The far side of the Moon is one of the most radio-quiet locations in the Earth-Moon system, which makes it an favorable spot for the Search for Extraterrestrial Intelligence (SETI), which scans the skies for radio communications.

Radio telescopes on Earth are located in isolated parts of the globe with minimal radio pollution, but they can’t compare to the far side of the Moon for blocking out radio interference. The idea is not a new one, but it has gotten fresh life thanks to a white paper submitted to the National Academy of Sciences’ Planetary Science and Astrobiology Decadal Survey 2023-2032. The team is led by Eric J. Michaud, a mathematics undergraduate at UC Berkeley, reports Phys.org.

The need to establish a site for a radio telescope is pressing, says Dr. Pete Worden, former director of NASA’s Ames Research Center. “There is some urgency in establishing a lunar far-side radio-quiet reserve before we get the burgeoning problem we have in Earth orbit with optical interference from communications satellites. We are already concerned about the Chinese communications satellites—so this needs to be a global consensus now!”

Radio noise could be mitigated all the more if the telescope were located in a crater. Crater walls would block out interference from orbiters or spacecraft that will become increasingly common on the Moon.

A lunar location would have two big drawbacks: One would be the cost of delivering the telescope to the far side of the Moon. Another, assuming the main energy source was solar, would be the difficulty of storing enough energy to last a two-week lunar night.

An alternative to a ground facility would be a telescope deployed in lunar orbit. One bonus: the weightlessness of orbit would do away with the need for a supporting structure. But the nature of the Moon’s gravitational field means that most lunar orbits are inherently unstable, which creates a new set of problems.

As Michaud concedes, much work needs to be done before the dream of a lunar SETI observatory can be realized.

Bacon’s bottom line: If the technical hurdles can be addressed, a SETI mission could add impetus to building a lunar transportation and logistical infrastructure and possibly a justification for maintaining a scientific staff on the Moon. Scientific investigation will lead the way in early lunar development.

Scientists at the Colorado University-Boulder have laid out a roadmap for a decade’s worth of scientific research on the Moon. As detailed by a CU publication, four university teams will participate in upcoming or proposed space missions using the Moon as a unique scientific laboratory for peering back to the dawn of the cosmos. The projects include:

• An instrument called Radio wave Observations at the Lunar Surface of the photoElectron Sheath (ROLSES), which is slated to land on the Moon in just over a year.
• Lunar Surface Electromagnetics Experiment (LuSee), which will collect similar data as ROLSES but on the far side of the Moon, where it will be shielded from interference produced by radio waves from Earth.
• A proposed satellite known as the Dark Ages Polarimetry Pathfinder (DAPPER), which could be in orbit around the Moon by mid-decade. The suitcase-sized satellite will carry four wire antennas and a box-shaped “patch” antenna, to pick up incredibly subtle traces of the early universe’s hydrogen clouds.
• Farside Array for Radio Science Investigations of the Dark Ages and Exoplanets, potentially by the end of the decade. FARSIDE will lay out more than 29 miles of wires on the moon’s surface in a spiral pattern to create a gigantic array for detecting cosmic signals.

more “Moon as Platform for Exploring the Universe’s “Dark Age””

High-energy physicists spend billions of dollars building sub-atomic particle colliders on Earth. Among other reasons the facilities are expensive is that they require vacuum conditions and frigid temperatures. As lunar colonization approaches, Nikolai Zaitsev at Cornell University has published a memo suggesting that the Moon might be the most promising location to build a new collider. The Moon may be remote and difficult to reach, but it has several advantages.

First, it’s very cold. Because the Moon has virtually no atmosphere, locations shaded from direct sunlight dip to minus 100 degrees Fahrenheit — in the range of typical cryogenic setups on Earth, summarizes Live Science. Cold temperatures are needed to ensure that the superconducting magnets that accelerate particles to near the speed of light don’t melt down.

Second, atmospheric vacuum comes for free. The Moon has a vacuum 10 times better than anything physicists have manufactured in their experiments, which reduces the number of stray molecules interfering with experiments.

Thirdly, summarizes Live Science, the Moon could serve as a platform for shooting high-energy neutrinos to the Earth and studying how they change “flavors” as they fly. The distance between the Moon and Earth gives them a greater distance to change form but is close enough that it would be possible to capture them in sufficient quantities to study. Similarly, a lunar facility could point particles to Earth for the study of cosmic ray research.