Gas

Across Britain, the old gas holders are being demolished to release inner-city space for re-development.

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For a century the national grid was supplied from these structures, a crude mixture of carbon monoxide and other volatile products from black coal, mined from abundant Carboniferous deposits.

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The holders encouraged their own design and architecture

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Now, natural gas is transmitted under pressure over long distances and there is no need for local storage systems.

The planet Neptune stores gas differently, the metal inside and the gas out:

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Beneath clouds of the outer atmosphere (1, above) there is also gas (2), ammonia, methane and hydrogen. Layer (3) is solid water and other ice. The core (4) is solid rock of silicates and metals.

[pictures from BBC]