A Black Hole's Gravity is Like a Spirograph | Accurate Append

A Black Hole’s Gravity is Like a Spirograph

Space and time are not fixed–or more accurately, seemingly fixed or regular movement across spacetime is actually “warped.” That warping causes the trajectory of motion to manifest as dynamic rather than nondynamic. A straight line is never really a straight line, and a regular orbit is never really a regular orbit. Before Albert Einstein developed the theory of general relativity, we could not explain, for example, the small anomalies in planetary orbits that should have been “regular” and unvarying according to Newtonian physics. 

The antecedents of general relativity and black holes (the real testing grounds of general relativity) were laid down long before Einstein’s articulation—around 1783 to be exact, by a clergyman named John Mitchell, and then again in 1796 by the scientist Pierre-Simon Laplace. They called them “dark stars” and later “frozen stars.” The idea was that in a star’s “last phase” of existence, under gravitational collapse, nothing would be able to escape that massive object’s gravitational pull, not even light. It wasn’t until the 20th century, however, that John Wheeler coined the phrase “black hole,” although even after two centuries, the term “dark star” connoted the same meaning.

In very simple terms, Einstein’s theory of general relativity provides several ways in which objects in orbit, and two objects exerting gravitational force on each other, will move dynamically rather than rotely or statically. Orbits “precess forwards in the plane of motion,” as one astrophysicist puts it.

So although it wasn’t a great surprise to scientists that a star circling a black hole would exhibit a dynamic orbit, there was still a profound elegance to the flower-like shape we can trace in its orbit. Astronomers at the Max Planck Institute in Munich monitored the star, called 52, for 27 years via the European Southern Observatory’s Very Large Telescope in Chile. They determined that it traces a “rosette.” This pattern occurs because the gravitational pairing remains dynamic even in the regularity of the orbit it facilitates. Ashley Strickland, writing for CNN, points out that this is the first time astronomers have ever studied a star “orbiting the supermassive black hole at the center of our Milky Way galaxy.”

In an instance of mathematical art imitating gravitational life, the rosetta orbit traces an oscillating pattern called a hypotochoid, and that is the mathematical basis for a toy known as the spirograph. The spirograph had already been a drawing device used to produce uniform curves when in the 1960s and 1970s it became a favorite toy and Hasbro trademarked the name. A mathematician named Bruno Abakanowicz invented the spirograph between 1881 and 1900, and others had different versions of it decades before. There are even instructions in a boys’ magazine in 1913 on how to make a “wondergraph”—essentially a much more solid version of a spirigraph—based in the principles of hypotochoids. That’s interesting because Einstein developed the theory of general relativity sometime between 1907 and 1915. 

Once a journalist asked Einstein to explain the theories of relativity in simple terms.Einstein responded: “If you don’t take my words too seriously, I would say this: If we assume that all matter would disappear from the world, then, before relativity, one believed that space and time would continue existing in an empty world. But, according to the theory of relativity, if matter and its motion disappeared there would no longer be any space or time.” One wonders if he also could have said that relativity is what causes you to draw a flower pattern when you might otherwise think you are only tracing a circle.

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