This is a story about comfort...

Halley's Comet will next be visible in our skies on the 28th of July 2061. If I live that long, I'll be 82 years old, which is not inconceivable given that the current life expectancy of a man in the United Kingdom is 81.6 years old. As a lifelong non-smoker, I've also enjoyed a highly nutritious diet and not done a lot of manual labour or worked with particularly toxic chemicals - in theory, I can reasonably expect to live longer than the current national average, which increases quite steadily. In fact, on average, most men my age can expect to live into their 90s.

Edmund Halley was able to calculate how regularly the comet that now bears his name, would be visible in our skies, in 1705 - just 18 years after Isaac Newton published Principia Mathematica which famously contained the inverse-square law of gravity.

Today, we are lucky enough to have telescopes capable of tracking celestial objects with incredible accuracy. We are also blessed with Albert Einstein's General Relativity which allows us to calculate the movement of the heavenly bodies, in agreement with our observations. Before Einstein's GR superseded Newton's law, the orbit of Mercury had not matched up with the predictions of the prevailing theory.

The question that we are left with is this: were the scientific community to discover a huge space rock hurtling towards Earth on collision course, would it be ethical for them to tell the general public?

I'll rephrase and repeat that question again for emphasis: if it were to be discovered that we're all going to die when a massive asteroid smashes into the planet at 38,000 miles per hour, then should we know about it?

Ignorance is bliss.

There will be a certain proportion of society - those who believe all the plants, animals and the Earth were created by a sky monster in just 6 days - who would be resistant to anything that challenges their dogma, no matter how incontrovertible the evidence. There are people who are ridiculously wilfully ignorant, despite the facts, scientific consensus and oversimplifications that spell things out in words of four letters or fewer, complete with cartoon picture-books.

However, one would have to assume that a large proportion of society would accept that they're going to die in an incinerating fireball, earthquake, tsunami, shockwave or some other catastrophic consequence of a huge rock vaporising at millions of degrees, as it collides with the globe.

We could know the specific day that almost everybody is going to be wiped out. Any survivors are likely to die soon after the asteroid impact, due to a cloud of dust and ash that will block out all the heat from the sun. If we were to burn all the coal, oil, gas, trees and use every other energy reserve we have on the planet, we'd only be able to keep ourselves alive for a matter of hours.

Leaving the planet to go and live on the Moon or Mars is a ridiculous idea - only a handful of people would be able to go, and they'd soon die without shuttles from Earth to restock them with everything that moons and planets lack to support life.

The choices are: stay and die, or leave and die.

Given that most of us are going to die in a horrible catastrophe here on Earth, do you think we're just going to sit back and calmly let the billionaires leave and watch our death from space, like some kind of firework show?

Knowing that we're going to die on or around a certain date, along with our family, friends and virtually everybody else on the planet, do you think we're going to act like normal until it happens?

Obviously, there would be anarchy, chaos, looting, barbarism.

If the general public were to learn of the impending doom, wouldn't they plunge civilisation into such chaos that any efforts to save the planet would be derailed - it would become a self-fulfilling prophecy, because the scientists and engineers who might be able to save the entire Earth and its residents, would be ripped limb-from-limb by a crazed mob.

The public might not mean to shoot themselves in the foot, but they surely would. Some people who've seen too many Hollywood movies would endlessly insist that we fire off our entire nuclear arsenal to vaporise the asteroid in space, which would in fact cause masses of fragments of highly radioactive rock to be rained down on half the globe, in a far more destructive bombardment than anything we'd suffer in a single impact.

Deflecting an asteroid could never be done on its impact orbit - the object would be too heavy and travelling too fast - so we simply wouldn't have enough time once we'd discovered the huge rock on collision course to kill us all.

We would be rabidly demanding the impossible, or simply wanting to live a few hours, days or possibly months longer, at the expense of 7.6 billion other souls - diverting our precious resources into lifeboats that would carry us into the hostile vacuum of space: out of the frying pan and into the fire.

Those who grasped the hopelessness of the situation would resign themselves to their fate. Knowing that it would be unethical to bring children into a doomed world, would we kill ourselves, live with the melancholy or become hedonists in our remaining time on Earth? Why bother going to work? Why bother paying your rent or your mortgage or otherwise attempting to lead any kind of life like your ancestors, when an extinction event is inevitable?

If the general public learned of their imminent demise, the collapse of civilised society would be inevitable. So, is it ethical to tell people? In some ways, I'm glad that the world is full of climate change deniers and people who believe that the Earth is flat. It seems plausible that we may have already reached the point of no return, and there are individuals who know beyond all reasonable doubt that we're all going to die, but they are comforted to know that the general public are sufficiently stupid to not realise until mere moments before their death.

Don't scare the horses.

Tags: #physics