Who Was Alexander Friedmann?

Alexander Friedmann (1888–1925) was a Russian scientist who was the first to propose the theory of expanding universe, discovering a set of equations, now called Friedmann equations – before dying prematurely aged only 37.

Not only that, Friedmann also gave lectures on aeronautics for pilots and flew aircraft during the first world war. His students included such distinguished scientists as George Gamow and Vladimir Fock.

Early years

Friedmann was born to a very artistic household – his father was a professional ballet dancer while his mother was a trained pianist. From an early age, he was interested in the arts, sciences and politics. When he was 17, Friedmann was a student leader at his high school.

In 1907, when Friedmann had freshly joined the St Petersburg university for a physics degree, his father passed away suddenly. Consequently, Friedmann had to work part time as a tutor, earning a small salary that would support his education.

Friedmann received a bachelor's degree in 1910 and quickly joined Saint Petersburg Mining Institute as a lecturer.

Training

By 1913, Friedmann also completed his master’s degree and began taking part in flight lessons to study meteorology. This training came handy during the first World War, because Friedmann decided to volunteer in the air force. He was soon involved in bomb raids.

Friedmann used his physics knowledge in modelling bombing targets and helped other pilots too. Considering his aviation, scientific and leadership skills, Friedmann was promoted to the topmost position in an airplane factory.

His love of the pure sciences encouraged Friedmann to exchange letters, while fighting the war, with mathematician Vladimir Steklov – a friend from college days, in order to stay updated on new activities in the world of physics.

A new theory

German-born physicist Albert Einstein published a ground-breaking theory of gravity in 1916 that made him a celebrity figure. After the world war was over, Friedmann regretted participating, "I achieved what I set out to do, but what’s the use of it all now?" Friedmann decided to return his focus on physics.

In 1919, Arthur Eddington confirmed Einstein's theory by observing how stars near the sun were displaced from their original positions, due to curvature by mass. Friedmann wrote to Paul Ehrenfest a year later regarding his interest in the general theory of relativity.

In June of 1922, Friedmann introduced his own idea that the entire universe’s curvature could be a function of time.

Friedmann solved the field equations in general relativity to suggest three cases: 1) The universe could be expanding over time. 2) The universe could be shrinking over time or 3) The universe’s curvature could change periodically over time.

Revolt

Einstein, a supporter of steady state theory, did not view Friedmann’s evolving universe work favorably. Friedmann immediately wrote a letter to Albert Einstein requesting him to reconsider.

He wrote: “Should you find the calculations presented in my letter correct, please be so kind as to inform the editors of the Zeitschrift für Physik about it, and publish a correction to your statement.”

The letter reached Berlin, but since Einstein was touring Japan at the time, he did not read it until six months later. In 1923, Einstein admitted his error and wrote to Zeitschrift für Physik:

“My earlier criticism was based on an error in my calculations. I consider that Mr Friedmann’s results are correct and shed new light.”

Friedmann gained a widespread recognition in the scientific community as a result of proving Einstein wrong. He was invited to colleges across Europe to explain his findings.

Sadly, Friedmann died in 1925 because of a misdiagnosed typhoid fever. He was only 37 years old. Friedmann's theory was verified by Edwin Hubble 4 years later, who discovered red shift in the galaxies – implying an expanding universe.

Summing up

If Alexander Friedmann were alive in 1929 when Hubble found evidence for a changing universe, he should have won the Nobel Prize in physics. He was an adventurous man who did the most amazing work in the last few years of his life.

Friedmann received many honors after death, including a crater on the Moon which is named after him. Also, a prestigious Friedmann Prize is awarded once every three years to a single scientist for outstanding work done in cosmology.

Why You Should Read Astrophysics For People In A Hurry?

Human beings have been fascinated by the cosmos since time immemorial. Our current understanding of the universe comes from centuries of wonder, observation and experiment. One cannot help but ask – is there a single book that has laid out all the scientific progress in a clear and concise manner?

