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| Image: pixabay |
Life on Earth has been evolving for more than 4 billion years. During these 4 billion years, due to events like asteroid impacts and climate changes, many species have become extinct, while many new species have emerged, and life continues to thrive on Earth to this day.
However, life on Earth cannot remain permanent. This is because the Earth itself is not permanent. After 7.5 billion years, all the fuel in the Sun will be exhausted, and it will transform into a Red giant star, eventually engulfing the Earth. But by that time, no life will remain on Earth. Scientists believe that the living organisms on Earth could be completely extinct within just a few billion years.
In this article, we will explore the various possibilities for the complete destruction of life on Earth..
Meteor Attack:
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| Image: pixabay |
About 66 million years ago, a meteorite hit the Gulf of Mexico, wiping out the entire dinosaur species, along with several other species. But, the human race was not created at that time. Perhaps if the meteor had not hit the Earth, dinosaurs would still be roaming the Earth today. We would have to live in hiding. In that way, this meteorite attack was safe for humans. Scientists also believe that the human race could be wiped out by a future asteroid strike like the dinosaurs.
Because at least once every 100 million years, a large asteroid hits the Earth. When they hit the earth, all the water in the earth evaporates. Scientists believe that this will destroy all life on Earth (including humans). This is only possible because of the massive asteroids in the current solar system , Pallas and Vesta . Both these meteorites are over 500 kilometers in diameter.
The moon was formed when the asteroid Theia hit the Earth 4.4 billion years ago . But life did not appear on earth at that time. Another surprising fact is that almost 17,000 meteors hit the Earth every year. Only 500 of them reach the Earth's surface. But all of these are very small in size and do not cause much harm to humans.
Deoxygenation :
The Great Oxidation Event, which occurred 2.460 billion years ago, created a large amount of oxygen on Earth. During that time, cyanobacteria (or blue-green algae) evolved in abundance, filling our atmosphere with oxygen.
But during The Late Ordovician extinction , which occurred 450 million years ago, the oxygen in the atmosphere was drastically reduced. At that time, all the continents on Earth were a single continent called Gondwana. Also, most of the life was in the sea. Vegetation was beginning to come into the landscape. Due to climate change, the whole world was covered with ice. This event killed many species. The second wave of this event decreased the amount of oxygen on earth drastically.
The reason for this has not been clarified till date. And because of this lack of oxygen, 80% of the world's life at the time was destroyed. Even now, due to climate changes, the oxygen in the ocean surface is decreasing drastically, and some marine life is being destroyed due to this, researchers say. Many researchers believe that if air pollution continues to increase, there will be massive oxygen deficiency in the future.
Gamma-ray burst:
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| Image: wikimedia commons |
A Gamma-ray burst is an explosion that occurs in newly forming galaxies, neutron stars, binary pulsars, etc. In this burst, large amount of gamma rays are emitted. Perhaps, if this explosion occurs in our Milky Way, there will be a mass extinction on our planet. Even if the radiation from that explosion hit our Earth for just 10 seconds, half of our ozone layer would be destroyed. Various types of organisms can be destroyed by this. However, scientists believe that the chances of this gamma-ray burst occurring in our Milky Way region are very low.
When these gamma rays strike the Earth's atmosphere, the oxygen and nitrogen gases there combine to form nitrogen dioxide gas. It is these gases that cause massive amounts of smog on Earth. So, when gamma rays hit Earth, Earth's atmosphere is filled with nitrogen dioxide gas. This will also block the sunlight.
Due to this, the entire earth will be covered with ice. Scientists have speculated that this gamma ray burst may have been one of the reasons why Earth was surrounded by ice 450 million years ago.
If not because of a gamma-ray burst, then surely all life on earth will one day die out due to lack of oxygen. Because scientists predict that in a few hundred million years, the amount of carbon dioxide on Earth will decrease drastically. Thus, all the plants that absorb carbon dioxide will be destroyed. Hence, oxygen deficiency will also occur and all life on earth will be destroyed. But, all this will happen after several hundreds of millions of years.