Sighting in Marly, February 25, 2018

At about 3:30 in the morning, a motorist was driving under a clear, starry sky when they noticed a bright white ball of light in the sky. It seemed to move along with them, then stop at the moment they brought their vehicle to a halt. They heard no sound. A passenger filmed the phenomenon. GEIPAN collected only one witness account.

The investigation found that the case is a very good example of the "following ball" illusion, which arises when a celestial body is mistaken for something else by an observer who is moving. The witness did not recognise the object as an astronomical body and took it for a nearby phenomenon. As long as the car held a roughly constant heading, the body stayed fixed relative to the vehicle and moved past with the landscape. The witness perceived this as an object travelling alongside the car, with starts and stops. When the car's heading changed, the object's apparent position relative to the road changed as well. The witness's video illustrates these effects well.

A reconstruction at two points along the route, once with Jupiter in line with the road and once to the left, shows unequivocally that the object was Jupiter, which was very bright that night. GEIPAN therefore classified the case as A: observation of Jupiter.