Whatever direction life on Earth takes over the next few billion years there is one certainty. One day it will all end. Life may cease to exist on Earth before the end of the planet, there are many potential scenarios that could lead to this happening, but it is absolutely certain to end when the Sun reaches the end of its life cycle. Stars have a finite life cycle and in five and a half billion years our Sun is due to expand into a massive Red Giant, engulfing the Earth. However, whether humans are still around to see it remains debatable.
The fate of humanity realistically must be different to that of planet Earth. Given the enormous time scale until the expansion of the Sun it would seem reasonable to assume that our species would have moved on from our current form. If four billion years has been enough time for all of life on Earth to evolve to reach civilisation then by adding almost twice as much time again we’ll be sure to see some drastic changes. A question is will the human race, or our descendents, remain until that time or will be have been long wiped-out?
The possible outbreak of World War Three and a nuclear apocalypse is a topic that has been widely spoken about and explored. The threat of nuclear war reached an all-time high during the Cold War and it is believed that the world stood on the brink during the Cuban missile crisis. Fortunately no bombs were launched and with the dissolution of the Soviet Union and increasing nuclear disarmament the threat of a nuclear annihilation seems to have passed.
Man’s end may come from self-imposed means or any number of natural disasters. A large impact event could prove fatal to life, and large volcanic activity, cosmic ray bursts and even extra-terrestrial invasions have been discussed by scientists as possible ends. The validity of many of these concerns is variable and the fate of mankind is enough for an article in itself, what I would like to look at here is what will certainly happen, regardless of whether our species lives or not.
The Sun, the object that provides all the energy used by the Earth, will be the cause of its end. Stars go through complex life cycles, starting with their birth and eventual demise. Each star will last billions of years, and depending on its mass and elements can form into a number of different types. Currently the Sun is a main sequence star, generating energy through nuclear fusion of hydrogen into helium. The Sun will spend around 10 billion years as it is now before going on to the next stage of its life.
The Sun becomes brighter and larger as it grows older. In its first four and a half billion years it is estimated that the Sun has increased in brightness by around fourty percent. In one billion years time the Sun will have increased in brightness by around ten percent, boiling the oceans and scorching the surface. This in itself is enough to end life as we know it now. However in five and a half billion years the Sun will run out of hydrogen to burn in its core. It will start burning the hydrogen from the outer layers, shrinking the core and massively expanding the volume of the Sun, transforming it into a red giant.
Mercury and Venus will be swallowed by the growing star, while the fate of Earth is less immediately clear. If the Earth escapes being consumed by the growth of the Sun it will be burned to a charred, lifeless rock. After the red giant phase the Sun will continue to shed its outer layers into a planetary nebula until just the core remains. The core will cool into a white dwarf star and fade over billions of years. The Sun is not large enough to form a black hole or a supernova and it seems that the relatively inglorious end of forming a white dwarf is inevitable. The fate of Earth also seems to be certain and while not a concern for us living here at the moment, at some point in time it will be a very real problem, although quite what form life takes by that point remains to be seen.
Growth in computer speeds and capabilities has accelerated at an almost exponential rate since the 1960s. The changes show no signs of slowing down as the 21st Century continues. Intel co-founder Gordon Moore predicted the growth in computing technology in 1965 stating that processor speeds and memory sizes would continue to double every two years. His predictions have proved to be entirely accurate and all progression in computing has followed the trends he laid out. The Internet and mobile computing technology have been the most visible and significant developments in society since the start of the 21st Century. With the world’s information and ever-increasingly powerful computers at people’s fingertips it is interesting to wonder where the technology may go and what future inventions hold in store.
Looking back at developments in media over the lifespan of humanity it is easy to see a clear path from the advent of language to writing, art, music, radio, television, computers and the Internet. Each stage of this development signified a great leap forward in civilisation and quality of living. What is interesting to note is that it takes less and less time to progress to each stage as we move on. The jump from basic language to writing took thousands of years, and then thousands more to art and music. From the renaissance to the invention of radio was just a few hundred years, television arriving just decades afterwards. The world wide web reached global use within a decade of its inception.
Each of these technological leaps are notable for the fact that they would engulf the previous development. Remember the song Television Killed the Radio Star? Well it proved to be oddly prophetic as television replaced radio as the primary source of entertainment and news in the home, just as the Internet has done to both in the 2000s. The Internet is perhaps even more significant as it is looking like it will render all previous technologies obsolete, entirely engulfing them. It is possible to watch TV, listen to radio, read the news, do your shopping and almost everything in-between online. Anything that the Internet does not engulf it will become an intrinsic part of.
Given its almost certain all-pervasive nature it can be hard to see where the next leap forward may come from. What could supersede the Internet? It is foolish to think that nothing will, after all would renaissance painters have predicted the rise of television and radio? Would people in the 1940s have predicted the introduction of mobile phones and personal computers? Just because we cannot see the next step it does not mean it will not happen. At some stage the Internet will become consumed itself.
