Satellites can fry. Power lines can stop transmitting. And in 1859, a particularly powerful punch known as the Carrington Event sent auroras into the tropics and disrupted telegraph signals, blocking messages.

Now imagine that you’re looking at Earth’s radio signals from afar — alien far. How would the sun’s activity affect our planet’s transmissions as seen from other stars? That thought experiment — brought to life in a recent paper — seems to reveal assumptions that have affected our 60-year-long hunt for extraterrestrial radio signals. Maybe, some scientists suggest, we need a different way of contacting E.T.

Where this conversation goes is likely shaped by the science fiction movies you’ve enjoyed the most; the gamut of reactions runs something like Project Hail Mary at the most optimistic, to Alien at the chest-burstingly pessimistic. But as we explore our methods and limitations of looking for so-called “intelligent” life, the debate illustrates how many assumptions we need to make about life like us, somewhere out there.

Let’s begin with “The Great Silence”, a term recently used by the Search for Extraterrestrial Intelligence (SETI) Institute astronomer Vishal Gajjar, which describes the puzzling lack of signals from aliens after six decades of searches.

“What's going on?” asked Gajjar in a recent talk at an International Astronomical Union symposium about technosignatures, or the search for alien radio signals. “We don't know exactly what SETI might be doing, so that's obviously the one reason,” Gajjar added. But what his team was interested in was whether they were making too many assumptions of narrowband searches — or in his words, “needle-like signals in frequency.”

These thin slices of radio are what radio SETI searches usually look like, but an Astrophysical Journal paper from Gajjar and SETI research intern Grayce C. Brown highlighted issues. Stars, like our sun, are producers of plasma both through coronal mass ejections (blasts of material) as well as the solar wind (the constant stream of charged particles flowing out from a star).

Gajjar focused on scintillation — radio waves changing shape in response to charged particles. He likened the phenomenon to the patterns seen at the bottom of a pool, as visible light goes through the water.

“We kind of somewhat understand what interstellar medium does to a narrowband signal,” he said, pointing to the “phenomenal work” done by the California Institute of Technology’s Joe Lazio, also working on a NASA Jet Propulsion Laboratory mission concerning the sun and radio signals. “They argue that scintillation is a good thing, because sometimes it can enhance the signal by several orders of magnitude.”

But the scientific research focused on scintillation in the interstellar medium, or the environment between stars. To Gajjar’s and Brown’s knowledge, nobody has talked about the interplanetary medium, or the plasma flowing between planets. Or space weather, as NOAA and NASA like to call it.

The solar wind from the sun is not a continuous stream of particles, but it clumps and experiences turbulence. Should a signal go through that turbulence, the new paper suggests the signal would be “smeared” by plasma.

If an extraterrestrial race were detecting an Earth signal from a perspective where our planet was closer to the sun, the smearing caused by local space weather would make the signal drop its power across a wider frequency range. Like a drop of ink blotting and fading across a paper as you run your finger through the color, the signal also faintens, making it harder to detect.

“Is it something we can detect? And the answer is yes, it is quite significant,” Gajjar said. Using measurements from numerous spacecraft, the paper’s authors built a model that ultimately was used as a simulation of observing at the 1 GHz frequency of a million nearby stars. They especially focused on M-dwarfs, which are slightly smaller stars than our sun that are popular for searching for potentially life-friendly worlds, although limitations include that M-dwarfs are quite stormy.

Gajjar and Brown found that “higher wind speed, lower observing frequencies, and high density fluctuation give rise to higher spectral broadening,” he said. Specifically, most systems showed more than 1 Hz of broadening, and M-dwarfs tended to smear signals tenfold more to 10 Hz. If a coronal mass ejection pops up, the signal smears into thousands of Hz. And right there, your hopes of finding aliens fade dramatically.

SETI’s release on the work, summarizing Gajjar’s and Brown’s work, said there might need to be a rethinking of how to do searches in the future. “Search strategies may need to remain sensitive to signals that are slightly wider than traditionally expected,” officials stated.

And that could have implications for the Square Kilometer Array (SKA), a joint South African and Australian radio project, Gajjar said. There would still be time to make adjustments as science operations on the first phase are not expected until 2032, and the SKA team is working on a technosignature paper of their own.

Gajjar said that a forthcoming paper is needed because scientists “do have to worry quite seriously about SKA… especially because when you go to these low frequencies. As I have mentioned in my talk, these effects are some of the most prominent effects that you will probably have to worry about.”

While passive signal searches could be changed as a result of the technosignatures research, there is another direction: perhaps we could deliberately message aliens. That is the aim of projects such as the METI or Messaging Extraterrestrial Intelligence Institute.

The nonprofit research organization is “dedicated to transmitting intentional signals to nearby stars”, according to the biography of its president, Douglas Vakoch. Vakoch is a long-time researcher of SETI and contributor to what some people call “active SETI”, meaning telling the aliens we are here.

Vakoch founded METI in 2016, around the same time that Breakthrough Listen announced a 10-year, $100 million search in a hunt for alien communications. Famed physicist Stephen Hawking, who was alive when Breakthrough launched, expressed some worry about what could happen if we actually find E.T.

“If you look at history, contact between humans and less intelligent organisms has often been disastrous from their point of view, and encounters between civilizations with advanced versus primitive technologies have gone badly for the less advanced,” he told reporters at the Breakthrough announcement, as reported in Time. “A civilization reading one of our messages could be billions of years ahead of us. If so, they will be vastly more powerful, and may not see us as any more valuable than we see bacteria.”

METI responded to those concerns in a 2024 blog post penned by Bob Silberg, a previous long-time science and technology writer for NASA’s Jet Propulsion Laboratory. He acknowledged Hawking’s (and others') concerns about “expos[ing] ourselves to possibly hostile beings who are our technological superiors.”

But as Silberg points out, it’s too late to completely hide because we already have radio waves speeding away from Earth at the speed of light, carrying radio and TV broadcasts. That said, he suggests there are three forms of “extraterrestrial societies”: those who are unable to participate in sending or receiving messages, those who can (like us) but can’t travel long distances, and those who know how to make interstellar hops.

Given that to us, Star Trek and Star Wars star-jumping tech remains far in the realm of science fiction, Silberg said interstellar journeys are “an extremely tough nut to crack, and it's reasonable to think that far fewer extraterrestrial worlds achieve it than.”

Silberg argues that Earth has little to offer them. Natural resources, he said, could be found on other planets much closer to the extraterrestrials’ homes. Slave labor could be achieved with robotics, and human “snacks” (as he put it) would be unlikely given how different evolution would be across different worlds. Granted, alien motives can’t be read, but to Silberg, there is little beyond ordinary caution to exercise.

“Look, when you move into a new home, the safest course of action might be to close the blinds and avoid doing anything that might attract the attention of neighbors who, for all you know, could be serial killers,” Silberg said. “But chances are you'd be better off reasoning that the risk is low, and outweighed by the potential of their becoming interesting and supportive friends.”

All of these discussions about searching via SETI or METI, of course, assume that something is actually out there besides ourselves — as covered in famous arguments like the Fermi paradox and the Drake equation. We don’t quite have the evidence yet to say, one way or another, how many civilizations (as you could term it) might be out there or what their intentions are, but one thing is clear: given the amount of space and time the universe encompasses, we may be in for a very long search.