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Researcher claims we might have already detected the presence of life on Mars

NASA had sent two Viking landers to Mars in the 1970s. This mission gave some very important insights about Mars along with some very intriguing results. One of the experiments hinted about the detection of life on the Red Planet. The evidence at that time was not found to be fully conclusive however Dr Gilbert Levin, one of the experimenters says that he is highly convinced that we had found extraterrestrial life at that time. His findings are reported in the Scientific American journal. 

The experiment named Labeled Release (LR) had a simple setup. A drop of diluted nutrients was added to the Martian soil sample which was tagged with a radioactive carbon isotope. If there were lifeforms emitting carbon dioxide on the surface of Mars, the radioactive tag would have been released hence getting detected by the experiment. 

The experiment was conducted by both of the Viking landers. One collected a sample exposed to sunlight and the other collected one from beneath a rock. Both of these experiments reported detection. This was again repeated after a week by using the same sample however there was no detection at that point. Hence the results were deemed inconclusive by Levin and partner Dr Patricia Ann Straat. 

Since the Viking Experiments failed to detect life, NASA concluded that the detection by LR was nothing but a result of chemical reactions. However the results of the experiment have been under assessment over the last few years and scientists have argued that this might be the first detection of alien life. This along with the results of several other experiments have made Mars a strong candidate for sustaining life. 

Levin mentions in his paper that there is no evidence against the possibility of life on the Red Planet. Studies have also shown that few terrestrial microbes could grow on Mars. 

Levin is correct in suggesting that the possibility of life cannot be ignored although we cannot take lack of proper evidence as proof for existence. He mentions that efforts should be made for life detection experiments in the next mission to Mars. An improved version of the LR experiment with an ability to detect chiral metabolism have been proposed by Levin and his partner scientist to be sent for confirming the existence of life. Living things can distinguish between left and right handed organic molecules which cannot be done by non-biological chemical reactions. 

Existence of life on Mars has been debated for several years now, there has been no concrete proof yet but we might be nearing towards some solid evidence.

Curiosity obtains traces of salt in the last lakes of Gale Crater

Curiosity obtains traces of salt in the last lakes of Gale Crater

The lakes on Earth turn salty on drying out and the same incident happened when the Curiosity Mars climbed to identify the younger rocks. It found some of the salts which were left behind gathering insights on life could have prospered, rather than the mere survival on Mars. Gale crater was selected in part as it provides the possibility to investigate sedimentary rocks of different ages layered on top of each other. Curiosity has found periodic clay-bearing deposits containing 30-50 percent calcium sulfate by weight as reported in a Nature Geoscience paper.

All the rocks are 3.3-3.7 billion years old dating to the Hesperian period. Likewise, rich deposits have not been found in the older rocks of the crater. According to Dr. William Rapin of the California Institute of Technology and co-authors, the salts are present due to the percolation in the rocks by the waters of the bygone lakes which were very salty. Older rocks were much less salty although they were also exposed to the waters. Curiosity might detect more recent examples even though the younger ones were never touched by water.

Like a desert lake on Earth, the waters of the Gale crater evaporated, leaving a saltier residue, but it was an intermittent process on Mars that lasted 400 million years. The rocks have been subjected to forces of weathering over this vast time period even without water, and the calcium sulfate-enhanced portions are more resistant to erosion, producing mini versions of the formations in places such as Monument Valley, where harder rocks extend above the terrain.

Curiosity found a 10-meter (33-feet) slope containing 26-36 percent magnesium sulfate, in the 150 meters (500 feet) of calcium sulfate-enriched layers. Researchers believe that before the deposition of more soluble salts, it precipitated out first.

The paper mentions that their outcomes do not compromise the life search in the Gale crater. Terrestrial magnesium sulfate-rich and hypersaline lakes are known to sustain halotolerant biota while the preservation of biosignatures may be supported by crystallization of sulfate salts.

The occasional bursts of salty water are observed even today hence it is not unique to Gale crater in having such salts. As the planet dried, sulfate deposits have been identified by Martian orbiters across several places on Mars and it is the first instance where a rover has been operated its instruments over these samples. The periodic bursts of sulfate salts found by Curiosity showed Gale crater had many rounds of drying with several wet periods rather than one single great drought.