Currently all advances in technology have been made due to human intelligence. It is what separated us from animals to begin with, and it is what continues to drive us now. Ever more complex leaps have been possible as intelligence is pooled and people are able to collaborate on how to solve problems that will lead to the next advancement. Language allowed communication, and then writing allowed the storage of ideas and the passing of information to other tribes and individuals. Radio, television and Internet technology in the 20th Century has opened up human intelligence to everyone as communication becomes instantaneous world-wide. The global nature of communication in the 20th and 21st centuries are inevitably why our greatest achievements have come in the last hundred years. It is no accident that the industrial revolution occurred with the introduction of the telephone and long range communication.
So taking the fact that human intelligence and communication is guiding the development of civilisation it is reasonable to expect that we will reach the point where our own intellects are unable to take us further. I believe we are reaching the point where communication and the sharing of ideas will start to plateau. We already have instant communication to anywhere on the planet and future developments in this area will only be able to accelerate this process. Granted, faster and faster Internet access will help a great deal in sharing scientific data, but at some stage we will need greater-than-human intelligence. Some people, such as the Singularity Institute for Artificial Intelligence, believe that this will come from a form of artificial intelligence either through an AI software or augmentation of the human brain.
The birth of an artificial super intelligence is often referred to as the singularity in reference to the singularity of a black hole. Similar to the black hole where known laws of physics break down in the singularity at the centre so would our model of the world once it contained intelligences greater than our own. There are many technologies already combining to create an artificial intelligence and many scientists believe that the singularity will occur during our lifetimes. Certainly if Moore’s Law and the accelerating rate of paradigm shifts are anything to go by then this prediction seems reasonable.
The creation of a truly super-human AI would completely change the world and our way of living extremely rapidly. It is thought that the invention of this AI would be the last thing that the human race ever needs to design. An AI with above human intelligence would then have above human capacity to improve itself. By improving itself once it would then become more intelligent than it was before, enabling it to improve itself further. This positive feedback loop would lead to the AI becoming massively intelligent and powerful very quickly, it is possible that civilisation would change overnight as the AI exponentially increases in intelligence.
By point of comparison human neurons can send signals at a speed of 150 metres per second and the speed of light is 300,000,000 metres per second, two million times faster than the human mind. The Singularity Institute states that an increase in speed of thought by a factor of one million would mean a subjective year would take only 31 seconds and the time from ancient Greece until now would take twenty two hours. The evolution from primates to humans needed an increase in brain capacity by a factor of three. The difference between us and chimpanzees is unarguably large, so it seems easy to agree that an intelligence many factors greater than ours and magnitudes faster would be capable of things far beyond our comprehension. We are as capable of guessing what it could do as chimps are of predicting the rise of human civilisation given that the gap between brain power would be similar.
Along with the theories of a singularity and the birth of intelligent machines there are always the inevitable doomsday scenarios thought to be possible such as those depicted in films such as the Matrix and the Terminator. It is hard to say what the AI would do, and eliminating the human race may well be in its best interests. However it is likely that considerable work will go into making the AI an ally of its creators and to build a system that we are capable of working alongside to accelerate our development and improve our living conditions and understanding of the world around us. There is already a lot of work being done to ensure this happens and that we avoid the doom that popular fiction predicts.
An interesting thought is to combine the theory of the singularity with that of natural selection. We already know that machines can do things that we are incapable of doing. Robotic probes are exploring places inaccessible to humans, countless examples are visible in space exploration programs. There are robotic vehicles on Mars exploring the terrain. The landscape is too harsh for a human visitor with our current technology but machines have already made the journey. Probes have been sent to every planet in the solar system and some have even left it entirely.
It may be that mechanical life is simply more suited than carbon-based life to the conditions of the universe. A machine does not need to eat or breathe and will be able to survive low and high atmospheric pressures, making them perfect for extra terrestrial exploration. The machines will need a power source, but provided that they develop a reliably powerful way of creating energy then in theory there is nothing to stop them from colonising the solar system relatively quickly.
Machines and artificial intelligences could simply be the next step in the evolution of life on Earth, it is hard to see any animal rising above humans now with the control that we exert over the planet. By the time the Earth is swallowed into the Sun it may be that it is inhabited solely by mechanical life forms, all of which are better suited to escaping the supernova from the death of the star. In terms of the eventual fate of the planet is is clear that machines and artificial intelligence is more suited to continued existence with its capability to migrate to different planets.
By Darwinian theory it may even be said that artificial intelligence is more suited to life on Earth and will replace the life that we know today. It is certainly an interesting concept and we may even find out whether it will come true within the next fifty years. With any luck the creation of a super-intelligent machine will bring a time of great advancement that solves a lot of the major problems that face humanity today and massively enhance the standard of living across the planet.
The extinction of the dinosaurs and the end of the Cretaceous period saw the start of the Tertiary period. This time leads right up until around 1.8 million years ago and the evolution of humans. The Tertiary is split into two main eras, the Paleogene and the Neogene, both of which are split into smaller time periods. These times would see the evolution and eventual domination of mammals, birds and insects as life re-evolved to fill the niches left by the departure of the dinosaurs.
