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Doomsday Scenario

Humans are mortal. Not just as individuals, but also as a species. We can defend against many of the existential dangers to humanity. Threats such as global warming and pollution are well understood, and we can take steps to address them if we have the will. Even cosmic threats such as a civilization ending impact can be mitigated given time. But what about a deeper cosmic threat? What if the Universe could destroy not only our planet, but the entire galaxy, and what if we could never see it coming?

Recently there’s been buzz about an idea known as the false vacuum scenario, and it’s terrifying to think of.

Usually a physical system will try to get to the lowest energy state it can, releasing that energy in some form. In classical physics, if a system reaches a state of low energy it will remain there even if a lower energy state is possible. Imagine a ball rolling into a small valley on the side of a mountain. If the ball could get out of the valley it would roll even farther down the mountain. But the ball has no way to get out of the valley, so it will remain their indefinitely.

However in quantum mechanics this isn’t the case. If a quantum system reaches a state of low energy, it might remain there for a time, but it won’t remain there forever. Because of an effect known as quantum tunneling, a quantum system can break out of its little valley and head toward an even lower energy state. Given enough time, a quantum system will eventually reach the lowest energy state possible.

Our Universe is a quantum system, so one of the big questions is whether it happens to be stable and in the lowest energy state, or in a higher energy state and only metastable. In the standard model of particle physics, the answer to this question can be answered by the mass of the Higgs boson and the top quark. These two masses can be used to determine if the the vacuum state of the electroweak force is stable or metastable. Current observations point to it being metastable, which means the current state of the Universe might be temporary. If so, the Universe could collapse into a lower energy state at any time. If it does, then everything in the Universe would be destroyed. And there would be no way to see it coming. We would just exist one moment, and dissolve into quantum chaos the next.

But how likely is such a scenario? It’s tempting to argue that since the Universe has existed just fine for nearly 14 billion years, it will probably exist for billions more. But that’s not how probability works. If you toss a fair coin ten times and each time comes up heads, that doesn’t mean it will likely come up heads the next ten times. The odds of each toss is 50/50, and just because you got lucky the first ten time doesn’t mean you will on toss eleven. However there is also the possibility that your coin isn’t fair, in which case you would expect to keep seeing heads. So if you get heads ten times in a row, what are the odds that the coin is fair?

We can use this idea to estimate the likelihood of the false vacuum scenario. We live in a Universe that is about 14 billion years old, and Earth formed when the Universe was about 9 billion years old. If the false vacuum scenario were highly likely, then the odds of our planet forming so late in the game would be tiny. The more stable the Universe is likely to be, the more probable a late-forming Earth is. As with the coin toss, the fact that we live on a planet that only formed 5 billion years ago means the odds of cosmic destruction must be quite small. Doing the math, it comes out to a chance of about 1 in 1.1 billion years.

So even if the Universe is metastable (and we still don’t know for sure) it is at least very, very stable. There are lots of other existential threats that are more likely, and we would do well to focus on them. If we rise to the challenge there is still plenty of time to explore the stars.

Paper: Max Tegmark and Nick Bostrom. Is a doomsday catastrophe likely? Nature 438, 754 (2005)
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Many people have a 'before-after' moment in their life. Mine happend more than 40 years ago, when I was a kid. I was born on a different continent, accros an ocean, on the other side of the equator, in a different hemisphere. You could say it was in another world. And when I was five everything changed. My parents emigrated, and took me along for the ride.

There are few things I remember from 'before'. There are memories, but at this point it's practically impossible to separate my recolections from the stories I was told about 'before' while growing up. I do remember banging on the old piano, that no-one knew how to properly play, making me as expert at it as anybody else. I remember picking up the phone, which had a wire, no buttons, no even a rotary dial, and having to wait for an operator to ask for a number which was, can you imagine, barely three digits long. I remember riding my tricicle while chasing my grandfather as he walked up and down the corridor. I remember being held in my mothers arms, at night, in the dark, after a major earthquake shook us all awake and cut the power lines, marveling at the sight of one of the grown-ups as he appeared out of the dark holding a petroleum lamp.

