As the predictions of modern theories in particle physics reach ever-higher energy levels, physicists are thinking of solutions to increase the power developed by particle accelerators. The simplest solution would undoubtedly be to build a new collider on Earth which would be the successor of the LHC. However, another solution would be to build this collider on the Moon. Very low temperatures, natural vacuum and gravitational locking with the Earth, so many arguments in favour of the construction of a lunar successor at the LHC.
As we deepen our knowledge of the Universe, our particle physics experiments have become increasingly complex. In order to reveal the secrets of the smallest subatomic particles, physicists must keep colliders and detectors as cool as possible, remove as much air as possible, and keep them as still as possible to obtain reliable results.
The question of placing these technologies on the Moon then arose. A proposal published on arXiv earlier this year argues that the Moon is actually a fairly optimized place to do high energy physics. First, it’s cold. Very cold. Without an atmosphere and without water, there is nothing to transport the heat of the Sun from one place to another. At night, with the Sun under the horizon, temperatures drop to -73 degrees C; in the range of typical cryogenic configurations on Earth.
Very low temperatures: they are necessary to maintain the superconducting magnets
During the day, the surface heats up a bit, reaching over 38 ° C in places. But as the ice hidden in the shadow of the lunar craters proves, all you need to cool the environment is a little shade. Again, without air or water, the areas away from direct sunlight are extremely cold.
Physicists need these cold temperatures for several reasons. In accelerators, cold temperatures ensure that the superconducting magnets – used to project particles inside the accelerator at speeds close to that of light – do not deteriorate. Second, the warmer a detector is, the more you have to fight against background noise to unravel the tiny signals of subatomic particles (more heat equals more vibrating molecules, which equals more noise).
A natural moon vacuum suitable for collision pipes and detectors
Besides the cool temperatures, the fact that the Moon has no atmosphere is also a boon. Physicists must create a vacuum within accelerators and detectors. But the Moon has a vacuum 10 times better than anything that physicists have developed in their experiments. And it is done naturally, without any effort.
Finally, due to the gravitational locking, the Moon always keeps the same face pointed towards the Earth. This means that a beam of particles from the Moon could be directed to a detection laboratory on Earth, taking advantage of the long-distance without having to exert much effort to align the configuration.
Lunar neutrino production to better study the oscillation phenomenon
The most promising use of a lunar physics experiment would be as a source of neutrinos. Needless to say, neutrinos are difficult to study and understand. They’re manufactured in large quantities in nuclear reactions, so all it would take would be to install a nuclear power plant on the Moon. The neutrinos it would produce would arrive on Earth, where we could capture and study them.
A property of neutrinos is that they are able to change type (or flavour) when they propagate; a phenomenon known as oscillation. With the long distance between neutrino generation and detection, we are giving more neutrinos a chance to “change flavour” and we can better understand this behaviour. The Moon is a perfect source: it is far enough away that we can get long distances, but close enough so that we can capture neutrinos in sufficient quantities to actually study them (and probably troubleshoot the installation if there is a problem).