Global warming, the fall of an asteroid, the invasion of alien civilization — that is the greatest threat to the Earth? Consider the options, opportunities and possible consequences.
We think that the Earth, our home comic — is a safe and secure place. Indeed, none of us have witnessed the global cataclysms and catastrophes around the next universe is not visible. But the fact that the first ancestors of modern humans appeared on Earth at least 4 million years ago, our planet is 4.5 billion years. And during this period there was a whole series of large-scale disasters, and the short history of mankind there was a lot. In fact, the Earth and its inhabitants are in constant danger — the question is the probability of disaster and its aftermath.
Asteroids: the point scale
The fall of the asteroid, "stones" with a diameter of several kilometers, many people consider the most likely end to mankind. According to specialists, the probability of falling to earth of the heavenly bodies with a diameter of tens of meters is quite high, once in 4 years. For "sky stone" with a diameter of about 100 m period of several hundred years, with a diameter of about 1 km — every few hundred thousand years, with a diameter of 100 km — tens of millions of years, and more than 100 km in diameter — once in several billion years.
NASA studies indicate that asteroids with a diameter 0.5 — 1 km fall on the Earth every 100 thousand years. These objects can cause serious damage, and due to the current high population density that way can end "visit" another space "shell." In this large-scale loss of life and destruction of the main achievements of civilization, according to estimates of the American space agency, can cause asteroid 2 — 5 km. Falling objects of this size occur from once to several times in a million years.
The problem is that most of the troubles that can happen to any of us, we know from the other. Air crashes, earthquakes, floods, etc. — All this is described in historical documents or filmed on camera. On the fall of the large asteroids we judge only in the wake of the craters, and the oldest of them have already "milled" tectonics of the planet. We can only extrapolate impacts of small (tens of meters) to compare the impact of asteroids and their fall to the explosion of our most powerful weapons — nuclear bomb.
Currently, the most accurately modeled collision with Earth asteroid Apophis. This asteroid will approach 270 m maximum with our planet in 2029, but guaranteed to miss. Due to errors in radar measurements allow scientists low probability of Apophis collision with Earth in 2036 — only 1 chance in 233 thousand, while the probability of a miss is 99.99957000%.
What will happen to our planet after the asteroid with a diameter of two hundred meters and weighing 27 million tons? First of all, we should note that in case of such an asteroid impact on Earth release the energy equivalent to the explosion of the atomic bomb with over 500 megatons. For comparison, the Soviet Union and the United States spent more than 1.7 thousand nuclear tests total capacity of just over 450 Mt, and the most powerful thermonuclear bomb in history is equivalent to 50 megatons. Its explosion circled the globe three times. If it had exploded in the center of Moscow, the city would be completely destroyed within 20 kilometers almost the entire population would have died within days from burns third degree. Second-degree burns (as of boiling water), people would get up to 40 km. Apophis to ALL these numbers can be increased by 5 times, for an asteroid 10 km in diameter — 100 times.
An asteroid with a diameter of about 10 km destroy almost the entire population of the central part of Russia to the border with Kazakhstan, Belarus to the boundary of Poland. Second-degree burns can get even the inhabitants of Iceland and Egypt, the North Pole will melt a lot of ice. A powerful blow causes a wave that will run on the earth's crust, destroying houses and other buildings within a radius of hundreds of kilometers. Earthquake, even a small drop of Apophis will be much more destructive conventional earthquakes that dissipate energy over a large area in a few hours.
Yes, asteroids, a few hundred meters can wipe out metropolis, and a few kilometers in diameter — the whole country. But will it ruin our civilization? Probably not. Mankind has spread throughout all continents and will be able to recover for a hundred years. In the history of the site suffered from the fall of large asteroids, but the biosphere of the planet as a result of recovering from the loss. The fall of the same asteroid with a diameter of 100 kilometers or more is very unlikely, and the asteroid belt until they found the objects of a size that could hit the Earth in the foreseeable hundreds of years. In addition, earlier this year launched an international project NEOShield, in which the technology will be developed to protect the asteroid hazard.
Global warming: hope for the mind
Global warming has long walks in candidates for the lead role in the apocalypse.
