Supermassive hearts of darkness and binary stars are both common denizens of the observable Universe. Supermassive black holes are thought to lurk hungrily within the centers of every large galaxy in the Cosmos–including our own Milky Way. The currently dormant gravitational beast that is situated at the center of our Galaxy is a lightweight, at least as far as supermassive black holes go. It has been named Sagittarius A* (pronounced sagittarius-A-star) and it weighs-in at “only” millions of solar-masses–in contrast to many others of its kind that weigh-in at billions of times our Star’s mass.
Our large spiral Milky Way is predicted to collide with the Andromeda galaxy, another large spiral member of our Local Group of galaxies, in about 3.75 billion years. When this happens, the duo of supermassive beasts residing in the secretive hearts of both galaxies will merge, and the resulting gravitational monster born from this collision will weigh-in at the hefty combined mass of the two separate black holes. While this collision–predicted to occur in our Galaxy’s distant future–will not necessarily disrupt many of the Milky Way’s celestial inhabitants, some recent models have shown that our Solar System may not be as fortunate. The catastrophic smash-up could dislodge our Sun, that will then zip screaming away from its location, carrying the rest of our Solar System along with it for the ride.
The Universe is turbulent. Supermassive hearts of darkness lie hidden in every galaxy, waiting for their next meal to wander tragically into their powerful gravitational trap. Alas, anything unfortunate enough to travel too close to a voracious black hole is doomed to be devoured. Captured objects are unable to liberate themselves from the extremely strong gravitational lure of the predatory black hole. Not even light can free itself if it passes the dreadful point of no return called the event horizon.
Black holes were already present when the Universe was very young. Clouds composed of gas and unfortunate stars somersault down, as they whirl into the vortex surrounding the black hole–never to return from the swirling maelstrom encircling this feasting gravitational beast. As the material travels down to its inevitable doom, it forms a wild storm of glaring material surrounding the black hole–the massive accretion disk. In the ancient Universe, these brilliant accretion disks dazzled Spacetime in the form of quasars. Indeed, Sagittarius-a-Star probably went though a glaring quasar phase in its flaming youth billions of years ago.
The dazzling material composing the accretion disk grows hotter and hotter, as it churns out a raging storm of radiation, especially as it travels ever closer to the event horizon. The event horizon is situated at the innermost region of the accretion disk.
In the 18th-century, the English scientist John Michell (1724-1793) and the French physicist Pierre-Simon Laplace (1749-1827) considered the possibility that there could actually exist in nature bizarre entities like black holes. Albert Einstein, in his Theory of General Relativity (1915) later made the prediction of objects possessing such powerful gravitational fields that anything unfortunate enough to travel too close to their lairs would be consumed. However, the idea that such strange beasts could actually inhabit the celestial zoo seemed so outlandish at the time that Einstein rejected the concept–even though his own calculations suggested otherwise.
In 1916, the German physicist and astronomer Karl Schwarzschild (1873-1916) devised the first modern solution to General Relativity that describes a black hole. However, its interpretation as a region of space, from which absolutely nothing can escape, was not understood for another fifty years. Up until that time, black holes were considered to be mere mathematical oddities. In fact, it was not until the 1960s that theoretical work demonstrated that black holes are a generic prediction of General Relativity.
Black holes come in different sizes. Pack enough mass into a small enough region and a black hole will be born every time. In addition to the supermassive variety, black holes of both stellar mass and intermediate mass are known to inhabit today’s Cosmos. When an especially massive star runs out of its necessary supply of nuclear-fusing fuel it goes supernova, and collapses into a stellar mass black hole.
Most of the stars in the Universe, both large and small, are members of binary systems. Our Sun is a solitary star today, but it may well have been born with a twin–just like most other stars. Stars are born in one of the many cold, dark molecular clouds–primarily composed of molecular hydrogen–that haunt our Galaxy in huge numbers. When a particularly dense blob within a star-birthing, beautiful molecular cloud reaches a critcal mass, size, or density, it starts to collapse under the merciless pull of its own gravity. As this collapsing cloud, termed a solar nebula, becomes increasingly dense, random gas motions originally present in the cloud average out in favor of the direction of the nebula’s angular momentum. Conservation of angular momentum results in an increase of the rotation rate as the nebula radius becomes smaller. This rotation causes the cloud to flatten out in way that has been compared to the way a blob of spinning pizza dough changes into a flat disk. The initial collapse takes approximately 100,000 years. After that time the baby star attains a sizzling surface temperature similar to that of a main-sequence (hydrogen-burning) star of the same mass. A star is born–usually with one or more stellar siblings because these star-birthing blobs tend to fragment. Each individual fragment produces a baby star. For this reason, it is thought that long ago our solitary Star’s stellar sibling likely wandered off to some distant region of our Galaxy–never to return.
Astronomers know that when a luckless star travels too close to a black hole, it is shredded by the black hole’s powerful gravity. But since both black hole binaries and stellar binaries are common denizens of the Cosmos they can frequently meet up–and that’s when things become more interesting. mkv movie download 2019