The universe hates you. Let's get that out of the way right now. The universe loathes your guts and is infuriated by the way you dress, and the stupid way you talk sends it into a murderous rage. It's just one bad morning and an empty coffee canister away from driving to your house and shanking you in the neck. With a supernova. It may happen tomorrow, or it may take billions of years. The universe is patient. It can wait. But rest assured: Some day, when you least expect it, it will reap a terrible vengeance from you. And it will go a little something like this:
#7. Hypervelocity Stars
What we tend to call shooting stars are really just meteoroids burning in the Earth's atmosphere. But actual shooting stars do exist. Yes, there are very real stars -- as in "great balls of nuclear fire a million miles across" -- with a velocity so great that they can actually escape the gravitational pull of their galaxies and roam free throughout the universe. These freewheeling stars are the Hells Angels of the cosmos: They're big, scary and notoriously difficult to stop, and if they move into your neighborhood, your property values are going straight to hell. Yep, there are sun-size balls of nuclear energy zooming wherever they want at speeds of up to 4,000 kilometers per second, burning everything they come across and fucking up every orbit they pass by. We just thought you should know that, in case you were running low on nebulous dread or something.
The stars want you dead. Just FYI.
How They Will Get Us:
But it's probably OK: We've only found like 16 of these things zipping about. When you take into account the fact that our solar system is but a speck of fecal matter in the giant toilet that is the universe, the chances of one of those ever managing to impact us are roughly the same as the chances of you ever managing to gather up enough courage to talk to that cute girl next door from atop your solid-gold BattleMech.
If you ever meet a woman who's impressed with your bat'leth skills, it's probably time to start worrying.
But the thing with the universe is that it's kind of a largish place. However sophisticated our current equipment may seem, it's still the equivalent of shining a cereal-box flashlight into the ocean to try to spot the bottom. So whenever new technology enters the game, new data enters the equation, and we have to revise our appropriate terror levels for it. For instance, the new Pan-STARRS telescope system has, within the past five months alone, found no less than 19 completely unknown asteroids that pose a potential danger to Earth. And these have been buzzing around a mere 7.5 million kilometers away. Universally speaking, that's not on our doorstep -- that's right in our goddamn living room, ransacking our drinks cabinet and making offhand remarks about our place looking really flammable and how "It would be a shame if anything bad happened to it."
"How about Earth? They're loaded. Send over a couple of asteroids to rough up the joint."
And we're not exaggerating that "hypervelocity" part, either -- an average HV star moves at a staggering 1.6 million kilometers an hour. So while there might not be any hypervelocity stars with trajectories directly threatening Earth that we know of, one could come hauling ass up into our business in a cosmic heartbeat. Plus, the aforementioned 16 are just those that humanity has found and is able to monitor. You know how many are estimated to be bouncing playfully around our galaxy alone? At least a thousand.
The whole universe is basically a grab bag filled with medical waste.
There's still precious little chance of hypervelocity stars ever being an immediate threat, though: "Cosmic heartbeat" is still kind of a long-ass time for humanity. If we geared up a new telescope tomorrow only to find one coming in from a previous blind spot as close as, say, one light-year away, we'd still have a few centuries before it would fry us, cause a cataclysmic collision within the solar system, and inflict some pretty intense gravitational disruptions. You're not going to be alive in a few centuries, though; that's the future's problem. And really, fuck those guys. All flying around in their precious jetpacks like they're better than you. They deserve what they get.
#6. Rogue Black Holes
It's not just stars that take apocalyptic joyrides randomly throughout the universe. Science has found out that black holes can move about at terrible velocities, too!
Oh yeah, great. We don't have enough shit to deal with.
Wait, what? Black holes? The great big space-whirlpool crushy things? The ones that you can't escape from, and you can't even see?
Yeppers! Those are the ones. If you thought that black holes were abstractly frightening but that you were safe as long as you didn't go gallivanting about space like some kind of space-asshole, think again. They can -- and do -- move, which of course means they're coming directly for you.
The stars are right ... on our ass!
