Radio waves emitted by human technology, such as cell phones and broadcast towers, continuously spread into space. Astronomers have estimated that these radio waves have reached 75 nearby star systems, serving as a signal to any potential extraterrestrial civilization that Earth harbors a technologically advanced species. While scientists have been listening to the ongoing radio transmissions from our planet for quite some time, they recently detected these signals originating from the moon for the first time.
During late February, a small radio telescope on the Odysseus spacecraft, which successfully landed on the moon on February 22, captured radio waves transmitted from Earth for a duration of 1.5 hours. This experiment, known as ROLSES, conducted its observations from Odysseus’ landing site near the Malapert A crater, located approximately 185 miles (297 kilometers) away from the moon’s south pole.
Astrophysicist Jack Burns, a co-investigator of the ROLSES project at the University of Colorado Boulder, referred to this moment as the “beginning of radio astronomy from the moon.” The goal is to study Earth as if it were an exoplanet in order to search for similar signals emitted by planets around other stars, which could potentially indicate the presence of intelligent life.
During a presentation at the 244th meeting of the American Astronomical Society, Burns displayed an image on the screen showing small white dots scattered across a dark background, forming mostly horizontal lines. He explained that these white specks are radio signals captured by the ROLSES experiment’s four antennas, originating from transmitters on Earth. Burns emphasized that this image is an unprecedented “frequency selfie” of Earth in radio wavelengths, surpassing any previous observations.
During its historic landing on February 22nd, the 14-foot (4.3-meter) Odysseus spacecraft experienced a faster descent than planned, causing it to tip over on its side. This was likely due to the spacecraft fracturing one or two of its landing legs after striking lunar terrain. As a result, the spacecraft’s antennas were not pointing back at Earth, significantly reducing the rate at which data could be transmitted.
Due to these issues, the ROLSES instrument was only able to record data for a total of two hours, instead of the desired eight days. This shortened recording time will impact the signal-to-noise ratio of the collected data. It remains uncertain whether the researchers will be able to decode the transmissions and determine the content of the radio waves.
In the provided image, we can see a gray depiction of the moon’s surface from a high altitude. On the right side, a magnified blue rectangle highlights a specific area of interest.
A grayscale image of the moon’s surface taken from a high altitude. On the right, there is a magnified blue rectangle.
During the mission, the researchers unexpectedly obtained 20 minutes of data when one of the antennas on the lander, named Odysseus, became slightly overheated and dislodged from its secure position. “We took advantage of this situation and turned on our radio spectrometer, resulting in some valuable data,” explained Burns.
After a week of operations on the moon, Odysseus went silent on February 29 when the lunar nightfall reached its landing site. This was expected, as the spacecraft was not designed to withstand the extreme cold of the lunar night. On March 20, when sunlight once again reached Odysseus’ solar panels, the Houston-based company Intuitive Machines, which constructed the spacecraft, attempted to receive its wake-up signal but was unsuccessful. Three days later, the company officially announced that Odysseus had permanently ceased functioning, solidifying its place in history as the first commercial lunar lander to successfully touch down on the moon.
Astronomers, including Burns, are eagerly anticipating the launch of a new small radio telescope, called LuSEE-Night, which is scheduled to be sent to the far side of the moon in 2026. This telescope is specifically designed to capture radio waves that originated 13.4 billion years ago during a fascinating period known as the cosmic Dark Ages. During this era, the universe was shrouded in a mist of hydrogen, concealing its first stars and galaxies. The James Webb Space Telescope has just started exploring this epoch, and LuSEE-Night will further contribute to our understanding of this mysterious time.