This scenario requires a foundational assumption: for the transistor to be invented in 1920, the understanding of quantum mechanics and solid-state physics would need to accelerate by roughly three decades. We must assume that the "Black Box" of semiconductor behavior was cracked early, likely by a convergence of physics and chemistry in the post-WWI research boom.

However, the integrated circuit (IC) requires photolithography and clean rooms, which are manufacturing technologies, not just physics. Therefore, while the transistor exists in 1920, the era of miniaturized chips will not arrive until the 1950s (instead of the 1960s).

Here is the trace of the "Early Solid-State" timeline from 1920 to 1980.

Phase 1: The Interwar Acceleration (1920–1939)

First-Order Effects:

• Portable Communication: By the mid-1930s, the "Crystal Radio" is obsolete. Regenerative transistor amplifiers allow for high-fidelity, battery-powered portable radios.
• Telephony: Long-distance lines require fewer repeaters. Transatlantic telephone service becomes commercially viable in the late 1930s (instead of 1956).

Second-Order Effects:

• Cultural Homogenization: News and propaganda travel faster and more reliably. The Great Depression is exacerbated by the speed of financial panic but mitigated by better logistics coordination.
• The "Electronic" Depression: The radio industry booms earlier, but because manufacturing is less labor-intensive than vacuum tubes, the electronics sector absorbs fewer workers. Unemployment remains high in the US and UK, fueling radical political movements.

Third-Order Effects:

• Totalitarian Efficiency: Authoritarian regimes (Nazi Germany, Stalinist Russia) utilize portable, reliable communication to tighten central control. The Gestapo and NKVD can coordinate more effectively, potentially making resistance harder in the late 1930s.

Phase 2: World War II (1939–1945)

The Technological Shift:

• Radar: Vacuum tube radar is replaced by solid-state microwave components. Radar becomes smaller, lighter, and more reliable. Fighter aircraft can carry radar in 1942 (instead of 1944).
• Cryptography: The "Colossus" computer is developed using discrete transistors. It is smaller, more reliable, and requires no massive power grid.
• Guidance: Early proximity fuses and radio-guided bombs are reliable by 1943.

Implications:

• The Battle of Britain: With smaller, more reliable radar and better night-fighter tech, the RAF inflicts higher losses on the Luftwaffe. Germany is forced to abandon the invasion of Britain earlier.
• The Holocaust: Faster intelligence processing allows the Allies to confirm the scale of the genocide by 1943. Bombing of Auschwitz might occur in 1944 (as it was historically debated), but with better guidance, the accuracy is higher.
• The Atomic Bomb: The Manhattan Project relies on complex calculations. With transistor-based computing available, the calculations for the implosion mechanism are completed faster. The first bomb is ready by late 1944.
  • Scenario: The war ends in early 1945. The bomb is used against a military target in Germany or Japan to force surrender, but the US is not yet the sole nuclear power; the UK and Germany have "dirty bomb" programs closer to fruition due to accelerated physics.

Phase 3: The Cold War & The Space Race (1945–1965)

The Digital Curtain:

• Computing Gap: The US establishes a massive lead in computing. By 1950, mainframe computers are in existence (similar to the 1960s ENIAC era). The Soviet Union struggles to replicate the "clean room" culture required for miniaturization.
• Intelligence: The CIA and KGB utilize early digital encryption. The Cold War becomes an "Information War" starting in the 1950s.

The Space Race:

• Sputnik: Occurs in 1957 (same as OTL), but the US response is faster.
• Apollo Program: Digital guidance systems are more reliable. The US lands on the Moon in 1962, not 1969.
• Satellite Constellation: Because transistors are lighter and consume less power, the first "spy satellite" constellation (Corona) is fully operational by 1958.

Geopolitical Consequence:

• Soviet Stagnation: The USSR's economy is heavily industrial but lacks the semiconductor sector. By 1960, the US GDP per capita is 3x the Soviet figure (instead of 2x). The Soviet Union becomes a "second-tier" power much earlier, potentially leading to internal collapse or reform in the late 1960s.
• The Cuban Missile Crisis: With better surveillance (satellites) and faster comms, the crisis