Normal view

Received — 24 June 2026 ⏭

Live Science
Something in space may be changing alien signals before they can reach Earth. Scientists have a solution. 23 June 2026 at 17:00

Something in space may be changing alien signals before they can reach Earth. Scientists have a solution.

23 June 2026 at 17:00

Humans have been searching the stars for alien radio signals for decades — and so far, E.T. has not phoned home. But that doesn’t mean intelligent life isn’t out there, a new study hints. Rather, something else could be interfering: according to the research, space weather surrounding alien planets could be preventing us from detecting technological signals from extraterrestrial civilizations.

The findings, published March 5 in The Astrophysical Journal, offer a potential answer to the Fermi paradox: Given the size of the universe, there are many potentially habitable planets that could support life, and yet we have not detected technosignatures from any of them ‪— so, "Where is everyone?" physicist Enrico Fermi famously posited in 1950.

In the new study, researchers found that space weather caused by a planet's star could broaden hypothetical technosignals, dissipating their power over a larger range of frequencies and making them more difficult to detect.

"If a signal gets broadened by its own star's environment, it can slip below our detection thresholds, even if it's there, potentially helping explain some of the radio silence we've seen in technosignature searches," Vishal Gajjar, an astronomer at the SETI Institute and first author of the paper, said in a statement.

One way astronomers search for alien life is by looking for very narrowband signals, which are sharp spikes in the power of a radio emission. This spike usually only covers a few hertz.

"These don't occur naturally," Evan Keane, an astronomer at Trinity College Dublin who was not involved in the research, told Live Science. "So, if you see something very narrowband, you know that it is from something of interest." Astronomers would, for example, be able to easily detect some narrowband technosignatures on Mars, coming from the Mars rovers. But they have not observed any such signals from a clearly non-human origin.

Distorting signals

The new research argues that astronomers may have been looking for the wrong signal shape. In the new study, the researchers found that alien signals could be distorted by stellar space weather surrounding their home stars, which could explain why they have not been detected.

Space weather refers to changes in the space environment caused by charged particles, radiation and giant lumps of plasma called coronal mass ejections emitted by the sun. Other stars also generate space weather in their vicinity.

Gajjar and SETI colleague Grayce Brown investigated how space weather has historically impacted communications between Earth and spacecraft such as Mariner IV, which flew by Mars in the 1960s, and the Viking probes, which launched in 1977 for a voyage through the solar system and beyond. They created one of the largest collections of signal broadening examples and used that information to determine how other sunlike stars would affect the environment around their exoplanets. From this, the team calculated what would happen to a hypothetical alien narrowband signal that originated on one of them.

A graph showing various wavy lines next to an exoplanet with a glowing sun in the middle of the image — A planet’s radio signal may begin as a sharp tone (left, white) but can be spread out by the star’s plasma winds into a wider, fainter signal (right, green). The new study suggests radio astronomers may be missing signals by mostly looking for the sharp white shape instead of the broader green one. (Image credit: Vishal Gajjar)

Then, they turned their attention to M dwarf stars, the most common type in the Milky Way. These stars account for three out of four stars in our galaxy, and some have been around since the early universe. That gives them a lot of time to have developed technologically advanced life, according to the paper.

There are no actual measurements of space weather around these stars, so Gajjar and Brown modeled what might happen to a narrowband technosignal that emerged from exoplanets and had to travel through interplanetary plasma. They found that hypothetical narrowband signals from these exoplanets were more likely to be smeared by space weather, making them even harder to detect.

In the paper, the authors propose a framework to estimate how much broadening would happen to a signal, given its frequency and the type of star its exoplanet was orbiting.

This new framework doesn’t totally answer Fermi’s infamous question, but it does give us a potential reason for the silence. The Fermi paradox "is not solely evidence for the absence of transmitters, but also a reflection of our detection limitations arising from a mismatch between the assumed signal morphology" and shape, the researchers wrote.

A step forward for SETI

Michael Garrett, an astrophysicist at the University of Manchester in the U.K. who was not involved in the study, welcomed the research.

