5 Awesome Stars You Won't Believe Science Class Left Out

5 Intergalactic Hypervelocity Star

Intergalactic hypervelocity star! Astrophysics often sounds like mistranslated anime about space police. Especially since SDSS J0907 is an intergalactic rogue, nicknamed the Outlaw Star, hurtled out of the galaxy by the loss of its partner.

Outlaw was half of a binary system, a pair of stars orbiting around a shared center, which didn't play by the rules, where "the rules" are "Don't dive into the black hole at the center of the Milky Way if you want to continue existing." In an awesome overlap of astrophysics with action movies, Outlaw's partner was killed, and Outlaw was slingshotted out at escape velocity. The escape velocity of the entire galaxy.

The result is an entire star speeding toward intergalactic space at over two thirds of a million meters per second. A star streaking along at five-hundredth of the speed of its own light. 0.2 percent isn't usually a big number, because we're not usually talking about entire stars and the speed limit of existence. That's the kind of cosmic kinetic energy that would beat Galactus at Chicken.

4 The Star from the Approximate Beginning of Time

Astrophysicists are wise beyond their years. In fact they're wise beyond almost all years, ever, because they've measured the age of the universe. And found a star that's been here almost as long.

HD 140283 is 14.5 plus or minus 0.8 gigayears old, compared to the universe's 13.80 plus or minus 0.04 gigayears, and some idiots are already in the comments complaining about that being impossible. It's ironic that many of humanity's worst errors don't understand how to read errors. The star was measured by the Hubble space telescope, a system designed to constantly remind us that the universe is unbelievably awesome.

This "Methuselah star" was most likely forged in a primeval dwarf galaxy, making the universe even cooler by sounding like a weapon for Thor. It survived when its birth galaxy was shredded by the Milky Way 12 billion years ago. Wow, the Milky Way sounds soft, but it's been floating around killing things like it's trying to create a stellar action hero.

If Methuselah is out for revenge, it's been biding almost all of time so far. Methuselah is massive confirmation of our calculations of the age of the universe. You'd think it would be easy to confirm things when you're talking about everything, ever. It turns out that measuring cosmic parameters with bald monkeys from thousands of light-years away leaves a lot of room for problems. But the great thing about science is solving problems. And the great thing about stars is that there are so many of them.

If you keep looking, you can find the perfect example of almost anything. Methuselah was nearby, unreddened; we know its chemical composition; it's in the most accurately age-specific region of the Hertzsprung-Russell luminosity-temperature diagram. The star is doing everything but shining its own light on its birth certificate for us.

The universe is about 14 billion years old. We worked that out despite rarely making it to a hundred. Just thinking about that will make permanent changes to your brain, all of them good.

3 Gravity Wave Radiation

Stars are supported against gravity by the thermonuclear fusion in their cores. Fusing lighter atoms into heavier ones releases energy, but those heavier elements require higher temperatures to fuse again. If the star isn't massive enough to ignite the next element, or if it reaches iron (which, Robert Downey Jr.'s characterization notwithstanding, is stable and can't sustain a star), fusion stops. Then gravity gets to continue the job it started billions of years before: crushing the absolute hell out of everything ever.

Small stars end up as white dwarfs, which are as dense as you can make matter without stomping on the fundamental concept of atoms. Larger stars become neutron stars by doing exactly that.

Most matter is empty space. In atoms, a cloud of electrons orbit the nucleus. In neutron stars, they're stomped into it, negative electrons physically crushed into the positive protons to create an endless mass of neutral neutrons. No space, no charge, no elements, chemistry itself crushed out of existence by all-dominating physics.

The resulting neutronium is 40 trillion times denser than lead. If you stood with a spoonful of neutronium, it would fall through the spoon, cut a hole in your foot, and punch through the Earth until it shot through the core and out the other side. Then it would turn around and do it again, and again, and again and again, until it got thermodynamically bored (aka slowed down and stopped by friction). It's a material so solid that merely trying to weigh it shoots your home planet through the heart multiple times. It's as dense as anything can get without giving up on matter entirely and becoming a black hole.