Journal Reference: Nature Geoscience

NASA detects organic compounds suitable for life in an ocean on Enceladus

NASA detects organic compounds suitable for life in an ocean on Enceladus

Scientists have detected the basic ingredients for life from an ocean on Enceladus, one of Saturn’s moons. Analysis of NASA data shows the presence of organic compounds in plumes of liquid water shooting into space from the ocean. The findings appear in Monthly Notices of the Royal Astronomical Society journal. 

These compounds contain nitrogen, oxygen and play a major role in creating amino acids, the building blocks of protein. Researchers previously detected organic molecules from the moon but this is the first time molecules were found to be dissolved in water. This indicates that compounds could take part in chemical reactions under the sea leading to amino acids. 

Frank Postberg, one of the study’s authors said that this work reveals the building blocks that are abundant in the ocean of Enceladus. This is a positive indication to carry out research for the habitability of the moon. Jets of ocean water and ice shoot out into space regularly through the cracks in the crust of the moon. 

The compounds were dissolved in the ocean water which then evaporated with surface water finally getting condensed and frozen into the crust of the moon. They were carried into space by the plumes and detected by Cassini spacecraft of NASA. This is an indication that Enceladus might have its own method of generation of life. 

In the oceans of Earth, seawater combines with magma which comes out through the cracks in the ocean floor. This results in the production of hydrothermal vents whose temperature can rise till 370 degrees Celsius. The water from these vents is rich in hydrogen, catalyzing chemical reactions of organic compounds into amino acids. These then combine to form proteins, one of the main components of life. This method works without sunlight and this is significant in the case of Enceladus where the sunlight is reflected back to space in its entirety. So life has to develop in the dark. 

Nozair Khawaja, the research team leader said that the molecules might follow the same pathway in oceans of Enceladus as that of Earth. The discovery of molecules forming amino acids is quite significant. The compounds discovered by the team last were not soluble in water hence researchers were not sure if the organic molecules on Enceladus were capable of life formation. 

Cassini was launched in 1997 and it spent 13 years in the exploration of Saturn and its moons. Scientists purposefully crashed the spacecraft into Saturn thereby ending its mission as they did not want to contaminate Enceladus or Titan in any manner.

Cassini found a global ocean containing liquid saltwater below the surface of Enceladus and captured images of water jets shooting to space. The data about their composition was collected in 2008. Scientists will continue studying the data collected by Cassini as NASA also plans of sending a probe to Titan, another moon of Saturn which also contains organic compounds. Dragonfly, a nuclear-powered helicopter will start for Titan in 2026 and arrive in 2034.

Reference: Monthly Notices of the Royal Astronomical Society journal.  

Fluorescent glow may reveal hidden life in the cosmos

Fluorescent glow may reveal hidden life in the cosmos

Astronomers seeking life on distant planets may want to go for the glow.

Harsh ultraviolet radiation flares from red suns, once thought to destroy surface life on planets, might help uncover hidden biospheres. Their radiation could trigger a protective glow from life on exoplanets called biofluorescence, according to new Cornell research.

Biofluorescent Worlds II: Biological Fluorescence Induced by Stellar UV Flares, a New Temporal Biosignature” was published Aug. 13 in Monthly Notices of the Royal Astronomical Society.

“This is a completely novel way to search for life in the universe. Just imagine an alien world glowing softly in a powerful telescope,” said lead author Jack O’Malley-James, a researcher at Cornell’s Carl Sagan Institute.

“On Earth, there are some undersea coral that use biofluorescence to render the sun’s harmful ultraviolet radiation into harmless visible wavelengths, creating a beautiful radiance. Maybe such life forms can exist on other worlds too, leaving us a telltale sign to spot them,” said co-author Lisa Kaltenegger, associate professor of astronomy and director of the Carl Sagan Institute

Astronomers generally agree that a large fraction of exoplanets – planets beyond our solar system – reside in the habitable zone of M-type stars, the most plentiful kinds of stars in the universe. M-type stars frequently flare, and when those ultraviolet flares strike their planets, biofluorescence could paint these worlds in beautiful colors. The next generation of Earth- or space-based telescopes can detect the glowing exoplanets, if they exist in the cosmos.

Ultraviolet rays can get absorbed into longer, safer wavelengths through a process called “photoprotective biofluorescence,” and that mechanism leaves a specific sign for which astronomers can search.

“Such biofluorescence could expose hidden biospheres on new worlds through their temporary glow, when a flare from a star hits the planet,” said Kaltenegger.

The astronomers used emission characteristics of common coral fluorescent pigments from Earth to create model spectra and colors for planets orbiting active M stars to mimic the strength of the signal and whether it could be detected for life.