Enter American astrophysicist Neil deGrasse Tyson with his bestselling book Astrophysics for people in a hurry. You may have dozens or more questions about our place in the universe, how it works, etc. and if you're looking for one book to know them all, one book to find them and in the curiosity bind them, this book is it.

What's so great about this one book is how vast and far it goes in describing the intricate workings of the universe. From the beginning of time to its possible end. With Tyson's playful sense of humor and elaborate report on the ins and outs of the cosmos, Astrophysics for people in a hurry is a joy to read.

The book takes you on a journey to 14 billion years back when all of space and time began. It explains practical astrophysics as well as theoretical, Einstein's blunder, cosmic microwave background, how dwarf galaxies far outnumber the normal, why Titanium is used on telescope domes, etc. in impressive detail.

On top of that, the book is written by one of the most famous scientists of our times – Neil deGrasse Tyson, who is the director of the Hayden planetarium in New York city, whose love for space sciences is contagious, as well as his appearances on television are loved by one and all. Thus, for any science and astronomy enthusiast, the 2017 book is a prized possession.

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Tyson's Astrophysics for people in a hurry is a collection of his essays that appeared in Natural History magazine at various times from 1997 to 2007. Although marketed as a book for beginners, some knowledge of physics will be of genuine help – even so, it is a great place to start learning more about the ever changing field of astrophysics.

So whether you are a high school student or just starting out college, a young working professional or someone in their sixties, Astrophysics for people in a hurry is the one book you turn to in order to discover thorough answers to why and how of the universe. It is a highly recommended addition to your library!

Five Quotes By Stephen Hawking On Religion

Stephen Hawking was one of the most brilliant minds of the 20th century who made fundamental contributions to the theory of black holes. Hawking is well known to the general public by his record-breaking book A brief history of time, which sold over 25 million copies.

Hawking (1942–2018) was given just a few years to live in his twenties, as he was struck by the paralyzing motor neuron disease in 1963. Not only did he beat the odds, but also revolutionized physics for next half a century.

When Hawking ended his bestselling book with the sentence: If we discover the theory of everything... it would be the ultimate triumph of human reason, for then we would know the mind of God, he raised quite a few eyebrows. Hawking later explained that he had used the word "God" figuratively.

On numerous occasions, Hawking had commented that even if God were to be real, he would be bound by the rules of physics. Therefore, is the idea of an all powerful creator even necessary, Hawking wondered often.

For example, Hawking told New Scientist in 2007: (1) I'm not religious in the normal sense. I believe that the universe is governed by the laws of science. The laws may have been decreed by God, but God does not intervene to break the laws.

In 2011, Hawking would go on to say: (2) We are each free to believe what we want and it is my view that the simplest explanation is there is no God. There is probably no heaven, and no afterlife either. We have this one life to appreciate the grand design of the universe, and for that, I am extremely grateful.

And it is true that Hawking lived life to the fullest. His life threatening disease did not hinder his goals and aspirations. Hawking said, I believe that disabled people should concentrate on things that their handicap doesn’t prevent them from doing and not regret those they can’t do.

In an interview to The Guardian, Hawking remarked on the question of death: (3) I regard the brain as a computer which will stop working when its components fail. There is no heaven or afterlife for broken down computers. That is a fairy story for people afraid of the dark.

On the question of creation, Hawking is clear: (4) Because there is a law such as gravity, the universe can and will create itself from nothing. Spontaneous creation is the reason there is something rather than nothing, why the universe exists, why we exist. It is not necessary to invoke God to light the blue touch paper and set the universe going.

It may be a coincidence but Stephen Hawking was born on the same day that Galileo Galilei died in 1642. It was Galileo, the father of modern physics, who laid the foundations of science and religion debate, building upon his inner contradictions as a deeply religious man.

Hawking continued the great legacy more than 300 years later. According to him, there is a fundamental difference between religion, which is based on authority and science, which is based on observation and reason. This is also the view held by such greats as Dirac and Feynman. 

