Researchers from the Indian Institute of Technology-Madras (IIT-M) created a ‘space fuel’ by simulating interstellar conditions in the laboratory, achieving a breakthrough in the exploration of cleaner and sustainable alternatives to fossil fuel.
The method, published in the journal Proceedings of the National Academy of Sciences (PNAS) this week, has the potential to convert atmospheric carbon dioxide into a next generation energy source to curb greenhouse gases and global warming.
A study of hydrates
With this research, IIT-Madras is one step closer to determining if fuels of the future exist in outer space. The study is focused on water molecules containing methane-like gases, which are usually found in permafrost (frozen soil) inside the earth or on the ocean floor.
Also known as clathrate hydrates, these molecules contain gases like methane and carbon dioxide trapped in well-defined cages of water molecules, forming crystalline solids. They are also found in glaciers such as in Siberia.
Such hydrates especially that of methane, are thought to be the future sources of fuel. Numerous programmes to explore hydrates in the ocean bed are underway, including one by India.
Usually thriving in high pressure and lower temperature, IIT-M researchers recently discovered these molecules in permafrost-form in the vacuum and freezing conditions of outer space, which led them to explore the possibility of extracting fuel from them.
Methane exists in interstellar atmosphere
In an unprecedented outcome, the team were able to form methane-containing clathrate hydrates in ultra-high vacuum (1000 billion times below the atmospheric pressure) and at a temperature close to -263oC. These are the conditions present in deep space.
Cages of water dont normally form under such conditions owing to the frozen state of water molecules, which cannot move at such low temperatures.
“What we have found is that molecules like methane and ammonia in space could exist in a completely different form than what is known to us,” chemistry professor and co-author of the study, Thalappil Pradeep, told PTI, adding that this may have several implications for the chemistry of such atmospheres.
Molecular confinement in hydrates can often result in new chemistry, especially in the presence of cosmic light in outer space. Understanding this chemistry may yield a better and new understanding of the origins of life.
How was this studied?
The formation of hydrates was studied by spectroscopy. A special Ultra-High Vacuum (UHV) was constructed with several spectroscopic probes. Thin layers of ice and methane were prepared by condensing a mixture of the gases on a specially made single crystal of ruthenium metal. The experiment was then repeated with carbon dioxide which too yielded such hydrates, researchers said.
When the gases were deposited at first, the spectroscopic features resembled solids of methane and water ice. As the formation of the hydrate cage began and methane got trapped in it, scientists observed that the molecule became ‘free,’ entering its gaseous phase. This observation was later confirmed by drawing a comparison with theoretical simulations. The results were also verified and the resulting hydrate compared to that formed by standard methods.
What the authors said about their breakthrough
The study was conducted by Jyotirmoy Ghosh, a research scholar at IIT-M, under the guidance of Professor Pradeep and Dr. Rajnish Kumar.
“Normally, in UHV experiments, spectroscopic changes are monitored only for minutes, may be an hour. I thought that why not wait for days and keep observing the changes. After all, ice and methane have been sitting in the space for millions of years,” said Prof. Pradeep.
“The excitement happened after 3 days. New features started coming. Then of course, several experiments were done under controlled conditions,” he said.
Another author of the study, Dr. Rajnish Kumar expressed greater joy with the CO2 leg of the experiment, saying “Trapping carbon dioxide in hydrates is a way to reduce global warming. One can sequester carbon dioxide gas as solid hydrates under the sea bed.
Prarthana Mitra is a staff writer at Qrius