Supersonic winds blowing at 20,500 miles per hour detected on a giant planet

An exoplanet named WASP-127b just smashed the cosmic wind record. Astronomers clocked supersonic gales racing around its waist at about 20,500 miles (33,000 kilometers) per hour, which is seven times faster than fighter‑jet speed.

“There is an extremely fast circumplanetary jet wind found on the planet. The velocity of the winds is surprisingly high,” said Lisa Nortmann of the University of Göttingen, lead author of the discovery.

The supersonic streak hugs the planet’s equator, which sits 520 light‑years from Earth in the constellation of Virgo.

Jet streams on WASP-127b

WASP‑127b is a hot Jupiter, a gas‑rich world that roasts close to its parent star. Its diameter is 30 percent larger than Jupiter’s, yet its mass is only one‑sixth, giving it a marshmallow‑like density.

That low weight lets starlight puff the atmosphere into a balloon thousands of miles deep, a feature that makes the planet easy to probe with modern telescopes.

Earth’s polar jet stream tops out near 275 mph (442 kph), and Neptune’s famous winds reach about 1,200 mph (1,930 kph).

WASP-127b’s 20,500‑mph (33,000 kph) supersonic gales lap the globe in less than a day, making it the most extreme sustained wind yet measured on any planet.

Chasing the jet with light

Scientists traced the wind using transmission spectroscopy. They watched the star’s light filter through the planet’s atmosphere during each four‑day orbit.

Molecules of water and carbon monoxide left fingerprints that slid in wavelength as the air sped toward and away from us, revealing two clear Doppler peaks.

If the planet merely rotated once per orbit, the equator would move around 1.6 kms^-1 (1 mile s^-1). Instead, the measured equatorial jet reaches about 9 km s^‑1 (5.6 miles s^-1), roughly six times that “tidally locked” pace.

That translates to a Mach number near three, which is well above the local speed of sound in the 2,060°F (1,127 °C) hydrogen‑helium air.

WASP-127b’s puffy atmosphere

The inflated envelope means that light from the star penetrates deeply, driving huge temperature contrasts between day and night.

Such contrasts push gas sideways, setting up the equatorial jet that now defines the planet’s climate.

More than 5,900 confirmed planets are cataloged today, but none show a wind like this. The result widens the gap between solar‑system weather and the extremes seen among exoplanets.

Fueling WASP-127b’s supersonic winds

Researchers think stellar irradiation is the main power source. Air heated on the perpetual day side rushes eastward, overshooting the limb before it can cool.

Modelers also point to the planet’s low gravity, which reduces friction and lets airflow accelerate to dizzying speeds.

The jet’s velocity wasn’t the only surprise. Researchers also found that the poles of WASP‑127b contribute almost nothing to the planet’s transmission spectrum, suggesting they may be veiled by thick clouds or cooled significantly compared to the equator.

That drop in signal matches predictions from general circulation models, where high-latitude air remains colder and more stable while the equator churns with superheated motion.

These regional differences matter, because they help scientists refine how heat and chemicals move across gas giants under extreme conditions.

Lessons for weather models

Earth science uses jet streams to steer storms. On WASP‑127b the jet alone shapes global heat flow, suggesting that “superrotation” may be common on close‑in giants.

Future climate codes must now reproduce both the speed and the double‑peaked pattern seen in the data.

The Very Large Telescope in Chile, newly upgraded with the CRIRES+ infrared spectrograph, supplied the precision needed to isolate 10 kms-1 shifts. CRIRES+ can resolve one part in 140,000, turning subtle molecular lines into a speedometer for alien weather.

New standard for planetary chemistry

Beyond wind speeds, the study locked in precise measurements of WASP‑127b’s C/O ratio and metallicity. Both values closely matched solar levels, contradicting earlier reports that suggested a carbon-depleted atmosphere.

That shift matters. Planetary formation theories often link atmospheric chemistry to where a planet formed in its protoplanetary disk.

The updated results mean WASP‑127b likely didn’t migrate as far as previously assumed, changing how scientists think hot Jupiters end up in such tight orbits.

Do other planets have supersonic gales?

Next‑generation instruments will test whether cooler, more temperate planets hide slower winds or exhibit surprises of their own.

For WASP‑127b, follow‑up work may track seasonal changes, map clouds at the poles, and refine the chemistry that rides the jet.  

The study is published in Astronomy & Astrophysics.

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