The Demons of Dante's Inferno

Most of Dante's demons come from Greek mythology.

Charon – Hell's ferryman. He carries souls of the newly deceased across the river Acheron. A coin to pay Charon for passage is sometimes placed in the mouth of a dead person. It is said that those who cannot pay are fated to wander the earth as ghosts for a hundred years.

Minos – Dante makes him the judge of the damned. He determines what part of Hell they will be placed. In Greek mythology, Minos was a king of Crete, the son of Zeus and Europa. Every nine years he made King Aegeus pick seven men and seven women to go to the labyrinth to be eaten by the Minotaur. After Minos died, he became a judge of the dead in Hades.

Cerebus – The three-head dog that guards the gates of Hell to prevent anyone from escaping.

Plutus – A wolf-like demon that guards the fourth circle of Hell, the hoarders and wasters.

Phlegyas – Ferryman of the river Styx and giant guardian of the Fifth Circle of Hell.

In Dante's inferno, the angels that rebelled against God led by Satan guard the City of Dis. They are not named.

Furies – In Greek mythology the Furies, Alecto, Tisiphone and Magaera are the children of Gaia and Uranus. In the Inferno they represent remorse and torment evildoers and sinners.

Medusa –  In Greek mythology, she is a Gorgon, a chthonic monster and the daughter of  Phorcys and Ceto. Gazing at her turns the onlooker to stone.

The Minotaur – A creature with the head of a bull and the body of a man. In mythology he dwelt in the labyrinth of Crete.

Three Centaurs, half horse, half human creatures, are mentioned in the Inferno. They are Chiron, Cacus and Nessus.

Harpies – In the Inferno, they are the guardians of suicides. They are often depicted as either beautiful women with wings or ugly winged bird women.

Demons of Bolga Five – Creatures who tear the grafters to pieces with claws and grappling hooks. Their leader is Malacoda.

The giants and Titans of Greek mythology are also mentioned. Nimrod, who built the tower of Babel, Ephistus, Briareus, Tityas, Typhon and Anterus.

Standing waist deep in ice in the lowest pit of Hell with three faces is Satan himself.

Planets suitable for life

Recently astronomers have discovered planets in orbit around most stars close enough to determine whether they have planets. But of all the billions of planetary systems, which of them have planets capable of supporting life? At present we do not have the technology to look closely at those systems. Of our own solar system, as far as we can tell, earth is the only one capable of supporting life. There are two other planets that might support life. Mars may have supported life in the past, but so far no concrete evidence of this has discovered. Europa, a moon of Jupiter, has a liquid ocean. Perhaps life developed there (if the ocean is water).

So what makes earth unique in the solar system. First, it is not too hot nor too cold to sustain life. Most of the planets and moons further from the sun than Mars are too cold. Mercury and Venus are too hot. Although Venus is not so close to the sun that a temperature within a range to support life is ruled out for that reason. Venus is sometimes regarded as earth's sister planet. Venus is only slightly smaller than Earth (95% of Earth's diameter, 80% of Earth's mass). Because of these similarities, it was thought that below its dense clouds Venus might be very Earth like and might even have life. Unfortunately, we now know that Venus may be the least hospitable place for life in the solar system.

The pressure of Venus' atmosphere at the surface is about the same as the pressure at a depth of one km in Earth's oceans. It is composed mostly of carbon dioxide. There are several layers of clouds many kilometers thick composed of sulfuric acid. These clouds completely obscure our view of the surface. This dense atmosphere produces a runaway greenhouse effect that raises Venus' surface temperature hot enough to melt lead. Venus' surface is actually hotter than Mercury's despite being nearly twice as far from the Sun.

Another factor to support life as we know it is the presence of water. Apparently Mars once had liquid water on its surface, but it no longer does. Another problem with Mars is its thin atmosphere. One possible reason that it no longer has water and air is its small mass. Any smaller planet would likely be completely airless like our own moon.

Hence, it can be seen that although three planets are in a zone capable of supporting life as far as distance from our star (the sun), only one can support life. The other two are too dry. One has an atmosphere that is too thick, the other an atmosphere that is too thin. Thus, it can be seen that planets capable of supporting life are relatively rare. The question is how rare. If ten percent of planets in the galaxy are capable of supporting life, there may be nine billion planet capable of supporting life. If this number is one percent there would nine hundred million; one tenth of one percent , ninety million. That's still a lot of planets capable of supporting life.

