Friday December 14, 2018
Home Science & Technology Comets: The h...

Comets: The harbingers of life on earth?

0
//
Republish
Reprint

 

Rosetta

 

By K.S.Jayaraman

Bengaluru: Did a comet strike jump-start life on Earth? The findings of the European Space Agency’s Rosetta Mission tend to suggest this possibility.

An instrument on board the Philae Lander of Rosetta Mission has identified 16 organic molecules on the surface of a comet that are potentially “prebiotic”, or necessary for life, the mission scientists have reported in a recent issue of the journal Science.

“These are the first organic molecules to be ever reported directly, from in-situ analyses, from the surface of a comet,” Chaitanya Giri, a co-investigator of Cometary Sampling and Composition Experiment (COSAC) of the Rosetta Mission and one of the authors, told IANS.

On November 12, 2014, Philae Lander became the first space probe to soft land on the surface of a comet called 67P/Churyumov-Gerasimenko. Besides COSAC, Philae carried several scientific experiments on board, with each trying to decipher the nature of the comet.

COSAC – which is a gas chromatography-mass spectrometer – aimed to study the surface ‘organic’ chemical composition of the comet, said Giri, a post-doctoral research scientist in the Department of Planets and Comets at the Max Planck Institute for Solar System Research (MPS) in Gottingen, Germany.

According to the report, the Philae Lander bounced off the comet’s surface multiple times after the touchdown before coming to rest. The dust cloud kicked up from the bounces entered the COSAC instrument, which analysed the dust. “The entire COSAC team studied the mass spectra data generated by it,” Giri said.

The COSAC team, led by Fred Goesmann, involved scientists from France, Germany, Ireland, the Netherlands, Spain, Switzerland and the United States. Giri, the only Indian on board, has been part of the team for the past five years in various capacities, beginning as a trainee doctoral student.

According to the Science report, as many as 16 molecules were identified by the experiment. Twelve of these had been reported earlier from remote ground-based telescopes and fly-by missions whereas COSAC has reported four novel molecules that have never been reported earlier, Giri said.

These new molecules are acetamide, methyl isocyanate, propionaldehyde and acetone. Other re-reported molecules include hydrogen cyanide, formamide and glycolaldehyde.

“All these molecules are of great significance for triggering pre-biotic chemistry – the precursor processes towards the formation of life,” Giri said. These are the same molecules that are known to be the building blocks for the origin of life on Earth and are major constituents of known molecular biological processes, he said.

For instance, Glycolaldehyde is known to play a crucial role in the prebiotic synthesis of sugars. Hydrogen cyanide is a known and important precursor for synthesis of amino acids and nucleobases. Formamide and acetamide are known to play a crucial act in the formation of nucleobases and phosphorylation of nucleosides to nucleotides. Within their chemical structure they also contain the so-called “CONH” bond that is the only known way to polymerize amino acids into peptides and further into proteins.

“For centuries, comets have been regarded as omens of destruction,” Giri said. “Our findings have revolutionized human perception of comets. The COSAC-reported potentially prebiotic molecules now point to the likely role of comets as harbingers of life on Earth.”

However, many important questions yet remain unanswered and further exploration of comets and other small bodies is indicated, he added.

“Rosetta is an icon of international co-operation, public support and state-of-the-art science and technology. Such missions are crucial prerequisites for human advancement in outer space. The knowledge gained through Rosetta urges us to explore even further,” he said.

(IANS)

Click here for reuse options!
Copyright 2015 NewsGram

Next Story

NASA’s Probe Discovers Signs Of Water on Asteroid Bennu

OSIRIS-REx will pass later this month just 1.2 miles (1.9 km) from Bennu, entering the asteroid's gravitational pull and analyzing its terrain.

0
Asteroid
This Nov. 16, 2018, image provide by NASA shows the asteroid Bennu. NASA

NASA’s OSIRIS-REx spacecraft has discovered ingredients for water on a relatively nearby skyscraper-sized asteroid, a rocky acorn-shaped object that may hold clues to the origins of life on Earth, scientists said on Monday.

OSIRIS-REx, which flew last week within a scant 12 miles (19 km) of the asteroid Bennu some 1.4 million miles (2.25 million km) from Earth, found traces of hydrogen and oxygen molecules — part of the recipe for water and thus the potential for life — embedded in the asteroid’s rocky surface.

The probe, on a mission to return samples from the asteroid to Earth for study, was launched in 2016. Bennu, roughly a third of a mile wide (500 meters), orbits the sun at roughly the same distance as Earth. There is concern among scientists about the possibility of Bennu impacting Earth late in the 22nd century.

 

NASA, asteroid
NASA’s OSIRIS-REx. Flickr

 

“We have found the water-rich minerals from the early solar system, which is exactly the kind of sample we were going out there to find and ultimately bring back to Earth,” University of Arizona planetary scientist Dante Lauretta, the OSIRIS-REx mission’s principal investigator, said in a telephone interview.

Asteroids are among the leftover debris from the solar system’s formation some 4.5 billion years ago. Scientists believe asteroids and comets crashing into early Earth may have delivered organic compounds and water that seeded the planet for life, and atomic-level analysis of samples from Bennu could provide key evidence to support that hypothesis.

“When samples of this material are returned by the mission to Earth in 2023, scientists will receive a treasure trove of new information about the history and evolution of our solar system,” Amy Simon, a scientist at NASA’s Goddard Space Flight Center in Maryland, said in a statement.

OSIRIS-REx, NASA, Asteroid
This illustration provided by NASA depicts the OSIRIS-REx spacecraft at the asteroid Bennu. The rocky remnant from the dawn of the solar system may hold clues to the origins of life. VOA

“We’re really trying to understand the role that these carbon-rich asteroids played in delivering water to the early Earth and making it habitable,” Lauretta added.

OSIRIS-REx will pass later this month just 1.2 miles (1.9 km) from Bennu, entering the asteroid’s gravitational pull and analyzing its terrain. From there, the spacecraft will begin to gradually tighten its orbit around the asteroid, spiraling to within just 6 feet (2 meters) of its surface so its robot arm can snatch a sample of Bennu by July 2020.

Also Read: Wintertime Ice Growth in Arctic Sea Slows Long-Term Decline: NASA

The spacecraft will later fly back to Earth, jettisoning a capsule bearing the asteroid specimen for a parachute descent in the Utah desert in September 2023. (VOA)