Everything You Wanted To Know About Black Holes
Is a black hole a portal to another dimension? Can you use a black hole to travel through space and/or time? Are we living in a black hole? Today we’re going to explore those invisible celestial bodies known as black holes and attempt to clear up some extremely common and popular misconceptions.
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What Is A Black Hole?
Quite simply, a black hole is a region of space where gravity reigns supreme. Nothing – not even light – can escape its intense gravitational pull. They are formed when an object’s internal pressure is unable to resist its own gravity. A common misconception is that an object has to be big to become a black hole. This is not entirely true. The density of the mass/energy is what triggers black hole formation. For example, if you compressed the Earth to the size of a nickel, the earth would itself become a black hole.
The most common way for a black hole to form is during the death of a star. When a star (roughly twenty times the mass of our sun) uses up all of its fuel, it explodes in spectacular fashion. This explosion is known as a supernova. Supernovae occur when the engine (or furnace) inside of a star runs out of fuel and is no longer able to sustain the internal pressure to fight off gravity. As the star begins to collapse in on itself, the outer layers start to fall inward then rebound outward violently producing the explosion. The inner dense core of the star continues to be compressed by gravity. With no fuel left to fight off gravity, the inner core collapses into a black hole. As the transformation takes place, energetic gamma rays are produced at the poles. These short ‘gamma ray bursts’ are the most luminous electromagnetic events known to occur in the universe and are a tell-tale sign of a supernova.
How Big Are Black Holes?
Black holes are commonly found in two flavors – stellar mass black holes and supermassive black holes.
Stellar mass black holes are the most abundant, and are formed when a star of sufficient mass dies. The upper limit on size so far discovered for this type is around 33 solar masses.
Supermassive black holes on the other hand, are gigantic. The smallest being hundreds of thousands of solar masses, the majority averaging millions of solar masses and the largest discovered so far topping out at 18 billion solar masses – roughly the size of an entire galaxy.
Each galaxy is thought to contain one at its center. Their growth and formation is a complex process, involving black hole cannibalism, galactic mergers and gorging on whatever gets near them for billions of years.
Can A Black Hole Die?
In 1974, Stephen Hawking showed that black holes are not entirely black but emit tiny amounts of thermal radiation. This effect is known as Hawking radiation. Due to this radiation, black holes lose energy/mass and can ‘evaporate’. While an incredibly slow process, it will eventually cause a black hole to ‘die’. Though, slow is a bit of an understatement. The process can take trillions of years or more for a black hole to evaporate away.
One common misconception is that black holes are shaped like funnels. A black hole is similar to a funnel but that visualization would only be accurate in a 2 dimensional universe. Black holes are spherical which means the ‘funnel’ would be three dimensional. Black holes are not much different from regular stars. You just can’t ‘see’ them and they have stronger gravity.
Could A Black Hole Be Used To Travel?
Another misconception is that black holes could be used as a portal to another dimension or can transport you across space and time. This is likely the result of speculation caused by the mathematics of general relativity and quantum mechanics breaking down at the singularity (the core) of a black hole. Unfortunately, even if this were true, you wouldn’t survive the trip.
Just outside and orbiting the black hole’s event horizon, (the event horizon is the ‘edge’ of a black hole. The boundary where even light cannot escape its intense gravity) is an orbiting ocean of super hot gasses and plasma. Gasses so hot, they’re hotter than the surface of the sun. Yet, even if you could somehow survive the extreme temperature and radiation, you still have to contend with gravity. The gravitational tidal effects of stellar mass black holes are beyond extreme. These ‘tidal effects’ rip matter apart down to the quarks that make them up. You’d be atomized before you could reach the singularity.
Are We Living Inside A Black Hole
It’s possible. Some scientist have postulated – in an effort to explain dark energy – that we might be living inside a black hole that exists in another universe. More specifically, a black hole that rebounded, like a spring. Using some cutting edge physics, Nikodem Poplawski of IU-Bloomington modified a version of Einstein’s general relativity equation to take particle spin into account. Including this variable allowed him to calculate torsion, part of the geometry of space-time. It also got rid of the black hole singularity paradox, a phenomenon that general relativity cannot explain. Though testing such a hypothesis is currently beyond our technological capability.
Alternative Hypothesis For Black Holes?
In string theory, some scientists believe the true quantum description of a black hole is what is known as a ‘Fuzzball’. Their theory removes two intractable problems that classic black holes pose for modern physics. The first being the information paradox and the second is the infinite space/time curvature at the singularity.
Under their hypothesis, black holes are formed the same way and act as explained above, but the singularity at the center of a black hole is replaced with a ball of ‘strings’, which they claim are ultimate building blocks of matter and energy. Strings are thought to be bundles of energy vibrating in complex ways in both the three physical dimensions of space as well as in higher, compact dimensions we cannot see or interact with due to their small size.
What Would It Be Like To Fall Into A Black Hole?
Physics Letters B – Volume 687, Issues 2-3, 12 April 2010, Pages 110-113
Cosmology with torsion: An alternative to cosmic inflation – rXiv:1007.0587v2 [astro-ph.CO]