While studying a protoplanetary disk it detected some interesting molecular chemistry – the precursor molecules needed to produce proteins and DNA. In other words, the JWST found the seeds of life circling a star far from our Solar
System.

The question of life originating in space has been argued for millennia. In the Western World, the first to propose life coming from space was the Greek philosopher, Anaxagoras, who almost 2,500 years ago hypothesized that the elemental stuff found among the stars bore the seeds of life. Even before Anaxagoras, Buddhist and Vedic philosophers expressed similar arguments.

The idea was revived in the 20th century, first by Svante Arrhenius in 1903. Today, Arrhenius is better remembered for his observations about increased carbon dioxide (CO2) in the atmosphere leading to climate change. He didn’t win much favour with the scientific community about climate change or his theory of life’s origins.

Another proponent of life from space was Fred Hoyle, a 20th-century British astronomer who proposed a theory called stellar nucleosynthesis. Later on, the name changed to panspermia.

I was a big fan of Hoyle as a young man interested in astronomy. I had several telescopes and was a member of the Royal Astronomical Society. I read Hoyle’s books about the origins of the Universe and later the origins of life. Hoyle believed in a steady-state theory of the Universe which was disproved by later observations supporting today’s inflationary model beginning with the Big Bang.

But Hoyle’s stellar nucleosynthesis may in the end prove to be right. He hypothesized that the Ort Cloud, sitting at the outer edge of our Solar System, was the likely source of life here. The Cloud, consisting of tens of thousands of small bodies circling our Sun in orbits lasting tens of thousands of years, is largely a carbon nursery where one can identify organic compounds that are almost indistinguishable from primitive bacteria. Disturbances within the Cloud that caused orbital changes, Hoyle believed, produced the comets that hurled themselves into the Inner Solar System. These comets, largely made up of carbon compounds and water ice rained down on the early Earth over 4 billion years ago. Many scientists today believe that the water in Earth’s oceans came from this cometary bombardment.

So how did the Ort Cloud become the nursery for life? Based on the JWST observations, the Ort Cloud was seeded from interstellar space. The protoplanetary disk circling a red dwarf star within the Orion Nebula could be one of billions of seeds of life nurseries producing carbon-based molecules. In this case, the JWST found a molecular compound called methyl cation (CH3+). It is deemed to be a significant building block for life’s origins because CH3+ interacts with a wide range of carbon molecules to create increasing complexity. Among those complex molecules could be the precursors of RNA and DNA. Previous to the JWST discovery, CH3+ had only been observed within the Solar System.

The basic molecular construct of our existence, the double-helix we call DNA, it turns out appears to spiral always to the right and not to the left. It doesn’t matter what type of life as we know it…always a right ascending spiral.

In chemistry, non-living molecules don’t discriminate. They mix both right and left-oriented constructs. But not the RNA and DNA, the molecules of life.

Why?

The article appearing in The Astrophysical Journal Letters entitled, “The Chiral Puzzle of Life” was published last month and talks about life having a “chiral bias.” That means the molecules display a specific orientation that cannot be replicated when looking at them in a mirror. The authors, Noemie Globus of New York University and the Center for Computational Astrophysics, and Roger Blandford of Stanford University, in their words, state that “living organisms comprise a system of molecules organized with specific handedness.”

In this case, it suggests a biological bias to right-hand dominance as determined by the RNA and DNA helixes. The helical structures of chained nucleotides rise up always spiraling to the right. This tendency ensures the stability of the genetic code and ensures few errors in replication. One could imagine if there were no chirality, that a percentage of DNA and RNA would display left-handed chirality, and the effect could become quite chaotic during replication.

What caused right-handed RNA and DNA?

The authors speculate that cosmic radiation played a key part. Subatomic particles like prions and muons delivered from the stars and cosmic background radiation may have bombarded long-chain molecules eventually leading to right-handedness becoming inherent to the beginning of life.

Muons, for example, contain enough energy to create a spin polarity when striking a molecule and the authors believe that this along with other potential particles within cosmic radiation became the instruments that led to stable helical structures ascending to the right.