Over the 42 million years of the Paleogene the Earth would change considerably. Continents continued to drift away from each other and into their current positions. Laurasia was still in one piece initially but Gondwanaland was splitting into what would become Africa, South America, Antarctica and Australia. India would eventually collide with Asia and form the Himalayas. After eight million years Laurasia was starting to break up into Europe, Greenland and North America.
It took just ten million years from the extinction of the dinosaurs for mammals to take over and evolve into larger herbivorous and carnivorous forms. The first mammals are considered quite primitive, with much smaller brain to body mass ratios than mammals that would appear later on. Little is known about them as remains are hard to come by, some are only identifiable from teeth fossils. By this point many of the main groups of mammals had their own evolutionary offshoots; platypus’, marsupials, the now-extinct multituberculates and placentals were all abundant. However true modern mammals would not evolve until later, in the Eocene era around 55 million years ago.
By the middle stages of the Paleogene mammals had continued to evolve, with hooved animals, rodents, primates, bats and marsupials all present. By this point in time mammals had also taken to the seas. Animals such as Basilosaurus and Prorastomus would be early precursors to whales and seals.
The few reptiles that survived would go on to form modern turtles, crocodiles and pythons. The reptiles would never prove to be as dominant as they were in the Jurassic and the Cretaceous but adapted fairly well to the cooling Earth.
Flowing plants and grasses would come to dominate the plant world, with deciduous trees overtaking the tropical forests of before. Towards the end of the Paleogene era in the Oligocene legumes, ferns, roses, beech and pine trees had all evolved.
Birds continued to evolve and thrive in the new conditions. After the complete extinction of the Pterosaurs the birds had the skies to themselves and diversified into a great number of species. Cranes, hawks, pelicans, herons, owls, ducks, pigeons and woodpeckers all evolved during this time. Some of the most striking birds of the time are ones that have been dubbed ‘Terror Birds’. Flightless birds standing up to three metres tall and running at speeds of up to 30mph, birds such as Gastornis were the dominant predators in their ecosystems. These giant birds would struggle with the arrival of larger carnivorous mammals, and would eventually become extinct as they were no longer able to compete.
With mammals now dominating the planet, primates would continue to evolve and grow into new species. Over time one species of great ape would emerge as the dominant species on the planet, with its brain capabilities far outstripping any other organism before and since.
The Jurassic and Cretaceous periods are known as the time of the dinosaurs. During these two vast eras of time the world was dominated by these giant reptiles. Some of the sauropod herbivores are the largest animals to have ever walked the planet, and the Tyrannosaurus Rex is the largest ever land predator. The periods also saw the development of flowing plants, birds and mammals, all of which are still alive and thriving today.
The start of the Jurassic period was signalled by the Triassic-Jurassic extinction event. With many species dying out, there were large ecological niches that would be filled over time. During the Jurassic the supercontinent Pangea broke up into two separate land masses, Laurasia in the North and Gondwana in the South. The climate at the time was much warmer than that of today, with no land at the North or South poles.
Marine crocodiles, dolphin-like ichthyosaurs and the plesiosaurs dominated the oceans. All reptilian, whales and dolphins would not enter the seas for millions of years to come. The Jurassic also saw a large increase in planktonic species.
During this time many of the ‘classic’ dinosaurs evolved. Long-necked herbivores such as Diplodocus and Apatosaurus were feeding from the abundant ferns, cyads and conifer trees. Their enormous size would have been a deterrent to predators and would also allow them to browse vegetation at levels that other animals could not reach. With such a long and flexible neck an animal such as Diplodocus would have been able to feed on almost all vegetation growing at the time. Large Tyrannorsaur-like therapods were also living at this time, possibly hunting sauropods. Little is known about the behavior of dinosaurs as so many fossil specimens are incomplete. During the late Jurassic the first birds evolved from smaller bipedal dinosaurs.
The Cretaceous period started around 145 million years ago and lasted until the extinction of the dinosaurs, around 65 million years ago. During the Cretaceous period the continents continued to break up and started to resemble that which we see today. South America, Antarctica and Australia all moved away from Africa forming the Atlantic and Indian Oceans. The planet continued to cool in temperature, although remaining much hotter than current climates. Tropical average temperatures would have averaged at around 37 degrees centigrade, with deep sea temperatures sitting around 20 degrees hotter than they do today.
The Cretaceous is notable for the spread of flowering plants, or angiosperms. Along with the development of flowers was the evolution of bees and other pollen-spreading insects. This flourishing ecosystem is an excellent example of where two organisms can greatly accelerate eachother’s development, commonly known as coevolution. Many leafy trees also began to show up during the Cretaceous, and plants started to look much more like they do in modern times.
The dinosaurs would continue to evolve and thrive during the Cretaceous period with many of the most well-known species flourishing during this period. Tyrannosaurus was the top land predator along with smaller bipedal dinosaurs such as Velociraptors. Pterosaurs would face increasing competition from birds and would dwindle significantly in numbers towards the end of the Cretaceous. Mammals were still restricted to smaller nocturnal creatures. At this point in the sea sharks and rays had fully developed and would remain the same even millions of years later.
