If you've ever seen movies like "2012" or "Armageddon," or read the book "On the Beach," you've probably envisioned some of the threats that could have killed our planet's life. complete destruction.
The sun can cause a few incidents. Comets can visit. Humans can eradicate each other with nuclear weapons . Those are just some of the many extinction-level events that are likely to occur. And there are still many ways to "goodbye life" anymore!
But first, what exactly is an "extinction level event"?
An extinction-level event (abbreviated as ELE) is a disaster that leads to the extinction of the vast majority of species on the planet. This is not the usual extinction that occurs every day, nor does it need to "purge" all living things. We can identify major extinction events by studying the sediments and chemical composition of rocks, fossils, and evidence of major events on the moon and other planets.
There are many phenomena that can cause mass extinction, but they can be grouped into several categories:
Life would not exist without the Sun, but the Sun is also what causes Earth's decline. Even without any other disaster on this list, the Sun will destroy us. Stars like the Sun over time get lighter and brighter as they burn hydrons into helium. In 1 billion years, it will be about 10% brighter. Although it may seem insignificant, this will cause more water to evaporate. Water is a greenhouse gas, so it retains heat inside the atmosphere, making evaporation more serious. Sunlight splits water into hydrogen and oxygen, causing them to fly into space. If life can be sustained, then fate will come when the Sun enters a period of giant red stars, swell to Mars's orbit. No life can exist within the Sun.
But, the Sun can destroy us right now if it wants to, by a solar eruption (abbreviated as CME). Hearing the name you probably guessed, that's when our brilliant star shoots out charged particles from its corona. Although a CME can shoot matter in any direction, it usually does not fire directly towards Earth. Sometimes, only a very small part of the particles reach the Earth, creating aurora or solar storm. However, there is still a possibility that CME will "bake" nine planets.
The sun also has its own "gang" (and they hate the Earth too). A recent supernova, supernova, or gamma ray burst (within 6,000 light years) can radiate onto organisms and destroy the ozone layer, leaving life in the "gun barrel" of radiation ultraviolet from the Sun. Scientists believe a gamma or supernova explosion was probably the cause of the late Ordovician Ordovian extinction.
The Earth is a giant magnet, and its relationship with life is also not so smooth. The Earth's magnetic field protects us from the worst things the Sun throws toward the blue planet. However, sometimes the position of the north and south poles reverses. The frequency of this, and the period before the field stabilizes, is a very difficult variable to determine. Scientists are not entirely sure what happens when the magnetic poles reverse. Maybe nothing at all. Or maybe the weakened magnetic field will cause the Earth to take in the solar wind, enabling the Sun to steal a large amount of our oxygen - the same gas that humans need to breathe! Scientists believe that magnetic polarity is not always an extinction event. Just . sometimes.
Perhaps you will be surprised to learn that the impact of an asteroid (asteroid or meteor) is only associated with a single mass extinction: the Cretaceous - Ancient Near extinction event. Other collisions may contribute to extinction, but not the main cause.
The good news is that NASA claims that about 95% of comets and meteorites larger than 1km in diameter have been identified. The other good news is that scientists estimate that an object must have a diameter of about 100 km to destroy enough to erase all life on Earth. The bad news is that they are among 5% of those unidentified comets and meteors, and there's nothing we can do much to prevent fate with technology like today! (Don't dream of using nuclear bombs to detonate meteors.)
Obviously, the creatures that live right at the impact area of the meteorite will immediately be wiped out. Many other creatures will disappear due to shockwaves, earthquakes, tsunamis, and fire storms. The creatures that survive the initial collision will have difficulty finding food, because dust and rocks being thrown into the atmosphere will cause climate change, leading to extinction. large tissue. Let's hope you're not unlucky in this collision area!
A day out on the beach sounds pretty interesting, until you realize the blue part of the giant rock we call Earth is more deadly than all the sharks living inside it. The ocean possesses quite a number of weapons that can cause extinction-level events.
Methane clathrate (molecules made up of water and methane) sometimes burst from the continental crust, creating a methane eruption, called a "clathrate gun". This muzzle fires a huge amount of greenhouse methane into the atmosphere. Such events have been linked to the late Permian extinction and the extreme warming period (Paleocene-Eocene Thermal Maximum).
A long rise or fall of sea level also leads to extinction. The sea level drops more terrifying, because it exposes much of the continental crust, killing countless marine creatures. This event will affect the terrestrial ecosystem, leading to an event of extinction.
Chemical imbalances in the sea also cause extinction events. When the middle or upper layers of the ocean become anoxic, a deadly reaction will take place. The Ordovician-Silurian, late Devoni, Permian-Triassic, and Triassic-Jurassic extinctions all include anoxic events.
Occasionally, the concentration of essential trace elements (such as selenium) decreases, leading to large-scale extinction. Sometimes, sulfate-reducing bacteria in heat slots are out of control, releasing an excessive amount of hydrogen sulfide, weakening the ozone layer, leaving all living organisms affected by deadly UV rays. The ocean also undergoes a periodic inversion process, in which surface water with high salt concentrations sink to the bottom. Anoxic deep water emerges from above, killing surface creatures. Late Devonian and Permian-Triassic extinctions were all related to this event.
By reading this, the sea is no longer as beautiful as it used to be?
Although the events of the sea-level reduction are linked to 12 extinction events, only 7 of them cause the number of living creatures to drop significantly. Meanwhile, the volcanoes have led to 11 extinction-level events, and all of them are extremely serious. The endings of the Permian, Triassic and Cretaceous extinctions are all linked to volcanic eruptions called "basalt floods". Volcanoes kill by emitting dust, sulfur oxide, and carbon dioxide, collapsing food chains by preventing photosynthesis, poisoning land and the sea with acid rain, and causing effects. global warming.
The ultimate cause of large scale extinction is global warming or cooling, usually caused by one of the other events mentioned above. Global cooling and glaciers are believed to have contributed to the extinction of the late Ordovician, Permi-Trias, and the end of Devon. While falling temperatures kill some species, the sea level drops because the water freezes has an even more terrifying effect.
Global warming is more than a seasoned murderer. But, the excessive heat of a solar storm or a giant red star is not necessarily the cause. A steadily increasing Earth's temperature is associated with the Paleocene-Eocene Thermal Maximum extinction, Triass-Jura extinction, and Permi-Triass extinction. The problem seems to stem from rising temperatures that create water, leading to greenhouse gases and causing the lack of gas events in the ocean. On Earth, these events have always been balanced over time, but some scientists believe that it is possible that Earth will be like Venus - in that situation, global warming will cause the whole planet will perish.
There are countless ways for humanity to perish - we can wait for a long time until asteroid crashes or a volcano erupts. We are also fully capable of triggering an extinction-level event through a global nuclear war, or exacerbating climate change through day-to-day activities, or by kill other races to lead to ecosystem collapse.
The awful thing about extinction events is that they tend to be magnetic , leading to a domino effect in which one event puts one or more species in a difficult position, which then leads to another. to destroy many other species. Therefore, any extinction usually includes many causes mentioned in this list.