Indeed, according to a study by the International Energy Agency, the Earth's temperature has already reached to the ceiling, where climate change becomes irreversible. Already in 2017, a huge amount of carbon dioxide emitted by burning fossil fuels, will lead to an increase in global temperature to 2 degrees Celsius in 25 years is 3.5, and in 2100, a dangerous step over the mark of 6 degrees.
The last digit will spell doom for many regions of the world: they are totally unsuitable for agriculture and housing. Severe droughts, floods and the ever-increasing periods of extreme temperatures make people desperate. And the consequences of the "six-degree barrier" will be felt in all corners of the earth, and each will have its own "climate hell", bringing annual economic losses and harm to human health. Late last year, researchers from the Center for Policy Research in New Delhi once again voiced serious problem: in the decades Southeast Asia will become the scene of the Battle of … water. Already the largest Asian erect a dam and reservoir are digging to have as much of this precious resource.
Biodiversity of the planet will be a crushing blow — many species will simply die because of the acidity of the water, the migration of marine and terrestrial organisms, changes in rainfall. Do not overestimate the adaptability of living creatures to dramatically changing climatic conditions: Earth knew many climatic catastrophes, and each was accompanied by the extinction of many animals. The adaptation of ecosystems will require millions of years.
Early last year, paleobiology at University of California at Berkeley, made a lot of noise when you said that already the sixth mass extinction. In the example, Permian extinction (251 million years ago) have disappeared 96% of marine species and 70% of terrestrial vertebrates. U.S. researchers looked at the current situation with mammals and found that over the past 500 years have disappeared at least 80 species from 5570. At the same time in the history of mammals average extinction rate was at least two species in a million years — it is much slower than it is now. Apparently, humanity has had an extremely powerful destructive effect on the biosphere, but yet completely dependent on it. It is hard to say exactly when this disaster will break — yet died only 1-2% of the species, and to predict the level of human impact on the ecology of the planet is difficult even in the short term.
In the case of global warming can only hope for the mind of humanity. Fortunately, in the developed world are seen positive developments: actively introduce energy-saving technologies and alternative energy, and looking for ways to download the ground and mineralization of excess carbon dioxide, etc. According to researchers at Stanford and the University of California, humanity, even with existing technologies capable of 40 years to move to renewable energy sources, and completely on fossil fuels. Sun and wind will give 90% of global demand for electricity, geothermal and hydroelectric power plants are about 4%, 2% — wave and tidal power, the remaining — other sources of energy. Thus, according to scientists, solar panels and wind turbines occupy only 0.4% and 0.6% of the land area, respectively.
Unfortunately, in developing countries, it is no time and money: the population is growing, and today takes a lot of energy, and therefore you need to burn more fuel. For example, China only started to shift from coal to gas, but by 2035 will consume 70% more energy than in the United States at this time.
Fiction: should be wary
The most popular version of the film and literature of the apocalypse — the alien invasion. It sounds too fantastic, but still the U.S. Army considered the ways and methods of dealing with the alien aggression. There is a theory that the mystery of silence of the universe (billions of stars — and no signals from intelligent beings) is related to the fact that there is a civilization-predators that are just waiting to be careless civilization made themselves felt. From this point of view, we act very foolishly: send out radio signals in all directions and spacecraft coordinates Earth.
In order to estimate the probability of an alien invasion, it is necessary to represent the motives of others. For a civilization that can cross interstellar space, our wealth and natural resources, including water — just a pittance for which is not worth a try. The same applies to living space — even with our primitive technology found hundreds of exoplanets, and for sure, a lot of good in the galaxy of worlds, not complicated by the biosphere and civilization stupid crap. It is possible of course, that an attack on Earth can make a million part xenophobic alien civilization or single-nomads — those predators. However, if we exclude the hatred for all living things, which may be of value to the aliens? Perhaps we have only one unique resource — the genes. Millions of years of evolution have developed unique mechanisms for adaptation, the complex biochemical processes, computer systems (including the brain), etc. Simulate the evolution of genomes of millions difficult — easier to create them from scratch. However, for "collectibles" genomes of earthly life is not necessarily to go to war — just a covert operation or banal deal with earthly government in exchange for "beads" like a toaster with an eternal battery.
So the fear of alien apocalypse is not necessary, be afraid of silence in the universe — it is possible that this silence is associated with manic tendency of civilizations to suicide. And this warning is worth considering.
Category: The prophecies and predictions, visions and hypotheses