How to Die in Space: A Journey Through Dangerous Astrophysical Phenomena

by Paul Sutter

What we call a “particle” is, in the view of the branch of physics known as quantum field theory, a piece of a … well, quantum field. You take a patch of the universe, look for the quantum field you want to energize, energize it, and voilà: you get a bunch of particles hanging around that part of space. They can go on to live their little particle lives, and sometimes can even disappear—meaning that the field in that patch of the universe lost the energy to sustain their particley existence. That’s all weird but fine, but here’s the real kicker: the quantum fields of our universe are never entirely quiet. It takes a mighty vibration to pinch off a particle from the field, but the energy of each field is never exactly zero. There’s always a little bit of wiggling and humming going on, and sometimes those wiggles become randomly big enough to spit out a temporary particle.

Space agencies are constantly monitoring the situation, with probes located near the sun.8 As soon as they see the familiar signs: a flare, a prominence, an ejection of material, they shout out a warning to the rest of the solar system. Satellites and ships hunker down in hibernation mode, their delicate electronics safer as long as they’re unpowered. After the storm passes they reawaken, checking for internal bruises. They hopefully return to normal operations, dreading the next event.

The Earth sits 93 million miles from the sun, which means any plasma-based temper tantrums have to travel a serious distance before affecting us. But habitable planets have to orbit nice and close to red dwarf stars—you can’t get all that far away from them before it gets too cold for water to stay wet. This means that if you want to take a vacation to Proxima b, the not-fun-at-all name we give to the exoplanet orbiting our nearest neighbor—you’d best pack some sunscreen.

It’s the little things that’ll get ya. Oh yeah, sure, the big things will get you too—Mother Nature has boundless imagination when it comes to devising death traps. But there’s a lot of little things out there too, and they can tear you apart, wear you down, and dissolve your organs just as easily as the big ones. Take, for instance, cosmic rays. You’ll encounter these guys and their friends an uncomfortably frequent amount of times in your adventures, so I’m sure I’ll mention them again—they’re kind of important—but it’s time we dug in and got our hands dirty. I really need you to understand just how little these things care for you and your precious internal organs. They’re called “cosmic,” so they must be in space. They’re called “rays” because the Earth scientists who originally named them thought they were a kind of light, like gamma rays or X-rays (unrelated to stingrays and manta rays, by the way). They were wrong, though. But who isn’t wrong every once in a while? You should know the feeling: for example, you’re wrong when you think you’ll make it out in space. Unfortunately for us, by the time everyone figured out just how wrong they were, the name had stuck. So now we’ve got cosmic rays that aren’t even made of rays. You’ll get over it.1 They are a kind of radiation, though: the kind of radiation that still gives you cancer. We’ll get to that in appropriately gory detail in a little bit.

The place where the solar wind meets the interstellar medium is called the heliopause, and most people who consider themselves experts on travel among the stars figure that the heliopause is the true boundary of our solar system.

The slowest and least energetic solar wind particles—which I should mention are just the usual mix of electrons, protons, and sometimes something a little bit heavier—have the most interesting fate. When they begin to reach our magnetic field they respond to those forces, and charged particles really love to draw corkscrew paths around magnetic field lines. And so, they do. Depending on their charge, they travel either north or south along our magnetic fields, following them wherever they go. And our magnetic field wraps around the Earth, puncturing our atmosphere near our geographic poles. And so that’s exactly where these charged particles go, screeching into our atmosphere at incredible velocities. And as they travel, they strip electrons off of the molecules in the upper reaches of our atmosphere. Eventually those electrons make their way back to their atomic homes, and in order to do so they release a little bit of energy in the form of light. The end result: as all these charged particles get funneled into our atmospheres, they put on a little light show for us.

We call them the aurora. And they’re very pretty.

So there you go: even if you live your whole life inside the protective layers of an earthlike planet, you still get an extra dose of radiation from the cosmic rays, equivalent to an extra X-ray exam every few years. Usually when we do X-ray exams, we balance the risk of slightly increasing your cancer risk with, I don’t know, figuring out what the heck is wrong with you right this very instant. But this is an X-ray exam that you didn’t ask for and you don’t need. It adds up, year after year: there’s an extra chance that a random cancer on Earth was caused by a star dying on the other side of the universe.

if microscopic black holes are produced in high-energy particle collisions, then our atmosphere has been serving as a black hole factory for the past … well, as long as we’ve had an atmosphere, which is about four billion years now and counting. If nature is capable of making a microscopic black hole, then guess what folks, there’s already one there at the center of the Earth.

