How Rutherford Became Father of Nuclear Physics

"It is JUST AS surprising - as if a gunner fired a shell at a single sheet of paper and for some reason or other, the projectile BOUNCED BACK."

This is how New Zealand physicist Ernest Rutherford described the result of alpha particle scattering experiment - conducted by his students Geiger and Marsden.

Introduction

Geiger and Marsden aimed high speed alpha particles at a very thin gold foil - it was only 1000 atoms thick. Around the gold foil was a zinc sulphide screen which glowed every time alpha particles would hit it.

If Thomson's plum pudding model of atom were correct, the fast moving and relatively heavier alpha particles would have passed straight thought the target, since electric field generated by evenly distributed charge is very minimal.

But the experiment revealed that a few alpha particles were deflected by small angles, while 1 in 20,000 particles got deviated by angle greater than 90 degrees.

Rutherford set out to explain these unusual findings by creating a new model of atom, because Thomson's model had failed.

Early life and career 

Ernest Rutherford [1871-1937] was a multi-talented student who did phenomenally well in mathematics, catching everyone's attention at his school as a consequence.

He won the scholarship to study at Canterbury College, University of New Zealand, where he participated not only in the lab but also in the debating society.

Rutherford was the head boy in college and played the rugged sport of rugby. He completed three degrees in this college - ba, ma and bsc.

Thereafter, he travelled to England in order to study under the guidance of J. J. Thomson at the Cambridge University. Rutherford worked with cathode ray tubes under Thomson's mentorship. 

In 1899, he heard about Henri Becquerel's discovery of radioactivity and became interested in exploring alpha and beta decay. Rutherford was among the first to prove that alpha particles were Helium nuclei.

"All science is either physics or stamp collecting." Rutherford used to say, but ironically he won the Nobel Prize in chemistry in 1908 for his pioneering work with on the chemistry of radioactive substances.

Discovery of Nucleus 

As discussed earlier, alpha particle scattering experiment was conducted by Rutherford, Geiger and Marsden in the year 1909, by passing alpha particles through a thin gold foil.

Rutherford argued that since most of the particles passed straight through the gold foil, the atom must be made up of mostly empty space - not a positive soup as Thomson had thought.

In fact, the atom is about 100,000 times the diameter of the nucleus. It is like putting a grain of sand in the middle of a soccer ground!

Positive charge must be localized, Rutherford argued, in a very small point at the center of atom, which explained bouncing back in a small fraction of alpha particles, since positive positive repel.

Negative charges in the atom must be located somewhere on the outskirts ... which explained smaller deflections.

Summing up

By creating a new improved model, Rutherford became the father of nuclear physics, as he initiated a whole new branch of physics. Scientists decided to probe further into the nucleus and many subatomic particles were discovered as a result.

Upon the discovery of atomic nucleus, Rutherford said: "I have broken the machine and touched the GHOST OF MATTER." But he regretted not being able to explain something deeper - "when we found the nucleus, we found the basis of everything, the greatest secret of all - except of life."

Is Oppenheimer Worth Watching If You Are Physics Student?

Oppenheimer by Christopher Nolan is dedicated to one of the greatest scientists of all time, J. Robert Oppenheimer [1904-1967] American physicist who is more famous as the director of Los Alamos laboratory during the second world war.

Oppenheimer once said: "It is occasionally true that I need physics more than friends." and that is what summarizes his college life. He was not particularly a social person and found merry in his own company. Nolan has shown how Oppenheimer dreamt physics all day long - a thing that drove him nearly crazy.

Nolan cleverly communicated that Oppenheimer was a genius physicist and not just some guy who led the Manhattan Project. That he made significant contributions to astrophysics, molecule theory, quantum mechanics and collaborated with some of the best minds of that time.

The movie is not about the bomb either. As titled, it is the story of J. Robert Oppenheimer who became victim of the second red scare during the 1940s and 1950s. He emerged as a war hero after the war but his closeness with communists - his brother being a former communist - led to his image assassination.

Communist or commie is a cuss word in America. People in the United States were systemically taught to dislike communism - so much so - that they started hating the idea and perceived it as something evil. Nolan has beautifully captured this struggle of Oppenheimer's to prove his loyalty and that he was not spying for communists.

Is there science in Oppenheimer, the movie? Yes a little bit of it here and there. For example, the Germans used heavy water as moderator, a very scarce resource which delayed their nuclear weapons program, while the Americans used a readily available Graphite - giving them a lead.

That is about it, more or less.

What about other greats like Einstein, Teller and Feynman? The first two scientists have played interesting, influential roles in the movie. However, Feynman was excluded except the part he started playing Bongo when the Trinity test was successful at 5.30 in the morning.

Who acted their part the best - was it Cillian Murphy as Oppenheimer or Robert Downey Jr as Lewis Strauss? There is a third possibility here - Matt Damon as Leslie Groves was mighty impressive. His screen time was comparatively less but acting was overpowering and top notch.

Overall, Oppenheimer is worth a watch for knowing how a "humble" scientist gets trapped by vindictive politics of that era. How human relationships change over the course and how some of them stand the test of time. What it means to be a scientist - to explore all possibilities, to fight for truth and to never give up.

