And carelessly. In other developed countries, there is compliance with all laws, the development of cleaning equipment, environmentally friendly fuels and machines. However, the threat of environmental pollution still poses a great danger.
When garbage is thrown out, the toxic substances contained in it enter the soil, poisoning it. Then they are washed out by groundwater and carried into rivers and seas. When more and more such substances accumulate, plants and animals die out in the water, and people's health deteriorates.
Air pollution leads to the greenhouse effect. Due to the substances ejected into it, the necessary amount of heat does not leave the Earth, but remains on the planet. This causes negative climate change. Which in turn can lead to natural disasters.
The ozone layer is a layer located in the upper atmosphere and protects the planet from cosmic radiation. It has already been practically destroyed over Antarctica, if it completely disappears, then all life on Earth will be burned by radiation from space. Substances that destroy this layer are emitted into the atmosphere, and now its partial reduction over the planet leads to an increase in eye diseases, oncology, and general deterioration in health.
nuclear threat
Despite the fact that many countries support the elimination of nuclear weapons, this threat remains relevant. Some countries do not agree to openly show their nuclear policy. The danger of this threat lies in the numerous extinction of people, animals, plants. Also, after a nuclear explosion, a huge territory will become uninhabitable for many decades to come.
Nuclear power plants can also cause nuclear explosions. Although safe stations are being built around the world, some danger remains. In 2011, there was an accident at the Fukushima nuclear power plant in Japan. It would seem that Japanese technology is one of the best in the world, but as a result of a strong earthquake and tsunami, the power supply system for cooling a nuclear reactor could not stand it.
Threat from space
Most asteroids flying near the Earth are not dangerous. They are too small and even if they fall on the planet, they do not bring any destruction.
But securing the Earth from a large asteroid is one of the most difficult tasks. An explosion in space of an atomic bomb is one of the methods being developed to combat the asteroid hazard.
Now there is a threat to the Earth from several large asteroids. However, there is a chance that they will fly by. The distance between these space bodies and the planet at the moment of approach will be very small.
Geological hazard
The reversal of the magnetic field is the so-called reversal of the poles. Despite the fact that humanity has not had to experience this phenomenon, scientists think that the inversion may occur in the not too distant future. During the change of poles, geological changes occur, which are accompanied by natural disasters. Also, the Earth's field, which protects against cosmic radiation, will be so weakened that it can destroy most of humanity, the animal and plant world.
Today it became known that astronomers of the Crimean Astrophysical Observatory discovered a 400-meter asteroid, which in 2032 may collide with the Earth. (RIA News)
Scientists around the world are constantly studying our Universe. Many recent discoveries are truly shocking. And the further scientists delve into the secrets of the Universe, the more dangers they find for our planet from the side of space. In our article, we have collected the most dangerous of them. (photos and illustrations: open sources)
Killer asteroids
Asteroid "Apophis"
In 2004 an asteroid "Apophis"(this name was given to him a year later) was too close to the Earth and immediately caused a general discussion. The chance of hitting Earth was higher, however. According to a special scale (Turin), the danger in 2004 was rated at 4, which is an absolute record.
In early 2013, scientists received more accurate data on the mass of Apophis. It turned out that the volume and mass of this asteroid is 75% larger than previously thought - 325 ± 15 meters.
“In 2029, the asteroid Apophis will be closer to us than our own communication satellites. It will be so close that people will see Apophis passing by the Earth with the naked eye. You don't even need binoculars to see how close this asteroid will pass. There is a 90% chance that Apophis will not hit the ground in 2029. But if Apophis passes at a distance of 30,406 km, it may fall into the gravitational keyhole, a narrow area 1 km wide. If this happens, Earth's gravity will change the trajectory of Apophis, forcing him to return and fall to Earth, seven years later, on April 13, 2036. The gravitational effect of the Earth will change the orbit of Apophis, which will cause Apophis to return and fall to the Earth. At present, the chances of Apophis delivering a fatal blow to the Earth in 2036 are estimated at 1:45,000.- from the documentary "The Universe. The end of the Earth is a threat from outer space."
This year, NASA scientists said that the possibility of a collision of Apophis with the Earth in 2036 is almost completely excluded.
Despite this, it is worth remembering: everything that crosses the Earth's orbit may one day fall into it.
Possible locations of the fall of Apophis in 2036 (source: Paul Salazar Foundation)
gamma burst
Every day, a bright flash appears several times in the universe. This bundle of energy is gamma radiation. In terms of power, it is hundreds of times more powerful than all nuclear weapons on Earth. If the flash occurs close enough to our planet (at a distance of 100 light years), death will be inevitable: a powerful stream of radiation will simply burn the upper layers of the atmosphere, the ozone layer will disappear and all living things will burn.
