Are We Alone? And Other Questions from an Astronomer

Image taken with the NASA/ESA Hubble Space Telescope
The galaxy cluster SDSS J1038+4849 seems to be smiling. Image taken with the NASA/ESA Hubble Space Telescope.

 

Besides a boy around 11 years old and his devoted but very bored mother, the average age in the room was coming in at a strong seventy. We were about to be posed some big, mind-bending questions but the pressing question I had was what brought each person here, other than the woman who let it be known that her husband is an astronomer. Another bemoaned the fact that she had missed Monday’s lecture on a Norwegian seal hunting vessel that was shipwrecked in 1908. Who was this blazered, bespectacled set gathered on a winter’s night in a lecture theatre with seating arranged in curves like the symbol for wi-fi? A group of five awkwardly shuffled to the only five available seats found together in the middle of an already seated row. A woman ‘sorry-not-sorry’ed an¬†acquaintance for not being in touch, blaming it on being terrible at Facebook. At the front of the room Dr Robin Catchpole stood in a pink and purple vertical striped shirt beneath a pink and purple diagonal striped tie. An astronomer with an impressive r√©sum√©, which you can find here, Dr Catchpole is visiting South Africa from Cambridge and offered to give a presentation at the University of Cape Town titled, Are We Alone? Considering why we might be the only self-aware observers of our universe. At a time where popular, and SETI, opinion is that we’re only decades away from detecting intelligent life, he raises a compelling argument as to why this might not be the case. As he was introduced, peppermint wrappers rustled and an obligatory ‘can’t hear!’ was called from the back of the room. Humans.

 

Courtesy NASA
The five layers of the full-scale engineering model of NASA’s James Webb Space Telescope sunshield being laid out by technicians who are conducting endurance tests on them.

 

What we do know is that the chemical building blocks of life are out there, the universe is full of the molecules that together make up everything we are and know: blazers, peppermints, lecture theatres. There are many (many, many, many) stars and many planets. And, as Metrodorus said in 400 BC, ‚ÄúIt goes against Nature, in a large field to grow only one shaft of wheat, and in the infinite universe only one living world.‚Äù It’s only logical that there is intelligent life out there. Right?

Using known facts and generally accepted theories about the history of the universe and of mankind, Catchpole arranges information in order for us to see things in a different light. While the number of stars in the sky is uncountable, specific events took place in order for us to exist. These are the things that Catchpole says make our Earth special:¬†Our location in the solar system is the sweet spot. We’re in the ‘goldilocks’ zone in relation to the sun: not too hot, not too cold.¬†Our sun is more stable than other stars like it. Scientists have suggested that a star needs to live several billion years in order for life to evolve on planets in its habitable zone (the orbital area where planets can have liquid water). The sun is around 4.6 billion years old (and halfway through its life), giving human life plenty of time to evolve. Anatomically modern humans are only 200 000 years old.

Our moon is the largest in the solar system in relation to its host planet. It stabilises Earth’s rotation which prevents extreme weather conditions and keeps our climate stable.¬†The idea of punctuated equilibrium and catastrophism suggests that rapid geological changes and evolutionary development is the result of catastrophes: your super volcanoes, comet impact or continental drift. In which case what we needed to evolve were a few comet collisions, but not too many to completely wipe out our chances.¬†Our lucky stars, Jupiter and Saturn protect Earth from (too many) comets and asteroids by way of their gigantic size and location in the solar system. A BBC article goes further to say that most planets orbit closer to their stars than mercury is to our sun, and that their Jupiter-sized planets are usually found orbiting in Earth’s location to the sun. A wild idea being shared is that at one stage Jupiter came in like a wrecking ball demolishing infant planets and clearing the plot for Earth, and life, to take root.

So depending on what you believe, we could at best be a miracle. At worst, a side effect.

 

Image taken with the NASA/ESA Hubble Space Telescope.
NGC 6496, a 10.5-billion-year-old globular cluster. Image taken with the NASA/ESA Hubble Space Telescope.

 

Throughout his presentation Catchpole is careful not to give definitive answers, because the only true answer is that we just don’t know.¬†Instead of risking a conclusion, he asks probing questions like:¬†Is advanced technology inevitable of a habitable planet?¬†If there are other civilisations, will ours last long enough to make contact?¬†If we are the only thinking, self-aware, beings in the universe, is it important we survive ?

He goes on to speculate that maybe we haven’t found intelligent life out there not because none has evolved, but because they simply didn’t survive long enough to get in touch. Perhaps space is silent because our alien brothers didn’t survive their own demise, or a super volcano, or a comet impact. In closing Catchpole offers a thought for ‘the young people in the room’ suggesting that we take the silence of the universe as a warning to look after our world.

At the end of his presentation, the floor was opened for questions. Unlike many seminars or talks I’ve attended where the Q&A session is a long uncomfortable silence, the questions came in hard, fast and educated. Except for the man who asked if global warming exists. A raised hand asked about using lasers to propel a space craft through the universe at an accelerated speed; another theory that popular science publications are throwing around.¬†An older gentleman wondered out loud how you’d then stop the craft being lasered through space. This solicited a cheeky, ‘you switch the light off!’ from a joker in the front row. The small crowd chuckled. The young boy raised his hand and confidently asked about the theory of bending space-time in front of and behind a vessel in order for it to travel at the speed of light. After an explanation of why he doesn’t think its plausible, our speaker relegated the theory to ‘a fun idea’ and the crowd chuckled again. The boy smirked. He’ll show us.

 

A photograph taken in April, 1990, of the Hubble Space Telescope.
A photograph taken in April, 1990 of the Hubble Space Telescope.
Image taken with the NASA/ESA Hubble Space Telescope.
Peering deep into the early Universe with the NASA/ESA Hubble Space Telescope.

 

www.ast.cam.ac.uk/~catchpol

 

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