That’s not to say that cosmic particles could equally have delivered left-handed spin producing very different constructs, but would they have led to a self-replication?

One can speculate that in the early Universe when stars and planets were first forming, left and right-handed chirality were equally on display producing all kinds of long-chain molecules of which some could have emerged as self-replicating.

To this day, we find evidence of amino acid molecules not just here on Earth that display left-handed chirality. Might this suggest that left-handedness chemistry constructs don’t lead to life?

The authors hypothesize how life emerged in the early Universe believing that its emergence had a lot to do with the building of long-chain molecules with stable architecture that allowed for rapid decoupling and recoupling of its sub-components, the nucleotides capable of grabbing the base sugars such as adenine, cytosine, guanine, and thymine which could be found nearby in the environment. The bombardment caused by cosmic particles influenced the molecules to spin to the right.

What would these early environments look like? Astrobiologists believe that good candidate environments include meteorites containing nucleotides, hydrothermal vents in the early oceans, volcanoes, and natural wet and dry cycles such as those brought on by tidal movements. All or one could have promoted the growth of long-chain molecules impacted by irradiation to display a polarity bias to right-handed chirality.

In any case, as we further explore the Solar System including asteroids, the Moon, and Mars, we may find biogenic evidence that supports universal right-handedness in life’s molecular origins. The authors of the paper described in this posting predict the likelihood that we will find just that, that all life in the Universe will display the same handedness which does nothing for me as a natural southpaw. But that’s life!

Current scientific perspective argues that early Earth was an RNA world. RNA stands for ribonucleic acid, the kid brother of DNA, the molecule of life here on the planet today. And according to the theory, the RNA molecule spontaneously organized prior to the arrival of DNA. RNA, like DNA, self-replicates. And RNA interacts today with proteins in our cells. But according to the hypothesis, back in the beginning, facilitated the development of proteins. From there the RNA along with its created proteins went on to develop DNA. The justification for the theory can be found in the structure of RNA which looks like half of the helical ladder that is DNA. So it sort of makes logical sense that RNA facilitated by proteins conjoined to become the first DNA molecule.

But not so fast states Ram Krishnamurthy, Associate Professor of Chemistry, at The Scripps Research Institute in California. What if life came about from chemistry that preceded the appearance of the RNA molecule? Krishnamurthy, a co-author of a new study published this month in Nature Communications, argues that “if you focus on the chemistry, the questions of origins of life become less daunting.”

So what is the chemistry he’s talking about?

Remember the expression when life sends you lemons, make lemonade. Well it appears that life may have come from chemistry similar to fake lemon juice. Called the citric acid cycle, it is present in all life today performing as the biochemical hub of every living cell whether in fungi or us. It is the essential chemistry behind glycolysis, the chemical process that combines glucose with oxidation to produce carbon dioxide (CO2). The citric acid cycle, in doing this, releases the energy stored within a cell.

Up to now scientists had conjectured that the molecules of life, RNA, and DNA, needed to exist way back when Earth was very young. But Krishnamurthy and his colleagues argue that it was chemical cycles that were needed for life to evolve in Earth’s early environment, one that would have been far too toxic for RNA and DNA to thrive.

In the article, published in the scientific journal Nature Communications on January 8, 2018, the authors write about protometabolic cycles as predating biological ones. They identify two: HKG and malonate. When combined, these cycles turn into a primitive version of the citric acid cycle as we know it today. In the press release that accompanied publication of the research, it states, “The two cycles use reactions that perform the same fundamental chemistry of a-ketoacids and b–ketoacids as in the citric acid cycle.” The byproducts of the reaction are carbon dioxide (CO2) and amino acids. And although the chemistry may be very similar to the citric acid cycle in our cells today, the molecules derived from amino acids back then would have been far different from what is present today. One molecule, glyoxylate, seems to have played an important part because it appears as part of the citric acid cycle in both early Earth and the present.