Scientists suggest that flashes of gamma rays occur due to the explosion of a large star, which is at least 10 times larger than our Sun.
The sun
Everything we call life would be impossible without the Sun. But this brightest planet will not always give us life.
Gradually, the Sun increases in size and becomes hotter. At that moment, when the Sun turns into a red giant, and this is about 30 times larger than its current size, and the brightness increases 1000 times, all this will melt the Earth and the nearest planets.
Over time, the Sun will turn into a white dwarf. It will be about the size of Earth, but will still be at the center of our solar system. It will shine a lot less. Eventually all the planets will cool and freeze.
But until then, the Sun will still have a chance to destroy the Earth in another way. Life on our planet is impossible without water. If the heat of the Sun increases so much that the oceans turn into steam, all living things will die from a lack of water.
In preparing the material, data from the popular science documentary film "The Universe" of 2007 were used.
And civilizations or even the whole universe. The threat can be both imaginary and real. For some, the expression "end of the world" causes fear, panic and horror, while others consider it absurd. Nevertheless, there is even a whole list of upcoming apocalypses. Before talking about them, you should find out the possible causes of the end of the world.
Possible causes of the apocalypse
There are many reasons for the end of the world. Some of them seem really impossible, while others could well lead to the death of all life.
- First, this is war. Biological or even nuclear.
- Secondly, possible genetic diseases that will eventually destroy the whole world, taking it so hard that attempts to cure humanity will be useless.
- Thirdly, famine, which, for example, can occur in the event of overpopulation.
- Fourth, an ecological catastrophe, when the cause of the death of the people is the people themselves. That is why environmentalists around the world are calling to protect their planet. Take, for example, the destruction of the ozone layer - all this is quite dangerous.
- Another problem, the fault of which is the man himself, is the exit from the control of nanotechnologies.
- Sixth, a sharp change in climate. Global cooling or warming will lead to the death of almost all life on the planet.
- The causes of the apocalypse can also be the eruption of a supervolcano, the fall of a huge asteroid, or a strong solar flare.
All these and many other reasons can radically change life on Earth, and possibly lead to its death. How dangerous are these events and is it worth waiting for the apocalypse in the near future? We will talk about this and much more further.
Mayan calendar end of the world
To begin with, let's remember 2012, when the whole world literally lived in fear of the end of the world according to the Mayan calendar. According to numerous sources, the apocalypse was supposed to happen in 2012. Why did everyone expect him on this particular day, and where did such a mythical figure come from?
The thing is that the people who once lived in Central America, the so-called Mayan people, kept a calendar that ended on this particular number. Lovers of mysticism and various kinds of clairvoyants said that supposedly the end of the world would come on that day. Such statements, which simply blew up the Internet, frightened millions of people. What earthlings, imbued with fear, did not expect: volcanic eruptions, strong earthquakes and tsunamis, and all this in one day.
“Silence and darkness will come in the world, and humanity will be destroyed,” the Mayans said. It seems absurd now, just as it did for geophysicists in 2012. They then said that it was simply impossible. An interesting fact is that people were offered to survive during the terrible apocalypse, surviving it in a secluded place with huge food supplies. Even the statement about the possible death of mankind was used by supermarkets around the world, which was very helpful to them. Trusting people with fear bought food for months ahead.
But not only supermarkets made money on such news. In many cities, even special bunkers were built, which supposedly could save people from the upcoming apocalypse. Living in such a safe place cost a lot of money. But, as it turned out, the apocalypse was not destined to happen, which is not at all surprising, because we have already survived several ends of the world and still live happily. Anthropologist Dirk Van Turenhut explained the situation by saying: "This is not the end, it's just one calendar followed by another."
Another loud end of the world
The apocalypse was also expected in 2000. People believed that with the transition to the new millennium, the very end of the world would come, and they even came up with a reason why this would happen - a parade of planets, the appearance of a second moon. According to some reports, an asteroid should have fallen.
The end of the world in this case would come at its collision with the Earth. We entered the new millennium, but the end of the world did not exist, and still does not exist. Then astronomers and predictors decided to move the expected apocalypse to 2001. What is its reason?
Apocalypse 2001
This is where things get even more interesting. "August 11, 2001, the planet Earth and the entire solar system will be sucked into a black hole," - such an interesting forecast was made by American astronomers. The following prediction was also made by an American scientist. According to him, in 2003 the end of the world will occur due to the disintegration of the Earth. The next apocalypse, apparently, was believed by few, otherwise how to explain the fact that there were almost no mentions of this in the media. After this prediction, humanity lived quietly for five whole years, after which it became known about the next end of the world.
End of the World - 2008
This year, several scenarios of the apocalypse have been announced at once.
