Which planet is recognized for having a thick atmosphere primarily composed of hydrogen and helium?

Jupiter is recognized for having a thick atmosphere that is primarily composed of hydrogen and helium. This gas giant's atmosphere is incredibly dense, making up about 90% hydrogen and around 10% helium, with trace amounts of other gases like methane, water vapor, and ammonia. The immense pressure and density of the atmosphere contribute to a variety of weather phenomena, including the famous Great Red Spot, which is a massive storm.

While other planets in the solar system, like Neptune and Saturn, also possess thick atmospheres predominantly made of hydrogen and helium, Jupiter's is the largest and most substantial, making it the best example for this question. Saturn, while similar in its hydrogen and helium composition, does not surpass Jupiter in terms of atmospheric thickness and volume. Mars, on the other hand, has a thin atmosphere that is mostly carbon dioxide, making it a poor candidate for this characteristic.