# Reach for the stars?

At the time of writing, nearly 5000 planets have been discovered outside of our solar system (so called exoplanets), an incredible achievement given just 30 years ago we knew of none. If we consider only planets which could potentially contain life (orbiting their parent star in the so called Goldilocks Zone), then it is estimated there are 300million planets in our galaxy alone. Multiply this by the number of known galaxies in the universe (excitingly the first extra-galactic planet may have recently been discovered), and the planetary options for life in the universe are staggering.

N = R* • Fp • Ne • Fl • Fi • Fc • L

The Drake Equation

The number of planets in the universe, or more precisely the fraction of stars with planets, forms an integral part of the Drake equation. Proposed by Frank Drake in the early 60s, his eponymous equation is an attempt to estimate how many extraterrestrial civilisations (N) exist within the Milky Way. Taking into account the rate of star formation (R*), the fraction of stars with planets (Fp), the fraction of those planets which could be liveable (Ne), the fraction of those liveable planets which develop life (Fl), the fraction of such life which becomes intelligent (Fi), the fraction of intelligent life which develops technology to send detectable signals into space (Fc) and the length of time those civilisations may broadcast for (L), scientists can provide a (very) rough estimate of the number of civilisations within the galaxy. Current estimates range from one (i.e. us) civilisation to many hundreds of thousands out there waiting to be discovered.

Assuming we are not alone in the galaxy (or universe) then the numbers suggest there should be at least tens of intelligent civilisations beyond our solar system. The problem, and this might be disputed by some of my readers, we have not seen hide nor hair (nor scales nor goo) of any of these proposed alien civilisations.

This lack of contact, or even just indirect evidence for their existence, has a name; the Fermi Paradox. Named for the renowned theoretical physicist Enrico Fermi, regardless of the solution to the paradox it comes with profound consequences for humanity and our place in the universe.

Numerous solutions to the Fermi paradox exist. It might be we have overestimated the likelihood of life starting on any given planet, or overestimated the length of time civilisation survives before going extinct (see also climate change…). A potential explanation would be we simply are not technologically advanced enough to detect life elsewhere in the galaxy, or perhaps getting out into the stars is harder than we think and not worth the effort of other civilisations. Given our propensity to be a rather aggressive and destructive species, it could be alien life is doing its best to avoid us, or just maybe it is already here 👽…

One potential explanation for the Fermi paradox is alien life is simply not interested in exploring or communicating with the Universe beyond their own planet. Assuming any planet with life beyond Earth is at least as varied and interesting as our home world, it might just not be worth spending the time and effort going to the stars. A variation of this explanation I have been thinking about more and more; could it be alien life has realised leaving their home planet and exploring the universe fundamentally changes who their are as a species.

## To go boldly…

Science fiction, particularly film and television, has been something of a love of mine for as long as I can remember. The Star Wars vs Star Trek debate has never been an issue for me, I love them both for different reasons, and whether it is a galaxy far, far away or our own galaxy being colonised in the not too distant future, exploring space has been an attractive dream for me for years.

In this dream I know I am not alone. For as long as humans have existed we have looked to the stars and many of us will have dreamt of going beyond Earth to see what is there. Since the late 1950s with Sputnik, we have begun to make our first tentative forays into the vast beyond. Today, a selection of obscenely rich individuals (who I will not name on principle but I’m sure you will know who they are) are spending eye watering sums of money to build rockets and satisfy their own desire to visit, or should that be escape to, space.

The idea of going into space, colonising and exploring the galaxy, building a Federation (and hopefully not the Empire) is a tantalising one, so it is with great pains that I write, I think it is time to give up on space…

## Humanity is Earth is Humanity

Human beings have not evolved to survive in space. It has taken our intelligence and ingenuity to develop some of the most complex systems in history to allow us to live in the hostile vacuum of space and beyond. The likes of the Saturn V rocket and the International Space Station (ISS) can arguably be called pinnacles of human achievement, at least technologically. They are marvellous machines, and without them astronauts (cosmonauts, taikonauts) would have no chance in space.

Even when an astronaut is provided with a state of the art spacecraft, the toll of long term space flight on the human body is well understood. From the physical burden of zero-G to the increasingly acknowledged psychological (and even psychiatric) challenges of prolonged isolation and confinement, space travel is no walk in the park. Challenges are of course there to be overcome, but as yet no one has been able to survive indefinitely in space (the record is currently just over a year at 438 days), and it is not clear landing on another planet such as Mars would be any different.

As I wrote earlier humans did not evolve for space, rather we evolved on Earth as part of a complex, and at times under appreciated, web of life. As we are seeing as a result of climate change, pollution and the like, the biosphere we survive in is an interconnected and fragile system which relies on each part being finely tuned and working in harmony for the system as a whole to function. Scientifically known as the Gaia hypothesis, this idea is not without its critics, but I think it has some merit, at least when it comes to defining who we are as people.

If I was to ask you to define yourself, you might choose to give a list of descriptors such as height, weight or maybe a series of personality traits and psychological drives. You might also choose to define your identity based on groups you belong to, be it your family, country, religion etc. In this case, it is in reference to factors external to you which are used to develop a definition of who you are.

We can of course also define ourselves as a species (even though species itself is a difficult term to define). In doing so, we may list features which are unique to our species (according to renowned primatologist Robert Sapolsky, this list is rather small), but ultimately we end up defining our species in reference to the rest of nature, just as we define ourselves in relation to external cultural factors. We define humanity in relation to the natural world simply because we are part of the natural world, and it is impossible to do otherwise.

As much as we might not wish to think it, humanity is a part of the natural world, and the natural world, the planet Earth, Gaia if you will, is part of what makes us human. Some of us may think of ourselves as strident individualists, standing alone and acting on our own terms, but this is a hubristic fantasy. Humanity is not a series of isolated individuals but a collection of interconnected people and groups. Similarly, life is not a series of isolated species but a group of interconnected ones, and the wellbeing of one part of the system (us) feels predicated on a connection with the rest of the whole. If being human includes being part of the wider biosphere, does leaving that biosphere take away a part of what makes us human?

On Earth we are increasingly isolating ourselves from nature in urban spaces, so much so people are purposefully seeking nature as a way to reconnect with what we have lost and help our wellbeing in the process. To think we can keep our humanity in space and beyond I fear is a folly, and no amount of houseplants on a space ship are going to mitigate this. Dreaming of taking to the stars has a long and extensive history, I wonder whether it is time to accept this will remain a dream, and start focussing on helping to shape an even better world for humanity and the rest of life here on Earth.

## Down to Earth with a bump

As I wrote earlier it does pain me to advocate for abandoning human space flight. If you offered me a place on the next rocket to the ISS I would find it very hard to resist. I am also not suggesting abandoning space exploration all together, something I should have made clearer a few paragraphs ago. Certainly robotic exploration is an exciting branch of science and I am sure will lead to some phenomenal discoveries in the coming years. I’m just not sure humanity needs to, or indeed can, follow them.

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