One of them was the fall to Earth of a huge asteroid, the diameter of which was 800 meters. Another reason could be the launch of a huge collider. This made the earthlings worry much more than the forecast of the fall of the asteroid. Fortunately, the excitement was in vain, but the fear did not leave us for long. They began to say that the end of the world will happen in 2011. As it will be?
2011
This version turned out to be much more interesting. The American Harold Camping predicted that on May 21 the dead would rise from their graves. Those who deserve to burn in hell will remain on earth and survive a series of terrible natural disasters: earthquakes, floods, tsunamis, and only then will they go to another world. The version itself is absurd, but, nevertheless, Harold Camping received a huge number of supporters, especially in the USA.
The preacher even gave hope that there would be a small percentage of survivors, consisting precisely of his followers. An interesting fact is that a US public relations company organized the release of huge posters with a doomsday statement. After nothing like this happened on the expected day, the prophet himself postponed the date of the end of the world to October 21 of the same year, explaining that the incident happened morally, and all that now needs to be done is to wait for the real, already final end of the world .
According to his new forecasts, it was supposed to happen exactly in 5 months. Despite Harold's predictions, the end of the world never came, and thousands of people calmly exhaled and continued to live. When Camping realized that his prediction was wrong, he admitted his guilt and even apologized.
And again about 2012
Well, the most anticipated in the list of the end of the world - the apocalypse of 2012. It has already been mentioned above. Perhaps the discussions of this end of the world are the loudest of all.
This date, indeed, frightened millions of people around the world, because not only the Mayan calendar spoke about the events of that year. Predictions about terrible events were made by Nostradamus and Vanga, known to the whole world for their prophecies. What did they really mean? Natural disasters, the beginning of a new life, or the death of the planet? All this remains a mystery. But Patriarch Kirill, regarding the year 2012 and the apocalypse as a whole, said that it is not worth waiting for it, because Jesus Christ does not give us instructions on any dates whatsoever.
Will there be a rebirth? Perhaps, but no one knows when it will come. Despite everything, people continue to listen to predictions and believe in the end of the world. So what threatens the Earth in the near future?
What do they promise for the future?
The next end of the world is scheduled for 2021. Such a statement was made by IA "SaraInform", which was presented with a new list of the ends of the world. The reversal of the magnetic field is the reason for the end of the world in 2021. And maybe not even the end, because they promise that not all of humanity will perish, but only a large part of it.
Scientists suggest that this end of the world will not take place, but it will be different, and it will happen in 2036. In their opinion, an asteroid called Apophis will fall on the Earth, but again, this information is not objective, since the asteroid may diverge from the Earth.
Another apocalypse is supposed to happen in 2060. Newton himself predicted it back in 1740 from a holy book. And in 2240 planetary epochs will change. So argued scientists who lived in different centuries. And also, in their opinion, this year the era of the Sun should end.
Other possible doomsday dates are 2280, 2780, 2892 and 3797. By the way, the last apocalypse was predicted by Nostradamus, therefore, we are talking about the fact that he did not think about the end of the world in 2012 as the end of all life in general. In his letter to his son, he wrote that the Sun would allegedly swallow the Earth, having exhausted all the hydrogen and reaching incredible volumes.
Other dates of the apocalypse are not yet taken seriously, but no one knows what will happen with time. By the way, these are far from all dates, there are some others - intermediate ones, but no one pays attention to them, since the probability of incidents is almost zero.
Will the end of the world come?
We examined the list of the ends of the world, to believe or not to believe in forecasts is a personal matter for everyone. It can be said with 100% certainty: no one knows and cannot know whether there will be an apocalypse and when exactly. What awaits the Earth in the near future? Whom to trust: predictors or scientists? Everyone has their own point of view, however, it is worth noting that the information of the latter is more reasoned and objective.
Instead of guessing, it is better to think about the real harm we are doing to our planet. For example, each of us can improve the ecological situation, because the Earth is really in a dangerous state, and people themselves are to blame for this.
The most famous example of an evolutionary shift caused by astronomical events is the extinction of the dinosaurs, which was caused by the fall of a giant meteorite 66 million years ago. This hypothesis was first proposed by Luis Alvarez, his son, geologist Walter, and their colleagues in 1980.
The researchers found that the sedimentary rocks that formed around the world during the extinction of the dinosaurs contain large amounts of the rare element iridium. Scientists have suggested that the iridium could come from the dusty debris of a meteorite that crashed into the Earth. In the asteroids that were the most likely source of the iconic meteorite, iridium is much more abundant than on Earth.
How exactly such a fall could have killed the dinosaurs -. But there are quite a few possibilities.
