Brief Answers to the Big Questions


Brief Answers to the Big Questions
Stephen Hawking was recognized as one of the greatest minds of our time and a figure of inspiration after defying his ALS diagnosis at age twenty-one. He is known for both his breakthroughs in theoretical physics as well as his ability to make complex concepts accessible for all, and was beloved for his mischievous sense of humor.

Book Summary - Brief Answers to the Big Questions by Stephen Hawking

Key Insights

Science and religion both seek to explain fundamental questions about the origins and meaning of life. However, they are often at odds with each other. Before many advanced scientific concepts were understood, God was used to explaining the most natural phenomena. Up until the 1960s, most scientists argued that the universe had always existed, and had no beginning and would have no end. The other alternative was to explain the origin of the universe using religion.

However, Albert Einstein’s theory of relativity revolutionized the way scientists understood the universe. Einstein discovered that space and time are not constants, but are changed and affected by matter and energy. Therefore, time and space are reliant on a universe to exist, which means there must have also been a time before the universe existed. The universe is also steadily expanding outward, which seems to indicate that it began from a single point and then continued expanding over time.

Humanity’s understanding of the universe advanced further when singularities were discovered. Singularities are a point where time and space cease to exist after the death of a star, and they are found in the center of black holes. Black holes, caused by collapsing stars, have a gravitational pull that is so strong that they pull all information and matter, including light, into them. Primordial black holes date back to the formation of the universe. Hawking believed that if primordial black holes could be located, they could explain much about the origins of the universe.

Although there are many theories explaining the origins of the universe, no scientists currently know for sure how the universe began. Understanding the origins of life is essential to understanding and predicting what might happen in the future, and how to ensure humanity’s continued survival as a species.

Key Points

The Big Bang And The Spontaneous Formation of the Universe

When the universe began, it was a dense point that was even smaller than a proton. The scientist Edwin Hubble discovered that the universe is constantly expanding and that all galaxies are moving away from each other. Therefore, there must have been a point in time when galaxies were extremely close together, possibly occupying a single dense point, called a singularity.

While material objects cannot appear out of anywhere, quantum physics shows that protons have the ability to appear and disappear spontaneously. The universe was likely formed in a similar way, with no specific cause setting it off. Einstein’s theory of relativity helped to prove this by discovering space and time were not constant and unchangeable, but rather woven into the interconnected fabric of space-time. Space-time can be warped by massive objects that exert extremely high levels of gravity, which can sometimes cause the time to stop. When the cosmos was only a small, dense singularity, time did not exist. Therefore, there could be no cause for the formation of the universe because time itself did not yet exist. The Big Bang was a random spontaneous occurrence.

While protons may appear spontaneously, complex living beings cannot materialize out of thin air. However, the theory of spontaneous generation was a popular scientific theory for many years. Scientists from Aristotle all the way up to the late nineteenth century believed that living beings, notably small creatures like mice or insects, could spawn spontaneously. The biologist Louis Pasteur finally disproved this theory by conducting an experiment that proved airborne microbes were responsible for bacterial growth. He put the broth in two vessels but sealed one off at the neck to prevent microbes from getting in. Substances grew in the open vessel but not the sealed one, showing that bacteria did not grow spontaneously out of anything. This discovery also led to the invention of pasteurization.

Investigating Life on Other Planets

It is likely that some form of life exists somewhere else in the universe. Earth only became habitable around four billion years ago. The universe is at least three billion years older than that, so it is highly probable some other life forms have existed during that time.

Intelligence is an evolutionary trait that is fundamental to humanity’s continued survival as the world’s dominant species. However, advanced intelligence is not necessary for the survival of most species. Simple organisms, like microbes and bacteria, have thrived on this planet despite having no intellect. This might help to explain why life on other planets has not yet been discovered. Other planets might have simple living organisms, but intelligent life is much rarer.

