Understanding Black Holes – The Basics


Black holes are frequently mentioned as a sort of metaphor. In reality, black holes are generally understood to be large, empty voids in space where light cannot escape. It’s almost as if objects and energy are sucked into them. Though this is the basic premise behind black holes, they are much more complex objects that can tell us a number of facts about our universe and how it began.

Definition of Black Holes

Black holes are the last evolutionary stage in the lives of enormous stars that were once 10 to 15 times the size of our own sun. At the end of their lives, they may explode in a gigantic “supernova” event that scatters matter, but leaves behind a cold remnant of the star that collapses in on itself. This is the budding black hole that begins to suck in matter and light. However, light and matter must pass so close to black hole so that they cannot escape. This point is called the “event horizon.”

The Study of Black Holes

Black holes have been theorized since the late 1700’s. Einstein’s theories also predicted the existence of black holes. However, it wasn’t until 1967 that physicist John Wheeler began referring to these phenomena as “black holes.” Though no one has ever seen one, these black holes gave way to much scientific study in recent decades.

What Black Holes Tell Us

The study of black holes has demonstrated how the universe can hide much of its matter. This fact helps to account for all the missing matter that falls outside the mathematical computations about the universe. Black holes not only probably existed when our galaxy was formed, but also aided in the galaxy’s formation. The study of black holes also suggests that all matter that exists can become a black hole if compressed to zero volume and thus, infinite density.

Facts About Black Holes

  • At the center of each black hole is a point where the laws of physics break down and space-time cease to exist.  This point is called a “singularity.”
  • Black holes vary in size depending on the size of the matter within it. No one has actually seen a black hole because light does not escape from a black hole. However, the dust and gas clouds that swirl around black holes emit radiation that can be detected.
  • Black holes can suck up other black holes when they are in close proximity to each other, usually with the larger ones devouring smaller ones. Black holes can also circle each other in a swirling motion.
  • As black holes age, they gain more mass because they gain more matter over time. Black holes will eventually disintegrate over trillions of years.
  • The nearest black hole in 1,600 light years away. It is called V4641 Sgr and is a rare type of black hole called a micro quasar. This black hole is located in the Sagittarius arm of the Milky Way.
  • Black holes have no temperature, but objects about to enter the black hole are heated to millions of degrees before they disappear. They also emit x-rays.
  • Black holes do not actually suck things into them. The objects simply fall into the black hole and disappear due to the dense gravity of the hole.
  • Black holes are the simplest objects in the universe and can be described completely by their mass, spin rate, and electrical charge.

Of course all of this could change tomorrow if someone were to somehow disprove the theories behind black holes. Many people debate whether they even exist or not however scientific research in recent years has generally reinforced their existence and role within the universe.

Image Credit: XMM-Newton/ESA/NASA

  • So what do you mean that mater just disappears once it enters a black hole? I thought matter could not be destroyed, only reconstituted in a different form. (Speaking from scientific ignorance here. Respond as if responding to a two-year-old so I’ll understand.)

    Thanks for sharing. This is a fascinating post.

    • Jason Carr

      Great question Xavier! Actually the black hole “feeds” on the matter and as it absorbs matter, it causes the black hole to grow larger and larger thereby enabling it to absorb even more matter. So the matter isn’t actually destroyed but rather absorbed as a sort of energy source. Some people believe that everything that black holes absorb are spewed out into other universes (alternate universes). Unfortunately until someone ventures into one, we’ll never truly know. This is a fascinating subject obviously open to much debate/theory. I’m hopeful that we’ll learn a lot more about them in the years ahead.

  • Jason Carr

    For anyone interested in Black Hole theory, there’s another one going around that is equally fascinating. You can read more here: http://news.nationalgeographic.com/news/2010/04/100409-black-holes-alternate-universe-multiverse-einstein-wormholes/

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