The released energy could cause global forest fires. The researchers calculated that to deliver the required amount of iridium, the meteorite would have to be on the order of 10 kilometers across. The impact of such a monster would release millions of times more energy than a hydrogen bomb. What's more, the dust and debris thrown into the air could block the sunlight and set off a gradual drop in temperature over the next few years.
In 1991, the fall hypothesis received a new boost when scientists discovered an impact crater more than 160 kilometers wide at the Chicxulub site in Mexico's Yucatan Peninsula. Its geological age exactly coincided with the period of extinction.
How exactly the meteorite impact affected the demise of the dinosaurs is not fully understood; there is evidence that they were already close to it. Nevertheless, it is logical to assume that such a powerful event should have left some imprint on evolutionary history. And this discovery has caused concern about the possible fall of a devastating meteorite today.
Also, meteor impacts are not the only explanation for the extinctions that took place 66 million years ago.
Tokuhiro Nimura is a scientist at the Japan Spaceguard Association, which formed to observe near-Earth objects that could hit the planet. In March 2016, Nimura and colleagues suggested that the extinctions, global cooling, and the iridium layer could be caused by the passage of the solar system through a molecular cloud: one of the large clouds of gas and dust in space from which stars form. As dust accumulated in the atmosphere, it formed a haze that reflected sunlight and cooled the planet.
The basic idea goes back to a suggestion made by British astronomer William McCree in 1975. He thought that if the Earth were to pass through an interstellar dust "stripe", it would start an ice age. At the same time, astronomers Mitchell Begelman and Martin Rees noted that such dust could affect the way solar wind particles enter the atmosphere. our planet, and expose the planet to high doses of radiation, further exacerbating extinctions and climate change.
Now Nimura has resurrected McCree's idea, arguing that the Chicxulub fall was not catastrophic enough to cause all the late Cretaceous extinctions.
However, this is mostly speculation right now.
"The idea struck me as very interesting and plausible, but so far it has not been developed and has no clear supporting evidence," says astronomer Martin Beach of Campion College at the University of Regina in Saskatchewan, Canada.
This 66 million year event was just one of several known "mass extinctions" in which many species across the planet suddenly disappeared.
The largest mass extinction of living species on Earth
The largest extinction occurred at the end of the Permian period 252 million years ago, when at least 96% of all life died out on Earth. All modern life descended from the surviving 4%, so it is clear that evolutionary history could have been completely different if that extinction had not happened. When species die off, those given the opportunity evolve and make the most of it, dictating species diversity that would otherwise not exist.
Paleontologists have long debated what caused these mass extinctions.
It is possible that, like smaller population declines, they may be integral to how ecosystems work. Since all life is interconnected, a small shift in one population can cause a domino effect, sending shockwaves through the entire system.
But it is more likely that at least some of the mass extinctions were caused by external influences on the living world.
One such mass extinction occurred at the end of the Triassic period. About half of all species on Earth have disappeared. This event could also be caused by an increase in volcanic activity, climate change, but most likely a meteorite fall.
Such catastrophic events cannot be the result of pure chance, a random comet or asteroid hitting the Earth. Instead, cosmic circumstances may systematically bring such objects closer to our world.
The most famous of these ideas is that the Sun has a dim companion star that is so far away that it has never been directly observed. This star, "Nemesis" or "Death Star", periodically pulls chunks of icy rock from the outskirts of the solar system and sends them to hang out in our neighborhood.
This idea was proposed in 1984 by two teams of astronomers: Daniel Whitmire and Albert Jackson and Mark Davis, Richard Muller and Pete Hut. They all built on a discovery earlier that year that mass extinctions have occurred at regular intervals of about 26 million years over the past 500 million years.
Solar System Mystery: Nemesis
So, perhaps the gravitational pull of Nemesis, which circles the Sun in an orbit 1.5 light years away from us, has disrupted the Oort cloud: a collection of icy objects that are 0.8 to 3 light years beyond the orbit of Pluto, weakly bound by gravity Sun. The Oort Cloud is the source of "long-period" comets that return to the inner solar system every two hundred years or so.
Nemesis must be a tiny star, perhaps a red or even brown dwarf no larger than Jupiter. Therefore, she was never noticed. At this distance, it would be difficult to see even with our most powerful telescopes.
But that's not the only problem with the Nemesis theory.
In a study published in 2010, astrophysicist Adrian Melott of the University of Kansas and paleontologist Richard Bambach of the Smithsonian Institution in Washington, D.C., set out to take a fresh look at fossils using the latest data. They confirmed that mass extinctions happened every 27 million years. But such a picture is too ordinary to fit into the idea of \u200b\u200bNemesis. Such a distant dwarf would inevitably be influenced by other nearby stars, producing a less constant stream of comets.
No, scientists decided. Mass extinction waves must be driven not by a companion star, but by another planet.
