Observations of the Night Sky Led to the Discovery of the Black Hole

by Ashley Luse, age 11

A fantastic discovery was made one night in 1844 by German astronomer, Friedrich Wilhelm Bassel. Bassel discovered a dark and mysterious force in the universe, now known as the black hole.

While using an advanced microscope to observe the brightest star in the galaxy, the ‘dog star’ Sirius, Bassel made a curious observation. Bassel expected his measurements to show the star moving in a straight line. Instead, after days of observation, he noted that the star seemed to be moving irregularly. He hypothesized this movement was caused by some gravitational pull on the star that could not be seen, which led to the theory of black holes.

The experiments Bassel did to explore the idea of black holes led to great discoveries, including the life stages of a star. Ninety percent of stars become black holes after progressing through their life stages. During the first phase of a star’s life, it is comprised of two elements, hydrogen and helium. When those two elements fuse together, great amounts of energy are released in a nuclear process.

Then outer layers of the star begin to slowly dissipate, until all that remains is the extremely dense core. One example of a star in its first phase is our sun. Fusion of hydrogen and helium continues, and over time the core of the star grows denser. At the same time, layers of the star expand, and it grows in size and turns a crimson color. The star is then known as a “Red Giant.”

After the star reaches this point, it emits a different wavelength of light. It is now called a “White Dwarf.” This type of star is what helped Bassel with all of his other discoveries. The final stage is when the “White Dwarf” collapses completely, creating the densest, smallest version of the star - a black hole. A black hole is millions of times smaller, but its gravitational pull is extremely powerful. So powerful, in fact, that any object near a black hole will be sucked into it.

There has been much speculation about the nature of black holes. While some scientists think that any object drawn into a black hole will simply burn up, others believe that they hold the future key to traveling through time and space itself.

[Source: Greatest Mysteries of the Unexplained]