Lunar Land Bridge

The Lunar Reconnaissance Orbiter Camera team recently released pictures of the first natural land bridge ever discovered on the moon:

While the scale is relatively small, it nevertheless proves the existence of an artifact that scientists had speculated on for years. This one appears to be a section of a collapsed lava tube.

There was actually a bit of controversy in the 1950s concerning a possible lunar land bridge. On July 29, 1953, the amateur astronomer John J. O’Neill, a writer for the New York Herald Tribute and amateur astronomer, saw what he thought was a land bridge on the western side of Mare Crisium. The dimensions of his putative bridge were absurd - 12 miles wide - but when he requested confirmation of his observation one prominent professional astronomer Hugh Percy Wilkins tentatively confirmed it, although shrinking its width to 2 miles (still a ridiculous figure.)¹

Others were not as receptive. After observing the area for several months during the period of the of the lunar day when the bridge should be visible, it became clear the the bridge that O’Neill thought he saw was simply an illusion created by the shadows of several prominences lying across the uneven terrain.

Wilkins’ reputation was damaged and he was forced to resign from his position at the British Astronomical Association.

Notes

¹“O’Neill’s bridge remembered”, Sky & Telescope. p. 105, January 1998.
²”The So-Called Lunar Land Bridge”, Bulletin of the Astronomical Institutes of Czechoslovakia, vol. 8, p.33, October 1957.