Recently, scientists have focused their search for extraterrestrial life on Mars. They have begun searching for alien bacteria, which would provide important information both about the existence of life on other planets and about the potential risks of humans traveling to or even potentially colonizing Mars. Microbes that are native to Mars are most likely hidden under the surface and could be unearthed if potential future inhabitants came from Earth and began digging for resources. These alien microbes might be fatal to humans if they become infected, and if they were transmitted to humans and made it back to Earth, they could pose a serious risk to humanity. Additionally, Earth’s bacteria and microbes change when they enter outer space. Even the common cold could prove to be lethal, which is why astronauts are kept in strict quarantine before leaving Earth.

Predicting The Future

Pierre-Simon Laplace, a French astronomer in the early 1800s, believed that accurately predicting the future and seeing into the past could theoretically be possible if scientists could determine the positions and speeds of all the particles in the universe. Laplace’s theory, that the universe’s present condition can be used to determine the future or past, is called scientific determinism. Scientific determinism is only possible if the universe is also subjected to certain constant natural laws. Natural laws are fundamental, unbreakable laws that apply to everything from the smallest to the largest beings in the universe.

In 1927, Werner Heisenberg proved it is impossible to know the speed and exact position of a particle at the same time using Heisenberg’s Uncertainty Principle. In fact, the more accurately one can predict speed, the less accurately they are able to predict the particle’s position and vice versa. Therefore, a completely accurate prediction of the future will never be possible.

Humans also fail to predict the future because they rely on the belief that conditions in the future will be the same as they are in the present, but this is rarely true. New factors are introduced, and humans are notoriously bad at predicting how these new factors will be used. For example, people failed to predict the significance of email or the telegraph when they were first invented because they did not understand the impact these new technologies would have on society. Predictions are useful to help plan for probable outcomes, but new factors will always impact society in unanticipated ways.

Black Holes

Black holes are an information paradox. This means that they bend or break the natural law that states information can never be lost or destroyed. Black holes absorb the information carried by light, X-rays, radio waves, or radiation, but scientists do not know if this information is permanently destroyed. Hawking was able to prove that black holes do steadily release particles, so some things are able to escape their pull. Scientists are working to solve this informational paradox because it is essential to understanding if and how natural laws can be broken in certain instances.

Theoretical physicist Caro Rovelli has put forth a theory to explain the information paradox called loop quantum gravity. In this theory, Rovelli posits the existence of white holes, which are a mirror of black holes and expel matter and information out rather than sucking them in. Eventually, all black holes will become white holes. According to this theory, the information in a black hole will fall through a warped space-time until it is eventually expelled from a white hole somewhere in the future, although it is unclear what condition the matter would be in once it emerges. Rather than singularities existing in the center of black holes, black holes only travel temporarily through a part of space-time where the general theory of relativity is suspected. However, much more study is necessary to confirm this theory.

Time Travel

For time travel to be possible, space-time would have to be warped enough to allow for the existence of wormholes. Wormholes are tunnels between two points in space-time that allow for travel between them. So far, no scientists have been able to find proof that wormholes exist.

However, some scientists believe that the hypothetical existence of wormholes may help explain the information paradox caused by black holes. One theory is that black holes are in fact actually wormholes because wormholes would not have boundaries. If wormholes existed, then theoretically so would gravitational echoes, caused by the reverberations of gravitational waves bouncing off wormholes. Some researchers believe they may have detected gravitational waves, although others believe these echoes were not caused by wormholes but were merely the sounds of black holes colliding.

Even if wormholes do exist, it would not be possible to travel through them until scientists devised a way to prevent them from closing.

Space Colonization

Over time, Earth is likely to become less and less habitable. Population growth, depleted natural resources, global warming, a sudden and unexpected catastrophe, or even a nuclear war may eventually make Earth uninhabitable.

For humanity to continue to exist, humans must devise ways to create habitable environments in outer space. Concrete deadlines are also essential to encourage space exploration and incentivize scientific discovery. Scientists currently have set a goal of establishing a camp on the moon by 2050 and a landing on Mars by 2070. Eventually, the goal must be to reach and inhibit a new civilization on an exoplanet, which is planets very similar to Earth but that revolve around a different sun. Scientists estimate that there are around forty-billion Earth-like planets in the Milky Way orbiting the Goldilocks Zone, the region where planets are capable of sustaining life. It is unlikely humanity will leave our current solar system, because our rockets are not fast enough to travel to the next nearest solar system, Alpha Centauri, which is 4.5 light-years away, in one human lifetime.

