The effects of climate change have made life on Bonaire ‘unbearable’, according to some of the island’s 27,000 residents – Copyright AFP/File David GRAY

A big problem for identifying life on other worlds is the Earth-centric spectrum of information available. It doesn’t follow that all life has to begin the same way. It definitely doesn’t follow that the chemistry of life on quite different planets can even behave the same way.

This is where the Assembly Index comes in. The components of any kind of life are subject to environmental factors, heat, cold, chemical availability, and above all, time. Unusually, the idea is based on the complexity of assembling chemical building blocks, which is called “selection”, a series of construction steps.

Think about it. Since Earth formed, the planet has pretty much recycled most of its materials. The environment has changed from what was effectively an alien planet to this. The availability of oxygen was a key catalyst in the development of modern life. Anaerobic life still exists and ironically often generates oxygen as a waste product, like cyanobacteria. From a huge single continent to a LEGO set of the current continents and the remains of continents. Change has assembled the conditions for life and life itself.

Now consider Venus. There is much chemical similarity, the same chemistry, but the two planets couldn’t be more different. The oppressive heat and atmospheric pressure of Venus can’t deliver the same outcomes. What can be assembled from its environment? How? When?

The Assembly Index is defined and measured by what Cornell calls “the amount of selection required for a given ensemble of objects”. OK, it’s not a simple definition, but it’s a criteria for critical biological mechanisms. It also includes, by default, the necessity to map the elements of life. “Assembly” may well be the single greatest understatement in the history of biology.

Consider how many species have existed on Earth. Each required a unique map of practical biochemistry to deliver living things. Many with the same ancestry diversified almost beyond recognition. From thermophilic bacteria to whales, there’s an assembly line to be mapped.

That’s just on this planet, and we’re still working on it.  Now add the number of species past and present we haven’t discovered yet. Apply this process to other worlds. How do you even recognize the assembly process elsewhere? The Assembly Index is a very good idea, a sort of audit trail for life.

Asimov wrote a novella called Mother Earth, which is a pretty apt analogy. As well as being a writer, he was also a biologist. This story makes the point that life on different worlds is unique by definition. The biology of one world doesn’t transfer to another, even with terraforming and any amount of technology. He makes the very necessary point that the people on different worlds adapt to those worlds. Humanity becomes a complex diaspora.

Now apply this perspective to all life in the universe. There’s no How To manual. There are and can be no fixed One Size Fits All criteria. Life writes itself. It’s learning how to read what’s written that we call science.

You can expect the Assembly Index idea to pop up in xenobiology and every possible theory of life. It’s more than likely that medicine will have to use it or something like it to solve the almost-unreadable problems of health and longevity.

The largest database in future science may just have found a name for itself.

_________________________________________________________

Disclaimer
The opinions expressed in this Op-Ed are those of the author. They do not purport to reflect the opinions or views of the Digital Journal or its members.