Some radiation is “ionizing”—it can rip electrons off of atoms and do some serious damage. But other radiation is “nonionizing”—it just generally waves at you. For example, microwave radiation is nonionizing. Microwaves can still be dangerous: I wouldn’t stand too long inside a microwave oven because the water in your body will start to boil, but it’s not going to rip apart your DNA.

It’s estimated that Earth to Mars travelers, without proper shielding, would lose about 5 percent of their cells to slower cosmic rays during the voyage. Five percent, including skin cells, heart cells, and precious brain cells. If the sun throws a coronal mass ejection event at you when you’re among the planets, it ends quickly. Instead of just slowly raising your risk of generating a cancer, it gives you acute radiation poisoning, and within a few days or even hours your internal organs simply fall apart. First comes the nausea and vomiting. Then the diarrhea. Maybe just a bad stomach flu, right? But then comes the severe headaches and the fever. Nasty, but survivable, right? Then the tremors, seizures, and lethargy, as your central nervous system shuts down. Then mortality.

From a far enough distance, there isn’t anything special about a black hole—gravitationally at least. It’s still a menacing and ominous hole in the universe, mind you. But you can orbit it just like any other object. Gravity is pretty cool like that: from far enough away, two objects will interact with each other as if all their mass was in a single point at the center of each object. You don’t need to care about odd lumps or bulging equators when computing the effects of gravity. Just total mass and distance.

will stay perfectly safe as long as they keep far from the black hole. How far? It depends on the exact mass, but “no distance is far enough” is fair advice. Although if you want to be technical, at least ten times the Schwarzschild radius of the black hole will suffice as a general rule of thumb.

This is called a tidal effect, since it’s responsible for the … wait for it … tides. One side of the Earth is slightly closer to the Moon than everything else, so it gets an extra tug, the oceans lifting up trying vainly to reach the moon, and there you go, a tide on that side of the planet. At the exact same time, the ocean on the opposite end of the Earth from the moon gets feeling a little left behind, and tries to float away—a tide appears there, too.8

we now call the Hertzsprung-Russell diagram, or H-R diagram for short because who the heck has the time to keep saying “Hertzsprung-Russell?” They found that stars follow very specific paths as they age, always getting brighter and hotter with time. And the more massive stars evolve much faster than the smaller ones (which makes sense: with more mass, there’s more gravity, which means the fusion rates go that much faster, and the whole game plays out in fast-forward). So by looking at a star and measuring its mass, you can pinpoint where on the evolutionary track it is, how old it is, and how much time you’ve got left until it gets worse.

Stars in this phase are especially dangerous. Called Mira variables, after the star Mira, the first of their kind to be found, they can change their brightness by a factor of ten in as many days.8 Within a couple weeks, a Mira variable and grow ten times brighter and ten times dimmer. Swelling, expanding, contracting, shrinking. Repeated ad nauseum. Pulsing and churning, sending their systems into total chaos. The name Mira itself means “amazing one,” when astronomers hundreds of years ago watched over the course of only a single year one of the brightest stars in the sky fade to invisibility. Mira still exists—you can see it with powerful telescopes and visit it if you’re foolish enough—but to those ancient astronomers, a familiar light in the night sky simply winked out of existence.

the guts of a sunlike star speckled across its former system. Up to half the mass of the original star. Half. The sun is, by far, the most massive object in the solar system, and the final phases of its life—the last big flashes—had enough energy to send half of it into deep space, never to return home.

This is how neon signs work: electrocute a tube of gas, filling it with energy, and make the molecules glow. Depending on what they’re made of and the amount of energy you pump in, different elements will have different signature colors. Hydrogen is red, helium is yellow, mercury is blue, and the classic neon is orange.

In its death throes, just before and during the creation of the planetary nebula, a star is at its most schizophrenic, switching chaotically from stability to catastrophe in a matter of days, blasting the system with renewed bouts of cosmic rays and radiation. Catching unsuspecting explorers and probes unawares. The stellar winds can go from a breezy 5 miles per second to a hurricane of 1000 miles per second in a matter of days. The nebula itself is rather safe: it’s just a cloud of hydrogen and a few other bits. Once ejected, it slows and cools quickly to safe and reasonably tolerant levels. Nothing too bad, I would say.

In binary systems, one star will cycle through its life faster than the other, through sheer random chance of being slightly more massive. And this often leads to the now-familiar setup behind everybody’s favorite kind of cataclysmic variable star. But the red giant that’s feeding the nova outbursts isn’t done doing its stellar thing. It too can progress all the way to a planetary nebula surrounded by newly revealed white dwarf (assuming it survives the nova outbursts of its companion intact, which is no small feat). The system is now left with two white dwarfs, which for various and poorly understood reasons, can spiral in closer together, eventually consuming each other in a final deadly kiss. These mergers release a potent cocktail of elements, especially an abundance of radioactive variants of titanium, which quickly go on to decay into scandium and on to calcium, which is stable enough to stop the decay train and hang on to existence for a while.