What does Chandrayaan-3's journey to the Moon look like?

Chandrayaan-3 is the latest Moon mission by the Indian Space Research Organization - ISRO. The main objective of the project is to conduct a soft landing on the lunar surface, which is expected to happen after 40 days voyage.

Earlier in 2019, the lander of Chandrayaan-2 deviated from its original trajectory and suffered a hard landing on the Moon. The orbiter of Chandrayaan-2 is still circling the Moon and keeps sending important data.

The journey

Chandrayaan-3 was successfully launched from Srihari Kota on 14 July, 2023. The distance between Earth and Moon is nearly 384,000 kms which will be covered in 40 days. Choosing July for launch was deliberate as Earth and Moon are the closest this time of the year.

The propulsion module will carry the lander and rover set up to 100 km lunar orbit. Then, the lander and rover configuration will separate and aim for the Moon's surface. If soft landing is achieved, rover will enter the Moon.

Objectives

The main objective is to demonstrate soft landing and loitering capabilities of the rover. The other objective is to study the lunar surface and compile data of its composition. The rover is designed to conduct experiments with soil to understand which mineral resources are available on the Moon.

Apart from that, the rover on Chandrayaan-3 will also seek the presence of water ice on the Moon. Earlier India's Chandrayaan-1 had discovered water molecules at the lunar poles. This time the aim is to further study the history and geology of Moon's surface.

Design

The lander is box shaped with four standing legs. Inside the lander exist the rover and various instruments for experiment. Rover on Chandrayaan-3 is a small six wheeled vehicle that weighs 26 kg. The rover carries a drill, cameras and spectrometer.

Summing up

The chandrayaan-3 mission is expected to complete a soft landing on the south pole region of the Moon. Doing so, it will put behind the failure of Chandrayaan-2 lander in 2019. The rover on Chandrayaan-3 will not only help in understanding lunar surface composition but also know the evolution of solar system as it studies craters at the south pole.

5 Spiritual Quotes By Erwin Schrödinger

Austrian physicist Erwin Schrödinger (1887-1961) is well known as one of the founders of quantum mechanics. Schrödinger's equation is to quantum physics what Newton's laws are to classical physics. For his pioneering work, Schrödinger won the Nobel Prize in 1933.

But there is more to Schrödinger than you know. In addition to contributions to physics, Schrödinger is equally famous for being closer to spirituality than any other contemporary scientist. He took particular inspiration from eastern philosophies, such as from India.

Following are five quotes by physicist Erwin Schrödinger on philosophy and spirituality that may be worth your time:

1. We do not belong to this material world that science constructs for us. We are not in it; we are outside. We are only spectators. The reason why we believe that we are in it, that we belong to the picture, is that our bodies are in the picture. Our bodies belong to it. Not only my own body, but those of my friends, also of my dog and cat and horse, and of all the other people and animals. And this is my only means of communicating with them.

2. The stages of human development are to strive for:

(a) Besitz [Possession]

(b) Wissen [Knowledge]

(c) Können [Ability]

(d) Sein [Being]

The goal of man is to preserve his Karma and to develop it further... when man dies his Karma lives and creates for itself another carrier. [from writings in 1918]

3. This life of yours which you are living is not merely a piece of this entire existence, but in a certain sense the whole. This, as we know, is what the Brahmins express in that sacred, mystic formula which is yet really so simple and so clear; tat tvam asi, this is you. Or, again, in such words as "I am in the east and the west, I am above and below, I am this entire world." [from My View of the World 1951]

4. I am born into an environment — I know not whence I came nor whither I go nor who I am. This is my situation as yours, every single one of you. That is why we are eager to find out about it as much as we can.

And that is science, learning, knowledge; it is the true source of every spiritual endeavor of man. We try to find out as much as we can about the spatial and temporal surroundings of the place in which we find ourselves put by birth…

Although Schrodinger rejected traditional religious beliefs - Jewish, Christian, and Islamic - but he loved to indulge in religious expressions and metaphors. Schrodinger, like Heisenberg was deeply inspired by Vedantic concepts that helped him cope with the absurdity of quantum mechanics.

5. I think that life may be the result of an accident, but I do not think that of consciousness. Consciousness cannot be accounted for in physical terms. For consciousness is absolutely fundamental. It cannot be accounted for in terms of anything else. (1931)

5 Rules of Quantum Mechanics By Werner Heisenberg

German physicist Werner Heisenberg is well known as one of the founders of quantum mechanics. Heisenberg was only 25 years old when he arrived at the uncertainty principle, which became the basis of Bohr-Einstein debate on the nature of reality.

For his pioneering contributions, Heisenberg was recognized by the Nobel Prize committee in 1932. He was among the youngest recipients of the Nobel Prize. The following are five rules or lessons in quantum mechanics by one of its creators, Werner Heisenberg.

1. The more precise the measurement of position, the more imprecise the measurement of momentum - and vice versa.

This is how Heisenberg summarized uncertainty principle in one line. Niels Bohr proposed later on that "complementarity" is a fundamental feature of reality. In other words, particles have certain pairs of complementary properties which cannot be observed simultaneously.

