You wrote from Nigeria and China, India and Pakistan, Iran and Singapore — hundreds of e-mails from around the globe to pay tribute to Albert Einstein and his most famous equation, E=mc2.
When we asked MSNBC.com users to name the famous physicist's "most influential achievement," his formula for the equivalence of mass and energy was the clear favorite among the more than 350 responses. After all, there are few other equations that have had books, movies and miniseries named after them. And although it's unfair to blame nuclear weapons on E=mc2, the equation and the bomb are still closely linked in the popular view of Einstein's work.
But that's not Einstein's only achievement, and in the view of many people in the know, not even the most important one. John Rigden, a physicist at the Washington University of St. Louis who wrote the book "Einstein 1905," argues that Einstein's theories on the particle nature of light, often referred to as the photoelectric effect, should trump relativity in his personal pantheon.
"Relativity is very important, and it is a revolutionary theory as we now look back on it and see the way it has influenced physics through the century," he said. "But at the time, relativity could not be considered a revolutionary theory, because many ideas were in the air, and many other people were thinking things that could be considered elements of the theory."
Some MSNBC users agreed, while others had yet other nominations for Einstein's most influential achievement. Here's a sampling of the e-mail we've received in the past week or so:
Walter Cicha, chemist and Einstein lecturer/historian, Schenectady, N.Y.: "[Einstein's most influential achievement was] the photoelectric effect. This was the real beginning of quantum mechanics, the most important and controversial theory of 20th-century physics. Its presence is felt in much of our modern technology, including the vast number of satellites circling the globe which are so critical for most modern forms of communication. The satellites are powered by solar cells — the most prevalent of many direct applications of the photoelectric effect — which in turn are powered by our friendly star, the sun. Photovoltaics (a fancy term for light to electricity conversion) will play an increasingly important role in helping solve our energy needs of the future. The Nobel Committee had it right when they awarded the 1921 Physics Nobel Prize to Einstein predominantly for the photoelectric effect. Relativity was not even mentioned, although this was the focus of his belated acceptance speech."
Noel, Toledo, Ohio: "The photon. His other achievements were all going to be discovered sooner or later. The background knowledge was there, but his idea of a photon — light as a particle — is fundamental and has so many implications in today's society that it is the best and the most influential."
Alan Fay, State College, Pa.: "Einstein's greatest achievement was his most practical one —explaining the photoelectric effect. He thus made possible photovoltaic solar cells and the whole semiconductor industry, as well as helping us understand light. How strange that the man who gave us the power to blow up the planet's face also gave us the ability to convert sunlight directly into electrical energy!"
Russell Moore, Rochester, Minn.: "I must say his special theory of relativity is by far the most influential. The photoelectric effect may have helped us understand light, but I believe the general public gets a bigger kick out of how unstable our knowledge is. Even the simplest things such as sound with the Doppler effect or what we see related to the speed of light is all dependent on our perspective; nothing is absolute. As a senior, I am well aware that this concept will still make me uneasy even when I am well along in my later years."
Syed S. Hossain, Dhaka, Bangladesh: "Einstein's most influential achievement seems to be his imposition of the value c ... as an absolute constant of measure in the universe. He imposed the speed of light in a vacuum as the limit of any speed. And the mathematics were made to work out. Whether we can attain that high speed or not is not the focus, but rather the fact that we have stopped thinking or imagining any higher magnitude of speed than the speed of light in free space."
Nick Robertson, Alexandria, Va.: "E=mc2. It 'only' drives nuclear weapons and fission reactors today, but in 50 years or so, it will power fusion reactors that will deliver power so cheap it will be almost free. And where will that lead? I can't wait to find out."
Mark Younger, Bradenton, Fla.: "The profound insight to realize that time is not absolute but relative. Nine out of ten people still don't know this. It has a profound effect on everything from the big bang to 'supernatural' things being possible within the laws of physics. The fact that someone thought of this in 1905 (actually when he was a teenager) is even more profound. Even though most people are stuck in Newtonian physics, that is not the way things work."
C.D.L., Dallas: "His theories ... inspired boundless waves of technology, including the luxuries that we enjoy today, i.e., a society moving toward a paperless existence. Just look how far we've come in 100 years. Love computers? Then ya better love old Al."
