Venus’ Mini Satellite Is the First Identified Quasi-moon in the Solar System; Zoozve Earned Its Name by Human Error

In our Solar System, Venus and Mercury are the only planets without moons. More than two decades ago, the first quasi-moon in the solar system was identified and found orbiting Venus.

(Photo: Wikimedia Commons/ Jet Propulsion Laboratory. California Institute of Technology)

Weird Little Moon

A quasi-moon refers to a celestial body that does not directly orbit a planet but shares a similar orbital path to that planet. While true moons maintain a relatively consistent distance from their planet, quasi-moons follow complex paths relative to the planet. This is caused by the combined gravitational influences of the planet and the Sun.

In 2002, astronomer Brian Skiff of Lowell Observatory discovered the first known quasi-moon. It was initially named VE68, or more precisely 2002VE68. This unusual object is an asteroid that appears to orbit Venus but is not gravitationally bound to it. It has an unstable path, which means that it will eventually be ejected from its quasi-satellite orbit.

A 2005 paper described the quasi-moon as having an orbit that takes it far afield from Venus. It passes within the orbit of Mercury as it dives in towards the Sun and travels outwards just beyond the orbit of the Earth. This path takes the shape of a butterfly since the asteroid and Venus travel around the Sun nearly in lock-step.

Such behavior means that VE68 has a very special property, as observed from Venus. This quasi-moon appears to travel around the Venusian sky about once every year. Without knowing that VE68 is traveling around the Sun, someone might assume that Venus has a moon of its own.

Since 1913, quasi-moons of this kind had been predicted as a theoretical possibility. However, none had been discovered until Skiff spotted and tracked the unusual satellite of Venus. Since then, astronomers have found a quasi-moon of Neptune and seven quasi-moons of Earth.

Unexpected Plot Twist

From its provisional name, the quasi-moon got its name as confirmed by the International Astronomical Union (IAU), the official body responsible for naming objects in the Solar System. It was later called Zoozve, a strange name accidentally given out by human error.

It all began when Radiolab podcast co-host Latif Nasser was putting his two-year-old child to bed. He happened to look at a poster of the solar system on the bedroom wall, and, at that moment, his eyes stopped at Venus, where a moon next to it was labeled "Zoozve."

Nasser was sure Venus had no moons, so he Googled it for confirmation. Sure enough, the Earth's twin planet is moonless, so he called a friend with connections to NASA to ask about Zoozve. She was equally baffled, so she searched for information and quickly found multiple links to the asteroid named 2002 VE68.

Upon receiving the news, Nasser contacted Alex Foster, who created the poster. Foster realized that he had misread his notes and mistook the number "2" for the letter "Z." As a result, he wrote "Zoozve" instead of "2002VE".

Nasser took the next logical step by petitioning the IAU to change the asteroid's provisional name from "2002VE" to "Zoozve." When a new celestial body is discovered, it receives a temporary name until its orbit has been well-established. As per standard procedure, the members of the IAU's Small Bodies Nomenclature Working Group took up the petition and put it to a vote. The body approved the request, and on February 5, it formally announced that the quasi-moon is officially named Zoozve.