Albert Einstein’s special mark on the universe

Editor’s Note: Jeffrey Bennett is the author of “What is Relativity? An Intuitive Introduction to Einstein’s Ideas, and Why They Matter” (Columbia University Press, 2014). His 2015 Relativity Tour has taken him to 25 cities to an audience of 10,000 people. He is the author of six children’s books that are being read by astronauts aboard the International Space Station for the Story Time From Space program. The opinions expressed in this commentary are solely those of the author.

It has been exactly 100 years since Albert Einstein presented his theory of general relativity to an audience of scientists on November 25, 1915. While virtually everyone has heard of Einstein and his theory, very few people have any idea of what the theory actually is.

This is a shame, not only because there is a great public thirst for understanding of it, but also because relativity is important, for at least four major reasons.

Jeffrey Bennett

General relativity provides our modern understanding of space, time and gravity – which means it’s crucial to almost everything we do in physics and astronomy. For example, you cannot understand black holes, the expansion of the universe or the Big Bang without first understanding the basic ideas of relativity. Though few people realize it, Einstein’s famous equation E = mc2 is actually part of the theory of relativity, which means that relativity also explains how the sun shines and how nuclear power works.

A second reason everyone should know about relativity lies in the way it changes our perception of reality. Relativity tells us that our ordinary perceptions of time and space are not universally valid. Instead, space and time are intertwined as four-dimensional space-time.

In our ordinary lives, we perceive only three dimensions—length, width and depth—and we assume that this perception reflects reality. However, in space-time, the four directions of possible motion are length, width, depth and time. (Note that time is not “the” fourth dimension; it is simply one of the four.)

Although we cannot picture all four dimensions of space-time at once, we can imagine what things would look like if we could. In addition to the three spatial dimensions of space-time that we ordinarily see, every object would be stretched out through time. Objects that we see as three-dimensional in our ordinary lives would appear as four-dimensional objects in space-time. If we could see in four dimensions, we could look through time just as easily as we look to our left or right. If we looked at a person, we could see every event in that person’s life. If we wondered what really happened during some historical event, we’d simply look to find the answer.

To see why this is so revolutionary, imagine that you met someone today who deeply believed that Earth is the center of the universe. You would probably feel sorry for this person, knowing that his or her entire world view is based on an idea disproven more than 400 years ago.

Can we solve the mysteries of the universe? —

Deep in the Kitakami Mountains of Japan, a group of impassioned scientists are working on proposals for a revolutionary project: a machine that will hunt for dark matter. The aim of the International Linear Collider (ILC) is to shed light on the mystery of what makes up most of the universe. This problem has been pursued for millennia, but could this machine hold the key? Here, we take a closer look at the ILC and go on a journey through time to look at some of the inventions that led to the most significant breakthroughs in scientific history. Gallery by Monique Rivalland

Atom smasher —

The machine is colossal. Once built, it will consist of two opposing tunnels that run underground for 31km -- over 10 times bigger than the current largest linear particle accelerator in the world. But what is a particle accelerator? Think of it as an atom smasher, a device that propels particles -- in this case electrons and positrons -- towards each other at extremely high speeds (almost the speed of light) so that they collide and create a myriad of other subatomic particles that otherwise might not exist or that we might not be able to see. Observing these particles could teach us critical things about our origins and even uncover entirely new dimensions.

What the experts say —

Scientists estimate that we remain in the dark about a mind-boggling 96% of the universe. Brian Foster, European Regional Director of the International Collider Collaboration and former professor of physics at Oxford University explained to CNN how the ILC would "recreate the conditions fractions of a second after the Big Bang that created our universe." "If we are lucky," he added, "the ILC will detect a whole new family of particles that might help us to realize Einstein's dream of uniting all the theories of physics into one overarching theory." Decisions on the multi-billion dollar machine looks likely to start by 2015 and construction would take 8-10 years.

Boson breakthrough —

Plans for the ILC follow the recent discovery of the elusive Higgs Boson, which resulted in professors Peter Higgs and Francois Englert winning the Nobel Prize in Physics last month. The Higgs Boson, a subatomic particle that may help us understand why other particles have mass, was proposed by the two winners (and Robert Brout) back in 1964 but only proved last year by use of a circular particle accelerator called the Large Hadron Collider (pictured) at CERN.

