The impact of a large meteorite on Earth will occur, experts say, what we do not know is when. This would be the devastating effect, step by step
Let’s put ourselves in the situation. The Netflix movie, Don’t Look Above, is about this: NASA discovers that in six months a comet the size of Everest will hit Earth. But let’s imagine that this time it’s not a movie.
What is going to happen sometime in history seems indisputable. In the B612 Foundation , dedicated to tracking space rocks, they are clear: “It is 100 percent certain that a devastating asteroid will hit us, but we are not 100 percent sure when”. And it was one of Stephen Hawking’s public fears. And in his latest book, Short Answers to the Big Questions, considered the collision of an asteroid the greatest threat to the planet.
What would happen if tomorrow a Dibiasky-type comet slammed into the Earth?
We assume that it is a comet 10 kilometers in diameter or more, a Dibiasky-type comet. If it hits, it will release an energy of about 100 teratons.
The impact of a 10-kilometer object can block the sun for a year or more
The energy released by its impact would be 100 teratons. Hiroshima and Nagasaki are on the 10-30 kiloton scale. Let’s see how the scale goes. One thousand kilotons is one megaton. One thousand megatons is a gigaton. One thousand gigatons is a tethon. Thus, its effect is not a speck of dust on the eye compared to the power of the Dibiasky-type meteorite.
- For starters, the initial impact creates a huge fireball that kills anyone who can see it.
- At the same time, the impact lifts the oceans. Among the terrible consequences of the meteorite that wiped out the dinosaurs, caused a tsunami such as has never been seen in modern history, which spread through all the oceans of the globe with waves up to a kilometer and a half high .
- The ejection (material thrown into the air) from the impact explodes in space and covers a large area, half the world, perhaps – with burning debris. (Something like this was seen when Comet Shoemaker-Levy 9 collided with Jupiter in 1994).
- It is as if the sky had caught fire, the heat unleashed by this rain of incandescent debris ignites forests and cities, burning them to embers.
- Then the dust from the impact and smoke from the fires surround the earth, engulfing our planet in the so-called impact winter.
- Sunlight disappears completely. A 10-kilometer object can block the sun for a year or more.
- Temperatures drop and there is no light for photosynthesis. The plants die. Animals that live underground, where roots and other sources of food, have a relatively high chance of survival.
- During impact, the comet shatters. It releases billions of tons of sulfur-laden dust, part of the comet itself, part of sulfur-rich rocks that can be found below the point of impact.
- The heat of impact also creates nitrogen oxides. The sulfurous material and nitrogen oxides produce a corrosive acid rain that strips any surviving vegetation.
- Acid rain runs into the oceans and kills marine organisms, especially along the continental shelves.
- Nitrogen oxides and debris thrown into the stratosphere by the initial explosion would destroy the ozone layer in a few days.
- The impact and subsequent fires also release an enormous amount of carbon dioxide into the atmosphere. After the initial impact, winter ends, a lot of carbon dioxide in the air that can result in a greenhouse effect of several centuries.
The meteorite that hit the Earth 65 million years ago wiped out more than 70% of the species that were on Earth. The dinosaurs were killed, and others survived, somehow occupying those ecological niches. Once the dust settled, they emerged to spread across the newly formed world.
The information in this article comes from the book by radio astronomer Gerrit L. Verschuur, ‘Impact: The Threat of Comets and Asteroids, published by the Oxford University Press