Great American astronomer, Carl Sagan, said in the original Cosmos: "Imagination will carry us to the worlds that never were but without it we go nowhere."

Carl Sagan was probably the first mainstream scientist who started campaigning for public understanding of science on a very large scale through media and TV.

A great many documentaries have been made for educational purposes by esteemed scientists which are watched by millions of people around the world. Following is a list of some of the best physics documentaries.

Einstein and The Theory of General Relativity

This documentary was released to mark 100 years of Einstein's famous theory of gravity. It was created by leading physicists in the world as a tribute to Albert Einstein. The experts in the field have developed new experiments with advanced technology and even hundred years after first publication, the theory still works.

Cosmos: A Personal Voyage

Thirteen episode series, rated 9.3 out of 10 on IMDb, created by Carl Sagan, based on his best-selling book of the same name. The visual effects are old but each and every topic is explained with great emphasis and detail. No doubt the show was much ahead of its time.

Cosmos: a personal voyage covers a wide range of scientific subjects, including the origin of life and a perspective of our place in the universe. Since 1980, it has been broadcast in more than 60 countries and seen by over 500 million people.

Cosmos: A Spacetime Odyssey

This much needed sequel of Cosmos, released in 2014, was created by American astrophysicist Neil deGrasse Tyson. The visuals are improved and animations have been included making it a wholesome documentary series. The show has received highly positive reviews getting a Metacritic rating of 83 out of 100 based on 19 reviews

Into The Universe

Physicist Stephen Hawking brings his vision of the universe to the screen for the first time to delve into questions like how the universe began, whether life exists on other planets, and whether time travel is possible.

Hawking appears on the show in linking scenes using his own synthesized voice while the voice over narration is provided in character as Hawking by renowned actor Benedict Cumberbatch. It was released on Discovery Channel.

Wonders of The Universe

Particle physicist Brian Cox discusses various aspects of the universe featuring a wonder related to each topic. The topics include nature of time, life cycle of stars and the effect of gravity in the creation of the universe.


Secrets of Quantum Physics

British physicist Jim Al-Khalili shows how quantum physics is in every day life such as robins navigate using quantum entanglement, how our sense of smell is influenced by quantum vibrations and that quantum physics might play a role in biological evolution. You can watch it on Amazon Prime.


The Elegant Universe

American physicist Brian Greene explains the eleven dimensions, parallel universes, and a world made out of strings. This is not science fiction; this is a proper mathematical framework called the string theory. You can watch it here.


Lise Meitner: The Mother of the Atom Bomb

Lise Meitner led the small group of scientists who first discovered nuclear fission of uranium when it absorbed an extra neutron. Her research into nuclear fission helped to pioneer nuclear reactors to generate electricity as well as the development of nuclear weapons in the second world war. This is also available on Amazon Prime.

Fun To Imagine

In 1983, BBC aired this special by Nobel laureate Richard Feynman who used physics to explain how the everyday world worked like why rubber bands are stretchy, why tennis balls can't bounce forever, and what you're really seeing when you look in the mirror.

The Amazing Science of Empty Space

How can the universe come from nothing? This question has haunted scientists and common people for a long time; different explanations have been provided throughout history. However, physicist Jim Al Khalili explores the meaning of nothing in the scientific terms. His journey ends with perhaps the most profound insight about reality that humanity has ever made: everything came from nothing. You can watch it on Amazon Prime.

Bonus: Universe In A Nutshell

This is entry level educational video produced by Big Think and hosted by Professor Michio Kaku. for the lay people. It has a holistic approach towards physics; a brief history, applications and what the future holds for physicists.

4 Applications of Einstein's Famous Equation E=mc²

Just like electric and magnetic phenomena are two sides of the same coin, in similar way, matter and energy, according to Albert Einstein, are also equivalent.

Einstein said, "It followed from the special theory of relativity that mass and energy are different manifestations of the same thing, a somewhat unfamiliar conception for the average mind. Furthermore, the equation in which energy is equal to mass, multiplied by the square of the velocity of light, showed that very small amounts of mass may be converted into a very large amount of energy and vice versa."

In the Second World War, Einstein feared that Germans might develop an atomic weapon based on his groundbreaking discovery. Despite being a long-time pacifist, he wrote a letter to President of the United States, out of necessity, to urge him to develop the atomic bomb before the Germans.

America succeeded, the unfortunate bombings of Hiroshima and Nagasaki happened, the Great War came to a close but at Great Cost. Robert Oppenheimer, part of the Manhattan Project, quoted from Bhagavad Gita, "Now I am become death; the destroyer of worlds."

In 1948, Einstein regretted, "If I had foreseen Hiroshima and Nagasaki, I would have torn up my formula of 1905," he said in an interview. But just how much energy is locked inside matter? Here's an example: shortly after Einstein's death in 1955 his brain was removed and weighed at 1.23 kilogram.

That would equal 26,000 kilotons of TNT worth of energy. Compare this to the bomb which burned 70% of Hiroshima: it was only 15 kilotons of TNT. This means that an average human brain would have roughly 1,700 times more explosive energy than the bomb which destroyed an entire city!

No doubt Einstein was worried. But to everyone's surprise, despite having Heisenberg by their side, although his involvement in the war is disputed by some historians, the Germans were unable to complete the bomb.

On the other hand, nuclear arms race began between the United States and Soviet Union; a competition for supremacy in the world; which ultimately led to greater tension; a possibility that some eccentric politician might blow up the whole earth.

But apart from war, the equation is useful in other instances. For example, in a nuclear reaction, mass of the atoms that come out is less than mass of the atoms that go in. The difference of which shows up as heat and light.

This would make a good alternative to fossil fuels. Clean energy is the need of the planet because just think how long can we rely on fuel from the dead? Furthermore, space travel in the distant future may also depend on such power.

Einstein's formula also explains why the crust of our planet is inherently warm. It is due to energy mass conversions occurring within radioactive elements such as uranium and thorium in earth's crust.

Uranium can be found almost everywhere: in rocks, soils, rivers, and oceans. It is in fact 40 times more common than silver in the crust. Thus, the built-in temperature of Earth crust, is directly related to E=mc².

Also the source of sunlight is mass energy conversion. The Sun is made up of 70% Hydrogen. In its core, where temperature is high enough, four hydrogen atoms fuse together to become a helium nucleus, which is slightly less massive than the four combining hydrogen nuclei. The lost mass was converted to light.

Without that sunlight, there'd be no life on earth. Without it, there is no growth in the plants hence no food; all the animals would ultimately starve to death. Hence, we owe our existence to E=mc². Thus, Einstein's little equation is a triumph of the power and simplicity of physics.