Brave new world?

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SCIENCE NOV: FORE THE development of lifeforms on Earth depended On several interrelated factors, but some of the most important were abundant sunlight, the presence of an atmosphere rich in nitrogen, the ability to generate hydrocarbons compounds of hydrogen and carbon -the basic building blocks of organic molecules), the presence of water and water vapour.

One of the commonest arguments of those who believe we are God's creation is the evidence from space exploration, which apparently shows that of all the objects in the Solar System, only the Earth can support life. Because we are unique. we must be Gud's creation.

The research of the US Spcae Agency NASA has been much criticised by socialists. Yet, some of its recent work has produced important results that socialists can use to advantage in debating the nature of life.

The Voyager space probes have surprised many by revealing that lurking amongst the moons of Saturn is the only satelite in the Solar System known to possess a substantial atmosphere. This atmosphere has many of the characteristics which could be conducive to the support of life later in the lifetime of the Sun.

The moon Titan is about one-third of the diameter of the Earth and has an atmosphere composed mainly of nitrogen with some metnane and more complex hydrocarbons, including hydrogen cyanide. The presence of hydrogen cyanide is important because laboratory simulations of the chemical steps that lead to the origin of life on Earth have used this substance as a starting material.

Although hydrogen cyanide does spawn more complex molecules on Titan at present it cannot produce compounds capable ot giving rise to life. There is a missing link -oxygen -which is locked in water ice comprising 45% of the freezing surface and interior of Titan. Surface temperature may be as low 180°C below freezing as point of water, and the water ice at the surface may support liquid methane oceans.

On Earth the relatively high surface temperatures mean that water and water vapour are abundant. The oxygen in water vapour can react with complex hydrocarbons and the liquid water provides a "soup" for the reactions Lo be facilitated and nurtured to yield life forms.

Titan

Life on Titan is impossible at the moment because it is so cold. But when the Sun enters its mature stage and grows to be a red giant Titan's temperature will be raised and may reach the point where conditions parallelling those of the present Earth will be achieved. In its turn, the Earth, being much closer to the Sun, will be vaporised or charred beyond recognition.

The religious emphasis on the uniqueness of life on Earth has therefore been struck quite a severe blow. If the conditions exist for two planetary bodies to develop environments conducive to the formation of complex organic molecules during the lifetime of one sun, then there must be many more examples amongst the millions of solar systems in the Universe.

Stuart Sutherland

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Socialist Organiser, Thursday 18 February, 1982 Fighting for union democracy