In 2016, astronomers found a rocky exoplanet named Proxima b – a potentially habitable world orbiting the active M star Proxima Centauri, Earth’s closes star beyond the sun – that might qualify as a target. Proxima b is also one of the most optimal far-future travel destinations.

Said O’Malley-James: “These biotic kinds of exoplanets are very good targets in our search for exoplanets, and these luminescent wonders are among our best bets for finding life on exoplanets.”

Large, land-based telescopes that are being developed now for 10 to 20 years into the future may be able to spot this glow.

“It is a great target for the next generation of big telescopes, which can catch enough light from small planets to analyze it for signs of life, like the Extremely Large Telescope in Chile,” Kaltenegger said.

methane mars nasa

Researchers have found new clues about methane on Mars

For 15 years, the search for life on Mars increased to a great extent and during this period, methane (An Organic Molecule linked with life on Earth) was observed. Since that time, attempts to study Mars’ atmospheric methane have produced varying results. In some cases, it was found in Normal concentration, in some, it was found in higher concentrations, while absent in others.

A recent study of a special team from Aarhus University stated that they have been looking for possible ways to remove methane gas from the atmosphere of Mars. Methane production on Mars varies from about 0.24 parts per billion (ppb) in winter to about 0.65 ppb during summer in the northern hemisphere.

Extended plumes were detected by Curiosity, one in December of 2014 and in June 2019. This indicates that it is released periodically from discrete regions. Different methods have been proposed for the production and disappearance of Methane over several years. In the case of production, these range from non-biological processes such as serpentinization to biological production by microbes.

As for how it is removed, that has remained a mystery as well, but even more so.

The most prominent mechanism for disappearance of methane known to us is photochemical degradation. It is the process of breaking down of Methane into carbon dioxide, formaldehyde, and methanol by UV radiation from the sun. However, this process cannot evaluate the rate of methane disappearance, which is a crucial part of the process.

In the scientific journal Icarus, the research team from Aarhus University’s laboratory proposed that wind-driven erosion (Saltation) could be responsible for the ionization of methane into compounds such as methyl (CH3), methylene (CH2), and carbyne (CH).
With the help of Mars-analog minerals such as basalt and plagioclase, the team detected that ionized methane during the erosion process reacts and bonds with the mineral surfaces. Also, in plagioclase which is a major component in Mars’ surface material, silicon atoms combine with methyl groups obtained from methane.

Based on these results, the team concluded that this mechanism is much more effective than the photochemical process and could explain how methane is removed from the Martian atmosphere and deposition within its soil in the monitored time period. These findings have the most interesting significance on the existence of life on Mars.

Further, the team proposes to carry out studies to investigate bound Methane (complex organic material) if it is originated on Mars or have been deposited by meteorites. Precisely, they want to see if the same erosion process is responsible for changing or removing of atmospheric methane.

The conclusion drawn from these investigations will guide future Mars mission like the ESA’s ExoMars 2020 rover and NASA’s Mars 2020 rover and will hopefully clear up important questions regarding the existence of life on Mars and preservation of organic materials there.

planet collision meteor

Researchers find cyanide compounds in meteorites which could hold answers to origin of life

Both carbon monoxide and cyanide are highly poisonous to human beings. However, a group of researchers from Boise State University and NASA have discovered compounds in meteorites containing iron, cyanide and carbon monoxide, which may have been helpful in the beginning of life on Earth. The compounds which are found in meteorites are quite similar to the active site of hydrogenases, the enzymes which provide energy to bacteria by decomposition of hydrogen gas. The results present the conclusion that these compounds were also there on early stages of Earth before the initiation of life. In this time period, several meteorites crashed onto Earth and there was a greater percentage of hydrogen in the atmosphere.

Dr. Karen Smith, a senior researcher at the Boise State University explained that most people think of cyanide as a compound which instantly kills a person if consumed but on the other hand, it was an important compound for the formation of life on Earth. Cyanide consists of a carbon atom bound to nitrogen and it is an important participant in the non-biological synthesis of compounds such as amino acids and nucleobases. These are the building blocks of proteins, nucleic acids that are used by all life forms. The study is published in Nature Communications.

