NASA’s James Webb Space Telescope has revealed a planet where sand specks rain down in subsurface probes.
The planet, Wasp-107b, is 200 light-years away in Virgo and has already caught the attention of astronomers because it is so large, yet so light, that it has earned the nickname „Candy Floss.” The latest observations provide an unprecedented glimpse of a strange and exotic world beyond our solar system, with clouds of silicate sand and rain, scorching temperatures, raging winds and the distinctive burnt-spark smell of sulfur dioxide.
„Our knowledge of other planets is based on what we know from Earth,” said Professor Leanne Dessin of the Catholic University of Leuven (KU) and first author of the research. „It’s a very restricted knowledge.”
The discovery was made in 2017 after astronomers discovered that the planet emits light from its host star at periodic intervals each time it passes in front of it. „It’s like a fly in front of a streetlight,” Tessin said. „You see a slight dimming of the light.”
James Webb takes these observations to the next level by measuring starlight filtering through the planet’s atmosphere. Because different elements absorb different wavelengths of light, the spectrum of starlight indicates which gases are present.
Wasp-107b is similar to Neptune, but nearly the size of Jupiter, and its wide, diffuse nature allows the James Webb Telescope to peer deep into its atmosphere.
„It’s a great target because it’s so fluffy. It’s one of the fluffiest planets out there that can get these big signals when you look at their atmosphere,” said Dr Joanna Barstow, a planetary scientist at the Open University who is working on separate JWST measurements of the same planet. . „We’ve been working on predictions for the past 10 years, but nothing prepared us for what we were actually seeing — both what we were finding and the quality of the data. It was very exciting.
Recent observations, Published in Nature, reveals sources of water vapor and sulfur dioxide, giving the atmosphere the smell of burning matches. This is the first time the chemical composition of clouds on another planet has been identified – in this case, silicate sand.
The planet’s atmosphere is similar to Earth’s water cycle, but instead consists of sand cycling between the solid and gaseous phases. From the warmer, lower levels of the atmosphere, with temperatures near 1,000C, silicate vapor rises, cools, and forms fine sand grains, too small to be seen. Eventually, these sand dust clouds will thicken and they will start raining back down into the lower layers of the atmosphere. Below a certain level, the sand will evaporate again, completing the cycle.
„The clouds look like a faint dust,” Tessin said. „And these sand particles are moving at very high speeds. A few kilometers per second.”
The James Webb Space Telescope’s central mission is to analyze the atmospheres of distant planets and search for biosignature gases that indicate the presence of life. Wasp-107b was not considered a viable candidate due to its 1,000C temperature and lack of a solid surface. „It’s completely hostile — not to us,” Tessin said.
Observing the atmospheres of rocky Earth-sized planets can be particularly challenging because, if they have an atmosphere, it is thin and dense. However, the amount of detail obtained from targets such as Wasp-107b is seen as an encouraging sign.
„There are many surprises in the universe,” Tessin said. „I imagine there could be many alternative ways for life to develop on another planet. It could be very different from what you know on Earth. We just have to expand our imaginations.”