The man behind the equations
Ron Tully, Mountain Lakes, N.J.: "Einstein personifies the ultimate scholar, reflected in his bridging of both the liberal arts and the pure sciences. His real achievement was in taking the best of human thought from the great philosophers of the ancient world, the Renaissance and the Enlightenment period, and blending that with the scientific thought of both ancient and modern times. ... We often talk of people who can think outside the box. Einstein is that perfect intellect capable of distilling knowledge within the box of human understanding and comprehending that the box actually is not a box at all, but a collection of electrons designed by nature to fulfill a specific purpose. Now that's genius!"
K.S. Gopal, Singapore: "He spoke, people listened."
M. Cole, St. Louis, Mo.: "Co-authoring with Leo Szilard and signing the letter to President Roosevelt in 1939 recommending that the United States begin development of an atomic weapon program."
Michael Vergara, Miami, Fla.: "I believe [his most influential achievement was] coming to the USA and informing the policy holders that we should look into a construction of a nuclear bomb. If that had not happened, the Nazis could have killed him and maybe would have made the bomb first, or would have made him make it for Germany. Think about it. How would life be now if Hitler made the first nuclear bomb."
Josh Hager, Las Vegas: "Let's skip 'influential,' as that will simply be an argumentative miasma. Instead, I'll promote his 'coolest' achievement, the relativistic effect of 'time dilation.' Simply put, if you travel faster than your surroundings, time will pass more slowly for you than for your surroundings. (Think of the jealous, uglier twin who rockets off in a spaceship, only to return in a decade to find that her previously gorgeous sister has aged by 25 years! Plastic surgery will never be the same.) ..."
Michael Yundt, Montgomery, Ala.: "I see his most influential achievement being the departure from the idea of fields. He refused to accept the convenient notion of a field being the cause of gravity or electromagnetism or any of the other unexplainable forces in nature. The fields were convenient ways of saying 'I don't know.' Instead, he allowed an entirely different view of the world (literally, of the universe) to describe and explain nature. Despite the complex field equations, his theories of space-time and relativity were and are so beautiful and so simple."
Brad, Blasdell, N.Y.: "I believe that Einstein's greatest achievement wasn't E=mc2 or his theory of relativity, it was his challenge of the norm. You have to remember that he was not a hero or or even very well-liked, for that matter, for most of his life with his colleagues. He never really had a home (country) of his own, but he still went after what he believed to be as truth. He gave the world the idea not to accept the word 'impossible' and to show God what our humanity is capable of. We have made more advances, in all fields of study, in the last century than all the others combined. Who else in history can say that they have had a hand in that?"
O. Gould, California: "Aside from his many scientific achievements, I think that Einstein's most influential achievement was his humanity. He was a man who believed in peace and civil rights. Two things he believed in so strongly, that he urged the scientific community to use science to create world peace and freedom. Einstein did not want the bomb to be used, he wanted mankind to seek peace and tolerance."
John White, Anchorage, Alaska: "Albert Einstein forced conventional science to think outside the box, and presented the evidence to force them to do it. He never proclaimed 'I am right' — he suggested, 'I might be right, you might be wrong — and here is why.' And his reasoning was so brilliant it required conventional thinkers to consider it. He showed that the power of the brain could challenge the greatest instruments of experimental science by asking the question 'what if.' Empirical evidence could be challenged by the 'thought experiment.' He forced science to stretch itself beyond the physical to question — and in a perfect world — even validate the spiritual."
Robert D. La Gesse, Castle Hills, Texas: "I think the greatest contribution is the legacy of achievability he has left our new young scientists. If Einstein could change the world with the meager tools he had at his disposal then, what might our new young scientists achieve today? I believe Einstein is probably still one of the greatest forces pulling people into science fields today."
Bill Rhinesmith, Newport Beach, Calif.: "Einstein woke us up! He woke us all up. Not just academia — but at the most elemental level of civilized societies, he alerted us to the possibilities. For the 'mathematically impaired' — while we still didn't understand the actual mechanics of what he was exposing, we did understand that these things, these 'theories,' were real and that they could be harnessed to achieve real things that were formerly thought of as almost black magic."
Mari Dickson, Oconomowoc, Wis.: "When asked what Einstein thought was his greatest discovery, he replied, 'That I can wear shoes without socks.' The man had a marvelous sense of humor, or was it modesty? I am one of his greatest admirers."