THEORIES ON THE ORIGIN OF THE ORIGIN OF THE UNIVERSE Big Bang Theory The Big Bang Theory is a cosmological model that explains how the universe evolved. The theory suggests that the universe started its expansion, not a literal "explosion", about 13.8 billion years ago which is considered as the age of the universe. It has 2 eras namely the Radiation Era, which is named for the dominance of radiation right after the big bang, and the Matter Era, the era that started when the gravitational effect of matter began to dominate the effect of radiation pressure. One famous analogy to explain the expanding universe is imagining the universe like a loaf of raisin bread dough. As the bread rises and expands, the raisins move farther away from each other, but they are still stuck in the dough. Steady State Theory A theory that states the universe has no beginning and end, and that the universe is always expanding. And as it expands new stars and galaxies are formed. To sum up, the theory states that the universe creates new matter while maintaining its density as it continuously expands. This theory is not parallel to the law of conservation of energy and mass. Oscillating Universe Theory A modified Big Bang theory, also known as the Pulsating Theory, proposing that the expanding universe eventually reverses and contract after the energy of the big bang is used up and when it reaches singularity again, will start to expand again. The drawback of the theory is that the postulated end of the universe is by a big freeze or heat death. THEORIES ON THE ORIGIN OF THE SOLAR SYSTEM Nebular Theory A theory that suggests that the solar system originated from a giant cloud gas and dust that orbited the Sun. Nebular theory is a view where nebula flattened into a protoplanetary disk and became a solar system consisting of star with orbiting planets while planetesimal theory also uses materials from the disk and are pulled together by gravity to form small chunks and in time grows larger and larger until they become planetesimal. Encounter Theory The Encounter Theory proposes that the planets were formed from the material ejected from the sun, during an encounter with another celestial object, such as a rogue star.This fragments will then form into small lumps and become planets. Accretion happens when gravity attracts tiny bits of matter towards an object. This will result to gradual increase of the object’s size. Homogeneous accretion is when Earth accreted from materials of the same composition after condensation. Differentiation followed accretion in the process. Heterogeneous accretion is when Earth accreted during condensation, forming a differentiated planet as it grew in size. What makes sunlight, air, and water essential for life on Earth to exist Nothing is more important to us on Earth than the Sun. Without the Sun's heat and light, the Earth would be a lifeless ball of ice-coated rock. The Sun warms our seas, stirs our atmosphere, generates our weather patterns, and gives energy to the growing green plants that provide the food and oxygen for life on Earth. Is there an infinite supply of sunlight, air, and water We have a big supply of sunlight, air and water but its not infinite. Can human activities affect the supply of sunlight, air, and water? Yes, human activities can affect the supply of sunlight, air, and water. Most especially water because the waste we produce pollutes the water sources. In terms of air, when we cut down trees, there will be higher amounts of carbon dioxide and lower amount of oxygen. Additionally when we emit various gases from our vehicles, we contaminate the air and affect rainwater quality. What can we contribute to conserve these three resources? Simple things such as reduce, reuse, recycle will have great effect in conserving these natural resources. Careful usage of fossil fuels will also make a great difference because it will lower greenhouse gas emission. Use reusable goods, choose sustainable products, volunteer and educate. Origin of Water The prevailing hypotheses say that Water came from comets that collided with Earth. Other studies suggest that water was already present within Earth since formation as volatiles trapped in magma. Sun The Sun is the Earth’s main source of energy, and powers many of the processes in the planet. Plants are dependent on the Sun for photosynthesis. The Atmosphere The atmosphere is crucial in enabling and maintaining life on Earth. It contains many gases that form the air we breathe, and traces of water vapor. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation and reducing temperature extremes between day and night.
