Big Bang for Kids and Laymen

BIG BANG! From the origin of the universe to the creation of the earth

From "A Kid’s Short Guide to the Universe"


The graceful, winding arms of the majestic spiral galaxy M51 (NGC 5194) appear like a grand spiral staircase sweeping through space. They are actually long lanes of stars and gas laced with dust. This sharpest-ever image of the Whirlpool Galaxy, taken in January 2005 with the Advanced Camera for Surveys aboard NASA's Hubble Space Telescope, illustrates a spiral galaxy's grand design, from its curving spiral arms, where young stars reside, to its yellowish central core, a home of older stars. The galaxy is nicknamed the Whirlpool because of its swirling structure.

M10 - The Whirlpool Galaxy

PHASE 1: Uniform rapid plasma/energy driven expansion from a “singularity.” Energy pressure alone powers the expansion. With no matter to slow it down the expansion grows at a fantastic rate. Since there is no gravity the expansion is much faster than the speed of light. This rate of expansion decreases relative to the inverse of the cube of the time since the start.

PHASE 2: The plasma cools as it expands. [Sound familiar?] Quarks and gluons begin to form into particles including electrons, protons and neutrons. Power/energy still dominates as there is little or no matter and gravity is negligible.

PHASE 3: Energy/matter mix cools - energy begins to change into matter as protons capture electrons and become hydrogen molecules. Mass begins to exist and gravity starts to grow. Rapid energy pressure driven expansion starts changing as the inertia/gravity battle begins to control and greatly slow the expansion. This phase change could take place over a very short time. Hydrogen clouds begin to form as the hydrogen differentiates under the effects of gravity. Turbulence in the clouds causes them to begin clumping into what will eventually become galaxies, groups of galaxies and super groups of galaxies. The energy remaining from the initial explosion that has not become matter radiates and ricochets throughout the universe under the control of the combined gravity of all the mass. This energy we can still detect as microwaves - the MW background radiation.

PHASE 4: Matter now completely dominates the gravitational coalescing of the hydrogen clouds. Dense parts of the clouds under the influence of rotational energy coalesce into “disks”of hydrogen gas - the beginnings of spiral galaxies. Smaller parts of the hydrogen clouds begin to collapse into gravitational “sinks” compressing the hydrogen gas until it begins to fuse into helium under the intense pressure. This fusion of hydrogen into helium generates energy and “stars” begin to “turn on “ and light up the previously “dark” universe as stars of all sizes fire up and emit light. Many of the first stars are huge and soon fuse all their hydrogen into helium. Then the helium fuses into the heavier elements with carbon. Oxygen, silicon and iron being the most plentiful. When fusion into iron takes place, the sudden implosion compresses the iron until it suddenly can on longer be compressedas it becomes a sphere of protons and neutrons. This sudden halt to compression transfers the tremendous gravitational energy into a “bounce” that sends a powerful shock wave outwards through the outer shells of the star and blows much of the material in those outer shells into space in what we see as a supernova explosion.

PHASE 5: Many types and sizes of galaxies form from swirls and turbulence in the clouds of hydrogen. Those gravitationally bound hydrogen clouds that have little or no rotational energy, become elliptical galaxies. Those with enough rotational energy form into disks that evolve into spiral galaxies. The larger stars within these galaxies eventually collapse and “bounce” into supernova explosions and blow their outer shells containing varying amounts of all of the elements out into the hydrogen clouds. Smaller stars do not explode and, like our sun, have very long lives. The larger the mass of a star, the shorter its life. The large stars that explode collapse into neutron stars. Still larger stars collapse into “black holes.” Elliptical galaxies form very few new stars after the initial star formation depletes the hydrogen gas. Spiral galaxies form as matter “falls” from the outer reaches of the galaxy in toward the center. As this matter moves inward, it rotates faster and faster for the same reason an ice skater spins faster when they bring their arms closer to their body, the conservation of rotational inertia. This is also the reason that planets rotate faster around the sun the nearer they are to the sun. Collisions between spiral galaxies can also create ellipticals as the rotational inertia of one cancels out that of the other when they merge. It is thought this will happen to our own galaxy when the Andromeda galaxy collides with it in about five billion years. [Worry! Worry!]