That decay process, from titanium to scandium to calcium, also releases an abundance of positrons.14 For those not in the know, a positron is a kind of antimatter. And if that hasn’t set off alarm bells yet, it should. Antimatter is just like normal matter, which the exact same properties except for one crucial difference: it has opposite charge. So a positron has the exact same mass and spin as an electron, but is positively charged. That’s cute. What’s not so cute is that when matter and antimatter meet, they annihilate each other, converting all of their mass into pure energy. Radiation. It’s the ultimate expression of Einstein’s E=mc2, which tells us how much energy is in every bit of mass. In a matter-antimatter meetup, 100 percent of that juicy m is converted into raw, terrible E. To give you a sense of just how senseless this is, two pounds of antimatter, when merely placed in contact with two pounds of normal matter in the worst mashup in history, would release the same amount of energy as all the weapons used throughout the entirety of World War II (including the nuclear bombs). Ten times over.

Small star? You will live a long, simple life, burning quietly for trillions of years before fizzling out. Medium star? Near the end of your days you will grow red and violent before turning inside out. A white dwarf is your ultimate fate. Massive star? You burn too hot. You will die soon, leaving only a neutron star or a black hole. And when those massive

With enough weight pressing down on the core, the carbon can fuse into neon and a few friends. Remember that our sun burns hydrogen at a temperature of around 15 million kelvin. In order to switch to helium fusion, it has to reach ten times that. For carbon ignition? Ten times that, or over a billion kelvin. Only the most massive stars, well over eight times the mass of the sun, can accomplish this fantastic feat. Otherwise the carbon and oxygen just stay there, being inert and degenerate, while the rest of the star tears itself to shreds.5 But at a billion kelvin, after the star has burned through both its available hydrogen and helium, it can extract some energy from the carbon in its heart.

At a temperature of 2 billion kelvin, the oxygen there burns. Six months after the onset of oxygen fusion, it peters out. The fusion of oxygen produces silicon, which starts and ends fusion in a few months. The very last element produced in the heart of a massive star, created from the fusion of silicon, is nickel. The kind of nickel that’s produced is rather unstable; it doesn’t have the right combination of neutrons and protons. As soon as it forms it says, “Whoops, never mind, I was never invited anyway,” and decays into iron. More than an entire sun’s worth of iron is manufactured in a handful of days.

within fifteen minutes of the appearance of an iron core in the heart of a massive star, it will be all over, violently. Remember how I briefly mentioned that degeneracy pressure can only go so far? Yes, the quirks of quantum mechanics offer a source of pressure able to stave off complete gravitational catastrophe. But even quantum mechanics has a limit; the pressure supplied by the electrons in the iron core can crack. Eventually too much iron settles into the core, overwhelming the degeneracy pressure that was briefly holding up the star. Then things so haywire, fast. Once the support from electron degeneracy fails, the core simply collapses, so quickly—parts of it reaching a quarter of the speed of light—that it completely detaches itself from the rest of the star. Like the pillars knocked out of a skyscraper, the rest of the star follows blindly along, trying to chase after the core that supported it for so long. There’s nothing stopping it: the only force is gravity, which has finally won out against the energy produced in the core. As the core shrinks and folds in on itself, it reaches truly unimaginable densities, far surpassing even the crushing extremes of a white dwarf. It becomes so intense that any stray electrons find themselves literally inside atomic nuclei, a place where they absolutely hate to be. And once there, they then find themselves crammed inside of protons, their very mortal enemies. When a proton is squeezed together with an electron, two things h...

One by one, iron atoms melt from the assault, and their protons swallow electrons, turning into neutrons in the process. The end result is a giant, ghastly core of neutrons, weighing more than the sun but compressed down into the size of a city, surrounded by layers upon turbulent layers of infalling stellar atmosphere.

So the core is no longer just a dense clump of iron atoms; it’s now essentially a single atom a few miles across: a giant ball of neutrons all shoved together as close as they can get. Those neutrons naturally repel each other. Not through any electric repulsion, since they are, after all, neutral, but through a combination of the vagaries of the strong nuclear force and their own version of degeneracy pressure. Neutrons are fermions too, which means they can only be squeezed down so tightly before they refuse to go any further. And since neutrons are much, much heavier than electrons (almost two thousand times heavier), they can cram much more tightly together before the wonderful quantum degeneracy effects kick in.

