File photo: In this photo taken on Aug. 3, 2014 by Rosetta’s OSIRIS narrow-angle camera Comet 67P/Churyumov-Gerasimenko is pictured from a distance of 285 km. (AP Photo/ESA/Rosetta/MPS for OSIRIS-Team ) (the Associated Press)
It all starts to resemble life here began. The number of potentially habitable worlds has exploded. Organic molecules are found in comets and cosmic clouds. Thus, there is an interstellar conveyor belt seeding life in the milky way?
Monash University Professor John Lattanzio told the annual meeting of the Astronomical Society of Australia hosted at Swinburne University this week that he thinks that this may be so.
The idea is called panspermia.
There is still no ‘smoking gun’ that life on Earth is an offshoot of the interstellar tracks.
But there are enough clues floating about to make the concept attractive.
“A series of astronomical observations obtained over the period 1986 to 2018 to support the idea that life is a cosmic rather than a purely terrestrial or planetary phenomenon,” Professor Lattanzio says.
“The detection of biologically relevant molecules in interstellar clouds and comets, mid-infrared spectra of interstellar grains and the dust from the comet, a diverse set of data of comets including the Rosetta mission shows the connection with biology and the frequency of Earth-like or habitable planets in the Milky way.”
He says that this evidence all converge on the idea that comets are cast about on the interstellar wind can wear their own active biology – and not only the chemical building blocks of life.
But there is only one way to get the idea.
Find life somewhere else.
And we are engaged.
Professor Lattanzio reported on the work done by an international team of researchers who have come up with a set of specific predictions about the nature of extraterrestrial life, if it is found on Enceladus, Europe or beyond.
Usually, they don’t expect to be fundamentally different from our own.
If so, is the concept goes out the window.
“A radically different biochemistry, and elsewhere can be regarded as a falsification of the theory of interstellar panspermia,” he says.
FOLLOW THE INSTRUCTIONS
The idea that the cosmos is an active promoter of life dating back to the Greek astronomer Aristarchus of Samos, who lived in the 3rd century BC. He believed that “spermata” – the seeds of life are everywhere in the universe.
The concept was picked up by Lord Kelvin, and presented to the British Society for Advancement of Science in 1871. It was supported by the late Professor Stephen Hawking. The modern version of panspermia is developed by Professors Fred Hoyle and Chandra Wickramasinghe, the last part of the team reporting the latest developments in the Australian meeting.
“The modern version of panspermia got a major boost when the Australian astronomers Dayal Wickramasinghe and David Allen measured the way light is absorbed by interstellar dust,” Professor Lattanzio says. “Hoyle and Chandra Wickramasinghe (Dayal’s brother) showed this to be matched almost perfectly by the dried E. coli bacteria. This was unexpected, of course.”
The panspermia argument is that there is insufficient direct evidence supports the theory that a chance chemical accident led to the creation of life on Earth about 4 billion years ago. This theory is called abiogenesis.
Organic material falls to Earth from space it is now generally accepted. It is found in meteorites. The Stardust recovery mission found organics and glycine – the simplest amino acid.
Then Rosetta mission to 67P/Churyumov–Gerasimenko found abundance of oxygen (02), ozone (03) and methanol distributed under the comet ice.
“This cannot co-exist in balance together,” Professor Lattanzio says, “and are in accordance with the active biological processes”.
Phosphorus is also found on 67P. And this is an essential component of RNA and DNA. And the concentrations it was found in ten times higher than occur elsewhere in the solar system, and “in accordance with the biological processes and the concentration of the mechanisms,” he says.
And now we know that comets can cross the interstellar void.
“We thought that the comet and the asteroids that travel between stellar systems would be rare because of the distances,” Professor Lattanzio says. “But now we have discovered an example, in Oumuamua. The fact that we found an example, so soon after the development of telescopes, argues that they must be rather more common than we think.”
Could be a fossilized alien evidence?