Does the ninth planet exist?
In 1985, Whitmire and his colleague John Matese suggested that there could be a relatively small, rocky planet five times the mass of Earth, orbiting far beyond Neptune in the solar system. This planet may be constricting comets, not from the Oort cloud, but from the closer Kuiper belt. This is another ice rock disk at the edge of the solar system, Pluto and its moon Charon are recognized as members. Whitmire and Matese named their hypothetical object "Planet X".
It is possible that we have not yet managed to find another planet in the solar system that is larger than the Earth. Before the New Horizons spacecraft reached Pluto and Charon in 2015, we had some pretty bad pictures of these objects, and we were just beginning to search for larger bodies in the Kuiper Belt. If planet X is dark and does not reflect light, it could well elude our telescopes.
Moreover, in January 2016, astronomers suggested that in the solar system there could be, beyond Neptune, with a mass of 10 Earth. The proposal grew out of observations of visible Kuiper belt objects that appeared to be .
If this planet exists, it is unlikely to do what it claims to be behind planet X. But history shows that we don't know much about our own backyard.
Whitmire, now at the University of Arkansas, decided to take the Planet X hypothesis even further. In 2015, he showed that this idea is consistent with the 27-million-year extinction cycle observed by Melott and Bambach. Moreover, Whitmire says that the second such object is planet Y? - could explain another fluctuation in the fossil record.
This painting was noticed by Richard Muller and Robert Rohde in 2005. They found that the diversity of marine species rises and falls every 62 million years: this fluctuation must be caused either by a change in the rate of extinction or the rate of speciation.
Comet waves caused by "hidden" planets could be the explanation for these patterns, Melott says. But he adds that other, more distant cosmic events may be behind these fluctuations.
In 2007, Melott and his colleague Mikhail Medvedev stated that the 62-million-year pulse could be caused by a regular feature of our solar system's journey through the Milky Way.
Our galaxy is shaped like a dish. As it rotates, the Sun rises and falls on the galactic plane, like a horse on a merry-go-round. These changes in position can change the amount of cosmic rays that stream through the solar system and hit the Earth.
Cosmic rays and their impact on life
Cosmic rays are high-energy subatomic particles, protons and electrons, flying through space. It is believed that they must be born in high-energy astronomical processes. Some are born in supernovae: stars that explode when their fuel runs out. Others are born in black holes at the centers of other galaxies.
There are various ways in which they may have affected the environment of the Earth and our evolution.
Cosmic rays themselves can be harmful. When they collide with molecules in the air, they create showers of particles that can cause mutations in DNA. Usually it's bad for life. However, low mutation rates can actually increase diversity, make life more diverse.
Cosmic ray collisions can also change the chemical composition of the atmosphere. They can produce electrically charged particles that affect the formation of clouds and hence the climate, or they can destroy the ozone layer that protects the Earth from the sun's harmful ultraviolet rays.
Because many cosmic rays are thought to be created by supernovae within our galaxy, the up and down wobble of our solar system can change the flow of cosmic rays, with all the implications for earthly life.
However, it is rather strange that these effects only appeared among marine fossils. In any case, one would expect that organisms living in the sea are better protected from showers of harmful particles than those living on land.
Even Melott now thinks that this idea cannot explain the 62-million-year cycle in the fossil record. In 2011, he suggested that it could be an innate geological "Earth pulse", possibly related to changes in tectonic activity.
There is a similar pattern of changes in marine sediment composition, Melott says. This is what one would expect from changes in the rate of mountain building and erosion caused by shifts in the movement of tectonic plates.
Death rays from space seem to be a good reason for some of the evolutionary shifts seen in the fossil record.
We are constantly exposed to low levels of cosmic rays. But a single supernova can unleash such a deadly burst of these particles that it sterilizes a planet if it's not lucky enough to be nearby and in the right direction.
How can the birth of supernovae lead to the extinction of all life on Earth?
Stars go supernova all the time; during this, they can temporarily glow brighter than entire galaxies. Every year we see many supernovae in other galaxies, but in our own galaxy, people last saw a supernova 140 years ago. Another, which was born in 1572, was so bright that the astronomer Tycho Brahe saw it with the naked eye and successfully described it.
Supernova Tycho was safely distant, 7,500 light years away. If such an explosion happened much closer to us, it would be a serious disaster. The earth would be shaved bald in a shower of particles and x-rays and gamma rays.
Has this ever happened?
It is believed that a supernova would have to be within 30 light years to have devastating effects on Earth. There aren't many stars that close to us.
However, in 2002, research by astronomers showed that there could have been 20 supernovae within 420 light-years of Earth in the last 11 million years, from just one group of stars. Such events could well leave imprints in the fossil record.