Super HILAC 1972 —

Two scientists show the scale of an earlier accelerator at the U.S. Department of Energy's Lawrence Berkeley National Laboratory. The Super HILAC (Super Heavy Ion Linear Accelerator) was one of the first accelerators that could accelerate the ions of all known natural elements to energies where they could be smashed apart. The lab is aptly named after Ernest Lawrence who invented the first circular accelerator at the University of California, Berkeley, back in 1929.

Bubble chamber 1970 —

It looks like a prop from a sci-film but in fact it's a research vessel called a bubble chamber. The bubble chamber was first used back in 1970 to detect subatomic particles called neutrinos. By filling the device with super hot liquid hydrogen scientists were able to watch particles interact. This 15-foot version was installed in the Bubble Chamber Building at U.S. research center Fermilab in 1971. Now obsolete, the chamber has been on public display since 2004.

Discovery of quarks 1968 —

Up, Down, Strange, Charm, Bottom and Top. These are the six 'flavors' of quarks. But you can't taste them -- they're the elementary particles that make up bigger particles such as neutrons and protons. Quarks exist only fleetingly outside of these particles and thus only be detected by their behaviour in high-energy collisions, which is precisely what happened back in 1968 at the Stanford Linear Accelerator Center (pictured), when scientists observed Up and Down quarks. Initially proposed by Murray Gell-Mann and George Zweig in 1964, the discovery of quarks gave further credence to the "Standard Model" of physics and prior to the discovery of a Higgs Boson was widely regarded as the most significant advancement in physics of the last 50 years.

Nuclear chain reactor 1942 —

In the throes of World War II, an important letter arrived for President Franklin D. Roosevelt. Written by Hungarian scientist Léo Szilárd and signed by Albert Einstein, the letter warned the President that Germany may be working on a powerful bomb. For the previous 10 years Szilárd, along with Italian scientist Enrico Fermi, had been experimenting with nuclear chain reactions and had filed a patent for a simple nuclear chain reactor. Finally, on December 2, 1942, the first artificial nuclear chain reaction took place in a racquets court at the University of Chicago (artist's impression). This launched the Manhattan Project and three years later the U.S. produced the first atomic bomb.

Electron microscope 1933 —

Szilárd was a canny young scientist who also filed a patent for the electron microscope back in 1928. However, it was Ernst Ruska in 1933 who managed to build the first electron microscope that exceeded the resolution of a standard light microscope. His invention, today an everyday piece of research equipment, used electron beams to illuminate tiny specimens and produce a magnified image of their structure.

The Geiger counter 1932 —

This very instrument was used by the scientist Sir James Chadwick, who discovered the neutron. As a young man he studied radiation in Germany under the creator of the counter, Hans Geiger. The Geiger counter detects the emission of nuclear radiation and is perhaps one of the world's best known radiation instruments. Still in Germany when WW1 broke out, Chadwick spent a few years in a detention camp west of Berlin, but after the war went on to be knighted for his achievements in physics.

Einstein's theory of relativity 1916 —

The most famous equation ever written by arguably the most famous scientist ever to live, Einstein's greatest tool was his brain. This is the earliest and longest manuscript on relativity that he ever wrote. In it he negates many assumptions made in earlier physical theories and redefines concepts of space, time, matter, energy, and gravity. While the equation denotes his theory of special relativity, which is concerned with light, Einstein's theory of general relativity helps us to understand planetary dynamics and the evolution of the universe.

Cathode used to discover electron 1897 —

This apparatus was used to discover the electron. In 1896, in Cambridge, Joseph John Thomson began experiments on cathode rays. Thomson showed that the cathode rays were particles with a negative charge and much smaller than an atom. They were later named electrons and in 1906 Thomson was awarded the Nobel Prize in physics for discovering one of the fundamental building blocks of matter.

Ionisation chamber 1896 —

This device was developed by French physicist Pierre Curie and used by him and his wife, Marie Curie, in radioactivity investigations. Both were awarded the Nobel Prize in physics alongside Henri Becquerel in 1903 for their pioneering work in spontaneous radioactivity -- a term that Marie coined. Marie Curie went on to use her knowledge of radioactivity extensively in medicine, for example to treat tumors. With it, she also discovered the elements polonium and radium.