So we have white dwarfs, the densest thing you can get without breaking atoms, and neutron stars, the densest thing you can get without breaking the existence of matter, and PSR J0348+0432 has both. A binary system built out of the two densest anythings, ever, orbiting each other every two and a half hours. A system twice the mass of the sun whipping around in less time than it takes to watch The Hobbit. That's not an orbit, that's how you blend space-time. Large masses can bend space, but these are rippling it, jumping up and down on the fabric of reality so hard that they're sending out waves of existence-deformation.

We can't observe these waves directly (although you must remember that every such statement in science ends with YET), but we can measure their effects. Scientists watched the stellar remnants spinning around -- the intelligent opposite of Dancing With the Stars -- and found that they're slowing down at exactly the rate predicted by gravitational radiation. And the constant loss of energy means that -- like with all the most heavenly dancing -- they're getting closer and closer as the fundamental forces of physics shout "Kiss! KIISSSSSSS!" And if their swirling sweeps waves across reality, their collision will be a bang so big, it'll make the heavens move.

2 The Largest Star

Stars are born by pulling in as much material as they can, but above a certain size shine so brightly that it blows away any new material. This creates an upper limit on the size of stars around 150 solar masses. Which is why it was surprising to find one with 260 shining in the Arches cluster.

The last time there was anything this ludicrously powerful and unstable in the heavens, he was called Zeus. Scientists were delighted to find R136a1, because in science something that proves you wrong is the most precious thing in existence. It's how you learn new things (and write the first paper about them). Astrophysicists think some stars skipped over the stellar mass limit by ganging up on it, creating something twice the size of everything ever seen before by cannibalistic cosmic collisions. The resulting stellar Constructicon is 10 million times more luminous than the sun.

The resulting star will explode in hypernova. That's what scientists say when "supernova," the brightest and most violent event regular matter can conceive of, simply doesn't do the process justice. The star is so massive that its collapse could break the load limit on space-time itself, ripping a hole in our understanding of reality as it collapses into a black hole, a gravitational singularity excising itself from the observable universe, an ultimate everything-compactor from which not even light can escape.

Well, that's the second most violent thing it could do. It could also undergo a ...

1 Pair Instability Supernova

Pair instability supernova. The only reason that's not a punk romance anthem is that not enough singers know how awesome existence truly is (although Kim Boekbinder does well with the hottest music video ever made). Stars explode when they run out of core fuel, but if they're truly ludicrously gigantic, they can go into meltdown long before using up all their ability. Just like Hollywood stars.

If a star is literally burning with the hatred of over a hundred suns, energy density in the core can get high enough to start spontaneously generating antimatter. Energy so intense, it starts congealing into mass as pairs of electrons and positrons.

The one thing everyone knows about antimatter is that it explodes when it touches matter. Very few places in the universe have more matter than a star's core. And all of those are created from a star's core. But this superstar's core is so ludicrously energetic that mere antimatter annihilation wouldn't even dent it. All that would do is release the energy again. The problem is the instant of delay as it back-and-forths across E=MC2. For that infinitesimal sliver of time, the energy wasn't countering gravity.

And now the star is doomed.

Scores of suns suddenly clench down, spiking the pressure and temperature, setting off total fusion in the core. Most stars burn as reactors. This one goes off as a bomb. Something several dozen times more massive than the solar system suddenly detonates with a blast that would make Vishnu duck and cover.

The star is utterly destroyed. The blast leaves no core, no neutron star, nothing. An entire star is blasted into interstellar dust. And we've seen it happen.

SN2007bi was discovered by the Nearby Supernova Factory (and that's the "good band name" game officially won and ended forever). It was so violent that the blast alone fused over three suns' worth of material into radioactive nickel, 6 thousand million billion billion tons of new radioisotope, which then irradiated the wreckage to make it glow for months. That's an explosion so badass, it created more nuclear material AFTER it went off, just to make the remains glow in the dark longer.

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We can't let silly little things like thermonuclear explosions vaster than the planet steal all the glory, so we sent up astronauts to do the 5 Most Badass Things Ever Done in Space. Though they pale against star corpses in 6 Mind-Blowing Things Nobody Taught You About Black Holes. Or unleash your spacemagination with Pink Alert, and Other Emergencies on the Starship Enterprise.