The composition of the rock that a meteor hits when it reaches Earth will determine how dangerous the impact is, not just its size.
According to the Daily Mail, Earth has been hit by many meteorites during its 4.5 billion year life. A team of experts from the University of Liverpool (UK) has investigated why some meteorites cause mass extinction events while others have a softer effect.
The researchers analyzed 44 impacts over the past 600 million years. They found that meteors hitting rocks rich in potassium feldspar always lead to a mass extinction, regardless of the size of the meteorite.
Potassium feldspar is non-toxic but acts as a powerful ice-producing aerosol with great influence on cloud dynamics. It allows more solar radiation to pass through the clouds, which in turn, warms the planet and changes the climate.
When this happens, it also makes the atmosphere more sensitive to warming from greenhouse gas emissions.
Dr Chris Stevenson – a sedimentologist from the University of Liverpool (UK) – said: “For decades, scientists have wondered why some meteorites cause mass extinctions. series, and other meteors, even the really large ones, not”.
“It was surprising when we aggregated the data: Life went on as normal in an impact with a 48km-diameter meteorite, while a collision with a half-sized meteorite caused mass extinction event 5 million years ago,” Dr Stevenson said.
This opens up a whole new direction of research, including exactly what kills lives during each stage of impact, the team says.