For more about this collision, click on http://hubblesite.org/newscenter/newsdesk/archive/releases/1997/34/astrofile/

For more information about types of galaxies click on http://www.astronomynotes.com/galaxy/s3.htm

Elliptical galaxies are smooth and ovoid in appearance. There are four distinguishing characteristics of the ellipticals: (a) they have much more random star motion than orderly rotational motion (star orbits are aligned in a wide range of angles and have a wide range of eccentricities); (b) they have very little dust and gas left between the stars; (c) this means that they have no new star formation occuring now and no hot, bright, massive stars in them (those stars are too short-lived); and (d) they have no spiral structure.

Spiral galaxies: The most common type of large galaxies, spirals, possess loosely shaped arms which make their spiral structure less pronounced. Close examination of photos reveal that there are but two arms in any galaxy. These arms serve an important purpose in spiral galaxies. They are star-formation factories with shock waves compressing hydrogen gas and creating clusters of new stars. Probably spirals have the only really new stars in the universe. Our Milky Way galaxy is definitely a spiral and we are located in the trailing edge of an arm, closer to the outer reaches than to the center.

For a larger photo and description of a classic example of a spiral galaxy, M10, the Whirlpool galaxy, Click here for the photo. Click here for the original article.

The solar system: Probably formed from a cloud of dust and gas disrupted by a nearby supernova. The center compresses enough to become a protostar and the rest of the gas orbits/flows around it. There is no doubt that other such clouds form double, triple and even more numerous multiple stars with similar collections of dust and gas. Most of that gas and dust flows inward and adds to the mass of the forming star, but the gas and dust are rotating. The centrifugal force from that rotation prevents some from reaching the forming star. Instead, it forms an "accretion disk" around the star. When the star “lights up” with fusion energy, the electromagnetic “wind” begins to blow the lighter atoms and dust particles outward. As the disk radiates away its energy and cools off, the dust, objects and gas stabilize in orbits around the central star. Proto planets grow as their gravity sweeps up objects, dust and gas. Once these become planets, some with moons, the solar wind sweeps the lighter gas atoms outward in the same manner as it causes tails on comets. The force exerted on gas is proportional to the cube of the distance from the central star or sun. In addition, the amount of uncombined light elements that stay with planets, moons or other objects is a function of the gravitational pull of the object. For this reason, Mercury has virtually no light elements or atmosphere. It has an iron core and a thick, rocky crust heavily cratered from billions of years of bombardment. Our moon, the moons of Mars and the asteroids have a similar composition and surface. Venus, Earth and Mars all retain light gasses in an atmosphere. Next out from the sun, asteroids, run from pea to Delaware sized objects, with many probably loosely held together rock piles from their weak gravity. Uncombined water is rare among the asteroids.

The gas giants: beyond the asteroid belt lie the giant gas planets, Jupiter, Saturn, Uranus and Neptune. These planets probably have very small, earth sized cores of iron and rock surrounded by Light gasses, mostly hydrogen. Jupiter for instance is so light that it would float on water. The moons of Jupiter and Saturn are far enough from the sun that many of then hold water ice and some gasses.

The outer solar system objects, include those in the Kuiper Belt and then the Oort Cloud. All are gravitationally bound to the sun and may be representative of the material that first collected to start the solar system. These bodies are probably mostly water ice, thus the "dirty snowball" description of comets. These objects may become comets if their orbits are changed by coming close to or colliding with other objects. Should their changed orbits take them inside the orbits of the inner planets and near the sun they will form the characteristic tail of the comets they become.

For more information about the formation of the solar system Click Here!

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