A decade-long mystery cracked
Scientists have finally cracked the mystery of the Pink Planet. The James Webb Space Telescope peered into the atmosphere of GJ504b, a world 57 light-years from Earth, and found clouds made of salt — exotic compounds like potassium chloride and sodium sulfide suspended in its upper atmosphere. The discovery, published by Northwestern University researchers, provides the first direct evidence for salt clouds in a cold planetary-mass object, a phenomenon first theorized more than 15 years ago.
What makes the Pink Planet pink
Discovered in 2013, GJ504b orbits a sun-like star and weighs roughly 25 times the mass of Jupiter, placing it near the fuzzy boundary between giant planets and brown dwarfs. Its rosy color comes from the scattering of light by these salt particles. 'We were very surprised,' said lead researcher Aneesh Baburaj of Northwestern. 'People in general just don't observe any kind of signatures of clouds in such temperatures.' At 550 degrees Fahrenheit, the planet is cold by giant planet standards.
Webb's unique eye
Earlier ground-based telescopes could not analyze the planet's light because it was too faint. Webb's infrared sensitivity finally allowed astronomers to dissect the wavelengths in its atmosphere. The finding opens a new window for studying cloud chemistry on cold exoplanets and brown dwarfs, and suggests that salt clouds may be common on worlds in this temperature range.