"It is a solid contribution that SETI researchers and signal-processing teams should pay attention to," he told Live Science. "One of the strengths of the paper is that it's grounded in real measurements too, drawing on decades of spacecraft observations."

However, he emphasized that the paper focused on narrowband radio signals, which was only one way of potentially detecting an alien civilization. By contrast, Garrett's work explores the possible combined radio leakage from a technological civilization across a large range of frequencies.

Scientists Warn Extraterrestrial Encounters Could Endanger Earth—a Quarantine Facility on the Moon May Be Our Last Line of Defense

The Debrief

By: Micah Hanks

22 June 2026 at 14:28

During future space missions, humans may finally encounter extraterrestrial life forms, settling the age-old question of whether we are alone in the cosmos. But what if alien biology is so different from that of Earthlings that its presence could become a potential global hazard?

This is the concern raised by researchers Frederick I. Moxley and Anthony Ricciardi in a new study, which argues that in an era of sample return missions and space missions that are carrying humans and our robotic probes farther into the cosmos than ever before, we need to be prepared to enact measures to protect our planet against the unforeseen consequences of any potential alien encounters the future may hold.

“The advancement of space exploration into an era of sample return missions from Mars, asteroids, and icy moons raises the potential for biological contamination either to or from Earth,” the authors write in their recent study, published in the journal Ambio. Given the potential for such contamination, Moxley and Ricciardi approach the question of alien contact from the perspective of past examples where invasive species on Earth have caused major disturbances to the environments they encounter.

“We consider the possibility that extraterrestrial organisms introduced to Earth could behave analogously to invasive species by destabilizing ecosystems or interacting unpredictably with their new environment,” the authors write, pointing to the multitude of examples known to science, many of which involve the introduction of microbial organisms into new environments—often with devastating consequences.

In many cases, such organisms not only can survive in new environments, but can often adapt with remarkable speed, even in some of the most extreme environments.

This, the authors say, challenges the idea that extraterrestrial life might not even be capable of surviving on Earth, as expressed by some past research.

“The plausibility of encountering extraterrestrial life warrants stringent planetary protection measures grounded in biosafety and biosecurity principles,” the authors warn.

So how do they suggest protecting Earth against such potentially catastrophic events involving future encounters with extraterrestrials?

According to Moxley and Ricciardi, building a quarantine facility on the Moon could serve as Earth’s last line of defense against any unintended alien invasions that could radically disrupt Earth’s fragile ecosystems.

“Due to its proximity, natural isolation, and apparent lack of a biosphere, the Moon can serve as a secure site for biocontainment of extraterrestrial samples,” the authors write. In their study, they examine historical instances where biological invasions have led to catastrophic environmental changes and argue that constructing a biocontainment facility on the Moon “should form the cornerstone of modern astrobiological risk mitigation strategies.”

Moon base extraterrestrial — Artist’s concept of a future lunar base (Image Credit: NASA/SAIC/Pat Rawlings)

What the researchers propose falls in line with current plans NASA has for a permanent lunar base, which is one of the many ambitious efforts under its Artemis Mission. Such a lunar outpost, which will serve as the official Artemis Base Camp, is planned for construction near the Moon’s South Pole.

At a cost of close to $30 billion, the effort will help to facilitate an ongoing human presence on the Moon by as soon as 2028, according to current mission timelines, and will serve as a science hub in support of future lunar exploration.

For Moxley and Ricciardi, incorporating a quarantine facility within our future lunar infrastructure that can house any extraterrestrial life forms we may encounter could prove to be vital. Ultimately, having such a facility may play the important role of shielding Earth against unintentional contamination by a potentially invasive alien species.

The team’s recent paper, “Protecting earth from extraterrestrial contamination: The case for a lunar biocontainment facility,” was published in Ambio.

Micah Hanks is the Editor-in-Chief and Co-Founder of The Debrief. A longtime reporter on science, defense, and technology with a focus on space and astronomy, he can be reached at micah@thedebrief.org. Follow him on X @MicahHanks, and at micahhanks.com.