65 million years ago*
The asteroid that hit the Earth 66 million years ago created the Chicxulub Crater, which is buried beneath the Yucatán Peninsula off the coast of Mexico.
According to research, the Chicxulub asteroid sent up clouds of sulphur-based gases into the Earth's atmosphere along with lots of silicate dust.
The impact triggered volcanic eruptions and wildfires around the planet, which sent soot and carbon dioxide into the air.
This caused the Earth to be plunged into darkness because of the dirt and dust in the air, causing a 'winter' which lasted for around 15 years.
The scientists say this "impact winter" is responsible for wiping out 75% of all plants and animals on Earth.
The dusty air blocked out the sun's light, meaning that plants couldn't photosynthesise - make their own energy to grow - causing most of them to die.
I don't know why this is news, this is what I was taught in school 20 years ago.