The Cretaceous period was ended by a huge mass extinction event known as the Cretaceous-Tertiary extinction. It is thought that the extinction was brought on by a huge meteorite impact, the crater of which can be found on the Chicxulub coast in Mexico. The impact would have kicked up a huge dust cloud, blocking much of the sun’s light. The impact crater shows that the meteor struck the coastline and so would have caused massive tsunamis, which would have proved fatal to all animal life caught in them. Evidence of tsunamis is prevalent across the USA, with marine sand found a long distance in land. The impact produced a cloud of sulphur dioxide which would have caused reduced sunlight as well as acid rain. This would have killed plants and plankton, severely harming the ecosystems that depended on them.
The only survivors of the event were omnivores, insectivores and carrion-eaters. Ecosystems that were based on consuming detritus would have been able to survive, and mammals with their warm blood and diet of insects would have been able to live through events that killed the larger reptilian dinosaurs. Crocodiles also survived the extinction event, this is thought to be due to their ability to live as scavengers and go for months without food.
After this mass extinction killed off the vast majority of the dominant life-forms a vast number of ecological niches were left open for mammals and birds to fill. The next era is known as the Paleocene Epoch and would see the growth of mammals across the planet.
Once photosynthesising cells present in the oceans had produced enough oxygen to form the ozone layer conditions on land were much more favourable to life than before. Without exposure to ultraviolet radiation cells were much more likely to survive being washed ashore. After a major extinction event 488 million years ago plants and fungi started to grow in out and around the water. Genetic mutation and evolution would see life adapt to the new environment and go on to thrive. Arthropods are believed to be the first animals to appear on land, around 450 million years ago. These early creatures would have been able to feed from the new plants that were growing on land, albeit around the water’s edge.
440 million years ago there was another mass extinction that would kick start evolution. Extinctions are perhaps naively thought of as bad for life, being that most of it is killed off. While it is bad for the organisms alive at the time for obvious reasons, a mass extinction actually has a major benefit for evolution in the path to intelligent life. Every mass extinction to date has been followed by a surge in new species and evolution. The reason for this is that evolution can get into a rut relatively easily, without a mass extinction it is likely that life would stay the same with little adaptation. Extinctions force adaptations and so accelerate evolution.
The result of the extinction event at the end of the Ordovician period, around 440 million years ago, was fish evolving into land-dwelling tetrapods. As their fins evolved into limbs they adapted to breathing air and eventually would live their entire life on land, only returning to water to lay eggs. These animals were the first amphibians and are essentially the genesis of much of life as we know it. During this period plants would evolve seeds and would spread across land, sparking the full colonisation of land by life. In another 20 million years animals would have evolved the capability to lay amniotic eggs as well as having diverged into many distinct evolutionary paths. Insects, reptiles, fish and bacteria were all present at this point.
The next major event has become known as the Great Dying. The Permian-Triassic extinction event is the most severe in Earth’s history. It is estimated that around 96% of marine life and 70% of land dwelling vertebrates would die out. It is also the only known mass extinction of insects. The causes for this are thought to be numerous, including environmental change and a catastrophic event such as increased volcanism or meteorite impacts.
The result of this extinction event was the Triassic period and the start of the age of the dinosaurs. Extending from 251 million years ago until around 199 million years ago the Triassic age is bookmarked by two mass extinctions. During this time the first dinosaurs evolved and it is believed the first mammals, flying vertebrates and flowing plants evolved as well.
The most common land vertebrate during the early Triassic was the Lystrosaurus. It was a small reptilian herbivore about the size of a pig. It had a horny beak and tusks and accounted for 95% of the population of organisms at the time. The Lystrosaurus is notable for being the only species to dominate the planet in such a great number. It is thought that by surviving the Permian-Triassic extinction that they became free of predators and could reproduce with little resistance.
Seeding plants, conifers and cycads would go on to dominate and flourish in the plant world. This would lead to greater insect numbers and would allow greater biodiversity among vertebrates. Towards the end of the Triassic early dinosaurs had evolved along with pterosaurs in the skies and icthyosaurs in the oceans.
As dinosaurs grew in numbers they would force mammalian ancestors to live nocturnally on a diet of insects. It is thought that living in this way would lead mammals to evolve fur and their higher metabolic rates required to function in the cooler night time temperatures.
The Triassic period came to a close 199 million years ago during the Triassic-Jurassic extinction event. During this time around half the species on Earth died out, leaving vast ecological niches. These niches were quickly filled and gave rise to the domination of dinosaurs. The next two periods of time, the Jurassic and Cretaceous, would be inhabited by some of the largest animals that have ever lived and would set in motion the events that would lead to the evolution of modern mammals.
In the scientific community there are two main schools of thought on the origin of life on Earth. One is that life was started here via a process known as panspermia. This is where bacteria are carried through space from another planet on a comet or meteor. The idea is that these bacteria would somehow survive impact and then go on to flourish on the new planet, in this case Earth.
While the theory of panspermia is certainly valid, Earth was heavily bombarded by meteorites prior to the start of life, it still doesn’t answer how life came to be in the first place. The likelihood of something surviving an impact combined with landing somewhere where it could thrive seems like a remotely small chance as well. The more widely accepted theory is that life on Earth originated here and did not come from another planet.
