Japanese scientists have identified a 6,200-mile-long anomaly on the surface of Venus as a stationary gravity wave — the longest one ever recorded in our solar system. Unperturbed by the surrounding 225-mph winds, the phenomenon gives the planet’s atmosphere the appearance of having a bow-shaped streak run from top to bottom. Researchers at the Japan Aerospace Exploration Agency’s Institute of Space and Astronautical Science (JAXA) used the Akatsuki spacecraft to identify the wave. The findings were published Monday in the journal Nature Geoscience.
Before we go any further: gravity waves are not the same thing as gravitational waves. The latter — high-energy ripples in the strewn through spacetime by any object with mass — were finally found last year after a century’s worth of investigating, and they are very cool, but they are not what we are here to talk about today.
Gravity waves are a force of physics that causes buoyancy in particles of liquid in a given atmosphere — like waves on the surface of Earth’s oceans. This particular wave isn’t a fixed feature — the researchers watched it for several weeks and then found it had disappeared (though again, it doesn’t appear to be the winds that are disturbing it). The researchers believe that the wave is initially generated from Venus’s mountainous lower atmosphere and rises from there, and this is forcing them to reconsider some assumptions about the nature of weather patterns on the surface of the planet:
“…the formation and propagation of a mountain gravity wave remain difficult to reconcile with assumed near-surface conditions on Venus,” the team explains in the paper. “We suggest that winds in the deep atmosphere may be spatially or temporally more variable than previously thought.”
The scientists used computer models to verify the conditions and rule out other possible explanations. Team leader Makoto Taguchi of Rikkyo University told Gizmodo that further study would ideally shed some light on how surface conditions when the wave is present compare to those when it is not.
“Our simulations of gravity wave propagation showed a similar pattern of temperature distribution at the cloud-top altitudes as the observed one,” Taguchi explained to Gizmodo. “Ongoing computer simulations will be important to justify a hypothesis raised from the observational results.”
Venus is famous for its merciless winds. It’s not yet clear whether this wave is strong enough to power all the way up to the highest level of the atmosphere — we’ll need additional study of both the wave and the winds themselves to know for sure.