Scientists Discover 5400-MPH Winds on an Exoplanet

Artist’s impression showing the HD 189733 system, containing a Sun-like star orbited by HD 189733b, an exoplanet about the size of Jupiter.

Hold onto your hat: Scientists have discovered winds on an exoplanet that are 20 times faster than any gust ever detected on Earth. These megafast winds race across HD 189733b at 5400 mph—seven times the speed of sound.

As they published this week in The Astrophysical Journal Letters, astronomers from the University of Warwick discovered the winds on HD 189733b—a "hot Jupiter" 63 light-years away that is more than 30 times closer to its star than Earth is to the Sun and orbits its star once every 2.2 days—has winds that flow around its surface at a speedy pace of more than 2 km per second. This is the first time a weather system on a planet outside of Earth’s solar system has been directly measured and mapped, the researchers say.

They used high-resolution spectroscopy to detect the sodium absorption in its atmosphere. As parts of the planet's atmosphere move towards or away from Earth, the Doppler effect changes its wavelength, allowing the velocity to be measured.

This technique could be used in the hunt for Earth-like planets. "We are tremendously excited to have found a way to map weather systems on distant planets," study co-author Peter Wheatley, of the University of Warwick’s Astrophysics Group, explained in a press statement. "As we develop the technique further we will be able to study wind flows in increasing detail and make weather maps of smaller planets. Ultimately this technique will allow us to image the weather systems on Earth-like planets."