Bonilla observation

Did You Know?

• José A. y Bonilla was educated in engineering and astrophotography in Zacatecas, Mexico City, and Paris.
• He was elected the first director of the Astronomical Observatory in the State of Zacatecas in 1882.
• The observatory opened in December 1882 and is now known as the Meteorological Observatory Zacatecas.

Event

On August 12, 1883, Bonilla was preparing his telescope for a study when he noticed objects partially blocking the Sun. Over the next 48 hours he used the Collodion process to capture 447 ink photographs of the objects. He described them as fuzzy or misty with dark tails, and left descriptions and data to clarify what the low-quality images showed.

Investigation

Bonilla's observations were published in the January 1, 1886 edition of the French astronomy magazine L’Astronomie. The magazine's founder and editor, Camille Flammarion, could not reach a specific conclusion but believed Bonilla had misperceived birds, insects, or dust in front of his telescope as being in space. Bonilla died in 1920 in Mexico City. In October 2011, researchers Héctor Manterola, María Ramos Lara, and Guadalupe Cordero from the National Autonomous University of Mexico released a preprint concluding that Bonilla had witnessed fragments of a comet that exploded in space.

Manterola explained that parallax meant only places along the same latitude as Zacatecas could witness the event, and African and Asian civilizations on that latitude lacked the means to observe it. Assuming Bonilla's timings correct, the team calculated a distance to the objects between 538 kilometers and 8,062 kilometers above ground, and lengths between 68 meters and 795 meters. They likened the potential impact to the 1908 Tunguska event, stating that if the fragments had collided with Earth there would have been 3,275 Tunguska events in two days—probably an extinction event.