Faraday ring 1831 —

It may not look very complicated, but when Michael Faraday spent 10 days winding two long pieces of copper wire around an iron ring, he may not have realized the magnitude of his what he was doing. When he passed an electric current through one coiled wire, it induced electricity in the other -- he had created the first electric transformer. Today, transformers are crucial to mass supply of electricity to towns and cities as they reduce high-voltage electricity generated by power stations to a lower, safer voltage.

Glass prism 1800 —

This is the glass prism used by Sir William Herschel to discover infrared radiation. He discovered this invisible type of radiation by studying the area just past red on the color spectrum. To his surprise, it was hotter than all the rest. He was the first person to discover forms of light that are not visible to the human eye. Oh yes, and he also discovered Uranus and wrote 24 symphonies.

Isaac Newton's apple tree 1687 —

Could this really be the tree under which Sir Isaac Newton sat and conceived the universal theory of gravity as an apple conked him on the head? Well, we're pretty sure it isn't, considering the story itself is widely considered to be apocryphal. But, according to the Isaac Newton Institute for Mathematical Sciences at the University of Cambridge, where Newton was a fellow, it was taken as a cutting from the alleged tree at Newton's birthplace in Woolsthorpe Manor, UK. Other alleged cuttings have been replanted as far as Nebraska, Vancouver, and Tokyo.

Galileo's telescope circa 1640 —

Here are two of the telescopes belonging to Italian astronomer Galileo Galilei, who was famous for the improvements he made to the instrument. With his advancements in observational astronomy he was the first to see craters on the moon and confirmed the four largest satellites of Jupiter.

A journey of discovery: the inventions that taught us everything we know

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Now imagine that you met someone who still believed that time and space are independent and absolute – which, of course, describes almost everyone – even though we’ve known that’s not the case for a century now. Shouldn’t we feel equally sorry for all who hold this modern misconception?

It seems especially unfortunate once you realize that the ideas of relativity are not particularly difficult to understand. Indeed, I believe we could begin teaching relativity in elementary school in much the same way that we teach young children about the existence of atoms, even though few will ever study quantum mechanics.

My third reason for believing relativity is important lies in what Einstein’s discovery tells us about human potential. The science of relativity may seem disconnected from most other human endeavors, but I believe Einstein himself proved otherwise. Throughout his life, Einstein argued eloquently for human rights, human dignity and a world of peace and shared prosperity. His belief in underlying human goodness is all the more striking when you consider that he lived through both World Wars, that he was driven out of Germany by the rise of the Nazis, that he witnessed the Holocaust that wiped out more than six million of his fellow Jews, and that he saw his own discoveries put to use in atomic bombs.

Evolution of the universe

Related article Albert Einstein's colossal mistake

No one can say for sure how he maintained his optimism in the face of such tragedies, but I see a connection to his discovery of relativity. Einstein surely recognized that a theory that so challenged our perceptions of reality might have been dismissed out of hand at other times in history, but that we now live in a time when, thanks to the process that we call science, the abundant evidence for relativity allowed for its acceptance.

This willingness to make judgments based on evidence shows that we are growing up as a species. We have not yet reached the point where we always show the same willingness in all our other endeavors, but the fact that we’ve done it for science suggests we have the potential.

Finally, on a philosophical level, relativity is profound. Only about a month before his death in 1955, Einstein wrote: “Death signifies nothing … the distinction between past, present and future is only a stubbornly persistent illusion.” As this suggests, relativity raises interesting questions about what the passage of time really means.

Because these are philosophical questions, they do not have definitive answers, and you will have to decide for yourself what these questions mean to you. But I believe that one thing is clear. Einstein showed that even though space and time can independently differ for different observers, the four-dimensional space-time reality is the same for everyone.

This implies that events in space-time have a permanence to them that cannot be taken away. Once an event occurs, in essence it becomes part of the fabric of our universe. Every human life is a series of events, and this means that when we put them all together, each of us is creating our own, indelible mark on the universe. Perhaps if everyone understood that, we might all be a little more careful to make sure that the mark we leave is one that we are proud of.

So there you have it. Relativity is necessary to comprehend the universe as we know it, it helps us understand the potential we all share when we put our brains to work for the common good, and if we all understood it we might treat each other a little more kindly.

Isn’t it time that everyone discerns Albert Einstein’s amazing ideas?

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