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Albert Einstein Typed Letter Signed

Currency:USD Category:Collectibles / Autographs Start Price:NA Estimated At:20,000.00 - 30,000.00 USD
Albert Einstein Typed Letter Signed

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Auction Date:2021 Apr 14 @ 18:00 (UTC-5 : EST/CDT)
Location:15th Floor WeWork, Boston, Massachusetts, 02108, United States
ALS - Autograph Letter Signed
ANS - Autograph Note Signed
AQS - Autograph Quotation Signed
AMQS - Autograph Musical Quotation Signed
DS - Document Signed
FDC - First Day Cover
Inscribed - “Personalized”
ISP - Inscribed Signed Photograph
LS - Letter Signed
SP - Signed Photograph
TLS - Typed Letter Signed
TLS in German, signed “A. Einstein,” one page, 8.75 x 11.5, February 10, 1921. Responding to a question from a Swedish engineer about the meaning of the rotation signaled by Foucault’s pendulum, Einstein explains the General Relativity view of the pendulum’s functioning, implicitly referencing Mach’s Principle. Einstein here states (translated): “According to the general theory of relativity, one must consider that the Foucault pendulum adjusts itself to be rotation-free with respect to the total mass of the universe. This mutual influence should however not be interpreted as action at a distance: the [total] masses define the gµν-field [i.e. the gravitation field] in space, and this field defines the inertial behaviour of the mass of the Foucault pendulum.” Though Einstein does not explicitly label it so, the final clause of this letter (“the masses define…”) is an articulation of Mach’s Principle: the idea that a body’s inertial mass results from its interaction with the rest of the matter in the universe. In fine condition.

It was Einstein himself who first coined the phrase 'Mach’s Principle.' Einstein encountered the seed idea of the principle in Mach’s masterful text 'The Science of Mechanics,' where Einstein said he first came upon 'Mach’s bold idea that inertia originates in the interaction of [a given] mass point with all other [masses]' and where he was particularly struck by Mach’s critique of the 'bucket experiment' Isaac Newton described in the Principia (involving a rotating pail of water). Mach’s Principle was instrumental in shaping Einstein’s theory of gravity—profoundly advancing Einstein’s view of acceleration, rotation, and inertia—such that in 1918 Einstein explicitly affirmed Mach’s Principle to be one of the three pillars of General Relativity.

In 1912 Einstein performed a critical 'thought experiment' to test the validity and applicability of Mach’s Principle, leading him to discover an important 'gravitomagnetic frame-dragging effect' (now called the Einstein-Lense-Thirring effect)—an experiment that would later become a major empirical validation of General Relativity. This experiment convinced Einstein of the relativity of inertial mass, a conviction Einstein communicated to Mach in a historic 1913 letter where he also outlined his “thought experiment” and specifically referenced Foucault’s pendulum: 'It…turns out that inertia originates in a kind of interaction between bodies, quite in the sense of your considerations on Newton's pail experiment… If one rotates [a heavy shell of matter] relative to the fixed stars about an axis going through its center, a Coriolis force arises in the interior of the shell; that is, the plane of a Foucault pendulum is dragged around (with a practically unmeasurably small angular velocity).'

Dealing with a conceptual pillar of General Relativity—Mach’s Principle—and linking us to Einstein’s discovery of the Einstein-Lense-Thirring effect, the present letter is altogether exceptional for its content. Einstein letters relating to Mach’s Principle or to Foucault’s Pendulum or to the Einstein-Lense-Thirring effect are all extremely rare in commerce.

2021 marks the 100th anniversary of Einstein receiving the Nobel Prize.