Green fireballs

Although some ufologists and ufology organizations consider green fireballs to be of artificial extraterrestrial origin, mainstream explanations have been provided, including natural bolides.

Early observations of green fireballs date to late 1948 New Mexico, and include reports from two plane crews, one civilian and the other military, on the night of December 5, 1948.

[2] In a letter to the U.S. Air Force dated December 20, Lincoln LaPaz, an astronomer from the University of New Mexico, wrote (as reported by the ufologist Kevin Randle[3]) that the observed objects were atypical of meteors.

"[2] A February 1949 conference at Los Alamos attended by members of Project Sign, scientists including Joseph Kaplan and Edward Teller, and military personnel was unable to identify the origin of the observed green fireballs; secret conferences at Los Alamos and elsewhere, later in 1949 and addressing green fireballs, were also claimed by Edward Ruppelt and ufologists including Jerome Clark to have convened.

[1][4] The theoretical astrophysicist and UFO skeptic Donald Menzel claimed to have observed in May 1949 a green fireball near Alamogordo, which he later considered to be an ordinary meteor.