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Why comets appear black? Indian-led scientists’ group finally finds answer

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Dr. Chaitanya Giri, Postdoctoral Research Scientist, Max Planck Institute for Solar System Research
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Bengaluru: A study by an international team from Europe and the US led by an Indian planetary scientist has resolved one of the mysteries that baffled astronomers.

Astronomical studies have shown that several small bodies – Centaurs and Trans-Neptunian Objects (TNOs) – in the outer solar system are having surfaces that are extremely dark but the origin of this color had remained unclear.

Centaurs estimated to number around 44,000 are minor planets with diameters larger than one kilometer. And TNOs are similar objects at a distance farther than Neptune, the most distant planet in the solar system.

Now, in a report published in the International Journal of Astrobiology, Dr. Chaitanya Giri, who led the research from the Max Planck Institute for Solar System Research in Germany, and co-workers claim to have found why these objects appear dark.

They say they have obtained experimental evidence that the darkness of these objects is due to presence on their surfaces of highly ‘carbonized’ organic material analogous to ‘Titan tholin’ — a substance first synthesized in the late 1970s in the laboratory of Carl Sagan and another Indian scientist Bishun Khare at Cornell University to simulate the atmosphere of Saturn’s moon ‘Titan’.

“We investigated the chemical structure and composition of ‘Titan tholin’ using multiple analytical techniques such as laser desorption, mass spectrometry, Raman spectroscopy, and field-emission scanning electron microscopy,” Giri told IANS in an email.

“The investigation led to the discovery of novel graphitic structural components within the larger macromolecular structure of Titan tholin,” he said.

“Like the dark appearance of coal, our research indicates that the graphite within the Titan tholin-like material on Centaurs and TNOs contributes to their extreme darkness.”

According to Giri, since Centaurs and TNOs are progenitors of comets, “the darkness of the comet’s surface can also be attributed to similar material.”

For instance comet “67P/Churyumov-Gerasimenko”, which was visited by Europe’s Rosetta space mission in 2014, “was extremely dark,” said Giri, who was a co-investigator on the mission.

Giri, who is currently with Japan’s Earth Life Science Institute at the Tokyo Institute of Technology, says the findings of this research will have far-reaching implications.

“For astronomers and planetary scientists, the prospect of complex organic material present on several objects in our Solar System is striking,” he said.

Astronomers might further use “Titan tholin” to study the surfaces of exoplanets (that are planets beyond our solar system) and planetary scientists could probe into the role of tholin-like material in shaping up organic-rich atmosphere and geology of several solar system objects.

“Chemists could further explore the exotic conformations in which ultra-complex organics exist in the universe and biologists would further probe whether such organics play any role in the origin of life on Earth,” he added.

Giri noted that in the past few years, interest in the small Solar System bodies had been on an ascent.

“Besides Europe’s Rosetta mission, NASA’s Dawn mission to dwarf planet Ceres and the New Horizons mission to dwarf planet Pluto all have given us glimpses to our yet unexplored and enormously diverse Solar System.”

Giri said the “Titan tholin” for his study was synthesized at the NASA Ames Research Center while chemical investigations were carried out at the Max Planck Institute for Solar System Research, NASA Goddard Space Flight Center, and at the Universities of Maryland (US), Nice (France), and Goettingen (Germany). (IANS)(Photo: chaitanyagiri.com)

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All You Need to Know About Jagadish Chandra Bose

Polymath, physicist, biologist, biophysicist, botanist, archaeologist and one of the most early writers of science fiction- yes, this is one man

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Bose is considered the father of Bengali science fiction. Wikimedia commons
Bose is considered the father of Bengali science fiction. Wikimedia Commons
  • Jagadish Chandra Bose developed instruments like Coherer and Crescograph.
  • He is the father of Bengali Science Fiction.
  • A crater on the moon has been named in his honour.

Polymath, physicist, biologist, biophysicist, botanist, archaeologist and one of the earliest writers of science fiction- yes, this is one man. A man, who, according to Sir Nevill Mott, was 60 years ahead of his time. He did not believe in commercializing his work, he used to make it public. When he could have earned lifetimes for his generations, Jagadish Chandra Bose chose a way which led to further research.

He is the man who pioneered radio research and also, made some of the most significant contributions to the field of plant science. Bose is credited for laying down the foundation of experimental science in India.

You may also like: Mangalyaan Mission: A huge leap into space

Sir Jagadish Chandra Bose lived in British India’s Bengal Presidency. His father was Deputy Magistrate in Faridpur. Even though from a rich family, he attended vernacular schooling because his father believed that children should know their mother-tongue before any other language.

The father of Bengali science fiction. Wikimedia commons
The father of Bengali science fiction. Wikimedia Commons

Background

It was a time when sending children to English schools was an aristocratic status symbol, that Bose studied in a vernacular school. He used to sit with the Muslim son of his father’s attendant and the son of a fisherman. Even though his mother was an orthodox lady, she never practised discrimination. Bose never knew there existed a ‘problem’ (at that time) between Hindu and Muslim communities.

While speaking at the Bikrampur Conference in 1915, Bose said:

“They were my playmates. I listened spellbound to their stories of birds, animals and aquatic creatures. Perhaps these stories created in my mind a keen interest in investigating the workings of Nature.” 

He wanted to compete for the Indian Civil Services but his father told him “My son would rule nobody but himself.” Bose also attended the University of London where he studied medicine, though he had to come back due to illness.

Later, he graduated with a BA from Kolkata University. While he taught physics at Presidency College, he was simultaneously pursuing his own research in electricity and electromagnetic waves.

Work and research

Bose gave a demonstration of microwaves at Kolkata Town Hall, for the first time, in November 1984. He ignited gunpowder and rang a bell at a distance using microwaves.

Also read: How wheat production could increase three-fold

His instruments are still on display. Wikimedia commons
His instruments are still on display. Wikimedia Commons

‘Coherer’

He developed a device which could detect radio waves, it was called a ‘coherer’. The Englishman (18 January 1896) quoted from the Electrician and commented as follows:

“Should Professor Bose succeed in perfecting and patenting his ‘Coherer’, we may in time see the whole system of coast lighting throughout the navigable world revolutionised by a Bengali scientist working single handed in our Presidency College Laboratory.”

Bose was unwilling to patent the device as he believed that science should be for the benefits of all, and should not be used for money-making. Later he did submit a patent application, under pressure from his friends, to the US patent office. He became the first Indian to get a patent.

Radio waves made him believe that physics is far beyond what the naked eye can see. Bose was curious about the world of plants. Hence, he switched to investigating how plants respond to stimuli.

Crescograph

A crescograph is an oscillating recorder using clockwork gears and a smoked glass plate to measure the growth and movements of plants in increments as small as 1/100,000 of an inch. The plate caught the reflection of the plant and it was marked according to the movement of the plant. 

An image of a crescograph. Wikimedia commons
An image of a crescograph. Wikimedia Commons

Sir Jagadish Chandra Bose had a strong belief that plants have a sensitive nervous system. This belief was strengthened by his experiments. He was also astounded when he discovered that an electric death spasm occurs in plants when they die, this could be resourceful in accurately calculating the time the time of their death.

He revealed the wonders of the world of plants when he described his experiments and their results in his paper “Responses in Living and Non-Living”.

The paper revealed that plants could feel pleasure and even pain.

Sir Jagadish Chandra Bose’s place in history is prominent as ever. His work on microwaves has a major contribution to the development of radio communication. Instruments developed by him are on display and still can be used, after a century. A crater on the moon has been named after him.