Smith along with Mike Callahan, a co-author of the paper created analytical methods for extracting and calculating the traces of cyanide present in the meteorites. They saw that the cyanide belonged to a group of carbon-rich meteorites known as CM chondrites. In other types of meteorites, no cyanide was found. Jason Dworkin of Goddard Space Flight Centre of NASA said that according to the data collected by OSIRIS-REx spacecraft of Bennu asteroid, the cyanides are from CM chondrites. A sample of this asteroid will be delivered to Earth in 2023 by the spacecraft. Researchers will then search for the compounds for drawing a relation of Bennu with the known meteorites and also understand how compounds such as cyanide got delivered to Earth.

Although cyanide was found before in meteorites, scientists were surprised to find a bonding of cyanide and carbon monoxide with iron for the formation of stable compounds in meteorites. Two different kinds of iron cyano-carbonyl complexes were found in the meteorites with the help of liquid chromatography-mass spectrometry.

Hydrogenases are present in almost all types of modern bacteria. They are huge proteins but the active site is a very small metal organic compound present in the protein. The similarities between the active site of hydrogenases and cyanide compounds could be a possible explanation of the origin of life from non-biological chemical processes.

Representation of dna body strand

Researchers find evidence of DNA and RNA even before life on Earth

Scientists have found a piece of strong evidence that both DNA and RNA might have been formed from the same precursor molecules even before the evolution of life on Earth. The research published in Nature Chemistry shows that the first living beings on our planet might have had both RNA and DNA like all other cellular-based life forms. This is in contrast to the current understanding that the earliest life forms only possessed RNA and DNA was formed with the evolution of life. This is commonly known as the RNA World Hypothesis. After this new finding, scientists should not fully rely on the RNA World Hypothesis for carrying out investigations on the origin of life on Earth.

RNA and DNA are chemically quite similar but chemists have not been able to show how one could have been converted to the other in earliest stages of our planet without the help of enzymes which are produced by the organisms. Because of this reason, researchers have always concluded that RNA is the basic component of the earliest life forms. RNA can store genetic information like DNA and also store catalyse biochemical reactions like protein enzymes. Hence it could have performed the basic biological functions in the earliest forms of life.

Ramanarayanan Krishnamurthy, a chemistry professor at Scripps Research along with his colleagues found a compound which was present in pre-biotic Earth and performed the essential task of linking RNA blocks to larger RNA strands and could have done the same for proteins and DNA.

Scientists have identified a compound named thiouridine which was likely to be present on Earth before the formation of life and it could have been a chemical precursor to the nucleoside blocks of the early RNA. It was found that by means of few chemical reactions this compound could be transformed to deoxyadenosine, a basic building block of DNA. They could also convert thiouridine to deoxyribose which is very closely related to deoxyadenosine.

These findings are a strong indicator that both RNA and DNA developed together and were present in the earliest life forms. Scientists have also suggested that both RNA and DNA might have been combined to form the first genes.  Although no such organism has occurred naturally but a  paper by Scripps Research described an engineered bacteria which can survive with genes formed by a combination of RNA and DNA.

Irrespective of the ways in which life formed, both RNA and DNA with their respective strengths and weaknesses would have arranged themselves into a proper division of labour as evident in the cells today.

Nasa Kepler Exoplanet System

NASA’s Kepler Space Telescope detects the first exoplanet candidate in 10 years

At the fifth Kepler/K2 Science Conference which was held in Glendale, CA on Tuesday, March 5th 2019, Ashley Chontos, an astronomer of NASA’s Kepler Mission announced the confirmed identification of the first exoplanet candidate.

The Kepler Telescope was launched by NASA almost exactly 10 years ago. The mission was designed specifically to survey the region of the Milky Way galaxy to discover hundreds of Earth-size and smaller planets in or near the habitable zone and so far, it has done its best. It is in search of hundreds of billions of stars in our galaxy that might have such planets.

The Kepler-1658b was the first planet candidate discovered by the Kepler Telescope and so it was named after its telescope, which by the way characterized as a big star by the Kepler data later recorded.

It came out to be three times larger than previously thought. “Our new analysis, which uses stellar sound waves observed in the Kepler data to characterize the host star, demonstrated that the star is in fact three times larger than previously thought. This in turn means that the planet is three times larger, revealing that Kepler-1658b is actually a hot Jupiter-like planet,” said Chontos.

NASA Kepler Telescope

Illustration of NASA’s Kepler telescope. (Credit: NASA)

Although the team of astronomers led by Chontos had refined analysis and everything pointed to the object truly being a planet, but confirmation from new observation was still needed.