(5) We are just an advanced breed of monkeys—Hawking adds—on a minor planet of a very average star. We are so insignificant that I cannot believe the whole universe exists for our benefit (which is the view that religion has). But we can understand the Universe, and that makes us something very special.

5 Niels Bohr Quotes On Quantum Mechanics

Niels Bohr was a Danish physicist who made pioneering contributions to understanding atomic structure and quantum theory, for which Bohr was recognized with a Nobel Prize in 1922. Bohr was an active participant in the new quantum theory revolution that shook the foundations of classical physics.

Einstein, who was not ready to accept Heisenberg's uncertainty principle, as one of the cornerstones of modern physics, commented: God does not play dice with the universe. Bohr made peace with the uncertainty principle by developing the principle of complementarity.

According to complementarity, particles have certain pairs of interdependent properties that cannot all be observed or measured simultaneously. For example: position and momentum make such a pair.

Bohr regarded complementarity as an essential feature of quantum mechanics. It is said that Bohr replied to Einstein, who preferred the determinism of classical physics over the probabilistic new quantum physics: (1) "Stop telling God what to do."

In 1920, Bohr met Heisenberg for the first time. Bohr said, (2) What is it that we humans depend on? We depend on our words... Our task is to communicate experience and ideas to others. But when it comes to atoms, language can be used only as in poetry. The poet, too, is not nearly so concerned with describing facts as with creating images and establishing mental connections.

Some physicists depended on mathematical analysis to make sense of the quantum world. However, Bohr was not satisfied. (3) Even the mathematical framework helps nothing, I (Bohr) would first like to understand how Nature avoids the contradictions. (1927)

Bohr said further: Our experience in recent years has brought light to the insufficiency of our simple mechanical conceptions and, as a consequence, has shaken the foundation on which the customary interpretation of observation was based.

We can still use the objectifying language of classical physics to make statements about observable facts. But we can say nothing about the atoms themselves.

In the 1927 Solvay conference, Bohr and Einstein went head-to-head on the metaphysical and philosophical implications of quantum mechanics. Two legends, one defending the new-age probabilistic physics and another fighting for classical determinism. At the end, it was Bohr who emerged victorious and successfully established the probabilistic character of quantum measurement.

Niels Bohr wrote in 1934: (4) Isolated material particles are abstractions, their properties being definable and observable only through their interaction with other systems. Everything we call real is made of things that cannot be regarded as real.

In a 1952 conversation with Heisenberg and Pauli in Copenhagen, Bohr quipped: (5) "Those who are not shocked when they first come across quantum theory cannot possibly have understood it." This was most likely a reference to Einstein, who not only contributed to the new theory but also immediately taken aback by its bizarre results.

Richard Feynman Explains The Circle of Life

Nobel prize winning American scientist, Richard Feynman, was fascinated by simple things. From rubber band to fire, Feynman was delighted to explain the physics of day to day items in easy and poetic language. Here, Feynman described the life cycle of a tree as an example to illustrate that life comes full circle.

Where does the structure of the tree come from? To find out, we must start at the beginning. It is understood that seed sown in the ground will develop shoot of the plant, as it reaches out for the sunlight. At the same time, a root spreads deep in the soil searching for water.

Capillary action helps bring water up into the roots when the soil has higher concentration of water than the root cells. It is like putting a wick in oil lamp. But capillary action can only pull water up a small distance, when the plant is small.

In a mature tree, liquid water flows into the woody stem and then into green leaves where photosynthesis will occur. How does it work against the effects of gravity? The answer is cohesive forces that help to move water to the furthest leaf.

In the green leaves, some part of the water is used for photosynthesis. The other part, due to heat from sunlight, escapes into the atmosphere as water in gaseous form. In fact, if you wrap a plastic bag around a leaf, you can actually see vapor condense inside the bag.

