If the thought of receiving radio signals in space conjures up the image of Jodie Foster in the movie Contact personhunched over a computer console and listening to spacecraft programs beamed to Earth by intelligent beings from Vega, which are, um, a a decent first step in understanding what scientists think when they listen to space radio signals. It’s honestly a little cinematic, but that doesn’t make it boring.
Radio telescopes – most famously the Arecibo Observatory in Puerto Rico, but also scattered in deserts around the world – are not really for detecting intentional communication signals from extraterrestrials. That would be like having the eyes in your head to see rabid grizzly bears. That wouldn’t be an abuse, but it’s not an explanation of why they exist.
Radio signals are constantly appearing in deep space. Here they really are.
In fact, radio telescopes are like eyes in your head, because they don’t listen, as the word “radio” suggests, etc. to see what is sometimes called the “radio sky,” meaning everything found in the broad spectrum of emissions emitted by the cosmos itself at Earth’s peak – things like pulsar beacons, solar flares and their effects, and microwave background radiation of the universe. But the radio sky also includes signals from closer to home like space probes and even orbiting satellites.
In 2024, radio receivers on Earth and on Earth are picking up a variety of interesting emissions, some of which are mysterious, none of which may be from space invaders, and all of which are more interesting than fiction. Here are five of the most impressive signals for 2024:
Inexplicably slow heartbeat
Picked up by the Australian Square Kilometer Array Pathfinder (ASKAP) radio telescope, this signal known as ASKAP J193505.1+214841.0 was spotted earlier this year, but the team that found it published their findings in June 2024. This is a very confusing radio signal. signal that it repeats approximately every hour – every 53.8 minutes to be more precise. That’s too slow for anything astronomers currently understand.
Mashable Light Speed
The gap between ASKAP J193505.1+214841.0 is too slow to be a pulsar, as pulsars come from rapidly rotating neutron stars – literally achieving RPMs like a slow drill. The length of this newly discovered gap has left scientists baffled until now, but every new discovery about nature begins as the discovery of something that should be “impossible.”
A powerful, distant explosion
Imagine “staring” up into the radio sky (we’re talking about imagery here). To the radio stargazer, bursts of radio waves known as fast radio bursts (FRBs) can be seen as blinding flashes that temporarily drown out all other signals before quickly disappearing. FRB 20220610A is a powerful radio burst – which happened to travel through space for 8 billion years before being observed. That is old; The Big Bang was 13.8 billion years ago.
Not only is FRB 20220610A — again discovered by ASKAP, this time with the help of the Hubble Space Telescope — one of the most distant FRBs ever discovered, but it’s also one of the “brightest” (in fact very enthusiastic) bursts of radio signals that were once picked up by human receivers. The source may have been an area in space with “seven galaxies on their way to converge,” according to a NASA blog post about the discovery.
Radio pollution from Elon Musk
Researchers in the past have already complained about problematic signals provided by the more than 6,000 Starlink satellites operated by SpaceX that orbit the Earth, transmitting data to Internet users here on Earth. The signal emitted by satellites represents unwanted noise to some instruments trying to scan the radio sky. However, researchers at the LOFAR observatory in the Netherlands found in 2024 that the new V2-mini line of satellites emit 32 times more unwanted noise than previous Starlink models.
Starlink noise blocks astronomers’ detection of certain low-frequency signals needed to study exoplanets, black holes, and ancient cosmic phenomena. It has become common practice for legislation to intervene to protect radio telescopes from such noise. Radio-quiet zones exist to their advantage, but these zones are controlled by things like interference from nearby cell phones, and they don’t say anything about things launched into space. Satellite-based radio emissions are an unregulated frontier, and Starlink has launched about 6,000 satellites into that regulatory space. Thanks as always, Elon!
Another FRB with important clues for scientists
Another FRB sheds light on the mysterious origin of the giant radio signal burst in 2024. This is a new discovery from the study of so-called magnetic phenomena – in this case the magnetar SGR 1935+2154, which emitted its impressive signal in 2020. After identifying the source of the magnetar SGR 1935+2154, the team at Caltech’s Deep Synoptic Array-110 (DSA-110) now says that such signals come from neutron stars in massive, metal-rich star-forming galaxies. This discovery greatly reduces the probability of finding neutron stars with the attributes of creating an FRB, meaning that our understanding of where these extreme events occur is becoming clearer.