The Universe was created 14 billion years ago as a result of the Big Bang.Time and space were created with the Big Bang. There is no question of what caused the Big Bang because time did not exist before it. Happily we say the Big Bang occured spontaneously i.e. on its own. We also thing matter came into existence on its own. Some people think out of nothing matter and anti-matter came into existence. So the light from the Big Bang should have travelled a maximum distance of 14 billion light years by now. This can be considered to be the radius of the universe.
- Space Time
Einstein revealed that time and space are two ways of looking at the same thing.Space is curved at some placed. The more the curvature the slower time elapses there. In Black Holes time stops running as the curvature becomes very sharp.
- Matter and Radiation
The Universe is made up of matter and radiation. Radiation comprises of
- gamma rays,
- X Rays,
- Ultra Violet Light,
- Viible Light,
- Infra Red Light,
- Microwaves and
- Radio waves.
Matter comprises of electrons, protons, neutrons, quarks and other such sub atomic particles. The Universes comprises of stars, planets, asteroids,comets, clouds of dust and conglomeration of stars. A collection of stars usually containing billions of stars is called a galaxy. Galaxies are also observed to be conglomerated in groups.
Since the age of the Universe is 14 billion years, the oldest stars cannot be expected to be older than that.The lifespan of a common star is about 9 billion years. Our Sun is a star and it is 4.5 billion years old.It has another 4.5 billion years to live after which it will explode into a Red Giant and after a long time become a white dwarf.After tht stage it will become a neutron star or a pulsar. And finally it will become a black hole. Upon its explosion called a supernova explosion, it will scatter dust and gas in the environment. From this dust and gas a new star will be born as well as planets. We say it will be a next generation star. Our Sun is a second generation star.
Stars consist mainly of hydrogen. In the core of stars hydrogen nuclei fuse to become helium nuclei.In this process heat is released and this is the energy that is emanating from our sun.When all hydrogen is convertted into helium, then helium fuses to form heavier elements. This is where all the elements found on earth originate from. even our body is made from material formed at the centre of stars. " We are made of star dust".When a star has burnt all its fuel it explodes into a supernova.
The earth, Moon, planets and the Sun were formed about 4.5 billion years ago.We know of life on Earth only.Under appropriate conditions life can appear on a planet. It is thought water is essential for life to appear.What brought water on Earth was a comet which collided with earth. Comets are made of Ice and dust.
It is thought that interaction of particles result in primitive forms of life. Life evolved for a while now. Man is the only organism to possess intelligence.Intelligent forms of life appear after sufficient evolution. We are searching of other forms of life and other intelligent forms of life elsewhere in the Universe.
It is thought that if a big asteroid collides with Earth life might dissapear from earth. Actually what is more likely is that man might dissappear from earth. But life as a whole might not dissappear.So new forms of life would appear. However there is a single biology on Earth.The DNA of most species on earth is quite similar.So new forms of life are likely to resemble those here today. --Jeetendra Prakash Murdan 16:16, 22 November 2010 (UTC) = http://www.yahoo.com