A few years from now, a small radio telescope on the far side of the moon could help scientists peer into the universe's ancient past.
The moon instrument, called the Lunar Surface Electromagnetics Experiment-Night (LuSEE-Night), is a pathfinder being developed by the U.S. Department of Energy's Brookhaven and Lawrence Berkeley National Laboratories, the Space Science Laboratory at the University of California, Berkeley, and NASA's Science Mission Directorate.
LuSEE-Night is currently scheduled to launch on a private robotic lunar lander in late 2025. After it touches down on the moon's far side, it will attempt to gather first-of-their-kind measurements from the "Dark Ages" of the universe.
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The Dark Ages refers to a time in the early universe, between about 400,000 and 400 million years after the Big Bang, before stars and galaxies began to fully form. From the far side of the moon, LuSEE-Night will use onboard antennas, radio receivers and a spectrometer to measure faint radio waves from the Dark Ages, in search of what scientists are calling the Dark Ages Signal.
"So far, we can only make predictions about earlier stages of the universe using a benchmark called the cosmic microwave background. The Dark Ages Signal would provide a new benchmark," Brookhaven physicist Anže Slosar said in a statement. "And if predictions based on each benchmark don't match, that means we've discovered new physics."
LuSEE-Night isn't necessarily expected to make such big breakthroughs all by itself; after all, it's a pathfinder designed to pave the way for more ambitious instruments down the road. The larger project could end up shedding light on such big cosmic questions as the nature of dark energy and the creation of the universe, team members said.
The far side of the moon is a great place to look for the faint signals that could hold such clues, because it offers something Earth cannot: a deep and profound silence. Constant radio bombardment across our planet creates an environment too noisy for the supersensitive instruments LuSEE-Night will use. However, the faraway locale presents challenges as well.
Surviving there takes a feat of engineering. Though sometimes mislabeled "the dark side" of the moon, the part of Earth's natural satellite that faces away from us in the night sky does in fact have a day/night cycle, each phase of which lasts about 14 Earth days. Temperatures on the far side of the moon fluctuate between around 250 and minus 280 degrees Fahrenheit (121 and minus 173 degrees Celsius).
So LuSEE-Night will have to be designed to withstand two weeks of intensely unforgiving, non-stop lunar-day sun, as well as remain powered through two weeks of rigidly cold darkness — and do this over and over again. The mission design lifetime on the lunar surface is two years.
"In addition to the significant potential science return, demonstration of the LuSEE-Night lunar night survival technology is critical to performing long-term, high-priority science investigations from the lunar surface," Joel Kearns, deputy associate administrator for exploration in NASA's Science Mission Directorate, said in the same statement.
When it's ready, LuSEE-Night will launch on a future commercial lunar payload services (CLPS) mission, an initiative from NASA that, according the space agency's website, "allows rapid acquisition of lunar delivery services from American companies for payloads that advance capabilities for science, exploration or commercial development of the moon."
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My note. Using cosmology calculators, the redshift for 400,000 to 400 million years after BB is 1050 to about 11.5 or so. JWST already reports galaxies in the 11-13 redshift range now. It will be interesting to see the confirmation of H-alpha line and H1 21-cm line too, demonstrating that the early universe was indeed filled with hydrogen gas when the CMBR appeared as light. There is the issue of comoving radial distances too for these large redshifts for the Dark Ages and how fast space is expanding, multiples of the speed of light.
H-alpha has too little redshift to reach the radio band.
Is there some band of energies that we can't detect? I don't think so. We are detecting the "Cosmic Microwave Background" which is supposedly black body radiation from hydrogen at 1080 red shift. So, can't we devise some sort of "radio" or "IR" telescope to see whatever frequencies we need to see in the 1080 to 11 range of redshifts?
I agree that getting them to work on the far side of the Moon is an engineering puzzle to be solved.
For that matter, it would be nice if this article had explained how data taken by a robotic telescope on the far side of the Moon will send its data to human analysts here on Earth's surface, since its location is intentionally chosen to be out of direct radio line of sight.
And there is also the question about how long it will be before humans have put so many satellites into lunar orbits that we radio-contaminate this "quiet zone" out of usefulness.
Good question. Perhaps a small repeater could be plopped down, The combo use at L1 & L2 would work fairly well, but expensive I would think.
I’d bet there will be a nice base on the far side, someday.
I'm just guessing, of course.