Indian astronomer finds salty clouds on a planet that is completely pink

Using the James Webb Space Telescope, an Indian astronomer helped uncover salt clouds in the atmosphere of the pink world GJ504b. The finding offers rare direct evidence for long-predicted salt clouds and shows Webb can probe cold, faint worlds.

In Short

• Webb analysed faint infrared light to decode GJ504b's unusual atmosphere
• Researchers detected water vapour, methane, carbon dioxide and ammonia there
• The findings show Webb can probe colder, fainter worlds once inaccessible

Indian astronomer using the James Webb Space Telescope (JWST) has uncovered one of the strangest worlds ever observed: a mysterious pink-coloured planet-like object wrapped in clouds made of salt.

Known as GJ504b and nicknamed the "Pink Planet" because of its distinctive rosy hue, the object has puzzled scientists since its discovery in 2013. Now, after more than a decade of failed attempts to study it in detail, Webb has finally revealed what lies hidden within its atmosphere.

Located about 57 light-years from Earth, GJ504b orbits a Sun-like star and sits in a grey area between a giant planet and a brown dwarf. With a mass roughly 25 times that of Jupiter, astronomers classify it as a "planetary-mass companion" rather than a conventional planet.

What makes the discovery remarkable is not just the world's unusual colour, but the composition of its atmosphere.

Using Webb's powerful infrared instruments, researchers led by Northwestern University captured the faint light coming from GJ504b and broke it down into a spectrum, essentially a chemical fingerprint of its atmosphere. The observations revealed water vapour, methane, carbon dioxide and ammonia.

But the data initially made little sense.

Computer models struggled to explain the spectrum unless scientists added a previously theorised ingredient: clouds made of salt particles.

"We tried three different types of clouds, and salt clouds fit best," said lead researcher Aneesh Baburaj. "When we accounted for salt clouds, the results became physically possible."

The finding provides some of the first direct evidence that salt clouds can form in the atmospheres of extremely cold planetary bodies. Scientists had predicted such clouds more than 15 years ago, but until now, they had never been able to confirm their existence.

Unlike most directly imaged exoplanets, which can reach temperatures of 1,000 to 2,000 degrees Fahrenheit, GJ504b is relatively chilly at around 290 degrees Celsius, comparable to the temperature inside a bread-baking oven.

The study also suggests the object may be rich in heavy elements, although its origins remain unclear. Scientists are still debating whether it formed like a giant planet around a star or emerged more like a miniature star itself.

Beyond solving the mystery of the Pink Planet, the discovery demonstrates Webb's extraordinary ability to study cold, faint worlds that were previously beyond the reach of even the largest ground-based telescopes.

For astronomers searching for increasingly Earth-like worlds, the salty skies of GJ504b may be a glimpse of discoveries yet to come.

- Ends