Astronomers have discovered hydrogen sulfide on a faraway planet for the first time. This gas smells like rotten eggs. The James Webb Telescope found this gas on a planet called HD 189733b, which is about 63 light years away. This planet is very hot, nearly 1,000 degrees, and has strong storms that blow tiny glass particles around.

HD 189733b is a gas giant, like Jupiter, and is one of the most studied exoplanets because it passes in front of its star every two days, making it easy to observe. Scientists have found that its atmosphere contains water vapor, carbon dioxide, and carbon monoxide, along with the newly discovered hydrogen sulfide.

The discovery is important because it helps scientists understand more about the atmospheres of gas giants outside our solar system. Hydrogen sulfide is a key molecule that wasn't known to exist on this planet before. While this planet is too hot for life, finding this gas is a step towards finding similar molecules on planets that might be more suitable for life.

Interestingly, scientists did not find much methane on HD 189733b. They had suspected the planet was too hot for methane, and their findings confirmed this. The new data also suggest that the planet has a high amount of heavier elements, similar to Jupiter, indicating it might have a solid core made of rock, ice, and metals.

This discovery helps scientists learn how giant planets like Jupiter are formed. It suggests that HD 189733b likely formed from the gradual gathering of dust and rocks, which later attracted a thick gas atmosphere.