An artist’s concept of the alien planet Kepler-452b, the first near Earth-size alien planet discovered in the habitable zone of a sunlike star. NASA unveiled the exoplanet discovery on 23 July 2015.
We have found 3663 (and counting) planets around distant stars. About 50 are in the ‘Goldilocks zone’, that supports liquid water. A new study has whittled the number believed living to just three.
And the Earth is one of them.
Until now, the chief measure of a planet’s potential habitability is whether it is the right temperature for liquid water to exist.
But life — as we know — is more necessary than muddy puddles.
It should be a spice rack of essential ingredients.
And behind them, all the baking strength of UV-light.
A study published in Science Advances says the ultraviolet rays of the power of the chemical reactions required to make the building blocks of life. And, once built, recent discoveries on the comets hint that these have a tendency to assemble themselves into more and more advanced organic structures.
So they set about creating a new set of criteria for the determination of the most promising life-promotion of the planets. After the filtering out of these stars, which are not the ‘flavour’ of UV, only a handful of contenders remaining.
“This work allows us to restrict to one of the best places to search for life,” the lead author of the study Dr. Paul Rimmer says. “It brings us a little closer to addressing the question of whether we are alone in the universe.”
THE INTERSTELLAR BAKE ‘N’SHAKE
The cookbook for the primordial soup has not yet been written. But scientists have figured out a fair bit of the recipe behind all this.
It contains a number of surprises.
For example, one of the main ingredients is cyanide …
Researchers believe that the carbon in meteorites slamming into a planet the beginning of the atmosphere can react with nitrogen, hydrogen cyanide.
This then rains down on the surface, collecting in the pools of water.
Hydrogen cyanide, when it is mixed with hydrogen sulfite, can be baked by UV-light in sugars and polymers and phosphates. These are the building blocks of RNA. RNA as DNA, can carry evolutionary information. DNA carries just twice as much.
Co-author of this paper, Professor John Sutherland — who is specialized in the chemical origin of life on Earth — has tried to understand what initiates these chemical processes.
Working with astronomer Dr Rimmer, however, made a new perspective.
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“My first question is (was) what kind of light do you use that as chemists they haven’t really thought about it,” Dr Rimmer says. “I started measuring the number of photons emitted by their lamps, and then realized that the comparison of the light the light of other stars was a simple next step.”
The astronomers and scientists conducted a series of tests to see what the most efficient UV “temperature” was to cook up a primordial soup.
“There is chemistry that happens in the dark: it is slower than the chemistry that happens in the light, but it is there,” senior author Professor Didier Queloz says. “We wanted to see how much light it would take for the light chemistry to win over the dark chemistry.”
No light, the process produced inert substances.
People with UV-light the right stuff — but at different rates according to the brightness.
This productivity curve was then applied in the light of other stars known for hosting planets in their “Goldilocks Zone”.
Cool stars such as red dwarfs — not enough light to activate the chemical reactions, the study found. But others with a similar temperature to our own ideal.
This provides the ‘abiogenesis zone’ Goldilocks planets where there is enough UV light to activate the organic chemistry.
The RED DWARF WORLDS: Where the evolution will be very different
Simply put, it is true, the odds are the best that you can find primordial soup.
“Of course, be prepared for life is not everything, and we still don’t know how likely it is that the origin of life,” Professor Sutherland said. “Even certain favourable circumstances, if it really is unlikely than we can alone. But if not, we may have company.”
When plotted on a chart, two places come up trumps.
Kepler-62 is right on the edge.
And then there’s Kepler-452b.
When discovered in 2015, it was given the name Earth’s ‘cousin’.
This latest discovery could elevate ‘sibling’ status.
The more than 1400 light-years away, though. So, it is outside the ability of even our best telescopes have a clear look at.
We know that it is approximately 1.5 times as large as the Earth. Such as the Earth, it is in the ‘Goldilocks zone’ of the star.
And, like the Earth, it fits neatly in the vicinity of the centre of the new ‘abiogenesis zone’.
“I’m not sure how contingent life is, but given the fact that we only have one example so far, it makes sense to look to places that most of us,” Dr Rimmer says. “There is an important distinction between what is necessary and what is sufficient. The building blocks are necessary, but not sufficient: it is possible that you could mix them for billions of years, and nothing happens. But you want to at least look at the places where the necessary things of existence.”
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Cooler red dwarfs, the most abundant species in the known universe — are not without hope. The researchers say regular flares have the potential to kickstart the chemistry. And young red dwarfs are known to be restless. But they are also of long duration, the introduction of a sedentary adulthood causing molecular life to flourish.
But that is much harder to calculate.
And, of course, the life there can be none of that down here.
This story originally appeared on the News.com.au.