Previous: 3 Stars That Shouldn't Exist
Next: The Hunt for Water on the Moon



View count:387,480
Last sync:2019-12-08 11:20
Black holes are a wondrous force of the universe! Hank explains how we found a supermassive rogue black hole & how DNA behaves in space!
Get a free 30-day trial today by signing up at

Hosted by: Hank Green
Support SciShow by becoming a patron on Patreon:
Dooblydoo thanks go to the following Patreon supporters—we couldn't make SciShow without them! Shoutout to Kevin Bealer, Mark Terrio-Cameron, KatieMarie Magnone, Patrick Merrithew, Charles Southerland, Fatima Iqbal, Benny, Kyle Anderson, Tim Curwick, Scott Satovsky Jr, Will and Sonja Marple, Philippe von Bergen, Bella Nash, Bryce Daifuku, Chris Peters, Patrick D. Ashmore, Charles George, Bader AlGhamdi
Like SciShow? Want to help support us, and also get things to put on your walls, cover your torso and hold your liquids? Check out our awesome products over at DFTBA Records:
Looking for SciShow elsewhere on the internet?

It's hard being a black hole.  For one thing, no one can actually see you and also you demolish everything within reach, and sometimes you even get kicked out of your own galaxy.  In a study published this week in the journal Astronomy & Astrophysics, an international group announced that they'd found a supermassive black hole that's been thrown out of its galaxy with no hope of getting back.  The team was observing a galaxy 8 billion light years away called 3C186, using the Hubble Space Telescope, when they noticed something strange.  Normally, you would see a burst of radiation called a quasar in the middle of one of these galaxies, which tells us there's a black hole there, but instead, they found the quasar and therefore, the black hole, 35 million light years from the center of the galaxy and it's still moving away.

The black hole is traveling away from the galaxy at 7.5 million kilometers per hour.  That's like if you were going from Earth to Mars at that speed, it would take about a day.  Astronomers have found evidence of a few other runaway black holes before, but this is the farthest we've ever seen a supermassive black hole from its parent galaxy.  The researchers think that one or two billion years ago, two galaxies with their own supermassive black holes probably came together to form 3C186.  The galaxies merged, the two black holes started spinning around each other and, in the process, they shot out gravitational waves, those distortions in the fabric of the universe that happen when massive objects like these black holes accelerate, and since the black holes had different masses and rotation speeds, the waves wouldn't have been distributed evenly.  That asymmetry meant that when the two black holes finally came together, the black hole they merged into was sent zooming off in one direction.  

The astronomers plan to spend more time observing this rogue black hole to learn more about things like its speed and the gas that surrounds it, because, like, what else do you do when you find something this weird, and if they're right about how it came to be, it'll also be some strong evidence for the idea that supermassive black holes can merge.  

We know a good bit about how regular-sized black holes come together but we still don't understand exactly how it happens with the supermassive ones.

Closer to home, researchers are getting ready to learn more about what happens to our bodies in space, because microgravity does some weird things to human bodies.  When it comes down to it, we're all just a little too squishy and sensitive.  So in the next cargo mission being launched by spaceflight company Orbital ATK to the International Space Station, NASA is sending up an experiment that will teach us how space changes our DNA.  

The mission was supposed to launch on Monday but was delayed because of an issue with the rocket that was discovered during testing before the launch, but when it does launch, the goal of the study is to clarify what we've learned from NASA's twin study, which examined a pair of twin astronauts to learn how microgravity affects our bodies, because if we're gonna start traveling to Mars and beyond, trips that will take months or years, we should know what's gonna happen to us before we leave.

In March of 2016, Scott Kelly returned from a year aboard the ISS, the longest uninterrupted trip to space by an American astronaut.  Meanwhile, Scott's twin, a retired astronaut named Mark Kelly, spent that year here on Earth.  Since Scott came home, the Kelly brothers have participated in all sorts of medical exams and NASA will release a summary of their findings later this year, but we've already learned something surprising.  NASA found that Scott's telomeres, the protective caps at the end of chromosomes, had lengthened, which is the opposite of what researchers expected.  

As you get older or when you're under a lot of stress, your telomeres shorten, which can lead to diseases like cancer and liver dysfunction and researchers have thought living in space would cause that to happen prematurely, but it did not.  Scott's telomeres got longer while he was in space and then went back to normal when he got back to Earth, so this new experiment is trying to figure out why that happened.  It'll collect blood samples from the crew on the station and then send samples back to Earth for testing.  They'll be compared to blood taken before and after the crew's spaceflight and also to samples from control subjects on the ground.  That'll let researchers get a closer look at what microgravity is doing to the telomeres and see if there are any special mechanisms involved.

Since changes in telomeres are associated with so many health problems, it's important we figure this out before we start sending astronauts on longer missions, and with his new experiment and the whole twin study, we are already making great progress.  Also, having both your sons grow up to be astronauts, that, like, talk about parenting goals right there.  

Also, hey, right now Audible is offering SciShow Space viewers a free 30-day trial membership.  You can check out, where you can choose from a multitude of audio programs and titles such as Bad Astronomy by Phil Plait.  Go to for a free 30 day trial and download your free title today.  I use Audible.  Right now, I am listening to New York 2130, I think is what it's called, by Kim Stanley Robinson.  It's great and terrifying.  There is also lots of other great books, it--I mean, it's great.  I use it all the time and it makes my driving better and you should check it out.  Also it helps us out if you go to  That'd be great.

(End credits)