New data from the Spitzer Space Telescope suggest most brown dwarfs are roiling with one or more planet-size storms akin to Jupiter's "Great Red Spot," NASA's Jet Propulsion Laboratory in Pasadena, Calif., reported Tuesday.
Brown dwarfs form in the same manner stars do, but lack the mass to fuse atoms continually and blossom into full-fledged stars.
"As the brown dwarfs spin on their axis, the alternation of what we think are cloud-free and cloudy regions produces a periodic brightness variation that we can observe," Stanimir Metchev of the University of Western Ontario, Canada, said. "These are signs of patchiness in the cloud cover."
"We needed Spitzer to do this," he said. "Spitzer is in space, above the thermal glow of the Earth's atmosphere, and it has the sensitivity required to see variations in the brown dwarfs' brightness."
In a Spitzer program named "Weather on Other Worlds," astronomers used the infrared space telescope to observe 44 brown dwarfs.
Scientists say they think the cloudy regions on brown dwarfs take the form of torrential storms, accompanied by winds and, possibly, lightning more violent than that at Jupiter or any other planet in our solar system.
However, brown dwarfs studied so far are too hot for water rain; instead, astronomers say they believe the rain in these storms, like the clouds themselves, is made of hot sand, molten iron or salts.