They definitely left traces in the sedimentary rocks. Supernovae scatter the outer layers of an exploding star into space, including some atoms that are not abundant on Earth.
One such telling supernova product is iron-60, which does not occur naturally on Earth. In 1999, physicists discovered high levels of iron-60 in geological structures deep in the ocean - ferromanganese crusts formed over the past 5 million years. Iron-60 has also been found in lunar soil and appears to have come from two supernovae 320 light-years away, seven and two million years ago, respectively.
The latest explosions seem to have left traces in the fossil record.
In a study published in August 2016, astrophysicist Sean Bishop of the Technical University of Munich and colleagues reported the discovery of iron-60 in fossil iron oxide crystals. These crystals were originally made by bacteria that use magnetic oxide to align with the Earth's magnetic field. Iron-60 began to appear in such fossils in marine sediments formed 2.6-2.8 million years ago.
Life could be disturbed by these supernovae.
X-rays and gamma rays coming from such a distant source are not in themselves a problem. "They don't enter our atmosphere and therefore can't directly lead to sterilization or mass extinctions," Bishop says.
But he also says these rays can create an indirect hazard by damaging the ozone layer. "With the depletion of the ozone layer, as far as we know from the time of the Antarctic ozone hole, ultraviolet light from the Sun will penetrate the Earth's surface and could become a problem for organisms."
According to calculations by astronomer Narciso Benitez and his colleagues, supernovae at such distances have the potential to deplete atmospheric ozone.
What’s more, in a July 2016 study, Melott and colleagues calculated that cosmic rays from supernovae could increase the number of high-energy neutrons and muons reaching the earth, tripling the total radiation dose to terrestrial organisms. This could trigger cancerous mutations and also trigger climate change, scientists say.
2.6 million years, a small mass extinction did take place, at the turn of the Pliocene and Pleistocene epochs. But we can't say for sure that supernovae "had a hand in it."
In fact, there is no direct evidence that supernovae have ever interfered with the evolutionary history of life at all, Bishop says. “After millions of years, it will be incredibly difficult to prove.” For example, there is no way to collect and study fossilized DNA for mutations after such a long period of time, let alone compare it before and after the event.
However, there is another kind of cosmic explosion, even more powerful.
Emissions of gamma radiation
The skies are sometimes torn apart by explosions - gamma-ray bursts: extremely intense explosions that release gamma rays that live from fractions of a second to several hours. Gamma-ray bursts are among the most energetically powerful events in the universe. They are born when particularly powerful stars explode.
Fortunately, gamma-ray bursts have so far only been seen in very distant galaxies. But if one of these were born nearby, the supernova would be fireworks by comparison. To make matters worse, we could hardly have detected its approach in advance, no faster than a couple of hours. Fortunately, Melott says that 10,000 light-year GRBs in the area are born about once every 170 million years.
And although it is quite rare, the Earth has existed long enough to be hit many times. In 2004, Melott suggested that the mass extinction of the end of the Ordovician 440 million years ago could be due to a gamma-ray burst. And everything went according to plan: X-rays and gamma rays severely damaged the ozone layer, triggered global cooling due to the formation of dense smoke from nitrogen oxides in the atmosphere.
Melott argues that the late Ordovician extinction model fits into this picture. For example, shallow-sea marine organisms, which were more exposed to ultraviolet radiation than deep-sea ones, were more affected. In addition, the climate has become noticeably colder.
Could this happen again? The Earth has about two billion years left to live, after which the Sun will expand and make the planet uninhabitable. In a 2011 analysis, Beach calculated that during this time, there could be about 20 supernova events and one nearby gamma-ray burst that would cause harm. But these are slightly disturbing numbers.
In addition, Melott says that we will be able to see supernovae in advance, since we measure the age of nearby stars. The nearest one that could detonate soon - in the next million years - is Betelgeuse in the constellation of Orion. She's too far away to cause any damage.
Beach says it could theoretically be possible to change stars by engineering to avoid catastrophic explosions. “If a civilization knew that a supernova was going to burst in its vicinity, one of the options for survival would be to try some kind of super-engineering project.”
For example, they could deflect the explosion by causing the star to lose mass, or by mixing in some material that could slow its collapse. “How such a project could be physically implemented, I don’t know, but the physics of this situation and what needs to be done to extend the life of a star are quite well understood.”
Beach suggests that stars that threaten to go supernova could be good places to look for aliens. If such a star begins to behave strangely, this may be a sign of deliberate change in it.
The cosmic threats to life on Earth may be even more exotic.
Dark matter
In the 2015 book Dark Matter and Dinosaurs, physicist Lisa Randall of Harvard University suggested that a mysterious cosmic substance - dark matter - could be the absolute killer of the dinosaurs.