New elements: xenon, gold, lead, potassium, and more. All are manufactured in the insane cacophony of a supernova blast. It’s one of the few places in the universe with the right combination of ingredients and temperatures to make this happen. It’s called nucleosynthesis, if you’re keeping score.9

Some of the material gets swept up, trapped in the shock wave, rattled around, and ejected at a speed close to that of light. This mix of protons and heavier nuclei, now called cosmic rays, go on to stream throughout the universe, soaking unsuspecting travelers with poison from the blast.

Take for instance the Crab Nebula, the result of the awe-inspiring supernova of 1054. Even a thousand years later, with the guts of the former star spread out over a volume ten light-years across, still maintains a roasting 15,000 kelvin, and is home to a rich, potent soup of radioactivity. The magnetic fields in the nebula alone are strong enough to whip up particles to half the speed of light. A Chernobyl-like Exclusion Zone full of radioactive particles and intense X-rays. No sane traveler should enter.

Avoid multiple-star systems, unless you are positive that all stars in the system are in their normal hydrogen-burning phase.

The neutrinos are a warning. They are launched early in the event, and aside from kicking the shock wave in the rear end, most just stream right through, escaping the cacophony. That means that the neutrinos will reach you before the light (and radiation and cosmic rays and death) do. If you have a well-tuned, direction-sensitive neutrino telescope, you can maybe buy yourself a few seconds’ warning.

A strong enough field can overwhelm the forces that keep an atom in check, bending it to its own evil will. In the end, you go from nice ball-shaped atoms to … cigar-shaped atoms? Needle-shaped atoms? Whatever it is, it’s nasty business, and chemistry grinds to a halt. At just 1,000 miles away, these fields are also strong enough to magnetize your body. That’s not something you normally worry about, is it? You can play with magnets all day long without thinking about their effects on you. Even the strongest human-made magnetic fields don’t really affect people. But get near a magnetar or even a regular neutron star (side note: I would’ve called them neutrotars, but nobody listens to me), and your body chemistry simply breaks down. The arrangement of molecules, the biological processes that keep your heart beating and your brain thinking, can’t function. And then you just dissolve.

Since each pulsar has a unique frequency, they can be used for navigation: find a few known pulsars and you can triangulate your position anywhere in the galaxy. Beep, beep, beep, guiding you through the dark. Just don’t get so close.

Take two ultra-super-high-precision atomic clocks. Leave one just sitting around, like your brother-in-law. Put the other one in a jet and whiz it around the world for a few hours. The jet-setting atomic clock, when it gets back from its worldwide tour, will be a few fractions of a second behind the stationary one. Sign, sealed, delivered: this is the way the world works.

you can image the chaos as gas collides with itself, meets resistance, fights back, raises plumes of hotter material, drops balls of slightly cooled clumps. It’s messy. And if a big blob of gas happens to rise up out of the accretion disk, it carries with it a chunk of magnetic field lines. One part of this new lump of magnetic field will be closer to the black hole, and one will be further, because that’s how randomness works. But the bit of field line that’s anchored to the disk closer in has a faster orbit, doesn’t it? It does, good job. That extra lump of field gets stretched, pulled, and eventually wound back down into the main field of the accretion disk. And here’s your dynamo at work: it converts random turbulent motion—energy in the accretion disk itself—into ever-stronger magnetic fields. As more gas finds its way onto the disk, the fields grow more powerful. Nifty.4 For extra deliciousness, here’s the name of this particular effect: the alpha-omega dynamo. Sounds impressive, and people will think you’re smart if you say it out loud. Now here’s why I care so much about these magnetic fields, and why you should care, too. When magnetic fields are weak, you move them. When they’re strong, they move you.

When the universe behaves in a counterintuitive way, that’s its way of whispering its secrets to you. If you listen carefully and think hard enough, you can divine those mysteries.

Cosmic strings themselves have no mass. They’re not made of any substance. But as a frozen-in flaw in spacetime, they have enormous amounts of tension. In these regions, spacetime is forced to have a fold it doesn’t want to have, and is constantly trying to smooth itself out, but simply can’t, like a stubborn wrinkle in your shirt that just won’t iron out. In general relativity, any source of energy can affect spacetime around it: mass, energy, tension, you name it. So despite their masslessness (is that a word? It is now), their tension means they act as if they had mass. So much so that an inch of cosmic string would outweigh a mountain, and a mile would outweigh the Earth. And they’re long. So, so long. These things are fundamental flaws in space, and space grows with time (we live in an expanding universe, remember), which means cosmic strings stretch with the universe itself. It’s impossible to tell just how long they are, but a safe bet is “as wide as the observable universe.” And they vibrate, oh man do they vibrate. Kinks and cusps can zip up and down their lengths at the speed of light. (They’re not made of anything so this isn’t a big deal.)

the last time the universe went through this kind of subatomic furniture rearrangement was when the weak nuclear and electromagnetic forces split ways. I didn’t mention this earlier, but have you ever heard of the Higgs boson? If you haven’t, it’s a cool fundamental particle, and its job is to be the sheriff of this splitting: The Higgs does the job of setting the differences between those once-joined forces. Since the Higgs boson played such a major role in the last transition, its mass can tell us just how stable our universe currently is. And current estimates of the Higgs mass put us … right on the line between stable and unstable. As in, metastable.

