Are there aliens on far-away planets? Windspeed may blow us to the answer

On April 10, 1996, a tropical cyclone swept through a small island in Australia and set the world record for fastest wind speed ever recorded on Earth, by measuring winds at 408 kilometers per hour.

Those Earth winds may are puny compared to the swooping gusts that take place on objects outside our own Solar System. Yes, we're talking about wind speeds on exoplanets. More precisely, we're talking about the search for aliens on those exoplanets.

Windspeed can tell astronomers a lot about a planet's potential for hosting alien life.

A new study, published Thursday in the journal Science, provided the first measurement of atmospheric wind speed outside the Solar System. The leading scientist behind the study developed the new method to be able to measure winds in distant worlds, which could be applied to our quest to find habitable exoplanets.

“This is the first time the method we used to do this has been attempted,” Katelyn Allers, a professor of physics and astronomy at Bucknell University, said in a statement. “The idea is similar to how winds could be measured for Earth, but in terms of things that you could determine from afar.”

For the study, the team of researchers used data from NASA’s Spitzer Space Telescope and the Karl G. Jansky Very Large Array, looking at radio wavelength observations of a brown dwarf dubbed as 2MASS J1047+21, located around 33 light-years away in the constellation Leo.

A brown dwarf is a substellar object, and its mass falls somewhere between a gas giant planet like Jupiter and a small star. Although brown dwarfs are thought to form in the same way stars do, however, their core falls short of having a large enough density to trigger nuclear fusion.

When measuring wind speed on Earth, scientists first measure the speed of a continent as it rotates in and out of view from space while measuring the speed for a cloud that is being blown by the wind.The difference between these two values is because the wind has pushed that cloud relative to the surface.

For objects that are located much further out in space, scientists can’t exactly see the clouds. They can, however, observe the movement of the clouds in a different way. When a cloud rotates in or out of view, it changes the brightness of the planet.

Therefore, the scientists behind the new study monitored the brightness of the brown dwarf and used periodic changes in its brightness to determine the speed of the wind.

From their observations, the researchers were able to measure the distant world’s powerful winds, which whip at a chilling speed of an average of 660 meters per second, or roughly 2,400 kilometers per hour. An average windy day on Earth has wind speeds that measure between 11-13.5 meters per second.

The novel technique used in this research could be applied to exoplanets outside the Solar System.

Missions such as NASA’s Kepler and the Transiting Exoplanet Survey Satellite (TESS) have led to the discovery of more than 4,000 exoplanets to date. Scientists are studying these alien worlds in the quest to answer the biggest question of cosmology; are we alone in the universe?

In order to look for signs of habitability, scientists check for certain signs that the planet may contain some form of life. One of the most telling features of a habitable exoplanet is its atmosphere, and whether or not it has atmospheric conditions that could support life.

Therefore, getting a better idea of an exoplanet's atmospheric wind speed is one of the main pillars when looking for habitability on that planet.

Abstract: Zonal (latitudinal) winds dominate the bulk flow of planetary atmospheres. For gas giant planets such as Jupiter, the motion of clouds can be compared with radio emissions from the magnetosphere, which is connected to the planet’s interior, to determine the wind speed. In principle, this technique can be applied to brown dwarfs and/or directly imaged exoplanets if periods can be determined for both the infrared and radio emissions. We apply this method to measure the wind speeds on the brown dwarf 2MASS J10475385+2124234. The difference between the radio period of 1.751 to 1.765 hours and infrared period of 1.741 ± 0.007 hours implies a strong wind (+650 ± 310 meters per second) proceeding eastward. This could be due to atmospheric jet streams and/or low frictional drag at the bottom of the atmosphere.