I’ve been asked to write about what we should do after the end of the world. It sounds like this piece ought to be rather short. But actually, I’m here to tell you that the end of the world need not be all bad news. Yes, really!

Well, alright, I should come clean I suppose. The apocalypse would indeed be pretty bad news for almost all of us, and quite possibly for every single last one of us. Definitely, my Plan A would be to avoid the apocalypse if at all possible. Trying to duck the killer asteroid, or swim above the nanotech grey goo. Or despairing that “OK Google, ask my robot to stop trying to take over the world” no longer seems to work. The apocalypse really doesn’t sound like a lot of fun. But, if it is going to happen, is there a Plan B?

For those of you who like to see a silver lining surrounding even the bleakest of clouds, I place myself humbly at your service. I present to you a concise five-step astrophysicist’s guide to surviving the apocalypse*.

(*well, at best, a few brave souls might survive, and even that’s unlikely. But don’t let that take the shine off of an otherwise very positive message.)

Step 1: Buy some time

When in a sticky situation, it is always a good strategy to buy as much time as you can so that you can form a proper exit strategy. So, I start with advice that you may have heard before many times but which I make no apology for repeating: Look after the planet we currently live on! There’s a lot of life left in it yet if we are prudent. Even more so if we can bring our population growth under control.

OK, so from here on I will assume that we do not get to grips with looking after our planet or that we succeed but then a nasty killer asteroid comes along that is just as happy to wipe out a modestly populated planet as an over-populated one. What now?

Step 2: Gain a proper sense of perspective

Positive thinking is always good. For example, my job as an astrophysicist involves hunting for exoplanets – planets around other stars. So, from my standpoint, we should really view the apocalypse not as the end of the world, but merely the end of a world. I don’t know about you but I feel better already.

In fact, over the last 25 years we have discovered that there are plenty of other worlds out there. There are many techniques that we use to find exoplanets, such as the transit technique where we look for small dips in starlight as an exoplanet passes in front of its host star as it orbits around it. Amazingly, we’re finding that pretty much every one of the hundreds of billions of stars in our Galaxy hosts at least one exoplanet. We’re even finding exoplanets out in deep space that don’t seem to have a host star. Living on a planet where you never see the Sun is actually something I’ve become rather accustomed to since moving to Manchester. But the point is that exoplanets are everywhere. If ever there’s a Rightmove for exoplanets you’ll need plenty of time to search through it to pick your next ideal home.

We’ve also spotted that a significant number of exoplanets lie within the so-called “Goldilocks” zone. That’s the region around their host star where the planet can be at just the right temperature to host liquid water on its surface. Water is of course an essential requirement for us to establish our new home from home.

The frequency of potentially habitable exoplanets is still subject to investigation but early results indicate that it may be quite high for stars smaller than the Sun, which also happen to be the most common type of star in our Galaxy.

A good example of a Goldilocks system is TRAPPIST-1, discovered in 2017, in which a star about 10% of the mass of the Sun hosts at least seven Earth-sized planets, of which three may be able to host liquid water. TRAPPIST-1 is a mere 40 light-years away. If that sounds a bit far to you then I will try to suppress my thoughts about your sheer laziness and instead point out that there is also a potentially habitable planet around the Sun’s next door stellar neighbour, Proxima Centauri. That’s just four light year away – it really is literally just next door you couch potato! If you are one of those curmudgeons who mumble on about how many tens of thousands of years the journey would take, then read Step 3 and think again.

Of course, one of the things that makes life possible (for now) here on Earth is its atmosphere. What about the atmospheres of other planets? Well, we’re actually able to probe some of those already using a technique called transmission spectroscopy. For planets which transit in front of their host star we can measure the strength of the transit signal at different wavelengths. Since exoplanet atmospheres block and scatter starlight differently at different wavelengths, depending on their chemistry, their transit signal may be stronger at some wavelengths and weaker at others. By carefully measuring this variation and comparing it to the way in which Earth’s atmosphere blocks and scatter sunlight we can determine the chemical composition and potential suitability of exoplanet atmospheres.

In fact, we have probed the molecular composition of over 40 exoplanets to date, finding evidence for methane, water vapour, ammonia and many others species. For now this technique has been used mostly to probe the atmospheres of larger Jupiter-like exoplanets. In the relatively near future it should be possible to measure the atmospheres of smaller more Earth-like exoplanets, and perhaps even uncover evidence for bio-markers – molecular combinations like oxygen and methane that may indicate the presence of biological activity.

