Earth-grazer fireball with radio reflections recorded over New Mexico

An Earth-grazer fireball flew over New Mexico, US at 09:42 UTC (03:42 MDT) on October 25, 2017 and was recorded by amateur radio astronomer Thomas Ashcraft.

Ashcraft recorded it over his personal observatory "Heliotown" in Lamy, New Mexico.

"Earth-grazing fireballs are bright meteors that enter Earth’s atmosphere at a very shallow angle and skim along the top of the atmosphere. Some actually re-enter space," Vicent Perlerin of the American Meteor Society explained.

Ashcraft combines all-sky video camera observations with a forward-scatter radar array that is tuned to the plasma and ionization produced by meteors (Channel A 76.309 MHz CW – Channel B 54.309 MHz CW), Perlerin added.

Whenever a meteor passes through the upper atmosphere it creates an elongated paraboloid of ionized air behind it. Occurring at an atmospheric height of about 85 to 105 km (50 to 65 miles), this ionized trail is capable of reflecting radio waves from transmitters below on the Earth’s surface. This type of reflection behaves very similar to light reflecting from a mirrored surface, and is called a specular reflection.

Featured image: Earth-grazer fireball over New Mexico on October 25, 2017. Credit: Thomas Ashcraft