This protester’s sign may be a little premature, but he is correct. Humankind’s reign will eventually come to an end, and there is important work that (I feel) we must complete before we are extinguished.
There are three events that will cause the end of our collective existence: two are naturally-occurring and are in the very distant future. However, the third is one that we created ourselves, and may occur within the next 100 years. Let’s examine each one individually.
The Red Giant
Everyone who’s taken a high school science class knows that our sun will become a Red Giant in about five billion years. At that time, its diameter will increase until it becomes 200 times its current size, and its outer edge will be in the Earth’s orbit. This means that Mercury, Venus and the Earth will be consumed by the sun and completely incinerated. I admit this sounds disastrous, but during the next five billion years – assuming that humankind hasn’t nuked itself out of existence or rendered the Earth uninhabitable in other ways – I expect that we will have devised a way to travel to and colonize other planets, in order to continue our lives elsewhere. This event doesn’t particularly concern me.
Now let’s zoom out a little more and examine things on a cosmological scale.
The Big Crunch
I assume that most of you are familiar with the Big Bang Theory – not the television series, but the hypothesis that offers to explain how the universe was created. About 13.75 billion years ago, all of the matter in the universe was concentrated in a single point called a singularity, which then expanded very rapidly, much like an explosion. At this moment, our universe is still expanding (as it has been doing since it was created), but many people who subscribe to this hypothesis also believe that at some point in the future, this expansion will cease and the universe will then start contracting. This contraction will continue until all of the matter in the universe collapses into a single point once again, which will be denser than a black hole. This event is known as the Big Crunch – the Big Bang in reverse. It will be the end of space and time, the universe itself, and (most importantly) everything that was ever created by its inhabitants.
Although the Big Crunch won’t happen anytime soon, this is still a distressing thought. Everything that humans have ever created and accomplished – every book, building, invention, language, medicine, piece of art; all of our, music, poetry, sculptures and computer software – the entirety of our accumulated wisdom along with the fruits of all of our labours – will one day cease to exist. Preserving our collective knowledge as our sun becomes a Red Giant is a trivial matter – we simply have to move to Mars or to the outer planets in our own solar system – but there is no escape from the Big Crunch. There is no place in the universe where we can safely store this knowledge – no celestial bank vault or safety-deposit box – because, ultimately, all of the matter in the universe will eventually be destroyed. I realize that matter cannot be created or destroyed, but during the Big Crunch, the knowledge and wisdom and beauty contained in that matter will no longer exist.
A Global Catastrophe Of Our Own Making
While there’s still plenty of time before the universe collapses, there is another calamitous event that is just around the corner. Climate change could start making our planet uninhabitable, starting in less than a century.
- In a recent episode of Last Week Tonight with John Oliver, the shows host, quoting Princeton professor Michael Oppenheimer, warns of dire and potentially irreversible consequences for the planet’s food supply if we aren’t able to limit the global temperature rise to below 2°C, or our cumulative global CO² emissions to less than 2,900 gigatonnes. This upper limit is represented by the gray bar in the graph on the left. The red bar represents our present cumulative global CO² emissions. At our current rate of CO² emissions continue, we will exceed that threshold in about 20 years, as indicated by the graph on the right.
- Author and astrophysicist Neil DeGrasse Tyson, in an interview with CNN, is also worried that we are reaching the point of no return, and added “The longer we delay, the more I worry we might not be able to recover from this.”
- Stephen Hawking, in a recent interview with the BBC, warned that humanity was in danger of destroying itself within the next 100 years. Not only from global warming, but also from nuclear war, and genetically-engineered viruses. He then suggested that we need to colonize other planets if we hope to ensure our survival.
Saving Everything Humankind Has Created
When the Big Crunch occurs, everything that humankind has ever created will be destroyed, but now we no longer have billions of years to think of a way to save it. Unless we can curtail our carbon emissions, we will have less than a century before we reach the point of no return, and the beginning of the end.
