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Einstein received the 1921 Nobel Prize in Physics not for relativity but for explaining the photoelectric effect, in which light striking a metal knocks electrons out of it. He proposed that light comes in tiny packets of energy, now called photons, an idea at work today in solar panels and camera sensors.

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The prize took an unusual path. In 1921 the Nobel committee decided that none of the nominations met its standards, so the prize was held back and awarded a year later, in November 1922, while Einstein was travelling to Japan. Relativity was left out on purpose: it was still controversial, and some committee members doubted that experiments had confirmed it. The photoelectric paper of 1905 had solved a real puzzle. Faint blue or ultraviolet light can knock electrons out of certain metals while bright red light cannot, because each packet's energy depends on the light's colour, not its brightness. The American physicist Robert Millikan confirmed Einstein's equation by experiment in 1916. When Einstein gave his Nobel lecture, in Gothenburg in July 1923, he spoke about relativity anyway. As agreed in their divorce, the prize money went to his first wife, Mileva Marić.

Türkçe oku
Einstein, 1921 Nobel Fizik Ödülü'nü görelilik kuramıyla değil, fotoelektrik olayı açıklamasıyla kazandı. Bu olayda metale çarpan ışık metalden elektron koparır. Einstein ışığın, bugün foton dediğimiz küçük enerji paketlerinden oluştuğunu öne sürmüştü; güneş panelleri ve fotoğraf makinelerinin sensörleri bu fikre dayanır.

Ödülün hikâyesi de sıra dışıdır. Nobel komitesi 1921'de adaylardan hiçbirini ölçütlerine uygun bulmadı; ödül bir yıl bekletildi ve Kasım 1922'de, Einstein Japonya yolundayken ona verildi. Görelilik bilerek dışarıda bırakıldı: Kuram hâlâ tartışmalıydı ve komitenin bazı üyeleri deneylerle doğrulandığından kuşkuluydu. 1905 tarihli fotoelektrik makalesi ise gerçek bir bilmeceyi çözmüştü. Sönük mavi ya da morötesi ışık bazı metallerden elektron koparabilirken parlak kırmızı ışık koparamaz; çünkü her ışık paketinin enerjisi ışığın parlaklığına değil, rengine bağlıdır. Amerikalı fizikçi Robert Millikan, Einstein'ın denklemini 1916'da deneyle doğruladı. Einstein, Temmuz 1923'te Göteborg'da verdiği Nobel konuşmasında yine de görelilikten söz etti. Boşanırken anlaştıkları gibi ödül parası ilk eşi Mileva Marić'e verildi.

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Background reading: Albert Einstein
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