Wednesday, 29 June 2016

Our Universe

Our Universe

Our universe is everything that we can touch, sense, feel, observe, measure and detect. it includes all of us, living things, stars, planets, galaxies, dust clouds, light and even time. before the birth of our universe space, time, matter, nothing exist.
our universe
Our universe containing billions of galaxies, each of galaxies contains millions or billions of stars. but the spaces between these stars and galaxies are largely empty. however this spaces are not fully empty they contains scattered particles, dust or few hydrogen atom per cubic meter. Space is also contains radiation, magnetic fields and high energy particles(eg. light, heat, cosmic rays).
The size of universe is incredibly huge. If we want to go to our nearest star then it take more than millions of year from our fighter jet. To cross our milky way it would take 100,000 years at travelling with the speed of 3oo,ooo km per second.
Our visible universe is more than 93 billion light years in size. Where, one light year is the distance that light travels in one year and it’s nearly about 9 trillion km. we can’t no the exact size of our universe because no one se the edge of universe if they exist.
The size of our universe has not always been same .our universe is began with big bang before 14 billion years ago. Since then, at very high speed our universe has been expanding in outward direction. So  the area of space is expanding billions of time grater than it was when our universe was young. Galaxies and stars are moving apart and so the space between them has expands.
shape of universe

Our universe is made from spacetime fabric. Shape of space and time is define by general relativity. it says how spacetime curved and it’s bent by mass and energy. because of space time is curved we can’t see the whole universe. The section of universe which is observable is backward light cone. They delimits on cosmological horizon. Horizon represents the boundary between the observable and non observable universe.
Astronomers calculate the age of universe by lambda-CDM model. Assuming that it accurately describe the evolution of universe from hot, dense primordial state to present state. Measurements of parameter by variety of techniques and numerous experiments we find the best age of the universe which is about 13.799 billion year raging from 0.021 billion year more or less.


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