(From left) Prof Rajnish Kumar, Jyotirmoy Ghosh and Prof Pradeep around their ultra-high vacuum instrument

Mimicking conditions prevailing in interstellar space, a team of Indian researchers has synthesised in a lab tiny water cages containing trace amounts of methane and carbon dioxide at extremely low temperatures and pressure.

These nano cages, also called clathrate hydrates, assume significance because the scientists who created them speculate that various chemical processes on such hydrates in interstellar space may have led to the formation of relevant molecules that eventually gave rise to life on earth.

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New chemistry

Such molecular confinement can result in new chemistry, especially in the presence of cosmic rays present in the interstellar environment. This may have relevance to the origin of life, said the scientists from the Indian Institute of Technology (IIT)–Madras, in a paper published in the prestigious journal Proceedings of the National Academy of Sciences, on Monday.

“For a long time, scientists have been speculating that molecules of life had come from space. Maybe new kinds of molecules were born in space, not normally by a straightforward chemical reaction, but reactions in confinement, like, say, in a hydrate cage. In that sense pre-cursors of carbon-containing molecules could be hydrates,” said Thalappil Pradeep, professor of chemistry at IIT-Madras and a senior author of the paper.

This discovery of hydrates is highly unexpected at extremely low pressures and ultra cold temperatures as cages of water are not expected to form under such conditions as the water molecules are frozen and cannot move at very low temperatures, said Pradeep.

Normally, formation of clathrine hydrates requires high pressures and moderate temperature. On earth, they are found on the ocean floor or the permafrost region of earth. Such hydrates, especially that of methane, are thought to be the future sources of fuel. Many countries, including India, have already embarked on projects to explore hydrates present on the ocean bed.

The IIT scientists, led by Pradeep and his colleague Rajnish Kumar, created such hydrates in vacuum, one thousand billion times below the atmospheric pressure, called ultra-high vacuum, at temperature close to minus 10°Celsius.

The new findings may have practical applications in future “Trapping carbon dioxide in hydrates is a way to reduce to global warming. One can sequester carbon dioxide gas a solid hydrates under the sea bed,” said Kumar.

Pat from French scientist

This is a significant piece of work as the paper for the first time showed that clathrates can be formed at very low temperatures, said Olivier Mousis, a scientist with Laboratoire d’Astrophysique de Marseille, in France.

“Clathrate hydrates were suspected to be part of the building blocks of the ice moons, comets and the material accreted by giant planets. The missing part of the puzzle was the presence of experiments showing that they exist. It is done now,” he said.