  

Entangled Teleportation

Recently on Nova, there has been a series of programs to explain some of the latest findings in cosmology and quantum mechanics. One of the most unusual phenomena in quantum mechanics is called entanglement. Quantum entanglement occurs when electrons, molecules, photons and other elementary particles interact physically and then separated. They affect each other in the same way no matter how much distance separates them. This has been described by some as "spooky action at a distance" since nothing connects the pair and the change is instantaneous.

In 1998, physicists at the California Institute of Technology (Caltech), along with two European groups, successfully teleported a photon, a particle of energy that carries light. The Caltech group was able to read the atomic structure of a photon, send this information across 3.28 feet (about 1 meter) of coaxial cable and create a replica of the photon. As predicted, the original photon no longer existed once the replica was made.

The way that this would work on macroscopic scale -- in other words, the scale of things as we normally experience them as contrasted with the tiny world of particles and atoms – is that at one terminal of our teleporter would contain two booths. In one booth would be matter that is entangled with matter in a similar booth at the destination site. To teleport a person from the place of origin to the destination, the person would step into the second booth. The teleporter would then entangle the person's atoms and particles with the one in the other booth. This would destroy the person in the booth, but would cause an exact replica to be instantly created at the destination terminal.  

This brings up a philosophical question. Is the person who appeared at the destination site really the same person that was sent from the place of origin? He or she would be identical in every way including thoughts. If not, I don't think anyone would want to travel this way. It may be okay for transporting goods, however.

Black Holes

One of the most interesting phenomenon in the universe are black holes. For those of you who do not what a black hole is, it is a region of space from which nothing, not even light can escape. The existence of black holes is predicted by the General Theory of Relativity, which concludes that a sufficiently compact mass will cause space-time to form a black hole. Surrounding a black hole is a surface called the event horizon. Anything within the event horizon, including any sort of electromagnetic radiation such as light, can never escape.

Black holes are created when a star becomes so massive that it explodes into a supenova at the end of its life cycle. After a black hole is formed, it can grow by absorbing mass from its surroundings, such as other stars and even other black holes, eventually becoming what is called a super massive black hole. Some super-massive black holes have a mass that is as much as millions of solar masses. Super-massive black holes are often found in the center of galaxies. Our own Milky Way galaxy has one.

The question that arises is if no electromagnetic energy can escape a black hole, how can one be detected? It can be inferred through its interaction with other matter. Astronomers have identified many black holes in binary star systems where one of the stars is a black hole by studying the interaction with their companions.  Also, it turns out that quantum theory predicts that the surface of a black hole will radiate thermal energy.

A black hole has only three physical properties: mass, charge and angular momentum. These properties cause the black hole to be visible outside the hole. For example, a charged black hole repels other like charges.

When an object falls into a black hole, information about its shape or charge is lost to outside observers. Note: I doubt whether there are any inside observers either.

At a distance from a black hole, a particle can move in any direction, the only restriction is the speed of light. Close to a black hole space-time starts to deform. Once inside the event horizon the particle cannot escape. To a distant observer, clocks near a black hole slow down. This is called time dilation. On the other hand, an observer falling into a black hole does not experience these effects as he crosses the event horizon. According to his clock he crosses the event horizon after a finite time although he cannot determine the location of the event horizon from local observations. (There seems to be a science fiction story plot here.)      

Within a black hole there is a region of gravitational singularity, a region where space-time curvature becomes infinite. In a non-rotating black hole this region takes the shape of single point, but for a rotating black hole it is smeared out to form a ring singularity in the plane of rotation.

An observer falling into a non-rotating black hole is carried into the singularity once the observer crosses the event horizon. When they reach it, they are crushed to infinite density. However, in the case of a rotating black hole, it is possible to avoid the singularity. Hence there is the possibility of exiting the black hole into a different space-time. (This has been used to travel long distances in space in many a science-fiction story.) But, who knows where the other end of a black hole will take you. It might be an entire other universe.

There is much more to know about black holes. I have just covered the highlights.