Why Light Bends Because of Gravity If It Has No Mass?

Gravity affects light not because light has mass or not, but because gravity disturbs the fabric of spacetime itself. According to Einstein's theory of general relativity, massive objects like stars or planets, even mountains to some extent, bend the space around them.

Imagine space is a flexible, three-dimensional rubber grid. For example: planets like Earth or Jupiter, bend and create an impression in this grid. This curvature makes smaller bodies, their moons, follow the planets around in a circle.

Near massive objects, like a star or a black hole, spacetime is more curved, and objects move along more curved trajectories like an elongated ellipse.

Light, like moons and planets, also follows the curvature of this warped spacetime, causing it to appear as if it's being "bent" by gravity.

Does light have mass?

No, light does not have mass. Light consists of massless particles called photons.

The masslessness of photons is a fundamental property that contributes to some unique characteristics, such as traveling at the speed of light and having no electric charge.

Has general relativity been tested?

Albert Einstein proposed his theory of gravity, known as the theory of general relativity, in 1915 in a sequence of four papers. Time and time again the theory has been proven right, for instance in explaining the rotation of Mercury's orbit.

That's why general relativity is extensively used in modern technological applications such as atomic clocks, GPS, etc.

5 Quotes By Stephen Hawking On Black Holes

Stephen Hawking [1942-2018] was an English cosmologist and author who is most well known for his theory of black holes. Hawking is known for postulating the black hole thermal radiation. Hawking also made important contributions to the big bang theory of the universe.

Following are five noteworthy quotes on black holes by Stephen Hawking:

1. I used to think that information was destroyed in black holes. But the AdS/CFT correspondence led me to change my mind. This was my biggest blunder, or at least my biggest blunder in science.

2. Black holes ain't as black as they are painted. They are not the eternal prisons they were once thought. Things can get out of a black hole, both to the outside, and possibly to another universe. So if you feel you are in a black hole, don't give up. There's a way out.

3. Einstein was wrong when he said "God does not play dice." Consideration of black holes suggests, not only that God does play dice, but that he sometimes confuses us by throwing them where they can't be seen.

4. My discovery that black holes emit radiation raised serious problems of consistency with the rest of physics. I have now resolved these problems, but the answer turned out to be not what I expected.

5. It is said that 'fact is sometimes stranger than fiction', and nowhere is this more true than in the case of black holes. Black holes are stranger than anything dreamt up by science fiction writers.

5 Quotes By Isaac Newton To Inspire Students

Isaac Newton was an English physicist who is credited for the invention of calculus. He is best known for the discovery of the laws of motion and the universal law of gravitation.

Newton laid the foundations for modern physics. Following are 5 quotes by Sir Isaac Newton that everyone should know:

1. If I have seen further it is by standing on the shoulders of Giants.

2. To explain all nature is too difficult a task for any one man or even for any one age...

3. I do not know what I may appear to the world, but to myself I seem to have been only like a boy playing on the sea-shore, whilst the great ocean of truth lay all undiscovered before me.

4. God created everything by number, weight and measure. We must be righteous & do to all men as we would they should do to us.

5. I can calculate the motions of the heavenly bodies, but not the madness of the people.

10 Less Known Facts About Physicist S.N. Bose

Satyendra Nath Bose was an Indian physicist who is best known for his contributions to statistical mechanics. Together with Albert Einstein, Bose is famous for the theory of Bosons and Bose Einstein condensate.

Following are 10 unbelievable facts about S.N. Bose which you may not know:

1. Bose was well versed in several languages including English, Bengali, Hindi, French, German and Sanskrit. He is remembered by his colleagues as a polyglot.

2. Since Bose had not done a doctorate, Einstein’s recommendation helped him become a professor. He served as a professor in Dhaka and then in Calcutta until 1956.

3. Seven Nobel Prizes have been awarded for research related to the concepts of the Bosons and the Bose-Einstein Condensate but Bose himself never won the most coveted prize.

4. Bose was good friends with several famous physicists including Indian physicist Meghnad Saha, English physicist Paul Dirac and Swiss mathematician Marcel Grossmann.

5. It was said that when Niels Bohr got stuck with a problem during his lecture in Calcutta, S.N. Bose instantly resolved it.

6. In 1919, Bose and Saha translated Einstein's book on the theory of relativity which was in German and published it in English. It was the first English translation of Einstein's groundbreaking work of 1915.

7. Paul Dirac coined the term Boson in the honor of S.N. Bose.

8. Bose wrote a letter to Einstein about a collaboration. Einstein immediately recognized Bose's genius and extended Bose's idea to the atoms that led to the existence of Bose Einstein condensate - the fifth state of matter.

