The rush to return humans to the moon and build lunar bases could threaten astronomy’s prospects

The 2020s have seen many moon landing attempts, although several have crashed or fallen over. With all the excitement surrounding the prospect of humans returning to the moon, both commercial interests and scientists will benefit.

The moon is ideal for researchers to build telescopes that they can’t place on Earth, because it doesn’t have as much satellite interference as Earth, nor a magnetic field to block radio waves. But only recently have astronomers like me started to think about possible conflicts between the desire to expand knowledge of the universe on the one hand and geopolitical rivalry and commercial profit on the other, and how to balance these interests.

As an astronomer and co-chair of the International Astronomical Union’s Astronomy from the Moon working group, I am on the hook to explore this question.

Everyone to the South Pole

By 2035 – only about a decade away – US and Chinese rockets could be carrying people to longer-term lunar bases.

Both bases are planned for the same small areas near the south pole because of the near-constant solar energy available in this region and the rich water source that scientists say can be found in the darkest nearby areas of the moon.

Unlike the Earth, the moon is not tilted in relation to its orbit around the sun. As a result, the sun circles the horizon near the poles and almost never sets on some crater rims. There, the never-setting sun casts long shadows over nearby craters, hiding their floors from direct sunlight for the past 4 billion years, 90% of the age of the solar system.

These craters are actually pits of eternal darkness. And it’s not only dark there, it’s also cold: below -250 degrees Celsius. It’s so cold that scientists predict that water in the form of ice at the bottom of these craters — likely brought in by ancient asteroids that collided with the moon’s surface — won’t melt or evaporate for a very long time.

A close-up of the moon's surface, with the left half covered in shadow and the right half visible, with gray craters.  Small blue dots in the center indicate PSRs.

Research from orbit around the Moon suggests that these craters, called permanently shadowed areas, could contain half a billion tons of water.

The constant sunlight for solar energy and the proximity of frozen water make the moon’s poles attractive for human bases. The bases will also need water for drinking, washing dishes and growing crops to feed hungry astronauts. It is hopelessly expensive to extract long-term water supplies from the Earth, so a local watering hole is a big deal.

Telescopes on the moon

For decades, astronomers had ignored the moon as a potential location for telescopes because it was simply not feasible to build them there. But human bases offer new possibilities.

The radio-shielded far side of the moon, the part we never see from Earth, allows for the recording of very low-frequency radio waves. These signals likely contain hallmarks of the universe’s “Dark Ages,” a time before stars or galaxies formed.

Astronomers could also place gravitational wave detectors at the poles, because these detectors are extremely sensitive and the moon’s polar regions are not disrupted by earthquakes as they are on Earth.

Using a gravitational wave detector on the moon, scientists can collect data from pairs of black holes orbiting very closely around each other just before they merge. By predicting where and when they will merge, astronomers know where and when to look for a flash of light they would otherwise miss. With those extra clues, scientists could learn how these black holes form and how they evolve.

The cold at the moon’s poles also makes infrared telescopes much more sensitive by shifting the telescopes’ blackbody radiation to longer wavelengths. These telescopes could give astronomers new tools to search for life on Earth-like planets outside the solar system.

And more ideas keep coming. Next year the first radio antennas will land on the other side.

Conflicting interests

But the rush to build bases on the moon could disrupt the very conditions that make the moon so attractive for exploration in the first place. Although the moon’s surface area is larger than that of Africa, human explorers and astronomers want to visit the same few-mile sites.

But activities that will maintain human presence on the moon, such as water mining, will cause tremors that could ruin a gravitational wave telescope.

Furthermore, many elements found on the moon are extremely valuable on Earth. Liquid hydrogen and oxygen make precious rocket fuel, and helium-3 is a rare substance used to improve quantum computers.

But one of the few places on the moon rich in helium-3 is found in one of the most likely places to place a radio telescope on the far side of Earth.

Finally, at least two Internet and GPS satellite constellations are planned to orbit the moon in a few years. Accidental radio transmissions from these satellites could render a medieval telescope useless.

Now is the time

But a compromise is not excluded. There may be a few alternative places to place each telescope.

In 2024, the International Astronomical Union formed the Astronomy from the Moon working group to begin defining which locations astronomers want to preserve for their work. This involves ranking the sites according to their importance for each type of telescope and discussions with a key United Nations committee. These steps could help astronomers, astronauts from multiple countries and private interests share the moon.

This article is republished from The Conversation, an independent nonprofit organization providing facts and trusted analysis to help you understand our complex world. It was written by: Martin Elvis, Smithsonian attitude

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Martin Elvis is co-chair of the International Astronomical Union Working Group on Astronomy from the Moon

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