Previous: The Great Attractor: A Truly Massive Mystery
Next: How Do Satellites Get & Stay in Orbit?



View count:523,820
Last sync:2018-05-06 11:10
(Intro plays.)

Okay, I don't want to alarm you or anything, but astronomers say there's a super-massive black hole at the center of pretty much every galaxy, including ours. I know; I try not to think about it. But don't panic because it turns out black holes are actually good for galaxies and it could be a lot worse. Last week a team of astronomers led by the University of Cape Town said that they found three enormous black holes at the center of a distant galaxy. 

And those holes are in the process of spiraling into each other. Which is probably the weirdest thing you could imagine because we are talking about holes, colliding. The phenomenon was detected using a system of radio telescopes called a very long baseline array. At the center of this galaxy, 4.2 billion light-years away. Until now we'd only discovered four other galaxies with multiple black holes at their center. So finding these, and finding them so close to each other, makes us think we are getting closer to understanding how galaxies, and their black holes, grow over time. 

As you probably know, a black hole is an object so dense that none of the stuff around it, not even light can escape its gravity. And because it is so powerful, that matter and energy can be drawn into it incredibly fast, at near light speed. When matter moving that fast reaches one of the black holes magnetic poles, it flies outward, at nearly the speed of light in powerful jets of energy. 

So even though it might sound like a black hole at the center of your galaxy would just suck your whole neighborhood down a giant celestial toilet drain, astronomers think that these jets are actually responsible for making galaxies bigger by distributing the matter and energy at their cores far and wide, allowing them to grow and evolve. That's why astronomers believe that at least one super-massive black hole must lie at the center of every normal galaxy. But here's the thing, for galaxies to keep growing, it would make sense that their black holes would have to keep growing, too. 

And we think that black holes do this by simply merging with each other. As galaxies collide into one another their black holes would do the same forming super-massive black holes some many million times more massive than the sun. The new observations reported last week are the closest we've ever gotten to actually seeing this happen. Until now the closest we've seen black holes get was about 7,800 light-years apart. But in a new study, the nearest pair is only 455 light-years apart, each swirling around the other, drawing themselves in. 

Pretty soon, scientists say, these two null entities will just disappear into each other like a couple of goth kids making out on a park bench. Okay, they didn't put it exactly that way. But here is another phenomenon for you. A disappearing island on Saturn's moon, Titan. In case you've never been there before, you should know that Titan is the only other world in our solar system with stable liquids on its surface, and they're remarkably similar to ours. There are seas, lakes, rivers, even rain, only instead of water, it's all liquid methane and ethane. 

Last July NASA's Cassini space craft picked up radar images of an object in one of these methane seas named Ligeia Mare where they've never seen anything before. But then, on a subsequent pass over the sea, it was gone. The mysterious object was about 200 sq km in size, the surprised astronomers dubbed it "Magic Island." But it's probably not that, exactly. Instead, it's likely the result of, of all things, warm weather, because it's summer in the northern hemisphere of Titan. 

So, rather than an actual land mass, the so called island may have just been a patch of tall waves kicked up by a strong summer wind, or it could be material that usually sits frozen on the sea floor, but then bobs up in the summer temperatures, scientists just don't really know. But Titan experiences season changes very slowly, summer comes about every four years and Cassini has only been there for ten years. So it's likely we've just never noticed summertime before. The cool thing is that this is a chance to watch an alien version of Earth's own hydraulic cycle. That's how our planet constantly recycles water, evaporating into clouds in one place and raining down in another. 

Only in Titan's case, it's recycling methane. So by studying Titan's methane cycle we can better understand our own liquid cycle and the wonderful environments that result from it. Me, I'll stick with Earth and water, thanks. I mean, methane? I don't want to go swimming in that. Thanks for joining me for SciShow Space News! If you want to help us create this content you can go to and if you want to keep exploring the universe with us don't forget to go to and subscribe.