China constructs a "artificial moon" to conduct a gravity experiment.

 

Magnets will be used in the 2-foot vacuum chamber to simulate lunar gravity on Earth. (Photo courtesy of Getty Images/Loic Venance)

The researchers claim that a levitating frog inspired their experiment.

Chinese scientists have constructed a "artificial moon" research facility that will allow them to use magnetism to replicate low-gravity settings.

The facility, which is set to open this year, will make gravity "disappear" by using high magnetic fields inside a 2-foot-diameter (60-centimeter) vacuum chamber. The researchers were inspired by a previous experiment in which magnets were used to lift a frog.

The chamber, which will be filled with rocks and dust to imitate the lunar surface, is the "first of its kind in the world," according to Li Ruilin, a geotechnical engineer at the China University of Mining and Technology, and it could maintain such low-gravity conditions for "as long as you want," according to the South China Morning Post.

Scientists intend to utilise the facility to test equipment in low-gravity situations for extended periods of time before sending it to the moon, where gravity is only one-sixth of what it is on Earth. This will allow them to work out any expensive technical hitches, as well as test if certain structures will survive on the moon's surface and examine the practicality of establishing a human community there.

"Some studies, like the impact test, just take a few seconds [in the simulator]," Li explained. "However, other tests, like creep testing, can take many days." Under constant temperature and load, a creep test determines how much a material will deform.

According to the researchers, Andre Geim, a physicist at the University of Manchester in the United Kingdom who earned the satirical Ig Nobel Prize in 2000 for creating an experiment that made a frog float with a magnet, was the inspiration for the chamber.

A phenomenon known as diamagnetic levitation was employed by Geim and is now utilised in the artificial-moon chamber. Atoms are made up of atomic nuclei and tiny electrons that orbit them in little current loops, inducing tiny magnetic fields in the process. The magnetic fields of all the atoms in an object, whether they belong to a drop of water or a frog, usually cancel out, and no material-wide magnetism appears.

When those atoms are exposed to an external magnetic field, however, everything changes: the electrons adjust their speed and produce their own magnetic field to counteract the applied field. If the external magnet is powerful enough, the magnetic force of repulsion between it and the atoms' field will develop strong enough to overcome gravity and levitate the thing — whether it's a sophisticated piece of lunar technology or a befuddled frog — into the air.

The results of the chamber experiments will be used to advise China's lunar exploration programme, Chang'e, named after the Chinese goddess of the moon. Chang'e 4 landed a rover on the far side of the moon in 2019 and Chang'e 5 gathered rock samples from the moon's surface in 2020 as part of this initiative. China has also stated that a lunar research facility will be built on the moon's South Pole by 2029.