President of Switzerland
Begins a one-year term as President of the Swiss Confederation.
Permanent historical records · Updated 2026-11-03
1909 in Switzerland
Explore 9 historical events and records for Switzerland in 1909.
Historical records for Switzerland in 1909
Sorted by month and day. Records with no month are shown last. Showing 9 of 9 unique records.
9Unique records
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January
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Directional Momentum Assigned to Light Quanta
Einstein's radiation arguments associated localized quanta with directed momentum as well as energy, moving the light-quantum concept closer to the later photon picture.
Particle Contribution Identified in Radiation Fluctuations
A second term in Einstein's fluctuation analysis had the form associated with independently moving energy quanta, strengthening his argument that radiation also possesses particle-like properties.
Radiation Fluctuation Formula Separates Two Terms
Einstein derived a thermal-radiation fluctuation expression containing two distinct contributions, one with wave-like behaviour and another with the statistical form expected from independent quanta.
Radiation Pressure Fluctuations Analyzed
Einstein studied statistical fluctuations in radiation pressure and used them to expose both continuous-wave and discrete-quantum aspects of thermal radiation.
Salzburg Address Defends Dual Radiation Structure
At the Salzburg meeting Einstein presented radiation as a problem requiring both electromagnetic waves and quantum-like localized events, highlighting a central unresolved issue of early quantum theory.
Thermal Radiation Statistics Support Quantum Picture
Einstein used the statistical behaviour of black-body radiation to argue that purely classical wave theory could not account for all observed fluctuations in radiant energy.
Wave Contribution Identified in Radiation Fluctuations
Einstein interpreted one part of the radiation fluctuation formula as the signature of interference and wave structure within the electromagnetic field.
Wave-Particle Duality Proposed for Radiation
Einstein argued that a future theory of light would need to combine wave structure with localized quantum structure instead of choosing only one classical description.
How these records were prepared
Generated from the World History Database historical_events table. Identical display records are collapsed; descriptions otherwise retain the stored text. Coverage and source quality vary. Check primary and specialist sources before citing individual historical claims.