=== (AGENDAWATCHDOG) === A letter penned by Albert Einstein which is rare for containing his famous ‘E = mc²’ mass–energy equivalence formula has gone on sale for the sum of £282,000.
The German-born theoretical physicist corresponded with a fellow researcher in October 1946, telling him a question could ‘be answered from the E = mc² formula.’
The one-page letter, which is signed off ‘A. Einstein’, is being auctioned off by Boston-based RR Auction in a timed sale which will end next week, on May 20.
It is only one of four known examples of the mass–energy equivalence formula having been written down in Einstein’s own hand.
Composed on Princeton University letterhead, the letter was written to the Polish-American physicist Ludwik Silberstein, who had previously contested part of Einstein’s theory of general relativity.
Translated into English, Einstein’s response read: ‘Your question can be answered from the E = mc² formula, without any erudition.’
‘If E is the energy of your system consisting of the two masses, E₀ the energy of the masses when they approach infinite distance, then the system’s mass defect is E₀ – E / c2,’ he continued.
Following a more complex answer, Einstein went on to conclude that ‘one must first a theory that contains the correct unification of gravitation and electricity.’
The search for this ‘unified field theory’ would go on to consume the final third of the extraordinary physicist’s life.
Einstein demonstrated mass-energy equivalence in 1905 – his so-called ‘miracle year which also saw him publish ground-breaking papers introducing the theory of special relativity, explaining Brownian motion and outlining the photoelectric effect.
Special relativity – which involves the relationship between space and time – determined that the laws of physics are the same for all non-accelerating observers and that light’s speed in a vacuum is fixed, regardless of observer or source motion.
To this understanding Einstein later succeeded in factoring in acceleration and he published this in 1915 as his theory of general relativity, which explained that objects with mass distort the fabric of space and time, which we experience as gravity.