Uploaded August 2026 | Updated September 2026, 3 weeks ago
One of the coldest planetary-mass objects ever directly imaged has been hiding something unusual in its atmosphere: salt clouds.
Known as the “Pink Planet,” GJ 504 b is a mysterious world orbiting a Sun-like star about 57 light-years from Earth. At roughly 25 times the mass of Jupiter, it lies near the uncertain boundary between giant planets and brown dwarfs. It is also so cold and faint that previous attempts to study its atmosphere from the ground were unsuccessful.
Now, JWST has captured the first direct spectrum of GJ 504 b. The observations revealed an atmosphere containing water vapor, methane, carbon dioxide, ammonia, hydrogen sulfide, and other molecules. When researchers modeled the spectrum, they found that clouds—particularly salt clouds—were essential to explaining what JWST observed.
Join host Dr. Moiya McTier and lead author Dr. Aneesh Baburaj (Northwestern University) to learn how astronomers separated the faint light of GJ 504 b from the glare of its host star, what salt clouds can tell us about cold planetary atmospheres, and why scientists still are not sure whether the Pink Planet formed like a planet or a star.
Have questions for Aneesh? Add them in the live chat!
Read the paper:
iopscience.iop.org/article/10.3847/1538-3881/ae6919
Read the Northwestern University story:
https://news.northwestern.edu/stories/2026/06/famous-pink-planet-harbors-a-salty-surprise
#SETILive #JWST #Exoplanets
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One of the coldest planetary-mass objects ever directly imaged has been hiding something unusual in its atmosphere: salt clouds.
Known as the “Pink Planet,” GJ 504 b is a mysterious world orbiting a Sun-like star about 57 light-years from Earth. At roughly 25 times the mass of Jupiter, it lies near the uncertain boundary between giant planets and brown dwarfs. It is also so cold and faint that previous attempts to study its atmosphere from the ground were unsuccessful.
Now, JWST has captured the first direct spectrum of GJ 504 b. The observations revealed an atmosphere containing water vapor, methane, carbon dioxide, ammonia, hydrogen sulfide, and other molecules. When researchers modeled the spectrum, they found that clouds—particularly salt clouds—were essential to explaining what JWST observed.
Join host Dr. Moiya McTier and lead author Dr. Aneesh Baburaj (Northwestern University) to learn how astronomers separated the faint light of GJ 504 b from the glare of its host star, what salt clouds can tell us about cold planetary atmospheres, and why scientists still are not sure whether the Pink Planet formed like a planet or a star.
Have questions for Aneesh? Add them in the live chat!
Read the paper:
iopscience.iop.org/article/10.3847/1538-3881/ae6919
Read the Northwestern University story:
https://news.northwestern.edu/stories/2026/06/famous-pink-planet-harbors-a-salty-surprise
#SETILive #JWST #Exoplanets
📺 SETI Live is a weekly livestream from the SETI Institute, featuring researchers and discoveries that deepen our understanding of the universe—and our place within it.
If you like science, support the SETI Institute! We're a non-profit research institution focused on understanding the nature and origins of life in the universe. 💸 Donate here: seti.org/donate
Learn more about the SETI Institute and stay up-to-date on awesome science:
🛎 Subscribe to our YouTube channel at youtube.com/c/SETIInstitute
🕹 Watch our streams over on Twitch at twitch.tv/setiinstitute
🎧 Listen to our podcast feeds.libsyn.com/462636/rss
📧 Subscribe to our weekly newsletter seti.org/signup
👕 Buy merchandise from Chop Shop chopshopstore.com/collections/seti-institute/SETI
Don't forget to like and subscribe! Ring the bell for notifications of when we go live.