So the argument goes; that life originated as a byproduct of an early chemistry akin to artificial lemon juice, that begat complex organic molecules. Under such a scenario it is likely that RNA and DNA arose in tandem, the byproduct of the same chemical process that hides in plain sight within us today, the citric acid cycle (seen below).

There are implications from this research to the search for life elsewhere in the Solar System and our Universe. Should the experiments put on rovers on future visits to Mars or other off-world destinations check for the presence of HKG and malonate cycles rather than RNA, DNA, or primitive eukaryotic cells? Would the presence of these chemical precursors to the citric acid cycle tell us that conditions for life’s emergence exist elsewhere and are not limited to Earth alone?

Related articles across the web

• Scientists say they have created the ‘closest thing anyone has ever made’ to a new life form

Why? Because the microorganisms identified in Australian fossils, dating back almost 3.5 billion years, indicate the proliferation of living creatures in the first billion years of Earth history.

As reported in the journal Proceedings of the National Academy of Sciences (PNAS), scientists from UCLA and University of Wisconsin discovered 11 species of primitive microorganisms. Two species displayed photosynthesis-like processes, another generated methane gas, and two others consumed methane to create cellular wall structures. The fossils were found in Western Australia in banded Apex Chert rock formations. These are, to-date, the oldest known fossils of life on Earth.

States J. William Schopf, Professor of Paleobiology at UCLA, the evidence discovered provides “the first data that show the very diverse organisms at that time in Earth’s history …. This tells us life had to have begun substantially earlier and it confirms that it was not difficult for primitive life to form and to evolve into more advanced microorganisms.” Schopf concludes, “if the conditions are right, it looks like life in the Universe should be widespread.”

To find out what made these primitive microorganisms click, the researchers used a secondary ion mass spectrometer (SIMS), separating the carbon in the fossils and measuring the ratio of various isotopes. At the time these microorganisms lived the Earth had not yet developed a significant amount of oxygen. The photosynthesis capability of these microorganisms was probably the catalyst for the chemistry of Earth’s atmosphere to change over the next billion years or so. But the organisms would have had to evolve an ability to deal with the toxicity of oxygen as they expelled it.

Not all scientists agree that what is seen in these images is life. Some believe what we are looking at is very strange minerals that happen to look like fossils.

But if Schopf and his colleagues representing two university research teams are right, they have provided the most detailed study ever conducted on Archaea dating back to Earth’s early history.

Archaea is a classification of living creatures that today are referred to as extremophiles. They live in environments inhospitable to other life on the planet. You can find them on the surface of Earth living in hot springs, or at the bottom of the ocean congregating around black smokers. Or you find them in extreme alkaline and acid environments.

Archaea can also be found in the intestines of ruminant mammals like cows. It is they who contribute the vast amounts of methane to our atmosphere from cow farts.

And we can even find different species of Archaea in plankton.

But for the most part, Archaea thrives where no oxygen is present. That would explain why one would find them in Earth’s past when there was very little atmospheric oxygen.

So if indeed what Schopf and his colleagues have found are primitive life forms inhabiting Earth going back that length of time, it is highly likely that similar processes have led to life happening elsewhere in environments akin to what existed in our planet’s early history.

One cannot help but wonder about Saturn’s largest moon, Titan, with its methane seas. Could it be possible that Archaea are alive and well on Titan to this day, thriving in its extreme cold by digesting and using methane to replicate?

Or in the traces of methane periodically detected by our Mars orbiters, are we measuring the exhalations of Archaea still very much alive on the Red Planet?

Schopf and his colleagues don’t answer the question of more advanced life arising from Archaea. We certainly know it happened here on Earth. That should suggest it likely has happened elsewhere. And given the billions of years between life’s first appearance and today, could intelligent life capable of more sophisticated space travel than us be visiting here after all?

I remain a skeptic about aliens being the likely explanation for UFOs, but I am more than convinced that life populates our Universe, and that intelligent life on some planet or moon circling a distant star is staring up at the night sky and wondering if we exist somewhere in the cosmos.