The Future of Earth | The ultimate change of our planet explained briefly.
Over a period of hundreds of millions of years, random celestial events pose a global threat to the biosphere, which could lead to mass extinctions. These include the effects of comets or asteroids, as well as the possibility of a massive stellar explosion, called a supernova, within the 100-year-old luminosity of the Sun. Some major geological events are highly predictable. Milankovitch’s vision predicts that the planet will continue to pass through the ice at least until the end of Quaternary glaciation. These times are caused by variations in stiffness, axial inclination, and ground movement. As part of the ongoing global cycle, plate tectonics is likely to lead to global discovery in the 250–350 million years. For some time in the next 1.5–4.5 billion years, the Earth’s axial slope may begin to form volatile variations, with changes in the axial slope of up to 90 °.
Sunlight will gradually increase, leading to increased solar radiation reaching Earth. This will lead to a higher level of silicate minerals, which affects the carbonate-silicate cycle which will cause a decrease in carbon dioxide levels in the atmosphere. Nearly 600 million years from now, carbon dioxide levels will drop below the level needed to support the C3 carbon fixation photosynthesis used by trees. Some plants use the C4 carbon processing method, which allows them to insist on carbon dioxide concentrations of as much as ten parts per million. However, it is a long-standing practice that plant life is completely dead. Plant extinction will be the end of almost all animal life because plants are the basis of the world’s food supply.
In about a billion years, sunlight will be 10% more than it is now. This will cause the atmosphere to become “a humid place with moisture”, which has led to the evaporation of oceans. As a possible consequence, plate tectonics will disappear, and throughout the carbon cycle. Following this event, in about 3 to 3 million years, the planet’s magnetic dynamo may stop, causing the magnetic field to decay and lead to the rapid loss of volatiles from outer space. Four billion years from now, global warming will have the effect of escaping global warming, heating up enough space to melt it. At that time, all life on Earth will be gone. The most likely end of the planet being absorbed by the Sun is about 7.5 billion years, after which the star entered a large red phase and expanded beyond the current planet’s orbit.
Human influence
Humans play a vital role in the biosphere, with a large number of people ruling over most of the earth’s natural habitats. This has led to the continuous extinction of a number of other species during the present geological period, now known as the Holocene extinction. The massive loss of biodiversity caused by human influence since the 1950s has been called a biological catastrophe, with an estimated 10% of all species extinct since 2007. At present levels, about 30% of the species are at risk of extinction in the next 100 years. The Holocene extinction event is the result of habitat destruction, widespread distribution of invasive species, hunting, and climate change. In our day, human activity has had a profound effect on the face of the planet. More than a third of the world has been transformed by human action, and people are consuming about 20% of the world’s basic product. Emissions of carbon dioxide have increased by almost 50% since the start of the Industrial Revolution.
The effects of the ongoing biotic crisis have been predicted to last at least five million years. There may be a decline in biodiversity and the homogenization of biotas, which is accompanied by an increase in opportunistic species, such as insects and weeds. Novel types may also appear; especially taxa thriving in human-controlled ecosystems can quickly evolve into many new species. Microbes may benefit from an increase in the abundance of natural nutrients. No new types of large vertebrates are likely to emerge and food chains will likely be shortened.
There are many known risk factors that could affect the world. From a human point of view, this can be divided into surviving risks and ultimate risks. Risks that people are exposed to include climate change, the misuse of nanotechnology, nuclear annihilation, the fight against organized technology, genetic disease, or a catastrophe caused by physics experiments. Similarly, a number of natural events can pose a threat of doomsday, including the most devastating disease, the impact of an asteroid or comet, the effect of escaping the scorching heat, and the depletion of resources. There may also be the possibility of infection through the atmosphere. The actual effects of these occurrences are difficult if not impossible to detect.
If the human race ceases to exist, then the various elements that makeup humanity will begin to decay. The largest buildings have an average decay of half a life span of about 1,000 years. Surviving last buildings may be open mines, large dumps, highways, wide canals, and landfills. A few stone monuments such as the pyramids of Giza Necropolis or sculptures on Mount Rushmore can still live in some way millions of years later.
Possible events
As the Sun orbits the Milky Way, orbiting stars may be close enough to interfere with the Solar System. The stellar close proximity can cause a significant decrease in the perihelion ranges of comets in the Oort cloud — a circular area of cold bodies orbiting during half the solar year. Such a merger could result in a 40-fold increase in the number of comets reaching the Solar System. The effects from these comets could be the end of the great life on Earth. This disruptive reunion occurs on average once every 45 million years. The estimated time for the Sun to collide with another star in the solar system is approximately 3 × 1⁰¹³ years, much longer than the average Universe age, at ~ 1.38 × 1⁰¹⁰ years.
The energy released from the impact of an asteroid or comet with a diameter of 5–10 km (3–6 mi) or more is sufficient to create a global catastrophe and cause significant increases in biodiversity. Among the harmful effects of the catastrophic ejecta cloud cover the planet, blocking direct sunlight from reaching the earth’s surface thus lowering global temperatures by about 15 ° C (27 ° F) within a week and suspending photosynthesis for several months ( such as nuclear winter). The estimated time between major impacts is estimated to be at least 100 million years. Over the past 540 million years, simulations have shown that the scale of such impact is sufficient to create 5–6 weight loss and 20–30 low-intensity events. This is similar to the geologic record of significant extinctions during the Phanerozoic Eon. Such events can be expected to continue.
A supernova is a catastrophic star explosion. Inside the Milky Way galaxy, supernova eruptions occur on average once every 40 years. During the history of the Earth, many such events are likely to occur within a hundred light-years; known as the supernova near Earth. Explosions within this range could pollute the planet with radioisotopes and could even affect the biosphere. Gamma rays emitted by supernova respond to nitrogen in the atmosphere, producing nitrous oxides. These molecules cause the depletion of the ozone layer, which protects the environment from ultraviolet (UV) radiation from the Sun. An increase of 10–30% UV-B radiation is sufficient to have a significant effect on health; especially phytoplankton which forms the basis of a seafood chain. A supernova explosion at 26 light-years across will reduce the ozone layer by half. On average, supernova explosions occur between 32 light-years and every few hundred million years, leading to depletion of the ozone layer that lasted for centuries. In the next two billion years, there will be about 20 supernova explosions and a single gamma explosion that will have a profound effect on the earth’s biosphere.
The growing effect of planetary gravity is causing the Solar System as a whole to behave strangely in the long run. This does not significantly affect the stability of the Solar System at intervals of a few million years or less, but over billions of years, the orbits of the planets become unpredictable. Computer simulations of the emergence of the Solar System over five billion years suggest that there is little chance (less than 1%) that a collision could occur between Earth or Mercury, Venus, or Mars. At the same time, the probability that the Earth will disintegrate from the Solar by a passing star is set at one in 105. In such a case, the oceans can harden in a few million years, with only a few gallons of water about 14 km (8.7 mi) below ground. There is a long-term chance that the Earth will instead be captured by a passing binary star system, allowing the earth’s biosphere to remain stable. The probability of this happening is about one in three million. Continue reading…