Huge, white, circular shape hanging low in night sky in Union, NJ

I witnessed what I thought at first was a star in the sky. But then I realized it was not blinking so it could not be a star and didn’t have red and blue lights so it couldn’t have been an airplane.
 It was one singular circle in the sky.
 It was bizarrely low in the sky. It was the shape of a perfect circle and was the same color as a star but it was massive in size relative to the stars. It was maybe 4x the size of a star or larger.
 It didn’t appear to be a planet because there was no reddish tint and it was too low in the sky.
 It was perfectly still and I unfortunately lost sight of it because I was in the backseat of a car and we passed by some tall buildings. When the view reappeared the object had seemingly disappeared into thin air.
 Unfortunately, I was the only witness.