Science and Technology

Why India should train its sights on mining heavenly bodies

M Ramesh | Updated on June 06, 2021

Star trek with a pickaxe Asteroids are carbonaceous in nature, but mining them is some decades away   -  klyaksun

Discovery of graphene in meteorites underscores the importance of prospecting for ‘wonder materials’ in outer space

In 2008, two scientists, Andrew Steele of the Carnegie Institution, Washington DC, and Marc Fries of the US space agency, NASA, studied two meteorites — Allende and QUE 94366. These were chondrite meteorites, which were formed by the aggregation of the dust of the ‘protosolar nebulae’ — namely, around the time the solar system was beginning to be formed. The meteorites were about 4.5 billion years old.

Among the constituents of these rocks was something called the ‘calcium-aluminium rich inclusion’, or CAI, which can form only at extremely high temperatures — around 2,000 degrees C. And, embedded within the CAI, they found extremely tiny needles of graphite, called ‘graphite whiskers’. This discovery created quite a buzz in the scientific community and was written about in the Scientific American and Nature.

The existence of graphite whiskers had been earlier predicted by theoretical physicists, including the English scientist Fred Hoyle and his celebrated Indian mentee Jayant Narlikar. They had postulated the existence of graphite whiskers to explain ‘cosmic microwave background radiation’ (CMB), which some believe to be a relic of the Big Bang at the beginning of the universe. What was visible light then somehow got converted into the high-wavelength CMB. Scientists guessed that graphite whiskers were needed to absorb the higher wavelength light and emit CMB.

In 2016, Chaitanya Giri, a planetary and astro-material scientist, who is today a Gateway House Fellow of Space and Ocean Studies Programme, went to Washington DC to take a peek at the two meteorites. He discovered that the graphite needles were made of graphene — the one-atom-thick sheet of carbon. Graphene, a wonder material much sought by industry, is a chicken-mesh of hexagons, where each point is a carbon atom.

Recently, Giri, along with Steele and Fries, published a paper titled ‘Evidence for protosolar graphene in Allende and QUE 94366 meteorites’ in the journal Planetary and Space Science. After a detailed description of the discovery, using Raman spectroscopy for good measure, the paper notes that the graphene identified in the meteorites were “remnants of a vast reservoir of carbon allotropes that existed in the high-temperature and highly-reduced nebular zones around the proto-Sun”.

This is a notable point because carbon exists in many structural forms (allotropes) — the better known are coal, diamond and graphite. But there are also other structures — graphenes and fullerenes (bucky balls).

“There could be several other allotropes unknown to us,” Giri told Quantum.

Giri, who was also a scientific crew member of the European Space Agency’s Rosetta mission to comet 67P/Churyumov-Gerasimenko, believes that India should train its sights on asteroid and lunar prospecting.

“There are several small solar system bodies,” he says, “such as asteroids, trojans, comets, dwarf planets and trans-Neptunian objects that are carbonaceous in nature.” While mining them is some decades away, it is necessary to start prospecting projects, he says.

The first thing that comes to mind when you say “moon mining” is Helium-3, touted to be a great energy source and practically absent on Earth, but Giri says it is nearly useless to be thinking about it. There are potentially other materials, if only you care to look for them. The discovery of graphene on the two meteorites only underscores this point.

M Ramesh

Published on June 06, 2021

Follow us on Telegram, Facebook, Twitter, Instagram, YouTube and Linkedin. You can also download our Android App or IOS App.

  1. Comments will be moderated by The Hindu Business Line editorial team.
  2. Comments that are abusive, personal, incendiary or irrelevant cannot be published.
  3. Please write complete sentences. Do not type comments in all capital letters, or in all lower case letters, or using abbreviated text. (example: u cannot substitute for you, d is not 'the', n is not 'and').
  4. We may remove hyperlinks within comments.
  5. Please use a genuine email ID and provide your name, to avoid rejection.