Dark matter does not interact with light, so we cannot see it directly. It affects ordinary matter only through gravity: it has mass, so it attracts matter, like any ordinary substance. We don't know what dark matter is. No one has ever found a single particle of it. But most physicists and astronomers are sure of its existence. Without it, galaxies would not rotate so fast and would not fall apart. Dark matter outnumbers ordinary matter by a factor of five. It is believed that it surrounds each galaxy with a spherical halo.
Randall suggested that certain dark matter is different from the rest.
This "exotic dark matter" can sense another force, like gravity, a type of electromagnetic force that allows ordinary matter to interact with light. This exotic dark matter could have formed a disk in the galactic plane, and the passage of the solar system through this disk could have disrupted the comet's path in the Oort cloud, causing it to hit Earth 66 million years ago.
Biologist Michael Rampino of New York University expanded on this idea. In a study published in 2015, he suggested that some dark matter particles could be captured and destroyed in the Earth's core. This led to the release of energy, increased volcanic activity, and the creation of the "pulse of the Earth" that Melott had previously associated with extinctions.
Well, maybe so. But some scientists consider these ideas too dubious, and it is unlikely that they would attract much attention if they were put forward by someone else who was not as famous as Randall, and she is almost a superstar in the field of cosmology.
“You have to invent new physics to make this mechanism work,” says Melott.
"This argument seems far-fetched to me," agrees Beach.
But he adds that while it is not yet clear whether our galaxy actually has a dark matter disk, “we know so little about the distribution and composition of dark matter in the galactic disk and halo that any assumption within our current uncertainty is entirely possible.” So far, this is an interesting but dubious idea. Should I trust her?
All of the individual stories we have discussed are unsubstantiated, and many of them are controversial. But take a step back - and you will have no doubt that life on Earth is somehow connected and dependent on cosmic forces. The difficulty lies in figuring out which cosmic phenomena played a role in a single case. These factors have stretched over such vast time scales that it is not even worth worrying about the impending threat to our survival in this vein. In the foreseeable future, our planet is not threatened by any catastrophic meteorite, although it is certainly worth watching.
But no one says that human civilization is completely protected from cosmic threats.
Melott says our biggest fear is solar flares: violent flares from the sun that bombard the planet with particles and radiation. The electromagnetic pulse they produce can paralyze telecommunications.
One such event in 1859 wreaked havoc on the early telegraph networks, shocking several operators and causing fires. Today, with our gigantic communications network, the consequences will be devastating. We narrowly escaped this fate in 2012 when a solar superstorm passed us, but there was a big one in 1989 that disrupted the Canadian power grid.
If an event like this can bring civilization to its knees, it could also leave an imprint on the evolutionary record, because, ironically, it will stop the latest mass extinction that is happening now due to our fault.
Until the existence of extraterrestrial civilizations is proven, one can only leave the imagination and Hollywood bigwigs free to imagine what an alien invasion of Earth would look like. However, there are other dangers outside our planet that potentially threaten our existence. Some of them are unlikely, while others have already happened in the long-suffering history of the Earth and are quite real ...
Extraterrestrial civilizations died?
In the summer of 1950, in the cafeteria of the Los Alamos Laboratory, the Italian physicist and Nobel laureate Enrico Fermi (one of the leading figures in the American atomic bomb project) had an informal conversation with three other physicists. After listening to the arguments of his colleagues in favor of the existence of a great number of highly developed civilizations in the Galaxy, Fermi asked: “Well, where are they then?”
Oddly enough, this question, called the Fermi Paradox, is much more famous in our time than all the scientific achievements of the great Italian. In a detailed formulation, this paradox sounds like this: "The laws of nature are the same everywhere in the Universe, so any highly developed civilization has the same scientific, technical and technological capabilities as humanity." With spaceships capable of reaching speeds of at least about 10% of the speed of light, a civilization could spread throughout the galaxy and colonize habitable planets in just a few million years - a negligible time by cosmic standards. Therefore, if numerous civilizations really existed in the Galaxy, the first of them would have reached here millions (or even billions) years ago. But in this case, the very absence of aliens on Earth is a convincing proof of the absence of highly developed extraterrestrial civilizations as such.
Of course, since Fermi's conversation with his colleagues, many hypotheses have been put forward to explain this paradox. One of the hypotheses is that emerging civilizations are short-lived - each of them is eventually destroyed by a cosmic catastrophe. Such an assumption leads to sad thoughts - maybe the same fate awaits humanity? What space catastrophes can threaten our civilization?
Direct hit
The most obvious threat is the possibility of an asteroid or comet hitting the earth. A reminder of this threat are the giant craters left on the surface of our planet from collisions with asteroids in the past. Suffice it to recall the 10-kilometer Chicxulub asteroid that fell to Earth 65 million years ago - an event, according to many scientists, that put an end to the era of dinosaurs. From this catastrophe there was an impact crater located on the Yucatan Peninsula, with a diameter of about 180 km and a depth of up to 17-20 km.
