3.3 Michelson-Morley Experiment

TL;DR

The Michelson-Morley experiment disproves the existence of aether, the medium in which light was thought to travel, by showing no change in the velocity of light.

Transcript

MARKUS KLUTE: Welcome back to 8.20, Special Relativity. In this section and also the next one, we're going to make a case against aether. Aether was presumed to be the medium in which light traveled. We do this-- we make this case by studying the Michelson-Morley experiment. Michelson and Morley went out to detect the motion of the Earth relative t... Read More

Key Insights

• 🙂 The Michelson-Morley experiment disproves the existence of aether by showing no change in the velocity of light.
• 💐 Systematic uncertainties, such as the direction of aether flow, were addressed by rotating the table and conducting multiple experiments.
• 💻 The experiment's result, an interference pattern on the screen, confirmed the absence of aether.
• ❓ The possibility of aether being localized with the Earth or the universe is refuted by the Michelson-Morley experiment's findings.

Questions & Answers

Q: What was the purpose of the Michelson-Morley experiment?

The experiment aimed to detect the motion of the Earth relative to aether, providing evidence for or against the existence of the medium in which light was thought to travel.

Q: How did the Michelson-Morley experiment work?

The experiment used an interferometer setup, with a light source, mirrors, and a screen. By comparing the time it takes for light to travel on different paths, the researchers aimed to observe changes in velocity caused by aether.

Q: What did the Michelson-Morley experiment conclude about the existence of aether?

The experiment showed no change in the velocity of light, indicating that aether does not exist as previously assumed.

Q: How did the researchers address uncertainties in the experiment?

The researchers rotated the table and performed various sets of experiments to account for unknown factors, such as the direction of aether flow.

Summary & Key Takeaways

• The Michelson-Morley experiment aimed to detect the motion of the Earth relative to aether, using an interferometer to observe an interference pattern on a screen.

• The experiment involved comparing the time it takes light to travel on different paths, both against and perpendicular to the assumed aether wind.

• Despite various attempts to detect smaller effects, the experiment showed no change in the velocity of light, leading to the conclusion that aether does not exist.