No concrete theory has been put forward that shows how life can come into being from non-living material yet. Without perfectly sterile lab conditions and a few hundred million years it may prove impossible. However it is theorised that life began as a series of organic chemicals and molecules. One of these molecules gained the ability to replicate itself. The crucial feature of this replication is that it was not perfect, there would sometimes be ‘errors’ in the reproduction.
If an ‘error’ in reproduction left that particular strand at a disadvantage then they would not reproduce as much and would eventually die out. If an error or mutation left a strand at a clear advantage, however, then they would reproduce in greater numbers and would take over. This is the start of natural selection and evolution, the theory that is thought to govern the development of all life right from the beginning to where we are today. Eventually DNA would emerge as the dominant force in replication and life was well on its way to becoming cellular.
Eventually primitive life would evolve membranes and so cells were born. The leap to membranes is actually easier to comprehend as the phospholipids present in cell membranes form bilayers spontaneously when placed in water. This property would allow the contents of life to be contained within the confines of a cell. The cells that would go on to become the ancestors of all life on Earth were present at this time, just over 3.5 billion years ago. They were primitive compared to modern cells, still lacking a nucleus, mitichondria and chloroplasts.
The next main development that would change the planet came with the advent of photosynthesis. Photosynthesis would allow life to use sunlight as an energy source. Cells that did not develop photosynthesis would also benefit as they could consume the photosynthesising cells. The secondary effect of stimulating the growth of life was what is know as the ‘Oxygen Catastrophe’. Oxygen is a waste product of photosynthesis and was toxic to a great many organisms. The waste oxygen would have first become bound to limestone and iron in the sea, before it could escape into the atmosphere. The atmosphere would slowly build up in concentration of oxygen and the ozone layer eventually formed, guarding the planet’s surface from harmful ultraviolet radiation. As a substantial amount of life died from oxygen some would find a way to harness it to enhance their metabolism.
Cells would continue to adapt over millions of years, gaining organelles and nuclei. At this point in history, around 1.1 billion years ago, the first supercontinent was beginning to take shape and plant, animal and fungus cells had split and were clearly defined, although still single-celled. As colonies of cells built up in volume over time some cells in certain parts of the colony would evolve into specialist cells giving a benefit for the whole colony. As this division began to take place it could be said that this was the start of multicellular organisms. Around 900 million years ago the first multi-celled animals began to appear.
Around 770 million years ago scientists believe that the planet went through a phase that has become known as Snowball Earth. For 20 million years the oceans froze over and the Earth entered a severe ice age. Eventually after time volcanic eruptions would cause enough carbon dioxide to enter the atmosphere and heat the planet due to the greenhouse effect.
By 530 million years ago fish had evolved and were the first known vertebrates. With the ice melted, the ozone layer present and complex life thriving in the ocean it would only be a matter of time before life would take to land.
Nine billion years after the Big Bang the building blocks of the Solar System were present as a huge molecular cloud, several light years across. As parts of the cloud began to collapse there is strong evidence that there were several supernovae near to where the Sun eventually formed. The remnants of these short lived stars and their resulting explosions would create regions of over-density within the cloud, potentially leading to the collapse of material due to gravity and so the eventual birth of the Sun as a protoplanetary disc.
As the disc spins due to momentum, molecular collisions in the centre start to become more common, and the heat starts to rise. As more and more matter began to collect in the middle the Sun started to take shape as an extremely hot and dense protostar. Over time the mass and heat reached the point where nuclear fusion was possible, and the Sun as we know it today was formed, complete with a relatively small amount of leftover material that would go on to form the planets.
The formation of planets is again down to gravity. As the dust particles began to collect to form large rocks they would grow slowly larger through collisions. These early formations are known as planetesimals. The outer solar system was the only area where it is cold enough for molecules such as methane and water to condense, and so the inner planets are formed from heavier rocky elements. These elements are relatively rare and so the inner planets could not grow as large as the gas giants that would eventually form from lighter elements further out in the Solar System.
Initially there were up to a hundred small planets orbiting the Sun. Over the next hundred million years these would collide and merge to form the four rocky planets and their moons that we have today. It is thought that the Earth’s moon was formed from a collision with a Mars sized object towards the end of this period. Around four billions years ago the Earth and other terrestrial planets would undergo what is known as the Late Heavy Bombardment. This is a period in time that lasted for several hundred million years where the inner planets where peppered with meteorites and asteroids. The high number of impacts is credited to the migration of the gas giants causing gravitational instability in the Solar System. Evidence of this is present in the highly cratered surface of the Moon and Mercury as well as several large craters on Earth.
Once the Late Heavy Bombardment was over it is believed that solar winds will have pushed much of the excess material out into interstellar space and that the Solar System settled into what we see today, with nine planets and an asteroid belt separating the gas giants from the rocky inner planets.