So, to summarise, we can find Earth-like exoplanets that have the right temperature. In the near future we should be able study their atmospheres to work out if there’s water on them and perhaps biological activity that might please the panel on Gardener’s Question Time. We might be losing one world to the apocalypse but we are gaining knowledge of a few hundred billion others. Result!

Step 3: Be aware of your options – science fiction is becoming science fact

What about reaching one of these Goldilocks planets? It’s true that the fastest rocket to date would take around 70,000 years to reach even our nearest neighbour Proxima Centauri. To put that into context that’s even slower than it takes me to drive into the centre of Manchester by car along the A6 during rush hour. I therefore choose to cycle into Manchester. Unfortunately, it turns out that bicycles are utterly useless in deep space.

Instead we can adopt two approaches. One is to develop human hibernation methods so that planet-bound explorers of the future can effectively shut down for tens of thousands of years until they reach their destination, saving on water, food and Spotify subscriptions. The other is to develop near light-speed propulsion technology, which could allow us to travel arbitrarily far within a single human lifetime. “You’re a crazy dreamer!” I hear you say. Well, yes I am, it’s a job requirement.

But, incredibly, these technologies are both being actively pursued even today. In fact, a postage-stamp-sized satellite travelling at 20% light speed may be propelled towards Proxima Centauri in as little as 20 years time thanks to a team of scientists and engineers working on the Breakthrough Starshot initiative that is being bank-rolled to the tune of $100 million by Russian billionaire, Yuri Milner. Within the next 50 years or so we could have the first fly-by images of planets around another star system.

Step 4: Don’t wait for Armageddon – start preparations now

Of course, sending humans into space rather than stamp-sized probes is a whole different ball game, and requires a lot of forward planning, together with a sprinkling of people we might normally regard as insane.

One of the major obstacles to sending humans to colonise another world to avoid Armageddon is a sociological one. Who should we send? Unfortunately it wouldn’t be practical to try and ship out the entire population of Earth. Sorry, but most of us will have to stay behind and face the Grim Reaper with stoicism. Or blind panic if you prefer. But presumably, once a planet-bound rocket is built, tested and ready to launch just at End-of-The-World’s Eve, we might very well expect a not-so-orderly queue of rather flustered looking folk, without invites, rudely wanting to climb aboard. And they won’t take no for an answer.

This is where the forward planning and insane people come in. You see, there is no point trying to launch interstellar ships like lifeboats just as the good-ship Earth is sinking. They need to be launched long before then at a time when almost nobody in their right mind would wish to climb aboard. The right time is whilst Earth is still a relatively nice place to live on with no imminent threat of demise.

Step 5: Take that leap – fortune (marginally) favours the insane

The right people to make the voyage from Earth to another world are volunteers who fancy a change of scenery and long odds of a happy ending to their journey. Fortunately, such people exist and history is littered with them. They are the very people that today we regard as hero explorers who have helped to shape and define the world we live in.

People like the 16th Century seafaring explorer Ferdinand Magellan, often cited as the first person to circumnavigate the world. Actually he died before arriving back home, but a handful of the original crew did make it all the way around. These people left behind a relatively comfortable environment at home to spend years, mostly in a confined space, with the odds stacked against them that they would survive for long, let alone ever return.

Possibly the closest examples in the modern era are the early pioneers of space flight, from Gagarin and Tereshkova through to the Apollo Moon landers. Neal Armstrong estimated that the chance of success (which we can take to mean coming back alive) was around 50%. In July 1969 Neal, Buzz Aldrin and Michael Collins effectively tossed a coin to live or die in the cause of furthering the footsteps of mankind.

Those who volunteer to undertake journeys when the odds are stacked heavily against them might be regarded by many of us as mad. But these are people who define the summit of the human spirit. The fate of post-apocalypse humans rests with them, not with the rest of us. Those who may step aboard an interstellar rocket bound for another planetary system will be selected not so much because they bravely step forward but because the rest of us take a cowardly step back.

Perhaps the hardest part about trying to survive the apocalypse is starting to implement the plan. Maybe we actually need a feeling that the end of the world is, maybe not necessarily nigh, but nonetheless approaching within a few generations. That is the point at which we would need to start planning, building and testing. The development of a human interstellar travel capability would be a global grand challenge for mankind, requiring international cooperation and effort. It might just keep decision makers occupied long enough to stop lobbing missiles at each other in the meantime.

The feeling of impending doom might be a first necessary step on the ladder to our greatest achievement – to join the interstellar community. I won’t get there, and probably neither will you but we can start now at Step 1 and hopefully play our part in helping somebody in the future to reach for the stars.