Our Solar System

     The Sun is heavier than the Earth and the pull of its gravity is very strong. It keeps the Earth and the eight other bodies circling in space around the Sun. These bodies are the planets. We can see the five planets with our eyes from Earth - Mercury, Venus, Mars, Jupiter, and Saturn but Uranus, Neptune, and Pluto need to be seen using telescope.

     Years ago, many think that the Earth is the center of the solar system and that the moon, sun, and other heavenly bodies revolve around the Earth but, the Polish priest, Nicolaus Copernicus realized what was wrong. The Sun must be the center of everything and not the Earth. 

     The planets are divided into two groups. The small rocky planets and the giant balls of gas. The small rocky planets include Mercury, Venus, Earth and Mars while the other group includes Jupiter, Saturn, Uranus and Neptune. 

     The Red Planet. Mars is the fourth planet from the Sun. It is covered by a stony desert.The water and oxygen are locked up in the rusty deposits.

     Our galaxy - the Milky Way - is a spiral galaxy with arms extending from the center like a pinwheel. Our solar system is in the Orion arm of the Milky Way. Our Sun is one of about 100 billion stars in the Milky Way. And our galaxy is just one of roughly 100 billion in the visible universe (NASA).

The Origin of the Universe

     Universe is commonly defined as the totality of everything that exists including space, time, stars, planets and beyond. It is made up almost of hydrogen and helium. These are the two lightest elements. All the rest of the matter is very rare. The Universe is held together by forces.

     How did the universe originated? Was there any theories about this? Based on my researches, studies and discussions since then, there were theories that explain the appearance of everything from nothing.

     The Big Bang Theory. What was the Big Bang? The Big Bang is the most popular theory about the creation of the Universe. According to it, the whole universe was created in a split second in one huge explosion. All matter was squeezed together into a tiny, super-hot, dense ball that was smaller than an atom. The ball gradually expanded as it cooled, then exploded, releasing energy and matter in all directions. We cannot see the Big Bang because it would have happened billions of years ago. But we can see that the universe is growing bigger.

     The Big Bounce Theory. This is a theory about the formation of the universe. This is a bit the same with the Big Bang. It suggests that another universe went through a Big Crunch and then 'bounced' back and gave birth to this universe (Scientific American). 

     Steady State Theory. This is developed by Fred Hoyle and Thomas Gold in 1949. This theory had no beginning but it created new matter as older galaxies moved apart. The advantage of this theory is that its simple explanation.

     These were the answers of the questions How did the Universe begin, and when? How has it evolved? How will it end, and when?