However, I have an idea – not to save the planet, but a way that we might be able to preserve everything that we’ve created. I will admit, this is a long shot, both literally and metaphorically. Here’s what I propose: We can launch a space probe – one that contains a digitized version of all of our accumulated knowledge (in a multitude of languages), along with a device that will read and translate this data) – and send it hurtling toward the edge of the universe.
Right now you’re probably thinking “If the entire universe is going to collapse, then why bother sending out a space probe anywhere, since it will also be destroyed in the Big Crunch?” Yes, that is a reasonable question. The next step in this plan, after launching the probe, is ensuring that it will reach the edge of the universe. Before we can do that, we first need to find out if this is even possible. The universe is still expanding, but how fast is it expanding? After doing a bit of research, I found out that the rate of expansion has its own special unit, called the Hubble Constant. There is some debate over its exact value, but the best guess so far is 71 km/s/Mpc (kilometres per second per megaparsec). The expansion rate is actually a bit more complicated than a simple velocity, but for the purposes of this article, let’s just assume that the rate of expansion is 71km/s.
If we can get our space probe to exceed the speed at which the universe is expanding, then it will eventually reach the edge of the universe. Luckily, space is practically a vacuum, so as long as our probe doesn’t hit anything, it won’t slow down. A continual propulsion source (from solar panels or a small nuclear reactor) can ensure a continual increase in speed. As a reference, the Helios 1 and 2 space probes, launched in 1974 and 1976, respectively, achieved a speed record of 70.22 km/s in their orbit around the sun. Exceeding the speed of the universe’s rate of expansion does appear to to be attainable, which means that we can launch a space probe, filled with our accumulated knowledge, and (theoretically) have it reach the edge of the universe.
The crucial question is: what will happen when our space probe hits the edge of the universe? I have no idea, but after giving it some thought, I think that it will be one of the following scenarios:
- It will it bounce off the universe’s “wall”, and then simply proceed in the opposite direction, like a cosmic game of Pong.
- It will disintegrate or otherwise be completely destroyed because it came into contact with an out-of-bounds area.
- It will become stuck to the edge of the universe by some previously-unknown attractive force.
- It will re-appear on the other side of the universe, as is if entered a wormhole (much like the arcade game Asteroids, where moving your ship off the right edge of the screen makes it appear again on the left).
- It will re-appear in some random place in the universe, much like pressing the hyperspace button in the arcade game Asteroids.
- It will penetrate the edge, and enter some other dimension.
- It will penetrate the edge and enter the Creator’s World – much like an ant discovering a way through the plastic case of an ant farm.
Of these possibilities, the last two are the most intriguing, because they hold the promise of continuity along with the notion that something may exist outside our universe. When we die, most of us hope that there will be some form of afterlife, because we believe in the continuity of our awareness, or soul. We can’t accept that our essence can just cease, and that we will simply wink our of existence. Similarly, it would be just as tragic if all of our civilization’s accumulated knowledge and wisdom also vanished during The Big Crunch. The last two items in the list give us hope that our collective efforts may not ultimately be in vain, and that we, as a species, might be able to preserve what we’ve created, or present something of value to the creator of the universe.
For all we know, this may even be the purpose of our existence: to find a way to breach the universe’s barrier and give something back to its creator (or impress the creator with our literature, art, poetry, music and wisdom) before everything is ultimately destroyed in The Big Crunch. Our entire universe could even be a creator’s game: design a universe, let it unfold, and see how many civilizations will develop from the primordial ooze, and how many of them will eventually become technologically advanced enough to break through our universe’s barrier and send a message, before they annihilate themselves, destroy their homeworld or time runs out.
I have no idea which of these touching-the-edge-of-the-universe scenarios will turn out to be correct (if any), and I can’t even calculate the odds of a space probe reaching the edge of an expanding universe intact (although I’m sure they are astronomically low). However, if we do nothing, then all will be for naught – everything that every human has ever created will be destroyed. As for the most immediate threat, climate change, we have become a modern-day personification of Ebenezer Scrooge: unless we drastically change our polluting ways, we will also see our names on a (metaphorical) gravestone.
What are our chances for success? No one knows, but however infinitesimal they may seem, I believe that we have to try. Besides, you do buy the occasional lottery ticket, don’t you?