A video of what appears to be a fireball falling from the sky has attracted a lot of attention online. The video was first posted to a subreddit dedicated to UFO sightings on December 27 by a user who said the clip was recorded in West Virginia. The video was shared on Twitter and has attracted more than 1.4 million views.
But this type of sighting is actually a fairly common phenomenon. According to the American Meteor Society, the majority of these reported “fireballs” are not meteorites or other space objects. What we are seeing is called a contrail, which is created when exhaust gas from a high-altitude plane mixes with water vapor in very cold temperatures. The resulting linear clouds can appear bright red or orange because the sun reflects off them at sunrise and sunset, the AMS explains on its website.
Here’s what you need to know:
Condensation Trails Are Primarily Composed of Ice Crystals, According to the FAA
Contrails are seen often and scientists from the Environmental Protection Agency (EPA), the Federal Aviation Administration (FAA), the National Aeronautics and Space Administration (NASA), and the National Oceanic and Atmospheric Administration (NOAA) put together a fact sheet to dispel concerns about what people are seeing in the sky. The flying object that looks like a fireball is nothing more than frozen water.
According to the fact sheet from the government agencies, the “condensation trails,” otherwise known as “contrails,” form when an airplane is flying at high altitudes “several miles above the Earth’s surface.” As the plane emits exhaust fumes from the engine, the hot gases combine with the cold moisture in the atmosphere. If there is low humidity, the contrail will dissipate quickly. But if there is a lot of moisture in the air, the contrail can grow and will be visible in the sky. According to the fact sheet:
Contrails are line-shaped clouds or “condensation trails,” composed of ice particles, that are visible behind jet aircraft engines, typically at cruise altitudes in the upper atmosphere. Contrails have been a normal effect of jet aviation since its earliest days. Depending on the temperature and the amount of moisture in the air at the aircraft altitude, contrails evaporate quickly (if the humidity is low) or persist and grow (if the humidity is high). Jet engine exhaust provides only a small portion of the water that forms ice in persistent contrails. Persistent contrails are mainly composed of water naturally present along the aircraft flight path.
The FAA further explains how humidity levels impact contrail development:
A contrail will form if, as exhaust gases cool and mix with surrounding air, the humidity becomes high enough (or, equivalently, the air temperature becomes low enough) for liquid water condensation to occur. The level of humidity reached depends on the amount of water present in the surrounding air, the temperature of the surrounding air, and the amount of water and heat emitted in the exhaust. Atmospheric temperature and humidity at any given location undergo natural daily and seasonal variations and hence, are not always suitable for the formation of contrails.
The American Meteor Society explains how a contrail forms by comparing it to a common phenomenon humans see on frigid days:
A passing jet engine creates an artificial cloud by mixing hot moist air from the exhaust with the sub-freezing humid air it is passing through. You can observe a very similar mixing cloud by exhaling on a cold winter day – warm water vapor from your breath combines with water vapor in the air and condenses into tiny water droplets to form a breath cloud.
Fireballs Fall Through the Earth’s Atmosphere Within Seconds
The video posted to Reddit and Twitter described the glowing phenomenon as an “unidentified flying object.” The two people heard in the original video remarked that the object in the sky was “weird,” questioned whether it was a plane and exclaimed that something was “burning.”
But the fact that the video is nearly two minutes long immediately extinguishes the possibility that what they were seeing was a fireball. As the American Meteor Society explains, meteors fall through the sky within just a few seconds. The AMS states on its website, “If you had enough time to grab your phone to take a picture, it is certainly NOT a fireball. Fireballs usually only last a few seconds. Longer fireballs are extremely rare.”
The AMS adds that the presence of clouds is another indicator that the glowing linear line is not a meteor. If clouds are visible above the object, then “it is certainly NOT a fireball (meteoroids glow usually as soon as they hit Earth’s atmosphere and they entirely burn up between 60 miles – 100 km and 40 miles – 70km – the highest clouds can be found at 8 miles above the Earth’ surface).”
As NASA explains, “Fireballs and bolides are astronomical terms for exceptionally bright meteors that are spectacular enough to to be seen over a very wide area.” NASA adds that “objects causing fireballs are usually not large enough to survive passage through the Earth’s atmosphere intact, although fragments, or meteorites, are sometimes recovered on the ground.”
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