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Monday 19 December 2022

අයින්ස්ටයින් කළ වැරදි කිහිපයක්

 අයින්ස්ටයින් කළ වැරදි කිහිපයක්

මා පහත සඳහන් උපුටනය පළ කරන්නේ අයින්ස්ටයිනුත් වැරදි කළා කියන්න නො වෙයි. මුගලන් මහා රහතන් වහන්සේත් විශ්වයේ කෙළවර සොයන්න ගියා. අයින්ස්ටයින් තමයි විශ්වවේදය භෞතික විද්යාවට හඳුන්වා දුන්නේ. විශ්වවේදී නියතය (cosmological constant) ඉදිරිපත් කිරීම තමා කළ ලොකුම වැරැද්ද බව ඔහු වරක් ප්රකාශ කළා. එයත් වැරදි බව අද භෞතික විද්යාඥයන් කියනවා.
වැරදි කිරීම අප කාටත් පොදුයි. බටහිර විද්යාවේත් අනන්ත වැරදි කෙරෙනවා. අප කවුරුත් කරන්නේ හිතළු වැඩ කරනවා ද කියා බලා වෑඩ කරන හිතළු ඊනියා දැනුම ලෙස භාර ගැනීමයි. විශ්වවේදී නියතය විචල්යයක් බවයි මා නම් හිතන්නෙ. එහෙත් මා භෞතික විද්යාවේ පරිධියේවත් නැහැ.
මෙහි සඳහන් රොබට්සන්ගේ හා තවත් අයගේ නමින් විශ්වවේදයේ ඇති ප්රධාන මිතිකය හැඳින්වෙනවා.
Richard Muller
Prof Physics, UC Berkeley, author of "Now—The Physics of Time"
What was the worst mistake ever made in theoretical physics?
Since Einstein shares the honor (with Newton) as the greatest theoretical physicists of all time, let me give some examples of his mistakes.
He wrote a paper showing that gravitational radiation is impossible, that it does not exist. The paper was turned down by a referee who claimed it had mistakes; we now know the referee was Robertson, one of the great theoreticians of cosmology. Einstein was furious, and he said he would never again submit an article to that journal, but Robertson turned out to be right, as Einstein later acknowledged, and now we are directly detecting the kinds of waves that Einstein thought didn’t exist.
Einstein also published an incorrect answer for the deflection of light by the sun. Fortunately (for him) he later published a different result, one that Eddington then verified with an experimental measurement. That catapulted both Einstein and Eddington into prominence. (Once Eddington was asked, “Is it true that there are only three people in the world who understand general relativity?” He purportedly answered, “Who’s the third?”)
And, of course, Einstein wrote many papers explaining how the Copenhagen interpretation of quantum mechanics was wrong. Virtually all modern day theorists believe that Einstein was wrong in this work. Technically, he was simply raising issues that he considered to be paradoxical or ridiculous; I don’t believe anything he wrote on the subject actually contained a mistake.
The mistake that Einstein considered to be the greatest blunder of his life was his introduction of a “cosmological constant”. Here I quote from my new book:
——-quote from Now: The Physics of Time——-
Einstein … assumed that the universe was static [not expanding], and he had added a term to his equations called the cosmological constant that provided a repulsive force to overcome the mutual gravity that would otherwise cause the universe to collapse. He thought [theoretical physicist and ordained priest George] Lemaître’s idea of an expanding universe was ridiculous. He told Lemaître, “Your calculations are correct, but your physics is atrocious.”
After Hubble’s discovery [that the universe is expanding], Lemaître was suddenly famous. On January 19, 1931, headlines in the New York Times declared, “Lemaître Suggests One Single, Great Atom, Embracing All Energy, Started the Universe.” Einstein not only withdrew his cosmological constant, but regretted ever putting it in. [theoretical physicist] George Gamow said that Einstein described his inclusion of that term as “the biggest blunder of my life.” … There is a great irony in this statement, since today we believe the cosmological constant is, in fact, present and important in cosmology….
Had he not added it, he could have predicted the expansion of the universe! In what I consider to be the greatest irony of Einstein’s life, we now know that Einstein’s bigger mistake was not in sticking lambda in, but in taking it out. Had he left it in, he could have predicted the acceleration of the universe. Einstein’s greatest blunder was in calling the cosmological constant a blunder.
——-end of quote from Now: The Physics of Time