Since 1998 the Parkes Observatory, a radio telescope in Australia, would occasionally pick up faint whiffs of mysterious radio transmissions (see a common theme here?) that would disappear as soon as they arrived, flirting from one frequency to another. The signal didn’t appear to come from any particular direction on the sky, but did tend to cluster around midday. But no, it wasn’t the sun. They checked. They were dubbed Perytons, because that sounded fanciful enough. Papers were written about them. Could it be … ? But they didn’t check their cafeteria. It turns out that when you get a little too eager for your food to come out of the visitor center’s microwave, and yank the door open before the timer beeped, it took an extra fraction of a second for the stuff that makes the microwaves to actually shut off, leaking a little bit of radiation. And when you have a 64-meter radio telescope literally next door, you can trigger a flash of “mysterious” radio emission.5 People don’t write papers about Perytons anymore.

The only way to escape such a wormhole is if you happened to be inside the white hole when it formed. White holes have the opposite rule as black holes: nothing is allowed to stay in, so you get expelled, and it’s your choice whether to travel to Alice’s or Bob’s place in the universe.

But a white hole? It still needs a singularity—a point of infinite density, but the matter needs to flow from it rather than toward it. Yes, it’s technically allowed by the equations of GR … just like all the little water droplets in a lake can, suddenly and spontaneously and without anybody asking, decide to flow up the cliff, making a reverse-waterfall (a “waterclimb?”).

There’s nothing stopping a single random water molecule from jumping up the cliff face. But two? A hundred? A trillion? The entire lake? The math of thermodynamics (specifically, entropy) tells us that the chances of that happening are so extreme that it makes the astronomical numbers we’ve been using in our exploration of the cosmos seem downright comical in their smallness.

Both electrically charged black holes and their rotating cousins share one curious property: they automatically, without any hesitation or flinching, create a wormhole. What’s better, these wormholes work way better than their more straightforward relatives described earlier. There’s still a white hole anchored to the black hole by their singularities, but in this case you can enter the event horizon of the black hole, travel near the singularity without getting swallowed by it, and find yourself expelled out the white hole in another universe.

Remember that part, both in charged black holes (which we don’t really care about, but we’ll include for the sake of manic completeness) and rotating black holes, where you were rushing inward toward the singularity, slowed down, stopped, and reversed? That was just your experience, but what about the experience of everything else that fell into the black hole? All the matter, all the radiation accumulated over the billions of years of the black hole’s existence? From your perspective falling in, all the stuff that fell in previously is sitting there, waiting for you to get close enough (remember that gravitational time dilation is still a thing). When you get near, the entire past history of the black hole rams up into your face, hitting you with infinitely blueshifted, infinitely high-energy radiation.

Next, negative mass has an enormous amount of pressure, enough to force the tunnel open like the supports of a mineshaft. The amount of negative mass you have determines how wide your wormhole can be, and how much normal matter you can send down the throat before risking catastrophe. In case you’re wondering, and I know you are, to make this work, your material with negative mass has to be in the shape of a shell, to make the entrance to the wormhole in three dimensions.

Once you open up the negative energy can of worms, there’s no going back. And the very first worm to pop out is something called the Casimir effect, where two metal plates, when held very closely together, will feel an attraction to each other not through any force of nature, but because of the negative energy created between them.

It might (with a strong and healthy emphasis on the word “might”) be possible to thread a cosmic string through a wormhole, and let it loop back on itself through normal nonwormhole space. Closed cosmic strings vibrate like your hands after your fourth shot of espresso, and those wiggles might just have the right interaction with spacetime to make the local energy dip into the red, providing the necessary stability. At least, until the cosmic string vibrates itself into oblivion through the emission of copious gravitational waves.

Another possibility is the fundamental vibrations in the quantum fields themselves, the same ones that give rise to the Casimir effect. Sometimes playfully called the “quantum foam,” spacetime at that sub-sub-sub-sub-subatomic level is a frothing, seething mess.