“We alerted Dave Latham (a senior astronomer at the Smithsonian Astrophysical Observatory, and co-author on the paper) and his team collected the necessary spectroscopic data to unambiguously show that Kepler-1658b is a planet,” said Dan Huber, co-author and astronomer at the University of Hawaii. “As one of the pioneers of exoplanet science and a key figure behind the Kepler mission, it was particularly fitting to have Dave be part of this confirmation.”

Being three times larger in size than the Sun itself, Kepler-1658b is 50% more massive. It is one of the closest-in planets around a more evolved star orbiting at a distance of only twice the star’s diameter. As seen from the earth, the star would appear to be 60 times larger in diameter of the Sun if one is standing on the planet.

It is however, very rare for a planet similar to Kepler-1658b to orbit around an evolved star and the reason for this absence is poorly understood yet. The extreme nature of the Kepler-1658b system allows astronomers to place new constraints on the complex physical interactions that can cause planets to spiral into their host stars.

According to the studies and insights gained from Kepler-1658b, this process happens slower than thought earlier. Although, this might not be the primary reason for the lack of planets existing around more evolved stars.

“Kepler-1658b is a perfect example of why a better understanding of host stars of exoplanets is so important.” said Chontos. “It also tells us that there are many treasures left to be found in the Kepler data.”

About NASA’s Kepler Space Telescope

About Kepler Mission:
Launched in 2009, the Kepler mission is specifically designed to survey the region of the Milky Way galaxy in order discover hundreds of Earth-sized and smaller planets in or near the habitable zone and determine hundreds of billions of stars in our galaxy that might have such planets.

NASA Curiosity Rover at Gale Crater Mars Illustration

Traces of groundwater system found on Mars

Scientists in Geneva have declared, lately, that they have perceived the first ever evidence of an ancient groundwater system consisting of interconnected lakes on Mars. These interconnected lakes lay deep beneath the planet’s surface, five of which may have minerals vital for survival.

Although Mars appears to be a sterile land, its surface shows potent signs that once there were large quantities of water existing on the planet.

Researches and researchers have said that the history of water on Mars has been a complicated topic, and is intricately associated with understanding whether or not life ever arose there – and, if so, where, when, and how it did so.

The recent study, which was earlier predicted by models, says that: “Early Mars was a watery world, but as the planet’s climate changed, this water retreated below the surface to form pools and groundwater“.

The lead author Francesco Salese of Utrecht University, further added – “We traced this water in our study, as its scale and role is a matter of debate, and we found the first geological evidence of a planet-wide groundwater system on Mars”.

Salese and his colleagues explored 24 deep, enclosed craters in the northern hemisphere of Mars, with floors lying roughly 4000 meters below Martian ‘sea level’ (a level that, given the planet’s lack of seas, is arbitrarily defined on Mars based on elevation and atmospheric pressure).

Global Groundwater

How Mars Express gathered evidence for groundwater on Mars. (Source: NASA/JPL-CALTECH/MSSS; DIAGRAM ADAPTED FROM F. SALESE ET AL. (2019))

They found features on the floors of these craters that could only have formed in the presence of water. Many craters contain multiple features, all at depths of 4000 to 4500 meters – indicating that these craters once contained pools and flows of water that transformed and diminished over time.

These features include channels etched into crater walls, valleys carved out by sapping groundwater, dark, curved deltas thought to have formed as water levels rose and fell ridged terraces within crater walls formed by standing water, and fan-shaped deposits of sediment associated with flowing water. The water level aligns with the proposed shorelines of a putative Martian ocean thought to have existed on Mars between three and four billion years ago.

“We think that this ocean may have connected to a system of underground lakes that spread across the entire planet,” adds co-author Gian Gabriele Ori, director of the Università D’Annunzio’s International Research School of Planetary Sciences, Italy.

“These lakes would have existed around 3.5 billion years ago, so may have been contemporaries of a Martian ocean.”

Exploring these sites reveal the conditions suitable for finding past life, and are therefore highly relevant to astrobiological missions such as ExoMars – a joint ESA and Roscosmos endeavor. While the ExoMars Trace Gas Orbiter is already studying Mars from above, the next mission will launch next year.

ExoMars Trace Gas Orbiter Model at ESOC

ExoMars Trace Gas Orbiter, seen at ESOC in Darmstadt, Germany (Source: wikimedia.org)

Mars Express was launched on 2 June 2003 and reached 15 years in space in 2018. The studies and researches conducted lately, have been proved to be fruitful as we have got some really good results from them.