“Google Can’t Math Parsecs” by jefftk

Daniel Drucker pointed me at a fun bug in Google's calculator: the parsec is wrong when you do math on it. As the earth travels around the sun, closer stars appear to shift back and forth against the far-distant background stars. The closer the star is the bigger this effect is. Think of how when you switch which eye you're looking through you notice near things shifting relative to farther ones. For example, holding up my finger I see this out of my right eye: But this out of my left eye: If a star moves by two arcseconds (each 1 / 3600th of a degree) as the earth goes halfway around the sun (two "astronomical units apart) we say the star is 1 parsec away. This defines a triangle where two of the sides are far larger than the third, which means as long as we measure our angle in radians we can use the small-angle approximation and say a parsec is one AU per arcsecond. If I search [1 parsec in meters] I get the correct answer of 3e16 meters: The interactive unit converter seems to be [...] --- First published: June 20th, 2026 Source: https://www.lesswrong.com/posts/BmqzjcD4tGvy3bim8/google-can-t-math-parsecs --- Narrated by TYPE III AUDIO. ---Images from the article:Apple Podcasts and Spotify do not show images in the episode description. Try Pocket Casts, or another podcast app.