And I remember sitting in front of the TV, my grandparents, my parents and I, watching 'Mr Spock'. That's how Star Trek was know back then, back there. The translation of 'Star Trek' into my native language was neither as brief, nor as catchy as 'Star Trek'. So the show was referred to as 'Mr Spock'. The television was very present in that house, even back then. There was sesame street, for us kids. And there was football, for the men. And cooking programs, for the women.  But Mr Spock rallied everyone. That was really a family moment. And, come to think of it, we were a pretty nerdy family.

Mr Spock was always present in my life, both before, and after. And in our house maybe more than in most, as our bookshelves were stacked with often read science-fiction paperbacks, in many languages. Sci-fi was one of the staples in all the houses I've called home. And I've stayed with it, marveling at how strange new worlds keep flowing out of peoples fingers, be it through pen, typewriter of keyboard. It's a strange way of playing a different kind of piano, I guess.

Back in the times of 'before', I don't think I had ever seen a foreigner in real life, except for my aunt, who is from Holland, and my uncle, who is from Germany. Yet every week I would look at this wonderful extra-terrestrial, the ultimate foreigner. The day 'after' happened, I became a foreigner myself. I grew up in a city with historically a very mixed population. The founding myth of the city involves ancient Romans and a giant. Throught the centuries, many foreigners have come to call it home, stranding there through commerce or conquest or, in our case, chance. In my primary school, almost half the children were of foreign origin, their parents having been born in another country. My house was on the edge of the arabic neighbourhood, and just walking distance from one of the largest jewish ghettos in the world. The sight of people dressed in black, wearing big furry hats and having long curly hair hanging on the sides of their faces was an everyday sight, and even so saturdays remained forever special as these people would seemingly multiply and fill the streets, in their celebratiion of sabbath.

Where I live now, in the land of 'after', the news of Leonard Nimoy's last journey broke in the evening. It was a friday so the sabbath had already started. I find it fitting that, all over the world, many people who have never seen an orthodox jew up close have and will be be performing the jewish gesture that Mr Spock made famous in this world and many others, all of them strange and new, if you are willing to go where you have not gone before.

Spock/Nimoy was not only always there in my life, both 'before' and 'after'. He was also in a way immortal. Spock died in star trek, sacrificing himself when the needs of the many outweighed the needs of the one, which is a logical course of action. And still he came back to life because the opposite is also very true, in a very human if not logical way. He  later survived something even more perilous, a reboot of the Star Trek franchise which sent him into and somehow back out of a black hole and through time, and gave some welcome extra texture to the new universe. In the world of Fringe, William Bell died in another dimension to allow the survival of multiple worlds, and came back from death when stuff got even weirder, as they often get on the edge of things. He ended up going bad but his severed hand helped bring about the series resolution. I wonder if it was doing the Vulcan Salute when it got cought in amber? In a part of this world that few will ever get to experience, a young Leonard Nimoy survived the Shekhinah when during a congregation he dared to peek when he was supposed not to look. And us nerds were increasingly often faced with news of Nimoys deteriorated health and his rushed visits to hospital, but he always kept coming back. Until this last one, I guess.

There's two more 'before' memories I have and treasure. My dad took me and our dog on a trip in our Mini. A long trip north along the Panamerican Highway, into the desert. A desert that, curiously, looks a lot like the barren reddish planets so often visited by the Enterprise. I was three and the highway was really just a narrow road with lots of potholes where you had to stop at every fuel station or you wouldn't make it to the next. In that desert we came across another Mini, going the other way. That was back in the days when you'd stop when you encountered someone. And believe it or not, out of the other car stepped my uncle and his wife, the one from holland. She decided we had to celebrate the encounter and proceeded to make us some 'pannekoeken', pancakes.

Do you remember your first pancake? I do.

And I remember one of the places we slept, my dad, our dog, and I. It must have been a barn or something, because in the morning we were woken up very early by our hosts who brought milk, fresh from the cow. The barn (if that's what it was) was strange beyond my understanding because, even though we were inside, we could still see the stars. Logic and common sense now tell me there must have been a hole in the roof but I prefer to believe that place was big enough on the inside to contain a patch of the night sky. A night sky where the stars are different, where they turn the 'wrong' way and form different constellations. They are also much more numerous. And seemingly close enough for you to touch them. Almost.

Maybe there's a new star up there. I want to believe there is.

Peace, and long life.

#LLAP   #SpockLives  ﻿