9. Satyendra Nath Bose was devastated by the division of Bengal on the basis of religion in 1905. He was also depressed by the division of India and Pakistan and felt it to be a wound in the heart of his beloved nation.

10. Bose was also gifted when it came to music. He played an Indian stringed instrument called Esraj which sounded like a violin.

Why Edwin Hubble Never Won A Nobel Prize?

Edwin Hubble [1889-1953] was the first person to discover that the universe was expanding. He also found that Milky Way is just one of many galaxies in the universe. Thus, Hubble emerged as a pivotal figure in the field of astronomy in the 20th century.

Despite being a pioneer of his field, and doing work that revolutionized modern physics, why did American astronomer Edwin Hubble never win a Nobel Prize?

Early life

Hubble was more famous for his athletic prowess than scientific achievements in teenage life. He was gifted at baseball and football in high school. Not only that, Hubble led the University of Chicago's basketball team to their first major title in 1907.

Hubble's academic journey began with a bachelor of science degree, which he finished in 1910. As a college student, he served as a lab assistant to future Nobel laureate Robert Millikan, the discoverer of value of elementary charge.

Astronomy work

Hubble earned a law degree at Oxford University as a Rhodes scholar, demonstrating his diverse intellectual capabilities. He also studied Spanish for a while. However, his passion for science and astronomy prevailed over other interests.

In the 1920s, Hubble utilized a powerful 100-inch telescope at Mount Wilson Observatory in California to observe distant galaxies.

All the galaxies looked reddish in color. Like a siren whose sound gets lower and lower as it moves away. In terms of light, red is a color of low frequency. Hubble concluded that the galaxies were going away from us, so their wavelengths were stretched.

Ours was not a static universe like Albert Einstein had imagined, but it was an expanding universe, as Hubble had observed. This gave birth to the concept of the Big Bang theory.

Nobel prize

Edwin Hubble's notable contributions to the field of astronomy did not win him a Nobel Prize, and there are several reasons for this.

Firstly, at the time of Hubble's discovery in 1929, the Nobel Prize in Physics did not recognize work done in astronomy. Hubble spent the latter part of his career to have astronomy considered an area of physics.

Secondly, Hubble's work was truly groundbreaking, it changed our view of the cosmos, and the Nobel Committee may not have fully grasped the long-term implications immediately.

Thirdly, Hubble's work was more observational in nature and not supported by theory and experiment. It was dependent on Hubble's own interpretation of redshift data.

Legacy

Hubble's work was a key piece of evidence in supporting the idea of an expanding universe. Hubble has a crater on the moon and an asteroid named after him.

Hubble's legacy was further solidified when in 1990 Hubble Space Telescope was launched, capturing stunning images of distant nebulae, galaxies and other amazing cosmic phenomena.

5 Amazing Quotes By Max Planck On Science

Max Planck [1858-1947] was a German physicist who discovered energy quanta and laid the foundations of quantum mechanics in 1900. This won him the Nobel Prize in physics in 1918.

Best known for Planck's constant, denoted by h, Planck was a devout man who believed that his work with subatomic particles revealed to him the deepest secret of the universe.

According to Max Planck, the very greatest scientists of all times - such as Kepler, Newton, Leibniz - were permeated by a most profound religious attitude.

Early life

Max Planck was the sixth child in a family of intellectuals. His teacher Hermann Muller recognized the young talent and taught Planck astronomy and mathematics early on, aged 12.

Planck was gifted when it came to music. He played piano, organ and cello, and composed songs of his own. However, instead of music he chose physics for a career.

Planck's professor at University of Munich advised him not to study physics because in that field "almost everything is already discovered." Planck replied he just wanted to know more about the universe.

However, by discovering quantum theory Max Planck opened a whole new field of quantum mechanics which in turn gave rise to modern technology.

Quotes by Planck

1. Experiments are the only means of knowledge at our disposal. The rest is poetry, imagination.

2. Science cannot solve the ultimate mystery of nature. That is because, in the last analysis, we ourselves are part of nature and therefore part of the mystery that we are trying to solve.

3. We have no right to assume that any physical laws exist, or if they have existed up to now, that they will continue to exist in a similar manner in the future.

4. What we perceive as matter is merely the manifestation of a force that causes the subatomic particles to oscillate and holds them together in the tiniest solar system of the universe.

5. Over the entrance to the gates of the temple of science are written the words: Ye must have faith. It is a quality which the scientist cannot dispense with.

Why Astronomer Carl Sagan Was An Agnostic?