During and shortly after this time the Earth was very different to what it is now. Known as the Hadean eon the world was hot, dry and extremely volcanic. There were no oceans or oxygen in the atmosphere and the surface was molten. Due to this liquidity the heavier elements fell to the centre of the planet while lighter ones would remain nearer the surface. This process would eventually give rise to the layered structure we see in Earth today.
The next events on Earth would eventually give rise to the planet being hospitable for life. As gravity allowed more of an atmosphere to be retained temperatures would fall to such a level that the outer layer of the planet cooled and a rocky crust was formed. As gases were released from volcanoes and asteroid impact the Earth built up a significant atmosphere that contained water. As clouds formed and rain began to fall the oceans filled up. Within 750 million years the Earth had oceans of water and a rocky crust, although there was significantly less land then than there is now. While the atmosphere didn’t yet contain an ozone layer and very little oxygen the stage was set for the evolution of life. There was liquid water, a stable temperature and enough organic chemicals in circulation that would allow bacteria to thrive.
“In the beginning God created the heavens and the earth.” This is how the Bible kicks off, and for almost two millennia was the accepted theory for how the Universe and the Earth came into being. A tricky subject and something that takes a great deal of thought to even contemplate, the origin of time is not an easy thing to study. Up until modern technological advances and the advent of space telescopes it would in fact seem logical to credit a divine being with the creation of the Universe, simply for lack of a better explanation. However what this simple sentence does not explain is how the Universe was created, it merely says that it was done.
In the late 19th century and early 20th century scientific thinking began to overtake religious ideas as men such as Darwin and Einstein began to publish their theories. Many of the new scientific ideas would look to explain the laws that govern the way things are and the way that they came to be. While Darwin would upset a great number of religious people with his ideas on the origin of life on Earth, Einstein and his contemporaries’ ideas would cause relatively less stir in those circles due to the vagueness in the description of the start of time in the Bible.
While Einstein would lay the foundations for modern scientific thinking with his theories of special and general relativity his work would be expanded on later by numerous scientists, physicists and astronomers. Through the 1910s and 1920s it was discovered that the Universe was expanding, the term ‘big bang’ was actually coined as a derogatory term for the theory by Fred Hoyle while speaking on BBC radio. The genesis of the modern big bang theory started in the 1960s and has come on massively in the last ten years with additional data from the Hubble Space Telescope and NASA’s Wilkinson Microwave Anisotropy Probe (WMAP).
Big Bang theory states that the Universe was created in a single event 13.7 billion years ago. The initial condition of the Universe is still not fully known, but it is widely thought that it began as a singularity of infinite density and temperature. The first stage of the Big Bang is known as the Planck Epoch, lasting just a couple of trillionths of a second. At this tiny interval in time gravity was thought to have been as strong as the other fundamental forces, suggesting that everything was united as one single force. Understanding of this phase of the Big Bang is still limited, but experiments are planned in the future to gain a better knowledge of what happened. The Large Hadron Collider at CERN will enable further research to be done into the earliest phases of matter but will not allow research to be done directly into the Planck Epoch.
Still during the initial fractions of a second the Universe would undergo several major changes in its infant state. The main things being a cooling and then exponential growth through cosmic expansion. At this stage the Universe consisted of a quark-gluon plasma, which is essentially the building blocks of matter as we know it. As particles such as photons continued to form over the crucial first few seconds of the Universe the matter that was coming into being started to become more recognisable. After three minutes the temperature had dropped to the level where protons and neutrons can begin to combine into atomic nuclei. After 17 more minutes the temperature and density fell to a point where nuclear fusion was no longer possible.
For the next 70,000 years matter continues to form. Following this hydrogen and helium atoms start forming as the density of the fledgling Universe starts to fall and photons are free to travel, resulting in the cosmic microwave background that we can see present. This radiation gives us a picture of what the Universe was like at this point in time.
Over time the Universe starts to become transparent and structures begin to form due to gravitational forces. The Universe loses its homogenous nature as matter starts to clump together. After approximately 100 million years the first stars begin to form, eventually generating the heavy elements that will start to give life to planets. Even larger groups of matter will collapse and form galaxies. After billions of years the Universe begins to resemble that which we see today. Around 8 to 9 billion years after the Big Bang our own solar system is formed, with life evolving just one billion years after the formation of the Earth.
So while we have a fairly decent idea of how the Universe came to be it is quite apparent that there are a large amount of unanswered questions. Undoubtedly these will be solved in time. The Universe does however give us a lot more to work with in regards to how our solar system was made, and what the Universe was like to begin with than you might think. If you take into account the speed of light when we look out at the systems outside the Milky Way it is effectively like looking back in time as it has taken light millions, if not billions of years to reach Earth. The further out we look, the further back in time we’re looking.
As scientific theory advances and experiments are more detailed it’ll be interesting to see if there are any significant advances in the Big Bang theory and if any questions on the origin of our Universe are answered. When the Large Hadron Collider is switched on at CERN we may have some of these answers, and it’ll be interesting to see what conclusions are drawn.
Just recently I watched a trailer for the upcoming Terminator film, Terminator 4: The Future Begins. The series is one of my favourite film franchises and I’m looking forward to the new film, even in spite of the disappointing Terminator 3. Part of the reason that the films are among my favourites are the ways in which they deal with time travel and the paradoxes that it could potentially cause.