Earlier, the words "position" and "velocity" of an electron seemed perfectly well defined as per the mathematical framework of Newtonian mechanics. But actually when we are going to such unimaginably small scales, they are not well defined in accordance with uncertainty equation.

2. Wave particle duality arises because of limitation in our language.

By nature, light and matter are single entities. However we cannot describe them as they are - hence the solution is to split their overall behavior into wave and particle like properties. Because that is the limitation of human language, says Heisenberg.

Our language was invented to study and describe the experiences of daily life consisting of processes and objects involving large numbers of atoms. The apparent duality at small scales is a result of this limitation.

3. All particles are made of the same substance: energy.

In quantum mechanics, the smallest units of matter are not physical objects in the ordinary sense - they are forms and ideas which can be expressed only by means of a mathematical language. This makes true what Pythagoras famously said: All things are numbers.

Moreover, particles are not eternal and indestructible - they can be transformed into each other. For example: if two particles moving with a very high kinetic energy collide, then many new elementary particles may be created from the available energy and the old particles will have disappeared in the collision.

4. What we observe is not nature herself, but nature exposed to our method of questioning.

According to Heisenberg, physics does not simply describe and explain nature; it is part of the interplay between nature and ourselves; it describes nature as exposed to our nature of questioning.

As a matter of fact, every experiment destroys some of the knowledge of the system which was obtained by previous experiments. Can nature possibly be so absurd? asked Heisenberg, as he struggled to make sense of the world.

5. If you're not shocked by quantum mechanics, you don't understand quantum mechanics.

The very foundations of physics were shaken up by the arrival of new quantum theory. Heisenberg has said: Whenever we proceed from the known into the unknown, we may have to learn a new meaning of the word "understanding." Much of everything that was known before became null and void overnight.

For example: The law of causality is no longer applied in quantum theory and the law of conservation of matter is no longer true for the elementary particles.

That is why, before studying quantum mechanics one must discard all pre-existing notions about the world and forget what was learned in large scale or Newtonian physics.

How did Heisenberg cope? Heisenberg admired Eastern philosophy and saw parallels between it and quantum mechanics. He stated that after having conversations with Rabindranath Tagore about Indian philosophy "some of the ideas that seemed so crazy suddenly made much more sense".

10 Interesting Facts About Chien-Shiung Wu

Chinese American physicist Chien Shiung Wu [1912-1997] is most well known for performing an experiment in 1956 which proved that parity or mirror image symmetry is not conserved - when it comes to the weak nuclear force.

The result was a shocker. Nobel laureate Wolfgang Pauli said on behalf of the physics community: "We are all rather shaken by the death of our beloved friend, parity."

Wu was an acclaimed experimental physicist and her expertise in the subject evoked comparisons to Marie Curie. She was nicknamed the Chinese Madame Curie, queen of nuclear research, as well as the first lady of physics.

Following are ten facts on physicist Chien Shiung Wu...

1. Wu was extremely close to her father, who was an engineer. He created an environment for children that encouraged curiosity, questioning and research from an early age. Wu's mother was a school teacher who valued gender equality.

2. Wu received her primary education at a school for girls that was founded by her father. At home, she was surrounded by books, magazines and newspapers. Her hand writing was considered outstanding by others as she was praised for her Chinese calligraphy.

3. As a high school student, Wu struggled in the subject of mathematics. Her father bought self study guides to trigonometry, algebra and geometry one summer to help. That experience created a life long habit of self learning and gave Wu sufficient confidence.

4. In 1936, Wu was accepted by the University of Michigan, but she was shocked at the sexism in the campus. She decided to study at the more liberal Berkely in California. Wu was a popular student and among the most talented. Her nick name at Berkeley was Gee Gee.

5. Wu worked closely with Robert Oppenheimer on the Manhattan project in 1944 where she helped develop the process for separating uranium into isotopes by gaseous diffusion. Years later, Wu recommended the Taiwanese president not to build a nuclear weapon due to its destructive outcome.

6. In 1949, Wu was the first to conduct a successful experiment on quantum entanglement or as Einstein called it - spooky action at a distance. Her work was the first important confirmation of quantum results relevant to a pair of entangled photons.

7. When the communists came to power in China the following year, Wu's father wrote urging her never to return. Since her passport was issued by the former government, it became invalid to travel abroad. Wu became an American citizen in 1954.

8. Physicists Lee and Yang's theoretical studies showed that parity would be violated for the weak force. Wu was an expert on beta decay experiment, which is a consequence of the weak force. In 1956, she proved that beta particles from Cobalt were emitted asymmetrically and hence parity was not conserved.

9. Tsung-Dao Lee and Chen-Ning Yang won the Nobel Prize in 1957. However, Wu was not honored until 1978 when she won the inaugural Wolf Prize - the criteria for this award is those scientists who were thought deserving to win a Nobel Prize but did not win.

10. She spent her final years promoting STEM education for girls. Wu's dying wish was to be buried in the courtyard of the Ming De school that her father had founded and that she had attended as a little girl.