UFO Spotted During Venus Transit, Its Identity Revealed

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Sarah Roth
Given its size and transit time, it was either close and small, huge and distant. On the theory that astronomers would have already noticed an asteroid/planet of that size floating by, it’s almost certainly a terrestrial object, probably an airplane.

The object was in the west, heading “up” (towards the observatory in Nashville, ignoring any sideways motion). The distance to the horizon is given by D = sqrt(2*R*h), where R is the radius of the earth and h is the height of the observer. Since the Sun was at 3 degrees of altitude, this formula should be a good way to set limits on the object if it’s terrestrial.

The earth’s radius is 3,963.2 miles. The observatory is 1,050 ft = 0.2 miles above that, so it’s horizon is 39 miles distant. An airplane flying at 40,000 ft (7.5 miles) would have 243 miles to its horizon. So assume it was an airplane flying between 39 and 243 miles away). Commercial jets cruise at 540 miles per hour, so in 38 seconds it would have traveled 5.7 miles. The angular diameter of the sun is 0.53 degrees, and it crossed that arc of 38 seconds. Assuming the airplane was flying straight at us with no sideways motion (and more dubiously, assuming I’m remembering how to do geometry correctly), that yields a distance of roughly 60 miles to the airplane, well within the limits found earlier.

Ron Manly
The object possibly is an aircraft. The flight path appears nearly horizontal when you rotate the video to put north to the upper right and east to the upper left as directions on the celestial sphere would appear near the western horizon from Nashville, the time taken to cross the Sun appear slower than the time needed for a satellite, the silhouette of the object appears larger than the silhouette of a satellite would be, and a satellite would not leave a contrail. A commercial airliner probably would appear larger than the silhouette and therefore would be recognizable. An insect near the telescope might not follow such a steady path. An insect on the front surface of the objective would be completely out of focus and invisible.

A satellite in low earth orbit would travel at about 7.5 km/sec at an altitude of about 300 km. Ignoring the effect of atmospheric refraction a satellite 300 km high and 1,600 km from the observer would make an angle of 3 degrees above the horizon. The satellite would cross the Sun in much less time than 38 seconds unless the orbit of the satellite was nearly tangent to the line of sight from the observer to the satellite, which seems unlikely.

A commercial airliner would be cruising at 450 to 500 knots (230 to 260 m/sec) at an altitude of 30,000 to 40,000 feet (9 to 12 km). Ignoring the effect of atmospheric refraction, an aircraft flying 12 km high would make an angle with the horizon of 3 degrees when it is about 180 km away. An aircraft 180 km distant, flying at 230 m/sec would move an angular distance of 1/2 degree in 38 seconds if the course of the aircraft relative to the observer’s line of sight was roughly 10 degrees. An airliner with a wingspan of about 30 meters and 180 km away would appear to be about half the size of Venus and should be recognizable. A jet fighter would be smaller, and might cruise higher, therefore being more distant. I don’t know how fast the Air Force operates jet fighters over populated US territory, except that to conserve fuel and to prevent sonic booms they probably avoid going supersonic.

David Resuehr
It’s an airliner. The angular speed and the size of the object match a typical airliner flying at a distance of 160 miles from the observer. Typical values for airliner of speed = 500 mph, length = 100 ft, and altitude = 40,000 ft. The key is to draw the triangle from observer to aircraft to subaircraft point to observer. The sun is 3deg above the horizon, which is the angle at the observer in that triangle. With those numbers, the typical airliner would be approximately 160 miles from the observer. And, with that, the sun would be crossed in 1 minute and that the aircraft would subtend 1e-4 radians, which matches the size of Earth on the Sun as observed from Earth

Dan (who did not give a last name, posted on June 11th at 5:04 PM)
It’s clearly a commercial jet flying at a high altitude and a great distance away. The sun being at only about 3 degrees altitude would allow for anything farther away in the upper atmosphere to be more visible. This is most likely what happened. Another reason I believe this is the case is because I observed this scenario while watching the transit on my own scope, and the jet, although a bit closer, was traveling in the same plane as this object. If it’s not a commercial jet, it’s at least something in Earth’s atmosphere.

Contacts and sources: 
Liz Entman,