THEORIES on our UNIVERSE !

        As far back as recorded history goes, there have been two sets of opposing ideas, beliefs, theories, or teachings about the origin of the universe. It has either existed eternally with no beginning or end, or it was created at some point in time and will eventually come to an end. In the first part we examined the early cultural, religious, and somewhat philosophical views of how the universe began. We've also spent a little time looking at some ideas about our own beginnings from a religious and scientific point of view. In this section, we're going to take a brief excursion through the various theories that science has put forth to explain the origin of the universe

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Steady State

      The Big Bang Theory is naturalistic science’s preferred explanation for the origins of the universe. Even so, there are questions about the theory that persist. One attempt to fill the holes left in the Big Bang Theory is a concept first developed in the late 1940’s, known as Steady State Theory. 

      Steady State Theory proposes that matter is being continuously created, at the rate of a few hundred atoms per year. This would allow the density of the universe to remain constant as it expands. This violates the First Law of Thermodynamics, but then again, so does the Big Bang Theory. 

      Scientific discoveries have shed doubt on Steady State Theory, such as cosmic background radiation. This radiation was predicted by Steady State Theory, just as it was by the Big Bang Theory. Still, cosmic background radiation fits better into the Big Bang Theory. In the 1990’s, the discovery of accelerating galaxies renewed interest in the general concept of Steady State Theory. The accelerating universe discoveries have added a lot of uncertainty to the discussion of the Big Bang Theory.

Plasma Theory

         The "plasma theory," which rejects the big bang theory, is a recent and controversial concept of cosmology. Swedish Nobel laureate Hannes Olof Göst Alfvén is the chief proponent of the theory. He and his colleagues discredit the big bang theory in favor of electrical and magnetic processes involving plasma (hot electrical conducting gases). While the big bang cosmologists’ claim over 90 percent of the universe is invisible, primarily composed of dark matter, plasma theorists believe 99 percent of the matter is composed of plasma. The big bang universe is based solely on terms of gravity, using Albert Einstein's theory of general relativity; the plasma theory is based on electromagnetism.

Inflation Universe

          In the corresponding theory of inflation, the Universe, because of properties of elementary particles not accounted for in the standard big bang models, expands for a fleeting instant at its beginning at a much higher rate than that expected for the big bang. This period, which is called the inflationary epoch, is a consequence of the nuclear force breaking away from the weak and electromagnetic forces that it was unified with at higher temperatures in what is called a phase transition.

Big Bounce

        The Big Bounce is a theory about the formation of the Universe. It can be loosely related to the cyclic or oscillatory universe adaptation of the Big Bang. It states that the current Universe resulted from the collapse of a previous Universe. A kind of cosmic rebirth.

Cyclic Universe

       The Cyclic Universe model does not replace the Big Bang theory but offers a potential alternative to certain aspects of the Big Bang that are longstanding problems. Some scientists are excited about its potential while others are cautious or skeptical. The Cyclic Universe model incorporates concepts from standard physics, string theory, and M-theory. For anyone who has ever wondered what lies beyond the Universe, the Cyclic Universe model may provide some answers.

Big Bang

       The Big Bang Model is a broadly accepted theory for the origin and evolution of our universe. It postulates that 12 to 14 billion years ago, the portion of the universe we can see today was only a few millimeters across. It has since expanded from this hot dense state into the vast and much cooler cosmos we currently inhabit. We can see remnants of this hot dense matter as the now very cold cosmic microwave background radiation which still pervades the universe and is visible to microwave detectors as a uniform glow across the entire sky.

      

Celestial Bodies , The Planets !

 There are eight planets in the Solar System namely: the Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. We supposed to have nine planets but the ninth planet, the Pluto is very small. It is smaller than seven of the solar system’s moons (the Moon, Io, Europa, Ganymede, Callisto, Titan, and Triton) so they decided to emit Pluto as a planet. This eight known planets o the solar system are grouped into two classes – the terrestrial planets and gas planets. The terrestrial planets are Mercury, Venus, Earth and Mars. They are inner planets that are small and solid planets made up of rock and metal. The gas planets are Jupiter, Saturn, Uranus and Neptune. They are outer planets, they may have solid cores but they are made up mostly of gases, which are very different from the Earth’s atmosphere.

In Roman Mythology, Mercury is the god of commerce, travel and thievery, the Roman counterpart of the Greek god Hermes, the messenger of gods. It moves so quickly across the sky and this is maybe the reason how it got its name. It is the 8^th largest and the closest to the sun. It is the only body in the solar system known to have a rotational resonance or frequency with a 1:1 ratio. Mercury has no known satellites.

Venus is the goddess of love and beauty but its surface features were name for female figures. This was named this goddess probably because it is the brightest of the planets known to the ancients. It is the 2^nd planet from the sun and the 6^th largest. Its orbit is the most nearly circular of that of any planet, with an eccentricity of less that 1%. Venus has no satellites. It is usually visible with the unaided eye. Sometimes referred to us the “morning star” or “evening star”, it is by far the brightest star in the sky.

The goddess of the Earth was Tellus – the fertile soil. It is the 3^rd from the sun and the 5^th largest and the only planet with abundant liquid water and know life. The Earth is the heaviest body in the solar system. It is the only planet on which water can exist in liquid form on the surface and liquid water is of course essential for lie as we know it. Earth has only 1 natural satellite, the moon and it is called Luna.

Mars is the god of war. The planet probably got this name due to its red color. Sometimes it is referred to us the red planet. There are 2 tiny satellites in Mars namely: Phobos and Deimos. It is the 4^th planet from the sun and the 7^th largest.

Jupiter is the 5^th planet from the sun and by far the largest. It is more than twice as massive as all the other planets combined. Jupiter was the king of the gods, ruler of Olympus and the patron of the Roman State. It is the 4^th brightest object in the sky (after the sun, moon and Venus at some times Mars is also brighter). Jupiter has rings that are dark, dimmer and smaller than of Saturn. They’re probably composed of very small grains of rocky material. Jupiter has 61 known satellites: the 4 Galilean moons, 23 smaller known and named and many more small ones discovered lately but not yet named.

Uranus is the 7^th planet from the sun and the 3^rd largest (by diameter). It is the larger in diameter but smaller in mass than Neptune. Uranus was the 1^st planet discovered in modern times by William Herschel on March 13, 1781. It is composed primarily of rock and various ices with only about 15% hydrogen and a little helium. Uranus has rings, they are very dark and they are composed of fairly large particles ranging up to 10 meters in diameter in addition to fine dust. There are 11 known rings, all very faint; the brightest is known as the Epsilon ring. Uranus is sometimes just barely visible with the unaided eye on a very clear night; it is fairly easy to spot with binoculars. Uranus has 20 named moons (plus one recently discovered which has no yet given an official name). Uranus’ moons take their names from the writings of Shakespeare and Pope unlike the other bodies which have names from classical Mythology.

Neptune is the 8^th planet from the sun and the 4^th largest (by diameter). It is smaller in diameter but larger in mass than Uranus. Neptune was the god of the sea it has rapid winds confined to bands of latitude and large storms or vortices. Neptune’s winds are the fastest in the solar system reaching 2000 kilometers per hour. Neptune also has rings. These are very dark but their composition is unknown and these rings were named: Adams the outermost, next is an unnamed ring co-orbital with Galatea, then Leverrier and finally the faint but broad Galle. Neptune has 11 known moons; 7 small named ones and Triton plus 3 more discovered recently which have yet to be named.