How They Will Get Us:
When it comes to sneaking up on us unnoticed, hypervelocity stars up there have the minor drawback of, well, being giant balls of nuclear fire. They're pretty noticeable. Rogue black holes, however, get a +4 stealth bonus for being notoriously difficult to spot in the vast darkness of space. There could be one coming at us right now -- screaming your name followed immediately by "I COME FOR YOUUUU!" -- and we might never notice it. Well, until it rips the Earth apart, sucks us down and purees us before finally, mercifully adding us to the mass of its singularity. We'd probably notice that part.
Fortified bunkers can't save you from space.
And of course there are hundreds of rogue black holes roaming our galaxy alone. We don't know why you even bothered asking.
#5. Galactic Cannibalism
Ever put two hamsters in a cage together and then, come next morning, wake up to find only one fat, innocent-looking hamster? This is the same thing. Only the hamsters are galaxies.
No, they're not ... they're not shaped like hamsters. It's an analogy. Jesus.
Hey. HEY. Look back at the stars. Goddammit.
This phenomenon is called galactic cannibalism, and that's one of those rare scientific names that is as plainly accurate as it is bowel-seizingly terrifying. Basically, smaller galaxies succumb to the gravity of a bigger one and are slowly absorbed into it, thus adding to its mass and making it even larger, so it can eat more galaxies. It's a dog-eat-dog universe out there. Hell, even our own Milky Way is known to indulge in this behavior every once in a while.
Our galaxy, plotting douchebaggery.
How It Will Get Us:
It's not a matter of how; it's a matter of when. See, one of the bigger galaxies that's heavily into eating its kin is Andromeda. You know, our closest neighbor Andromeda -- the "way the hell bigger than our galaxy" Andromeda. See that picture up there? It's not just there to fill space. No, that's a computer simulation of what Andromeda is going to do to us someday. We, as a galaxy, are going to be eaten.
Via W Schoening/V Harvey/REU/NOAO/AURA/NSF
This will cause the two galaxies to slowly compress into a single mess of stars within the next 3 billion years or so, throwing us to the very outskirts of the new Galactic Scramble, or maybe even transforming our very own sun into one of those hypervelocity stars.
And somehow, those are the "nicer" options. Otherwise, our whole solar system could just be devoured by exploding galactic gas or crushed by a colliding Andromedan equivalent.
We spend all that money fixing the Hubble telescope and it repays us with promises of doom.
#4. Vacuum Metastability Event
Quantum physics, the study of "dual particle-like and wave-like behavior and interaction of matter and energy," is science-talk for "a bunch of far-out shit, man." The field has sprouted some of the more mind-blowing theories of life, the universe and everything. One of the more disconcerting ones is the suggestion that we (as in "we, everyone and everything in the universe") may exist in a false vacuum state. A lot of abstract terms such as "bubbles" and "vacuum levels" are involved, but in layman's terms, this means the universe was built from dodgy parts and ended up with an energy level too low for more than temporary sustenance. Therefore, at any given moment, it could call it quits and succumb to the pressure, only to be replaced by higher energy levels.
Via Wiki Commons
The End of All Things, in convenient chart form.
How It Will Get Us:
It's called a vacuum metastability event, which is what happens when the energy levels of our particular universe's vacuum go sour. Should this happen, the ensuing collapse would level Earth with a light-speed blast before any of us even had time to blink. It's probably a good thing that we don't survive long, because after that, things get really bad. All the laws of physics will go psychedelic on your poor, obliterated ass, until they eventually mutate into a completely new, improved set. There will still be a universe, just not the universe. In time, there may even be life -- just not the sort we'd be able to comprehend, even if our brains hadn't been smashed into inverted color parties riding the crest of an infinite mathwave.
It's kind of like surfing, only your entire body is slowly dissolving into ether, and everything tastes mauve.
In other words, quantum physics is basically telling us that Cthulhu and the Great Old Ones could come knocking at any minute now. That's right: Lovecraft was a scientist all along, just coldly documenting the facts as he saw them.
Via Howard Phillips Lovecraft
He's clearly terrified of whatever is immediately behind the photographer.