Orange 'fireball' over Estonia turns out to be aircraft contrails
A bright orange object that seemed to fall from the sky over Tallinn and Lääne County on Thursday afternoon was most likely sunlit aircraft contrails, according to a member of the Tõrva Astronomy Club.
Residents of Estonia, in Tallinn and Lääne County, spotted a bright orange object on Thursday afternoon that appeared to be falling towards the ground, the Estonian outlet Maaleht reported. Taavi Niittee of the Tõrva Astronomy Club said the photographs most likely show aircraft, or more precisely their condensation trails, lit by the sun low on the horizon.
How the effect arises
Contrails consist of small ice crystals formed from water vapor in aircraft exhaust, and depending on weather conditions they can persist in the sky for some time. When the trail of a high-flying aircraft is lit by the sun low on the horizon, as it is at this time of year ahead of sunset, it turns bright orange or red and resembles a burning object. If the aircraft is moving at certain angles relative to the observer, the glowing trail can look as though it is "falling" from the sky.
Niittee stressed that the sighting is nothing unusual. In his words, it is relatively common on clear evenings at this time of year.
Telling a meteor from a contrail
A meteor appears when a small body from space enters the atmosphere at high speed and begins to glow. It typically lasts only a few seconds. A contrail can remain visible for several minutes or longer, which makes duration the simplest way to tell the two apart.
Niittee advised anyone who sees something similar to check air traffic, for example on the Flightradar24 site. It shows flights in real time, as well as all flights from the preceding 24 hours.
