I thought my readers might enjoy this article :

A look at the scientific evidence for panspermia.

“The strongest evidence to support a cosmic origin of life and panspermia is the mind-boggling complexity of life.”

My colleague Sir Fred Hoyle famously commented :

In the 16 years since Fred passed,  we have discovered so much more about the complexity of “life” at the nano-scale. The more we learn about viruses and their contribution to our “human” biosystem, the more we become aware of just how intuitively right Fred was.

I thought I would finish this post with a reference to Wikipedia. With all its flaws it does attempt to be a source for the latest thinking even if you need to check what has been recently deleted to see the best latest and best hypotheses.

Here is a clip from Wikipedia on July 1 , 2017 :

https://en.wikipedia.org/wiki/Life

“Life is a characteristic distinguishing physical entities having biological processes, such as signaling and self-sustaining processes, from those that do not, either because such functions have ceased, or because they never had such functions and are classified as inanimate. Various forms of life exist, such as plants, animals, fungi, protists, archaea, and bacteria. The criteria can at times be ambiguous and may or may not define viruses, viroids, or potential artificial life as “living”. Biology is the primary science concerned with the study of life, although many other sciences are involved.

The definition of life is controversial. The current definition is that organisms maintain homeostasis, are composed of cells, undergo metabolism, can grow, adapt to their environment, respond to stimuli, and reproduce. However, many other biological definitions have been proposed, and there are some borderline cases of life, such as viruses. Throughout history, there have been many attempts to define what is meant by “life” and many theories on the properties and emergence of living things, such as materialism, the belief that everything is made out of matter and that life is merely a complex form of it; hylomorphism, the belief that all things are a combination of matter and form, and the form of a living thing is its soul; spontaneous generation, the belief that life repeatedly emerges from non-life; and vitalism, a now largely discredited hypothesis that living organisms possess a “life force” or “vital spark”. Modern definitions are more complex, with input from a diversity of scientific disciplines. Biophysicists have proposed many definitions based on chemical systems; there are also some living systems theories, such as the Gaia hypothesis, the idea that the Earth itself is alive. Another theory is that life is the property of ecological systems, and yet another is elaborated in complex systems biology, a branch or subfield of mathematical biology. Abiogenesis describes the natural process of life arising from non-living matter, such as simple organic compounds. Properties common to all organisms include the need for certain core chemical elements to sustain biochemical functions.

Life on Earth first appeared as early as 4.28 billion years ago, soon after ocean formation 4.41 billion years ago, and not long after the formation of the Earth 4.54 billion years ago.^[1][2][3][4] Earth’s current life may have descended from an RNA world, although RNA-based life may not have been the first. The mechanism by which life began on Earth is unknown, though many hypotheses have been formulated and are often based on the Miller–Urey experiment. The earliest known life forms are microfossils of bacteria. In July 2016, scientists reported identifying a set of 355 genes believed to be present in the last universal common ancestor (LUCA) of all living organisms.^[5]

I think Fred would concur with me that although this is an acceptable public representation of life, this misses the profound discovery that all visible life forms are not a simple single “entity” but a complex biosystem of interacting clouds of viruses, bacteria and as yet undiscovered nano-life forms.

I always smile when I think of this as it reminds me of just how great Fred’s  visionary novel was – the Black Cloud.