Scientists have named three possible scenarios for the end of the world

(ORDO NEWS) — Life on Earth appeared 4 billion years ago. Since then, the planet has gone through many cataclysms. None of them could destroy all life, but in general such a threat exists. Let’s talk about the end of the world

Decreased oxygen levels

About 2.5 billion years ago, the so-called “oxygen catastrophe” occurred. Cyanobacteria through photosynthesis filled the Earth’s atmosphere with oxygen and created a world where multicellular life could develop and breathe.

At the same time, the opposite happened about 450 million years ago. The planet’s oxygen levels have plummeted. This led to the Ordovician-Silurian extinction event, the second in history for the loss of living organisms.

The reasons are still being studied, but most scientists agree that the main one is dramatic climate change. In our era, something similar could happen again. Moreover, according to some estimates, global warming is already reducing the level of oxygen in the ocean, causing the extinction of marine animals.

Asteroid impact

In 1980, it was hypothesized that an asteroid impact about 66 million years ago led to the extinction of the dinosaurs.

According to scientists, the asteroid landed in the region of modern Mexico. Most amphibians could have died within hours or days of falling due to the sudden rise in temperature.

This collision could cause irreversible climate change, increase atmospheric acidity and change the composition of the oceans. Without it, humans might never have appeared, and dinosaurs would have ruled the planet, forcing mammals to constantly hide.

The likelihood of such an event happening again is extremely low. Every day, about 20 asteroids fall on our planet. They do not pose a danger, since in general their size does not exceed the size of a stone that can be held in the palm of your hand.

According to NASA, asteroids that can destroy a city or cause a devastating tsunami collide with the Earth every 1-10 thousand years. And the largest ones, with a diameter of 400 m, capable of causing a global cataclysm, on average fall on our planet every 100 thousand years.

Only the largest asteroids in the solar system, Pallas and Vesta, can completely destroy life. They are not going to fly to Earth in the near future.

Aging Sun

As the Sun ages, it will get brighter and the Earth will receive more and more solar energy. This energy will act on the planet’s surface, accelerating the weathering of silicate rocks such as basalt and granite. During this process, carbon dioxide is drawn from the atmosphere and, through chemical reactions, is fixed in minerals.

Theoretically, the Earth should begin to cool as carbon dioxide levels decrease, but in about 2 billion years this effect will be canceled out by the ever-increasing radiance of the Sun.

Carbon dioxide, along with water, is one of the key components that plants need for photosynthesis. With a decrease in its level, some species may become extinct. Less photosynthesis means less oxygen production.

Its concentration in the Earth’s atmosphere will decrease, creating a crisis for all life forms. As a result, it may drop to zero.

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