The film tells a story where in the near future artificial intelligence has taken over the planet and sends cyborg assassins back in time in an attempt to kill the future leader of the human resistance. At the end of the first film the robot terminator is crushed and destroyed, the only remains being the forearm and part of the microprocessor ‘brain’. The irony here is that the only way that the machines are eventually created is by using the parts left behind from the destroyed one.
It creates an interesting paradox in that the terminators would never have been invented if they hadn’t come back in time, so in theory the machines came into being by simply appearing out of thin air. The film dealt with the fate of John Conner, leader of the human resistance and whether his actions were predetermined or the result of a choice. In the end nothing he did could stop the inevitable and the machines started the war. The series raises a large number of interesting questions about time travel and the effects it may have.
This leads me onto the subject of time travel. Is it possible? It is a subject that has captured the collective imagination and inspired countless works of science fiction. As well as inspiring works of fiction it is a subject that has been the topic of serious scientific investigation and thought. Many notable physicists including Albert Einstein and Steven Hawking have done significant research into the prospects of the possibility of time travel. In this article I will have a look at some of the more common theories of how time travel may be possible and the effects it may have on the universe.
In fiction time travel has been presented in a huge number of different ways. The most common use is that of a time machine that can propel people backwards and forwards in time, or in some cases only in one direction. Popular examples include the DeLorean from the Back to the Future trilogy and the Tardis from the Doctor Who television series. In reality such devices are impossible but provide a romantic vision of how one might travel through time.
However despite these ideas of time travel it has been proven that time travel backwards in time is for the most part impossible. Time travel into the future, however is seen as being arguably possible. There are considerable (ie virtually impossible) boundaries to overcome but the possibility within the laws of physics is there for time travel into the future.
Theoretical time travel into the future would work on the basis of time dilation. If one was to travel away from the Earth at close to the speed of light before turning round and returning at the same speed then considerably more time would have passed for the people on Earth than those on the spacecraft. This would allow a form of travel into the future where people could arrive back at Earth several thousand years after they left even though they’ve only felt like they’ve been flying for a few years.
This is explained in Einstein’s theory of special relativity. A common way to relate this to time travel is with the twin paradox. The twin paradox states that if someone travels away from Earth at light speed and returns several years later they will find that their identical twin has aged considerably more than they have. The maths and physics behind why this happens is extremely complex and most likely far beyond the scope of this article, but it has been proven to happen. Experiments have even taken place on Earth that have proved the theory to be correct. The National Physical Laboratory in the UK flew clocks to Washington DC and back to London and found the results to be as Einstein had predicted.
Another factor that is able to cause time dilation is extreme gravitational forces. It has been calculated under general relativity that if a person was able to live inside a sphere with a diameter of five metres and the mass of Jupiter that their time would move four times slower than of the outside world. It has been proven in scientific experiments that clocks will appear to tick slower the closer they are to a strong gravitational pull. A person will see that a clock at ground level will tick more slowly than one up a tower.
With the knowledge of how time dilation works is it just a matter of time until we’re able to build a craft that can travel sufficient distances at a high enough speed that we see some more dramatic effects than a few nanoseconds? Imagine what kind of effects a craft that travelled at near light speed to a black hole and used the gravitational pull to slingshot back home would see. The combined dilation from the journey and the gravity of a black hole should see them arrive back on Earth a very, very long time after they’ve left.
The only way that we will be able to experience any kind of time travel is through this method, or by travelling through a wormhole.
A wormhole is a theoretical object that can link two distant points in space via a tunnel. The possibility of wormholes is driven by Einstein’s theory that objects curve space and time. Imagine space as a bed sheet that is pulled tight, when you drop a ball onto it the sheet will curve and the ball will roll to the middle. It has been theorised that if two objects with sufficient mass were to depress space in this way enough that they might meet in the middle and form a wormhole between the two points. Travel through these points would allow us to cross vast distances of space in a fraction of the time it would normally take to get there.
However if we were able to move and manipulate the mouths of the wormholes then it has been thought of that they may offer a way to travel into the past. From inside a wormhole the two mouths will always remain synchronised. That is to say if a clock reads 3000 on one end, it will also read 3000 on the other end. If we were able to bring two mouths near each other and then accelerate one away at relativistic velocities before bringing it back then the mouth that had been on the journey would have aged less. Let’s say the clock on the stationary mouth reads 3050 and the mouth that has been accelerated reads 3000. If you were to enter the accelerated mouth then both ends of the wormhole would read 3000 from inside. In this respect if you’re in 3050 with the stationary mouth and you enter the accelerated mouth you will exit in the year 3000, a trip back in time.
While theoretically possible this relies on technology that is far beyond our current understanding. However it does answer one of Steven Hawking’s queries on travel into the past. He asked that if time travel were possible then why haven’t we seen any tourists from the future? Well by using wormholes it would be impossible to travel back to a point before they were discovered and accessed.