Professor Lattanzio thinks so.
But there is a problem.
We have the fossilized bacteria.
They are small. They are delicate. And the possibility remains that an unknown geological process can look like them.
But as science and technology improve, we are getting better at sifting of the evidence.
Now NASA says that it found fossil ‘extraterrestrial nucleobases” or the basic nitrogen-bearing organic molecules – in two seductive meteorites (Murchison and Lonewolf Nanataks 94102). Amino acids are also found in the Murchison meteorite, including nine previously unknown species.
While the scattering of clues in meteorites that have already reached the Earth, there are many more because our star circling.
There is Methyl Chloride (CH3CL). On Earth, it is made only by means of biological processes, including micro-algae living in the oceans, with or without light.
Astronomers examine distant exoplanets have already suggested that the presence of Methyl Chloride would serve as a ‘biomarker’, which is a strong sign of the existence of life. It is now found by the Rosetta mission to comet 67P.
Then there is alcohol. It is without a doubt his influence on the minds of astrobiologists, since it was first found on comet Lovejoy. To be precise, Lovejoy is the transfer of ethyl alcohol (ethanol) and sugar.
“Lovejoy is emitting the equivalent of 500 bottles of wine per second,” Professor Lattanzio says. “Natural bacteria to produce ethanol from sugars …”
But the idea that the actual biological entities, such as cyanobacteria, can be transferred between the worlds of comets remains controversial.
Although the evidence is consistent with the idea of panspermia, it is not yet convincing.
“No wonder that the proponents of panspermia frustrated,” Professor Lattanzio says.
A MATTER OF SURVIVAL
Professor Lattanzio says panspermia does not explain the origin of life.
But the consequences are enormous.
“Knowing it does not arise here would be a major discovery,” he says.
“Good science does not say that there is no mechanism for this. Good science says: ‘there Is a phenomenon to explain?’ If so, then we need a mechanism.”
So is the idea that biology can cling to life on a comet in deep, dark and huge cold empty spaces between the stars even possible?
Professor Lattanzio says … maybe.
“We think that bacteria could not survive in the space. Direct evidence now contradicts this.”
He points to a recent experiment on the International Space Station. Antarctica rocks wearing bacterial colonies were exposed to space. After a year-and-a-half, samples were retrieved and rehydrated. Green alga and a pink fungus fast forward.
And then there is the dust that accumulate on the outside of the ISS since it went into orbit in 1998. It turned out to contain the DNA of the land and sea bacteria.
So, possibly because of the weather and storms, we see the life is kicked back out into the ionosphere from the surface of our planet. But it is also likely that it came with interplanetary dust.
How can hitch-hike through the immense cold between the stars?
Bacteria have been found that can survive regular freeze-thaw cycles, and continue to metabolize at temperatures of -20C. But the heat may not be as big a problem as it is made.
Professor Lattanzio points out the slow but steady decay of natural radioactive substances produces significant heat. The powers of geological processes on planets and moons.
It is possible, he argues, that comets larger than 400 kilometres across could, therefore, have liquid cores, regardless of how far from a warming of the earth star, they were.
And liquid water, with a good mix of minerals, it is an ideal travelodge for lifts bacteria.
And tests indicate that bacterial colonies may even survive the flare and crash of a comet into our atmosphere.
“There is a small, but finite survival fraction,” Professor Lattanzio says. “That is all the bacteria needs. They reproduce very quickly.”
But how can we tell, like the life was odd, or only the Earth on the basis of contamination?
Panspermia says that life here is very difficult to distinguish from that found.
Professor Lattanzio says that the only option is to find life on Mars, Enceladus or Europa, and examines the make-up.
“If we discover life with radically different biochemistry to that found on Earth, then that would be the rule of panspermia,” he says.
“Nothing of what I have said, is convincing evidence for panspermia. But there are a number of strange coincidences that we should consider.”
This story was previously published in the news.com.au.