Earth’s ‘Mini-Moons’ Offer Great Potential For Space Exploration

Unlike other planets in the solar system with moons, the Earth only has a single lonely moon. Unless the mini-moons count, of course.

What Are Mini-Moons?

Mini-moons aren't permanent fixtures, but asteroids that stick around for a time and orbit Earth temporarily.

In the review published in the journal of Frontiers in Astronomy and Space Science, researchers suggest that these space rocks can provide scientists with a good testing ground in near-Earth space.

"These asteroids are delivered towards Earth from the main asteroid belt between Mars and Jupiter via gravitational interactions with the Sun and planets in our solar system," Dr. Robert Jedicke, lead author of the recent study, says in a statement.

Each mini-moon is predicted to be around 3 to 6 feet (1 to 2 meters) in size. They're caught in the gravity of Earth's system, possibly simply making a fly-by or even completing at least one revolution around the planet. Eventually, these mini-moons either break free of the gravitational pull or enter the atmosphere.

Unfortunately, these cosmic objects have steered clear of detection so far. Despite their close proximity, existing technology can only find these mini-moons by chance and scientists have only confirmed the existence of one: 2006 RH120.

The Future Of These Mini-Moons

With technological advances such as the ultra-powerful Large Synoptic Survey Telescope in Chile that is currently under construction, this record could shoot up as astronomers become more capable of detecting and tracking these mini-moons.

The LSST is expected to be completed in the next few years, which is good news for those who are eager to study the planet's mini-moons.

The presence of these temporarily orbiting space rocks in the Earth system gives scientists the opportunity to test and troubleshoot their technology and missions somewhere relatively close.

"Once we start finding mini-moons at a greater rate they will be perfect targets for satellite missions," Jedicke says. "We can launch short and therefore cheaper missions, using them as testbeds for larger space missions and providing an opportunity for the fledgling asteroid mining industry to test their technology."

Furthermore, coauthor Dr. Mikael Granvik adds that mini-moons will also allow a closer and more intimate analysis of asteroids. Astronomers can observe orbiting ones more thoroughly and probes can even bring back chunks of the material to be studied.

"I hope that humans will someday venture into the solar system to explore the planets, asteroids and comets — and I see mini-moons as the first stepping stones on that voyage," Jedicke concludes.