source: Unlike the clouds on Earth, however, which are composed of crystals of ice, Neptune's cirrus clouds are made up of crystals of frozen methane.
target: Neptune's cirrus clouds are made up of crystals of frozen methane, not like the clouds on earth which are made up of crystals of ice.
references: Neptune's cirrus clouds are made up of crystals of frozen methane, not like the clouds on earth which are made up of crystals of ice. Neptune's clouds are made from frozen methane instead of ice like clouds on Earth. Unlike the clouds on Earth, which are made of ice crystals, Neptune's cirrus clouds are made of frozen methane crystals. The clouds on Earth are made of crystals of ice. But on Neptune, the clouds are made of crystals of frozen methane. Clouds on Earth are made of ice crystals. Cirrus clouds on Neptune are made of frozen methane crystals. Neptune's thin clouds have ice methane while the Earth has crystals of ice. Clouds on Earth are composed of crystals of ice.  Neptune's cirrus clouds are composed of crystals of frozen methane. The clouds on Earth are made of crystals of ice.  Neptunes cirrus clouds are made of crystals of frozen methane. Unlike the clouds on Earth which are composed of crystals of ice, Neptune's cirrus clouds are made up of crystals of frozen methane. Methane crystals make up Neptune's clouds. Earth's clouds are from crystals of ice.