Even larger is the Vredefort crater, located in South Africa. Formed two billion years ago, the crater has a diameter of 250 kilometers. One can only guess what kind of planetary catastrophe was the asteroid impact that led to the appearance of this crater (life on Earth in that era was limited to bacteria, but if complex organisms existed on Earth, they would probably be completely destroyed).
Fortunately, humans, unlike dinosaurs, can at least try to protect themselves from the asteroid threat. With the current development of technology, humanity will be protected from a suddenly appeared asteroid by missile strikes with atomic or thermonuclear charges. In the future, undoubtedly, more advanced mechanisms of "asteroid defense" will be created.
geomagnetic storms
However, technological progress, which makes life comfortable and able to protect against many threats, in some respects makes humanity more vulnerable. A reminder of this is the event that occurred on August 28, 1859. On that day, clouds of charged particles thrown out by the Sun reached the Earth and caused vibrations of the electric and magnetic fields of monstrous force. On the night of the 28th to the 29th, the aurora borealis covered the entire sky from the poles to the equator (even the inhabitants of tropical Cuba observed it). The arrows of magnetic compasses were spinning like crazy, telegraph systems went out of order one after another, transmission lines sparked, telegraph paper caught fire. So the most powerful geomagnetic storm in the history of observations came to Earth in 1859, also known as the Carrington Event (named after the astronomer observing the Sun that day), or the Solar Superstorm.
Two days later, the magnetic field returned to normal, the lights in the sky went out, and the damage to the telegraph lines was soon repaired. In the end, humanity got off with a slight fright - the crude mechanisms of the 19th century were invulnerable to a geomagnetic storm of any power. But it is difficult to even imagine the consequences of such solar activity for advanced modern electronically controlled technology. Today, a solar superstorm similar to that of 1859 will be a planetary catastrophe. An electromagnetic strike from space will simply burn out all unprotected electronics on the planet, so that humanity, which has become a hostage of its own technical genius, will face a severe test.
The streets will be clogged with stopped cars, buses, trucks (all of them are electronically controlled), and the failed cars will cause many accidents. Crash victims will wait a long time for the help of doctors - after all, ambulances, as well as fire and police cars, will also not start. Everything that was powered by batteries or from the mains will stop working. Anything in the sky - helicopters and planes - is likely to fail and crash.
As you can see, the repetition of the events of 1859 in today's world will mean a complete collapse of the entire technological base of mankind around the world - after all, both electronically controlled devices and the power systems that feed them will fail at the same time. It will take months of chaos and famine to restore the work of industry and the reconstruction of the energy system - will humanity have the will to hold out for so long without a social explosion and subsequent anarchy?
Fear and terror of supernovae
However, the cataclysm on the Sun directly threatens only electronically controlled technology. A much more dire (albeit much less likely) threat is a supernova explosion in the cosmic "vicinities" of the solar system. Such a cataclysm can burn out all life on the surface of our planet. Radiation will destroy the ozone layer in the atmosphere, and radiation will "sterilize" the Earth's surface. After all, the outbreak of a supernova is one of the most grandiose cataclysms in the universe.
A supernova occurs in the last stages of the existence of a star with a mass much greater than that of the sun. The existence of a star is determined by the ratio between the gravitational forces that tend to compress the star, and the pressure of the star's radiation, "bursting" it from the inside. When the radiation is insufficient to compensate for the huge gravitational field of the star, the luminary begins to contract, and this contraction occurs with acceleration. The density and temperature of matter in the center of the star grows, which at some point causes a catastrophic "explosion inward" - the process is accompanied by the release of a huge amount of energy.
The supernova briefly begins to shine brighter than all the stars in the galaxy combined. As a result, a cosmic explosion leads to the death of the star itself (its remnants become a neutron star or even turn into a black hole) and catastrophic consequences for planets in nearby star systems. Meanwhile, the star Betelgeuse - a close, by cosmic standards, neighbor of the solar system - may explode in the very near future.
Yet the explosion of a supernova will seem like an insignificant event compared to the catastrophe that occurs when black holes collide. According to the calculations of scientists, the energy of the collision of two "average" black holes is equal to the energy released into space by trillions of trillions of stars, equivalent to the Sun. And such energy is released in an incredible flash for a very short period of time! The collision of black holes is a rare event even in the vast expanses of space, but if it does happen, life will be destroyed on all the planets of the entire galaxy.
However, in the near future, humanity has no reason to fear something like this. Much more likely is the development of events in which civilization will eventually destroy itself ...
