Authorities discounted proposed explanations such as a plane crash, errant missile test, or reentering satellite debris and generally assumed it to be a meteor. Astronomer Paul Annear said the fireball was likely a meteor entering the Earth's atmosphere. Geophysicist George Wetherilo discounted speculations that it was debris from a satellite and agreed the reports were probably due to a meteor. Astronomers William P. Bidelman and Fred Hess said it undoubtedly was a meteor bolide. A spokesman for the Defense Department in Washington said first reports indicated the reported fireball was a natural phenomenon.