What I’ve Learned:
“Hypervelocity stars: what happens in the galaxy doesn’t always stay there.”
Many things move at a proverbial “million miles an hour”. Vacation days. Your heart, when a hot-bodied stranger in a swimsuit walks by. And your gossipy friends’ mouths, telling everyone how you drool over hot-bodied swimsuited strangers on your vacation.
You knew you should have never invited them to Cancun. Live and learn, gringo caliente. Live and learn.
Some things that don’t literally move that fast are stars. Sure, stars are usually clustered into galaxies, and galaxies zoom around the void at a million miles an hour or more — depending on which other bits of celestial fluff you measure them against. But the stars are just along for the ride; relative to their host galaxies, they don’t reach those insane kinds of speeds.
Except when they do.
The universe is full of exceptions — even Keanu Reeves made that one good movie once — and turbocharged stars are interesting examples. Known as hypervelocity stars, they whip around at speeds up to two million miles per hour, relative to galactic speed.
That’s like gunning a Ferrari down the highway and being overtaken by a cruise missile. Even your motormouth vacation friends can’t keep up that pace.
Hypervelocity stars are fairly new to astrophysics — predicted in 1988, and first observed in 2005. There are only a handful known to exist, mostly because confirming their speed requires measurements over a period of decades. We can’t exactly set up a speed trap and flash these things with a radar gun as they zoom past.
The really interesting thing about hypervelocity stars is that they move so fast, they can reach the escape velocity of their galaxies. Meaning, instead of swirling around in a galactic spiral forever like our boring old sun, these stars break completely free of galactic gravity and ping off into interstellar space, never to be heard from again.
(Maybe somebody could have pitched that to Keanu Reeves after the first Matrix. I’m just saying.)
What we don’t know for sure is how these stars get all hypervelocitized in the first place. But two theories explain the current observations pretty well.
It’s thought that some hypervelocity stars are formed near our galactic center, where a supermassive black hole looms. Computer models say if a binary system — two stars closely orbiting each other — got caught in the black hole’s clutches, one could be sucked in while the other is flung outward at ridiculous speed. Like a marble fired from a slingshot shot out of a cannon mounted on a jet plane. Times a lot.
The other, equally violent, theory also involves binary systems. Only in this scenario, the partner star isn’t stuffed into a black hole; instead, it goes supernova — exploding so catastrophically that it accelerates the surviving star to supergalactic speeds.
Either way, the presence of a hypervelocity star means that things went terribly, terribly wrong for that star’s old flame. So basically, if your sweetie ever tells you he or she wants to become a hypervelocity star some day, you should pack your bags and leave. Like, yesterday.
You can always take a rebound trip to Cancun. Your friends may gossip, but at least none of those swimsuited hotties are going to explode you or unceremoniously stuff you down a black hole. That kind of shit only happens in Las Vegas.
And apparently, all around the Milky Way. Stellar breakups are a bitch, yo.