Travel back in time would also raise the well known question of the Grandfather Paradox. This is the name given to a basic cause and effect paradox that could be raised from time travel into the past. For example, imagine you were to travel back in time far enough to a point before your father was born and kill your grandfather. This would mean that you would never be conceived and would never exist. If you never exist then how do you go back in time to kill your grandfather? Logic would say that you can’t and so that means your grandfather would live and you would go back in time and kill him, which of course we know you can’t. It is this example that is often used when saying that time travel into the past is impossible.
There is a school of thought though that you would be simply unable to change anything if you went back in time. Say you went to try and kill your grandfather. You would encounter a continuous stream of bad luck and you wouldn’t be able to do it, your gun would jam, you would miss, your shot wouldn’t be fatal, you would die, etc.
The idea of time travel into the past certainly raises an enormous number of paradoxes and questions on cause and effect, none of which are answered easily. While time travel into the future remains an exciting extreme possibility I do not think we will ever see time travel into the past, and certainly not at 88mph in a DeLorean.
Fourty-five percent of the American population believe that God created humans and placed them on the Earth less than 10,000 years ago. It is an incredible statistic. That’s 135,512,978 people in the USA who believe the Earth is 10,000 years old, twice the population of the UK.
The question of faith has always been a contentious, and interesting one. Causing more wars than anything else in history, religion has certainly been one of the more interesting phenomena that humanity has created for itself. The dominating religion in the Western world is Christianity and it is certainly hard to get away from it.
As scientific thinking and theories have improved over the last couple of hundred years there have been those religious fanatics who have chosen to reject reasonable ideas and logical thinking and cling to their spiritual beliefs in the wake of overwhelming evidence to the contrary.
What got me thinking about religion and it’s conflict with science was a particular branch of Christianity; Creationism. Creationism is the belief that evolution is a myth and that everything was created by an intelligent designer. In this case the designer is God. Strangely it isn’t actually the theory of intelligent design that irks me here, I like to think I’m fairly open to new ideas and generally accepting of religious beliefs, even if I do not agree with them. What does bother me is how the creationists present their views, and how they have such a large population completely brainwashed into the belief.
The creationist argument is that life and the universe as we understand it is so complex, infinitely so, that for it to have happened by chance is ridiculous. They believe that the Earth and all the life that lives on it has been designed and placed there by a divine creator, a God. Obviously this flies in the face of evolution, the theory with millions of years worth of hard evidence.
A common theory put forward by well known creationists is that the banana presents the ‘atheist’s nightmare’. They say that the banana is perfectly suited for a human hand, is colour coordinated to show how ripe it is, has a bio-degradable wrapper, is good to eat and is perfectly shaped for the human mouth. They say that with all these things taken into account it is so obvious that the banana has been designed for humans to eat and hasn’t just occurred by chance. What they fail to mention however, is that the wild banana is quite different. Filled with hard black seeds it is completely inedible. The banana that we know has been genetically modified over thousands of years into it’s current form. In fact the designer of the banana is Man himself, hardly proof of a divine creator.
They then go on to compare various man made structures to naturally occurring phenomenon. They say that to say a building has no designer is ridiculous, and so therefore it is also ridiculous to say that nature has no designer. What they fail to mention is that everything that is naturally occurring has had millions, or billions of years to evolve and come into being. To say that an eye has naturally evolved does initially seem far fetched, but when it is backed up with billions of years of chance it suddenly doesn’t seem so hard to believe.
Imagine playing the lottery every day for five billion years. You’d win quite a few times wouldn’t you? Well this is how evolution works. Over such massive time frames tiny chances of things happening become almost certain to happen. I would guess that religious believers have difficulty in comprehending the vast amount of time that existed before Man. The problem with religion and creationism is that everything is so centered around our own species when really we’ve only been around for an astronomical blink of an eye. Even in our own planet’s history we are quite insignificant, we’ve been around for 200,000 years as opposed to the 500 million years that fish have existed for. To say that a God has designed everything just for us seems entirely implausible to me.
Of course one could never be 100 percent sure that there was no God. You could never say that without having absolute knowledge of everything that exists, has existed or will exist. In this regard I am open to the fact that a God may exist, although I do not believe that one does.
I think that fabricating beliefs based on an old book and presenting them as fact is wrong, however. Surely science and rational thinking should be the basis on which opinion is formed. The purpose of science is to find evidence and present theories based on it. By turning yourself over to a religion you are able to just explain everything away with ‘God did it’. Against such an point of view it becomes difficult to construct an argument. Inevitably they will ask some questions that science does not have an answer for yet, and then they can answer it with ‘God did it’. Science does not pretend to have answers for things it does not understand yet, but preset facts based on real evidence and testing.
Organised religion and faith are relics from the past, unneeded in today’s society. They were used to govern primitive people and give answers to things that people could not understand yet. Essentially ruling people with the fear of going to Hell, religion is no longer needed now that we have organised rules and police forces. By perpetuating the falsehood of creationism and presenting religion as fact these people are slowing the scientific advancement and development of our species.
Religious evangelism needs to accept science or cease spreading its lies, for the good of everyone.