Since molecules of water in the root and stem stick tightly to one another because of cohesion, the vapors which escape from the leaves, kind of pull the remaining water, as a single unit, upward behind them. This process is called transpiration.

Going back to, where does the structure of the tree come from? Feynman comments: it is generally thought that plants grow out of the ground. However, apart from water and vital nutrients, the ground does not contribute in the building up of the tree.

Mass of the tree is primarily carbon and where does that come from? The atmosphere, but not in pure form, it comes as carbon dioxide. (In its lifetime, a tree soaks up tons of carbon dioxide from the air, which is why it is advised to plant more trees).

The absorbed carbon dioxide is reduced to pure carbon when acted upon by the sunlight. Trees utilize these carbon molecules to construct their body tissues, for example in the stem. The useless oxygen molecules, on the other hand, are spit back into the air.

Thus, a combination of water, air and light as they come from the ground, atmosphere and sun respectively, mediate the flowering and growth of the tree.

There is a beautiful end to the story. The tree is used as a fuel for combustion. When pieces of wood are rubbed, for example, heat is built up by friction and that leads to reunification of carbon molecules in the tree with oxygen molecules in the air, generating a "tremendous catastrophe" as Feynman puts it, fire.

If you think about it, this light and heat of the fire is the light and heat of the sun, that went in! Feynman says: it is kind of a "stored sun", that is coming out when you burn a log. Isn't it wonderful how nature manages to come back in a full circle?

Five Quotes By Paul Dirac On Religion

Paul Dirac was one of the most influential physicists of the 20th century who made pioneering contributions to quantum mechanics. Dirac predicted the existence of anti-matter in 1928 and won the Nobel Prize for physics in 1933.

According to Dirac, (1) God is a mathematician of a very high order and He used very advanced mathematics in constructing the universe. Many believers take this quote as proof that the greatest scientific thinker of the past century is one of their own.

However, it is forgotten that as a devoted physicist Paul Dirac stayed away from religious activity as far as he could. Dirac was well known for being against organized religion as its influence grew politically.

At the same time, Dirac did not identify clearly as an atheist like other physicists as Bohr, Feynman and Hawking, but he described the possibilities for scientifically answering the question of God. Most biographers today would agree that Dirac was an agnostic.

In 1927 Solvay conference, scientists were discussing religious and/or spiritual implications of quantum mechanics, to which Dirac strongly objected, saying: (2) I cannot understand why we are talking about religion. If we are honest—and scientists have to be—we must admit that religion is a jumble of false assertions, with no basis in reality. The very idea of God is a product of the human imagination.

As a young man, Dirac was upset by dishonesty and self deception in religion. He understood how religion was a political tool as he said: (3) If religion is still being taught, it is by no means because its ideas still convince us, but simply because some of us want to keep the lower classes quiet. Quiet people are much easier to govern than clamorous and dissatisfied ones.

Niels Bohr was impressed by this viewpoint, regarding it as "quite lucid". Werner Heisenberg was tolerant, while Wolfgang Pauli commented: (4) Our friend Dirac has his own religion and its guiding principle is, There is no God and Dirac is his prophet. Everybody present burst into feeble laughter, including Dirac.

In 1963, Dirac wrote for Scientific American that God used advanced mathematics in constructing the universe and as we develop higher and higher mathematics we can hope to understand the universe better.

Dirac mellowed as he grew older but still did not commit himself to any definite view. In 1971, Dirac proposed, (5) if life can start very easily and does not need any divine influence, then I will say that there is no god.

In other words, the discovery of life elsewhere in the universe or creation of life in laboratory would convince Dirac that there is no god. In 1996, a team of scientists discovered evidence for microscopic fossil life in a meteorite from Mars. But more research needs to be done on this.

In the meantime, scientists are looking for earth-like planets or mimicking conditions necessary for the creation of life in laboratory. The possibilities are endless. It is only persistent observation and exploration that will bring us closer to answering the question of God.