The Universe came into being 13.7 billion years ago. The most popular theory that explains how this universe was created is the Big Bang Theory. According to this theory the universe sprang out from a point known as “Singularity”. Our conventional wisdom would predict for the singularity as a huge mass that exploded and everything in the universe was created but there was no such thing like a bomb explosion. The big Bang Theory postulates that it was an expansion of the Singularity which refers to the point having zero volume (billions of times smaller than a proton), length, width and height, no time and space but all the matter and energy collapsed to infinite density occupying zero volume.
In simple words it can be said that the singularity from which this universe was created, was a point where every thing of this visible universe was contracted to the extent that almost nothing existed. Well, these generalizations regarding the singularity are extremely difficult to envision.
The singularity expanded like an inflating balloon and created this universe. The basic unit of the universe is a galaxy. A galaxy is a system of stars, dust and gas held together by gravity. There are several thousand billions of stars in a single galaxy. The galaxy to which our Solar System belongs is known as the Milky Way.
In the Milky Way the sun has more than a thousand billions brother stars scattered. Eight planets and four dwarf planets i.e. Ceres, Pluto, Makemake and Eris revolving around the sun in their respective orbits along with Asteroids, Meteoroids, Comets, Interplanetary dust and Interplanetary plasma constitute the Solar System. 
The astounding fact is that the Earth we live on is like a tiny particle of sand in a vast desert, the universe. What is beyond the universe is still unknown to human imagination and understanding.
Moreover, the universe is not a static structure rather the space among galaxies is increasing. This conclusion was made the advent of Hubble Telescope, when Hubble, a cosmologist, observed a Red Shift, i.e. due to expanding wavelength, in the wavelengths of light coming from far galaxies (Doppler’s effect) and this could only be possible when the galaxies were moving away from each other at high speed similarly to an ordinary explosion in which every fragment moves away from the site of explosion. The fact discovered by Edwin Hubble in 1929 is known as Hubble’s law. 
Keeping this law in view it is concluded that if we imagine reversing this expanding phenomena infinitely then whole the universe will contract infinitely to rebuild the singularity, a point which has no volume but infinite density. This is, probably, the idea why scientists have imagined the concept of Singularity. With expanding universe our solar system along with its galaxy is also moving away from other galaxies around except the Andromeda galaxy which is on the collision course with our Milky Way. The big bang theory is a theory not an approved fact. There are many other theories that explain this phenomenon quite differently.
Our solar system was born some 4.5 billion years ago. The age of the Sun is nearly the same. The source of energy for the solar system is the Sun which is made up of Hydrogen (90%), Helium (8%) and Heavy elements (2%). Nuclear Fusion is the mechanism by which the sun burns it’s approximately 616 million tons of hydrogen in one second to convert it into 612 millions of helium to impart 3.86×1026 joules of energy. By this process a certain amount of Sun’s mass is lost each second. However the situation is not much worrying since it has much amount of gases to go on for another period of nearly 5 billion years. After 1.1 billion years the brightness of the sun would increase by 10%, this will super-heat our planet Earth and boil away the oceans. This could be astonishing end of life on earth.
When the sun would have burnt all of its fuel, it is believed to cool down and expand out in all dimensions so as to occupy all the naked-eye-seen sky and engulf all the planets and other structures around it. 
The sun will be red and very large in size what scientists would call ‘Red Giant’. In about 12 billion years, the sun will eject its outer layer and become a smoldering, collapsed core that scientists would call ‘White Dwarf’.
Now coming to an interesting idea in this context, as mentioned above there are 1.1 billion years left for which life could survive on the earth after which earth’s surface temperature would rise to a level that it would eradicate life on the earth forever. Could human beings be able to find a new suitable system in the universe and migrate there to continue survival? I think it is premature to say anything with certainty. However, with advancement in Science and Technology no one can rule out such a happening in distant future. Besides many important inventions, recent invention of computers alone has revolutionized the course of our lives.
Apollo 11 was the spacecraft that took off on 16 July 1969 with three astronauts on board in the maiden manned journey to the Moon named Neil Armstrong, the first man to set foot on moon, Buzz Aldrin and Mike Collin. After traveling for four days, they reached moon on 20 July and came back home after another four days on 24 June.
More recently in August 2007, NASA sent Phoenix probe that landed successfully on Mars on 25 May 2008 and has been providing scientists valuable information about the Red Planet. NASA has planned for the next journey to moon in 2018 and for the first manned mission to mars in 2037.
The history of space exploration dates back to 1912, when Europe discovered the Cosmic Rays while experimenting with Balloon Flight. It shows that the process of space exploration is in its infancy since we have an experience of about one century. Even in this short period of time scientists have been able to explore solar system planets by robotic machines. At least we can roughly predict a fast development in coming centuries. What would be the scenario after 1000 years; it will only be witnessed by the generation at that time.
The space travel took four days to reach the moon which is only 4, 83,000 km away from the earth. For an expedition to the Mars the spacecraft will have to travel 490 million km and it would take nearly 6 months. The distance between the earth and the mars varies since they both revolve around the sun in different sized orbits. Earth completes its revolution in 365.25 days while the Mars takes 686 days. At their closest they are about 100 million km apart while at their most distant they are about 380 million km away from each other.
The nearest star to the sun is the Proxima Centauri which is almost 4.3 light years away from the sun. It means that the light which comes from Proxima takes 4.3 years to reach our solar system. 
Our solar system is 25,000 light years away from the center of the Milky Way and the diameter of the Milky Way is 120,000 light years. The farthest stars of the Milky Way are in the range of 95,000 light years.
If man attempts to migrate to the nearest system of stars they would have to travel about 406700 billion km. If we travel with same speed at which our probes travel to Mars, the journey would take more than 2 million years to reach the Proxima Centauri. Moreover Proxima Centauri may not be suitable for life. Therefore the journey is not unchallenging but not impossible either.
Scientists think that with advancement in science and technology experiments would be carried out before humans would attempt to migrate from dying earth. This would require fleets of giant spacecrafts that would take small colonies of people aboard with many other species of plants and animals. They would have to carry with them all the necessities for the sustenance of life during travel for ages and generations. These species would breed on board for many many generations before they could reach their destination to start a new life there.
Most of the readers of this article will find these assumptions thought-provoking, mind-boggling and to some people these may be ridiculous. But we should think that when humans lived jungle life, all naked, hunting animals and eating raw meat, had they imagined sitting before a computer and reading such an article? I think migration of life to other places in the universe could be possible maybe hundreds or thousands of years from now.
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