, probably caused by a magma plume.
A magma plume is a bit like what you see in a lava lamp. Just hundreds to thousands of miles in size and way hotter. When they reach the surface, the can completely melt it away and cause entire continents to literally melt into a huge lava sea. This has happened at least once.
The eruption of the Deccan traps was not _that_ extreme, it was “only” absurd amounts of vulcanism. That still most likely had a huge effect on the climate.
In the end, it quite possibly was the combined force of huge rock from above and lots of very hot molten rock from below. Maybe some few dinosaurs could have survived one of them, but two such cataclysmic events so close to each other definitely wasn’t fun.
They theororized it for a long time then they found a crater big enough and which dates to the right time frame and that pretty much put the nail on the coffin.
We have a fair amount of evidence. For one we know where it impacted, obviously such a large thing leaves a trace. Secondly based on the geologic record we can tell what followed the impact. The meteorite essentially caused a “nuclear winter”. People don’t realize this but the meteorite that killed the dinosaurs didn’t kill them in an instant on impact. What it did was drastically change the climate which made the Earth inhospitable to dinosaurs and they died out.
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