There is a risk that future generations may pollute newly colonized planets the same way Earth was polluted. While resources on new outer space civilizations will be scarce initially, it is possible that over time resources will be taken for granted, and once again waste and pollution will cause environmental destruction. In the new space colonies, it would be essential for people to keep in mind the importance of conserving resources, practicing sustainability, and preventing pollution and waste in the new colonies in order to avoid repeating the same environmental mistakes that were made on Earth.

Genetic Engineering

Human evolution takes thousands of years. However, the development of new technology that allows humans to alter their DNA will speed up this process, enabling humans to genetically engineer themselves or their children. They will be able to alter and enhance their DNA and prevent genetic weaknesses and deficiencies from occurring. However, genetic engineering raises ethical questions, including questions of fairness and equality among those who are engineered and those who are not.

A genetic engineering technique that uses the DNA sequences called CRISPR already exists. The technology is available for anyone to use, and many individuals have purchased CRISPR kits in order to experiment on their own. Most individual’s attempts to alter their own DNA have been largely unsuccessful.

However, these amateur experiments have raised alarm among some scientists and government officials. There is a possibility individuals will accidentally harm themselves while self-experimenting or inadvertently create a dangerous and contagious new disease. Government officials are also concerned that more skilled and nefarious agents might use CRISPR to create biological weapons. Genetic engineering has already been used to recreate a formerly eradicated strain of smallpox at the University of Alberta. As genetic engineering technology becomes more advanced, governments will most likely have to monitor and restrict access to genetic experiments.

Artificial Intelligence

Artificial Intelligence has the potential to surpass human intellect in the next few decades. However, for that to happen AI will first need to understand cause and effect. Right now, only humans are capable of forming hypotheses based on imagined scenarios and evaluating the hypothetical causes and effects of these scenarios. AI’s make their decisions using Bayesian networks, which use probabilities that are inputted by humans to evaluate different outcomes. Machines cannot currently imagine scenarios that have never existed or learn through observation.

However, machines are continuously advancing according to Moore’s Law, which states it is possible for computers to double their speed and capacity every eighteen months. This suggests superintelligent AI may not be as far off as it seems. If machines ever do develop these skills, many would argue that would make them almost human, as they would also possess a type of free will and ability to develop their own morality. This would raise many ethical questions, including what rights machines with AI should be granted or if they should be seen as equal to humans. AI that surpasses human intelligence also poses a great threat to humanity, since AI would then have the potential to end human life if their goals and motives differ from those of humanity. The risks and potentially unforeseen consequences associated with developing super-intelligent AI should convince scientists to pursue this technology with great caution.

The Main Take-away

Humanity has relied on science to provide the answers to life’s fundamental questions. Hawking has attempted to provide insight into the world’s big questions, such as the origins of the universe, the existence of other life forms, the future of technology, and the survival of humanity. The universe is subjected to a series of fundamental natural laws, which govern everything around us. However, there is still much in the universe that remains a mystery, such as a possibility for time travel, the ability to predict the future, or the information paradox of black holes. Space exploration may be the best option for the future of humanity, while Artificial Intelligence may be humanity’s downfall if the ethics of creating superintelligent AI are not seriously considered now. A strong scientific understanding of the origins and life of our universe is the most important tool for helping humanity continue to grow and thrive.

About the Author

Stephen Hawking was a theoretical physicist, cosmologist, and author of the bestseller A Brief History of Time. He was the former research director at the Centre for Theoretical Cosmology, the Lucasian Professor of Mathematics at the University of Cambridge, and a notable public figure in popular culture.

Hawking was educated at University College, Oxford, and received his Ph.D. in applied mathematics and theoretical physics from Trinity Hall, Cambridge. He made significant contributions to the field of quantum gravity and quantum mechanics, particularly to the understanding of black holes.

Hawking passed away in March of 2018. This book was published posthumously.

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