Telescopes on the Moon Will Let Astronomers See the Earliest Moments of the Universe in Stunning Detail
Earth’s surface is littered with the instruments of radio astronomy: There are giant dishes or clusters of individual antennae in West Virginia, Puerto Rico, China, Chile, Australia and South Africa, among many others. But that isn’t enough to satisfy some astronomers, who dream of setting up shop at a still more exotic locale—the far side of the moon.
It sounds like a wild stunt and would be incredibly expensive to implement, but there’s a very real need driving astronomers to consider the concept. Radio astronomers gather light with the very longest wavelengths, which means it can cross the entire universe, albeit as a faint signal. That makes it scientists’ best hope for studying the very beginning of the universe, since the farther light has traveled to reach us, the older it is.
But that super-faint ancient light has a ton of competition: Radio waves are what we humans use to power huge swathes of our communications technology, since they can cover long distances and we know how to encode information in them. And no matter how good your radio telescope is, it will always struggle to focus on light from a star 12 billion light-years away when a cell phone is blaring just 12 yards away. And the cell phones—and GPS satellites and television signals and Wi-Fi networks and every other form of radio broadcast—are everywhere, forming a barrage that scientists call interference.
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Which, let’s be clear, is good for humans. “Scientists are people too, we like our cell phones,” Liese van Zee, a radio astronomer at Indiana University, told Newsweek. That’s why she and a handful of colleagues lead the Committee on Radio Frequencies, a group of scientists that works with the Federal Communications Commission to make sure regulations take scientific needs into consideration, like banning the signals that most strongly interfere with observations.
Making deals will never be enough to rescue radio astronomy from interference but maybe the moon could be—quite literally, since the whole appeal is that the sheer bulk of the moon blocks all those radio waves from ever reaching the far side. “The far side of the Moon is the best place in the entire inner solar system” for radio astronomy, Joseph Silk, an astronomer at Johns Hopkins University, told Newsweek.
Of course, the logistics are challenging, to put it mildly: Humans haven’t even set foot on the moon since 1972. But Silk argues that much of the infrastructure scientists would need to do to support the telescopes would fit fairly smoothly into current Trump administration plans to return to the moon. If we’re setting up camp there anyway, he says, we may as well set up some telescopes as well.
“All of this is futuristic, it's going to take time,” Silk added. “But in principle, there should be no reason why we can’t do this.” Much of the construction work could be accomplished by robots, he says, although they would need some human overseers nearby to cut down on communications delays that would occur with Earth. “One can imagine just covering this large area on the moon with telescopes,” Silk said—potentially hundreds of them.
But lots of people dream about the moon, and other schemes could interfere with radio astronomy. “This is the one quiet place in our solar system, which we preserved,” says Jill Tarter, an astronomer at the SETI Institute who uses a California-based radio telescope array as part of the scientific search for extraterrestrial intelligence. “We’re now thinking about fantastic new space opportunities that could very well pollute it before we get a chance to exploit it for radio astronomy.”
That means that even without any current plans to build an observatory on the moon, it would be worth planning ahead to make sure we don’t bungle our chances, creating just the same problems on the moon as we have here on Earth. Tarter suggests that wannabe lunar communicators could build systems that can flip between settings so as to interfere less with astronomy, or establish a sort of timeshare arrangement. “The only opportunity that we have for that kind of thinking is the moon,” she adds.