FE Meme
Sun and Moon Same Size by Occam's Razor
#194: The simplest explanation is that the Sun and Moon are equal size and distance, not a 400-to-1 size and distance coincidence.
The Meme
Text block citing Occam's razor above a twilight photo with Sun and Moon disks appearing similar angular size.
Why It Spreads
Sun and Moon disks look similar in one twilight photo, so equal size and distance feels like the simplest story. Invoking Occam's razor makes the 400-to-1 size-and-distance coincidence sound like contrived special pleading. One snapshot becomes a cosmology argument without parallax or eclipse data.
What It Gets Wrong
An Occam's razor text block above a twilight photo where Sun and Moon look similarly sized (~0.5° for both disks) treats apparent diameter in one frame as ranging data. Angular size matches at present because the Sun is roughly 400 times farther and 400 times wider, about 1392700 km versus 3474 km diameter at 149.6 million km versus 384400 km. Lunar eclipses show Earth's shadow larger than the Moon; solar eclipses show the nearer Moon covering the Sun, and laser ranging separates their real scales by orders of magnitude. TestTheGlobe's A Local Sun Explains Day and Night and TestTheGlobe's Day and Night walk through the observations and predictions this image skips.
The Debunk
Similar angular size in one twilight snapshot (~0.5° for both disks) is not a distance measurement; lunar laser ranging still places the Moon near ~384400 km while the Sun sits near 1 AU. Occam's razor text over a Sun-Moon photo is inconsistent with eclipse geometry where Earth's umbra spans wider than the Moon. Use TestTheGlobe's Day and Night to compare the meme's claim with a measurable prediction.
- TestTheGlobe's A Local Sun Explains Day and Night: during total solar eclipses the Moon covers the Sun; during lunar eclipses Earth's shadow is wider than the Moon, inconsistent with equal-size bodies at equal distance.
- TestTheGlobe's Day and Night: lunar laser ranging returns ~384400 km to centimetre precision over decades, not an equal Sun-Moon distance pair.
- The text block cites Occam's razor above a twilight photo where Sun and Moon look similarly sized; apparent disk diameter in one frame is not ranging data.
- TestTheGlobe's Seasons Can Be Explained By A Circling Sun and TestTheGlobe's Sunsets Are Only Perspective add seasonal and horizon constraints that a nearby equal-size pair cannot satisfy globally.