Carl Sagan was a renowned American astronomer who is best known for his show, Cosmos: a personal voyage. Sagan, an expert in the field of exobiology, persuaded NASA for Mars missions and to search for exoplanets with signs of life.

When asked about his religious belief, Carl Sagan did not assertively pick a side. He did not know for sure if there was a God. Carl was also uncomfortable about being labeled an atheist. That is why, Sagan claimed to be agnostic—to not hold any belief about God's existence.

In an interview, Carl Sagan described his unique idea of God, as a set of physical laws that govern the universe, which is the same as what Albert Einstein also believed.

However, Carl Sagan was an open critic of blind belief. At one point, Sagan also believed that religion or God was unnecessary in modern day society.

"Where did God come from?" Carl Sagan asks believers. "If we say that God always existed, why not save a step, and conclude that the Universe always existed?" Carl argues.

Carl Sagan adds that science has enlarged our picture of the universe. In some respects, science has far surpassed religion in delivering awe. "The Universe is much bigger than our prophets said, grander, more subtle, more elegant", Sagan wrote in the book Pale blue dot.

Carl Sagan also criticized the idea of perfection - that God is perfect. He wrote in the book Contact - "Why didn't God start the universe out in the first place so it would come out the way he wants? Why's he constantly repairing and complaining? God is not good at design or execution".

Despite writing extensively not in favor of religion, Carl Sagan never described himself as an atheist, as boldly as contemporaries like Richard Feynman did. Carl Sagan was an agnostic because according to him: "Extraordinary claims require extraordinary evidence."

Richard Feynman was an atheist

"To be certain of the existence of God and to be certain of the nonexistence of God seem to me to be the confident extremes in a subject so riddled with doubt and uncertainty as to inspire very little confidence indeed". Carl Sagan adds.

On the other hand, Feynman had said: I call myself an atheist. Agnostic for me would be trying to weasel out and sound a little nicer than I am about this.

Who Was Eugene Wigner?

Eugene Wigner was a Hungarian American physicist who made important contributions to the physics of elementary particles. He was a Nobel laureate who was nicknamed "a silent genius" by his colleagues.

Advice for students

Wigner said: In science, it is not speed that is the most important. It is the dedication, the commitment, the interest and the will to know something and to understand it — these are the things that come first.

Early education

Eugene Wigner (1902-1995) was born to a middle class family and home schooled till the age of 9. During this time period, he developed an interest in mathematical problems.

Wigner started off by studying chemical engineering at the Technical University of Berlin. There he got the opportunity to attend seminars by leading German scientists: Max Planck, Werner Heisenberg and Albert Einstein. As a result, Wigner decided to pursue a career in physics.

Interesting fact

Eugene Wigner and Paul Dirac had become close friends in America. In 1934, at Princeton, Wigner introduced his sister Manci Wigner to Dirac, with whom she married.

Known for

Wigner was the first to identify several characteristics of the strong nuclear force, such as the fact that the force between two nucleons is the same, regardless of whether they are protons or neutrons. The strong force is charge independent.

Notable awards

Eugene Wigner won the Nobel Prize in physics in 1963. Earlier, he had won the Enrico Fermi award in 1958 for his work with nuclear reactors to convert Uranium into Plutonium.

5 Motivational Quotes By Madame Curie

Marie Curie (1867-1934) is the only person in history who has won two Nobel Prizes in two different sciences, physics and chemistry. Curie was prohibited from higher education in her native country Poland. She overcame all obstacles and became a leading figure in the academia.

Following are five inspiring quotes by Madame Curie:

Advice to her daughters

Life is not easy for any of us. But what of that? We must have perseverance and above all confidence in ourselves. We must believe that we are gifted for something, and that this thing, at whatever cost, must be attained.

To make a better world

You cannot hope to build a better world without improving the individuals. To that end each of us must work for his own improvement, and at the same time share a general responsibility for all humanity, our particular duty being to aid those to whom we think we can be most useful.

Science has great beauty

A scientist in his laboratory is not only a technician: he is also a child placed before natural phenomena which impress him like a fairy tale. We should not allow it to be believed that all scientific progress can be reduced to mechanisms, machines, gearings, even though such machinery also has its beauty.

The way to success

I was taught that the way of progress was neither swift nor easy.

Be humble

I have no dress except the one I wear every day. If you are going to be kind enough to give me one, please let it be practical and dark so that I can put it on afterwards to go to the laboratory.

Marie Curie got married to Pierre Curie, along with whom she won her first Nobel Prize in physics. The couple went on a bicycle tour of the French countryside for their honeymoon.