Download Your Free Black Holes E-Book from Sky & Telescope!

Black holes, the universe's spinning hearts of darkness, capture the imagination. They're the ultimate unknown — these rents in the fabric of space-time let nothing, not even light, escape. Yet the blackest objects of the universe can also be the brightest. Supermassive black holes at the centers of galaxies become powerful beacons when they feed. As gas flows into their gaping maws, it heats up and glows so bright that it can be see from the early universe. Each of the four articles covered in this free eBook from Sky & Telescope magazine helps reveal the mysteries of supermassive black holes, including how they form and what role they play in the larger galaxy. One day, we might even be able to observe the beasts themselves. Until then, we're left to marvel and learn as much as we can.
Black Holes - Endless Rents in the Sky This free eBook from Sky & Telescope magazine includes four articles from the experts, who explain various aspects of black holes.

  • "A Quasar in Every Galaxy?" by Robert Irion summarizes observations and theories about the supermassive black holes that lurk in the core of almost every major galaxy.
  • "How Black Holes Helped Build the Universe" by Christopher Wanjek shows how, without black holes, we wouldn't recognize the universe around us, and we might not even exist.
  • "Spinning Hearts of Darkness" by Laura Brenneman suggests that measuring black holes' spin can tell us how they form.
  • "Einstein's Shadow" by Camille Carlisle introduces a planet-wide telescope that has set its sights on imaging a black hole directly.

As a special thank you for downloading this free eBook, we'll welcome you to the Sky & Telescope family. This includes:

  • A free newsletter from Sky & Telescope filled with the latest astronomy and observing news.
  • Special offers from Shop at Sky on products any enthusiast would love.


Learn All About Black Holes in This Free eBook From Sky & Telescope Magazine!

To astronomers and lovers of the night sky, black holes are things of wonder. After all, these dark beasts can become bright beacons of light when they feed on hot gas, so bright they can be seen from the early universe. Yet they're still shrouded in mystery and many questions remain unanswered. How do they form? What role do they play in galaxy formation? And what is it really like deep inside a black hole?

What we do know is that without black holes, the world as we know it might be entirely different. Black holes shape the universe's evolution; without them, we might never have come into being. To learn more about these beasts, astronomers peer into the heart of nearby galaxies and measure black hole spins, which hint at how they formed and grew. And plans are underway to one day observe a black hole directly!

FREE Download: Black Holes Ebook

Subscribe to the Sky & Telescope newsletter to Download

Black Hole Image

Black Hole Article #1: A Quasar In Every Galaxy?

by Robert Irion
Observations are showing that in the heart of every major galaxy, there lurks a supermassive black hole millions or even billions of times the mass of the Sun. And not every one of these black holes shines bright as a quasar. When they starve, the black holes can't be seen. It's only when they feed on gas that they flare up for brief, glorious intervals. Even our Milky Way galaxy has a supermassive black hole at its core that could exhibit a magnificent display when it collides (several billions of years from now) with our neighbor, Andromeda Galaxy.

Did Black Holes Help Create the Universe?

Black Hole Article #2: How Black Holes Helped Build the Universe

by Christopher Wanjek
Without the black holes we find all across the universe, our galaxy might look entirely different. In fact, we ourselves might not even be around to admire the universe's beauty. By feeding on gas, black holes have been serving as the chief architects of the universe. The energy they consume, and that they blow away, triggers star formation, makes or breaks galaxy formation, and redistributes elements in a way that might have enabled life itself.

Is A Black Hole Really Dark?

Black Hole Article #3: Spinning Hearts of Darkness

by Laura Brenneman
However massive they are, black holes don't usually just sit there. They spin, sometimes at tremendous rates. Astronomers are measuring the rotation rates of black holes to find out how they formed, and how they grew over time. Of eight supermassive black holes mentioned in the article, three are spinning at rates near the speed of light, suggesting they've been feeding on gas for a long time.

Astrophotography Grows Towards Black Holes

Black Hole Article #4: Einstein's Shadow

by Camille Carlisle
The best way to learn about black holes, of course, would be to image one directly, a challenging task. But a group of astronomers is putting together a planet-wide telescope that aims to do just that. Rather than imaging the black hole itself, the astronomers are hoping to image the light bent around it. But seeing detail so fine requires a suite of telescopes spread across the globe.

Black Holes Are One Of The Most Fascinating Elements Of The Sky - Learn More Now!

Get Your FREE Black Holes Ebook