Discovering Black Holes



There are many myths surrounding black holes, such as sources for time travel, a cosmic vacuum killing off stars and planets, among just a few. Truth is, there is very little known about black holes. In simplest terms a black hole is a space with the absence of everything. Nothing can escape from this space. Since light is subject to gravity, even light is unable to escape this space due to its heavy gravitational pull. Since light has no way of refracting off any object within a black hole, that is why the center of a black hole is believed to appear like a black hole. Surrounding this dark hole, there is usually a lot of vibrant colors. This area is an undetectable surface that surrounds the black hole, in which once you have passed this boundary, you have hit the point of no return and its pull will \”suck\” its object in and seems to vanish.

The discovery of a Black Hole

The idea of a black hole first came about by one man\’s ingenious research and yes… imagination as early as 1783. A geologist by the name of John Mitchell wrote a letter to another professional Henry Cavindish with his suspicions of black holes. I found this excerpt from wikipedia, and felt it was so excellent I was going to quote it verbatim: \”If the semi-diameter of a sphere of the same density as the Sun were to exceed that of the Sun in the proportion of 500 to 1, a body falling from an infinite height towards it would have acquired at its surface greater velocity than that of light, and consequently supposing light to be attracted by the same force in proportion to its vis inertiae, with other bodies, all light emitted from such a body would be made to return towards it by its own proper gravity.\”

Pierre Simon Laplace was another who had begun to have similar suspicions, he was a mathematician. In the 19th Century these ideas were mostly ignored, since they felt that light would not succumb to gravity.

It was not until Albert Einstein debunked this idea in 1915 with his theory on general relativity, and realized that light is in fact affected by gravity.

It was not until Albert Einstein debunked this idea in 1915 with his theory on general relativity, and realized that light is in fact affected by gravity. Who knew? This did reignite some latent interest, but the interest did not last long.

As interest began mounting in the late 1950\’s more and more scientists began to research whether black holes really existed. Up until a decade later, they did not have a name for what believed to be a fictional phenomena. In the late 1960\’s, John Wheeler coined the term \”black hole,\” in a lecture and the term became mainstream. He does insist that, although he was the first to publicly refer to them as black holes, he was not the creator of the name. There is documentation from 1964, where someone did refer to this phenomena as a black hole in a letter to the American Association for the Advancement of Science by Anne Ewing.

It was not until two years after John Ewing first coined the phrase black hole that someone did \”discover\” a black hole. I use the term \”discover\” loosely since black holes cannot actually be observed directly and therefore not truly discovered. The black hole that was discovered is also known as the X-ray binary star Cygnus  X-1. It was dubbed a black hole, because of its unusual impact on the stars around it, plus its mass is much too large to be called a neutron star. It measures at about 8.7 times the solar mass of the sun.  Plus Cygnus X-1 is a powerful X-ray source. It is in the X-rays that scientists have learned the most about black holes.

How we study Black Holes

The only way we can study a black hole is by observing the matter surrounding it.

The only way we can study a black hole is by observing the matter surrounding it. Since once an object enters a black hole, it does ever return, we have no way of sending an object into it and detecting it from there at this point. What has been observed by stars surrounding a black hole is that as it gets nearer and nearer the center, the objects begin to become more attracted by it. Once they have gotten past the event horizon or Schwarzchild radius(*), the undetectable surface earlier mentioned, the object will actually spiral inward towards the black hole. As it spirals it begins heating in temperature and emitting radiation that can be detected by our Earth\’s telescopes. To give you an idea of how close you have to be to a Schwarzchild radius before being sucked in, let\’s imagine a black hole the size of the sun. The sun is 700,000 kilometers, something would have to get within 3 kilometers before the black hole would suck it in. Which means, you could get very close without being sucked into a black hole.

Supermassive Black Holes

In 1998, astronomers believe that they uncovered a supermassive black hole in our very own galaxy, the Milky Way. One thing to understand how large something is, you have to know how astronomers determine these things. For instance, things in space are measured in solar mass. This is determined by the size in comparison to the sun, its gravitational pull, and it\’s distance from the sun. Through these 1998 studies, they believe that this supermassive black hole was 2 million solar mass. Recent studies have measured it closer to 4 million solar mass! This is massive. To think the Earth is only a mere 0.00000300343905 solar mass. Other estimates supermassive black holes at 10 to 15 times as large as the sun.

There is a belief that all universes have supermassive black holes. It is also believed that these remain in the middle of each universe, and can give clues as to how the universe began. Recently in 2007, there was a triple supermassive black hole finding. As it has been believed that these are the center of universes, they are hoping that this new finding will lead to eventual discoveries  of how the universe was created. Still so much is unknown of our universe, or even our world.

(*)The Schwarzchild radius was named after a man who has studied and tried to better understand black holes, Karl Schwarzschild. Others like Karl Schwarzchild; Jayant Narlikar and Stephen Hawking have been studying the works of Einstein in hopes to have a better understanding of black holes. Since there is so much unknown and hard to study, they remain a constant source of intrigue and curiosity.