Scientists Find First Direct Radio Signal From Exoplanet

To get from Earth to Pluto in a car (if such a thing were possible), you’d need to drive for about 6,000 years at motorway speeds.

This is just the distance between two planets in a single solar system. One light-year is about six trillion miles; the galaxy to which we belong, the Milky Way, is 100,000 light-years across.

Experts think there could be one to two billion galaxies in the universe. So, perhaps it’s no wonder that scientists have long wondered whether we can really be alone in that unfathomable expanse.

Astronomers have been listening for radio signals and other signs of life and activity for decades now.

And while it’s not linked to life on another planet, a team from the Centre for Astrophysics Harvard & Smithsonian and the University of Oregon has announced an exciting first: they’ve picked up on radio signals that come directly from an exoplanet, or a planet beyond our solar system.

It was transmitted from the not-very-catchily-named exoplanet Beta Pictoris B. That’s important because previously, we’ve only been able to attach a radio signal to an exoplanet’s star, and not the planet itself.

More specifically, the radio signal originated from the planet’s aurora – charged particles interacting with its atmosphere and magnetic field, like our Northern Lights.

Scientists think the source is an aurora because of how the signal behaves. It showed up in “rapid, recurring, and highly circularly polarised bursts”, which you’d expect from conditions like these.

Beta Pictoris B is a “young, massive” planet which orbits the relatively new Beta Pictoris star.

But, the experts write, “no physical mechanism known to cause radio emission in early-type stars can explain the observed emission”.

The paper suggests that this is “the first direct measurement of magnetic field strength for an exoplanet”. It looks like Beta Pictoris B could have a magnetic field thousands of times stronger than Earth’s, possibly strengthened by its rapid spinning (a full Beta Pictoris B day lasts about eight hours).

But this finding might also mean we’re getting better at finding exactly where faraway signals are coming from.

The researchers found signals near Beta Pictoris B using South Africa’s MeerKAT radio telescope, and later narrowed its location down to the specific planet it likely belongs to by looking at active galaxy cores called quasars.

Seven other exoplanets in five solar systems close to Beta Pictoris are now being considered for closer examination.

“A ∼5x to 7x improvement in instrument sensitivity, expected from next-generation radio observatories, will bring them within reach of detection,” the paper, which has not yet been peer-reviewed, added.