科学美国人60秒:Jupiter Crackles with Polar Lightning

Thirty-nine years ago, Voyager 1 swung by Jupiter on its journey to interstellar space. As it did, it picked up spooky low-frequency radio signals <CLIP: Voyager 1 whistlers>

The whistlers, as they're known, were radio broadcasts from unusual, natural antennas: lightning bolts, which act like radio transmitters, with current moving through a channel. 

Along with photos of the dark side of the planet, the whistlers confirmed the existence of lightning on Jupiter. But the limited observations made it hard to pin down where electrical storms gathered… and the bolts were thought to be rare, compared to Earth.

Now the Juno spacecraft has detected the first high-frequency radio signals, and 1,600 new whistlers <CLIP: Juno whistlers>..., which together suggest lightning on Jupiter is much more common than scientists thought. And a lot more similar to Earth lightning, too. The discharges also appear to be between clouds containing liquid water and others containing water ice…, the same kind of conditions for cloud-to-cloud lightning here on Earth.

The findings appear in the journals Nature and Nature Astronomy. [Ivana Kolmašová et al., Discovery of rapid whistlers close to Jupiter implying lightning rates similar to those on Earth and Shannon Brown et al., Prevalent lightning sferics at 600 megahertz near Jupiter’s poles]

There is one twist to this Jovian weather story: Jupiter's lightning storms congregate near the planet's poles, not its equator—the opposite of Earth. A detail that makes this familiar phenomenon still seem a bit otherworldly.

—Christopher Intagliata