Radio signals from an exoplanet have been detected by a team of radio astronomers. Find out how this discovery contributes to the search for life beyond Earth.
Not many scientific observations become known only as “Wow!” Yet, that was the name scientists gave to a radio signal detected back in 1977.
The robust, narrowband signal came from the direction of the constellation Sagittarius. Astronomer Gerry R. Ehman detected it using the Big Ear radio telescope at Ohio State University.
Poring through recorded data, when he saw the anomaly, he wrote “Wow!” beside it on the computer printout. The name stuck, and the Wow! Signal became the subject of widespread speculation, including the idea that it came from a civilization on a distant planet.
The Wow! Signal Became the Subject of Speculation
Forty years later, Antonio Paris of the Center for Planetary Science offered up a more mundane explanation. He released findings in 2017 that suggested that the signal came from a comet in our solar system.
Some scientists, including Ehman, aren’t convinced by the comet hypothesis. Today, the source of the Wow! Signal remains controversial.
Now, a research team may be stirring up a new and similar controversy. The group is reporting in the journal Astronomy and Astrophysics that they have detected a radio signal from the direction of the constellation Bootes.
Radio Signal Originated from a Planet
The team believes that the signal originated from a planet orbiting the star Tau Bootes. One of the study’s co-authors is Jake Turner, a postdoctoral researcher at Cornell University.
He explained their findings this way, “The signal is from the Tau Boötes system, which contains a binary star and an exoplanet. We make the case for an emission by the planet itself. From the strength and polarization of the radio signal and the planet’s magnetic field, it is compatible with theoretical predictions.”
The planet from which they believe the signals originated falls under a category known as “hot Jupiters.” These are gas giant planets, but unlike Jupiter, they’re very close to their suns.
First Emission with a Significant Radio Signature
Tau Bootes is about 51 light-years away. Although the team has picked up faint, possible radio emissions from the directions of star systems in the constellations Cancer and Andromeda, the Tau Bootes signal is the first time they’ve found an emission with a significant radio signature.
Whenever scientists suspect that they’ve detected a radio signal from a planet, their discovery ignites speculation that the emission comes from an alien civilization. Disappointingly, a hot Jupiter planet orbiting a binary star is a poor candidate for hosting intelligent life.
The radio emissions the team has detected are probably tied to the planet’s magnetic field. So, in a roundabout way, this could still lead to discovering life on other exoplanets because magnetic fields seem crucial to the origin of living things.
Probably Tied to Planet’s Magnetic Field
Earth’s magnetic field shields us from the charged particles that make up the solar wind and cosmic rays. Turner explains, ““The magnetic field of Earth-like exoplanets may contribute to their possible habitability by shielding their own atmospheres from solar wind and cosmic rays, and protecting the planet from atmospheric loss.”
Scientists may find ways to refine the team’s techniques and identify magnetic fields on smaller planets. Determining which of the Earth-like planets we’ve observed have magnetic fields would help narrow the search for life.
The team didn’t discover these radio emissions by chance. They’ve been planning their approach for more than two years.
Planning Their Approach for More than Two Years
They started out by looking at the radio signature of Jupiter. Then, they calculated what that signal would like if Jupiter were anywhere between 40 and 100 light-years away.
Then, they started combing through more than 100 hours of observation data from a radio telescope in the Netherlands called the Low-Frequency Array (LOFAR). They found that LOFAR had received signals that matched the model they had created based on Jupiter.
As Turner succinctly explains, “We learned from our own Jupiter what this kind of detection looks like. We went searching for it, and we found it,”
Need for Follow-Up Observations Is Crucial
Their discovery is still controversial, though, because the signal is somewhat weak. Turner would be the first to acknowledge this. He qualified his findings, saying, ““There remains some uncertainty that the detected radio signal is from the planet. The need for follow-up observations is critical.”
Now the team is working through data from various other radio telescopes. They’re hoping to either confirm or falsify their theory on the source of the signal from Tau Bootes.
Studying the cosmos has many benefits for humanity, including the simple sense of awe it instills in us. Even so, if the truth were told, most stargazers are after the answer to the simple question, “Are we alone?”
Demands to Know If There Is Life on Other Worlds
Our innate curiosity seems to demand to know whether life exists on other worlds, if that life is intelligent and if we can communicate with it. Science is gradually homing in on a fact-based story with meaningful answers to these profound questions.
Turner’s postdoctoral advisor, Professor Ray Jayawardhana, is also a member of the research team. He added that “If confirmed through follow-up observations, this radio detection opens up a new window on exoplanets, giving us a novel way to examine alien worlds that are tens of light-years away.”
We always have more to learn if we dare to know.
Learn more:
Cornell postdoc detects possible exoplanet radio emission
The search for radio emission from the exoplanetary systems 55 Cancri, upsilon Andromedae, and tau Boötis using LOFAR beam-formed observations
Astrobiology: 3 Questions We Need to Answer
Earth-Like Planets Orbit Half of All Sun-Like Stars
Intelligent Life on Other Planets: Odd of Finding It
