13.7 billion years ago, there was a huge explosion – what we all know as the big bang.
A sea of particles formed due to big bang. Matter and antimatter collisions resulted destruction of almost everything that was formed from the bigbang. Only a billionth of what was left over goes into making the current universe after baryogenesis and Big Bang Nucleosynthesis.
300 million years after the explosion, stars start to form. Stars are formed due to gravity which causes hydrogen to come together. Temperature of stars begin to rise as Nuclear Fusion starts. Stars in close proximity form galaxies.
Milky way was formed 13 billion years ago. It is 6000 billion miles in diameter with 2000 billion stars. Earth was formed 4.6 billion years ago, nearly same time as the Sun.
As conditions became conducive, life formed on planet earth. Life is what matter does mysteriously. Bacteria have lived on without intelligence for over 3 billion years now. The last asteroid strike was 65 million years ago and it wiped out dinosaurs. For 10000 years now, humans have dominated the planet. They say that mass annihilation of life in this planet could happen in 2012. In year 2029, asteroid 99942 Apophis could strike the earth. At some uncertain time in the distant future, gamma rays from WR104 could fry our planet.
Even if none of that happens, within 5 billion years, the sun will grow in size as it ages. As sun becomes a red giant, the temperature of the planets in the solar system would rise. Oceans of the earth would evaporate. Tiny life forms would would outlive the human race by several million years. Will we have to escape to another planet? How about Gliese581d? Does Gliese581d have low gravity could possibly weaken muscles of future generations? Would it be void of an ozone layer like our Mars? Eventually, all life on earth would perish because of the heat. Even later, the earth will be pulled into the sun.
Like the earth, the sun will perish too. Gravity Vs Fusion. Gravity will finally win.
Not all stars would die quietly like the sun. Some stars explode as Supernovae. With the end of a life of a star by explosion, a black hole is born. Gravitational singularity is the centre of a black hole where time and space stop. A singularity is where our present science stops. Its scientists way of saying “We dont know”.
A black hole will pull every thing towards it. A black hole the size of a golf ball will weigh as much as planet earth. But black holes can be as big as a solar system. Some of them can be super massive black holes.
A 11 million mile diameter super massive black hole is at the heart of our own Milky way. Stars revolve super massive black holes. A quasar is a compact region in the center of a massive galaxy surrounding the central Super massive black hole. Quasars are the brightest known things in the universe and we already know about thousands of quasars. Quasars calm down when galaxies age.
No mass or energy can escape a black hole. Matter and energy are but interchangeable things. What happens to all that that goes into a black hole? No one knows.
As you approach a black hole, you would reach the Event Horizon. Event Horizon is where time is stopped by gravity. Physical laws as we know them stop working at the event horizon. Black hole is an object that changes physical laws as we know them. Yet, our SWIFT mission reveals that a black hole is formed every day within the space known to humans. We dont yet know what physical laws govern a black hole.
Some feel that black hole might be the reverse of a big bang. Matter enters a black hole by gravity and exits through a big bang. Black holes seem to drink up matter and then spit it out into a parallel universe. A black hole could be the connection to a parallel universe. Black holes could be universe’s way of renewing itself.
While we know black holes can eat up stars and even galaxies, we also know that the expansion of the universe is accelerating contrary to all known laws of gravity.
Dark energy is the term used by cosmologists to explain why the expansion of the universe is accelerating rather than slowing due to gravitation. The behavior of dark energy would determine if the universe would be headed for a big freeze, big rip, big crunch, big bounce, multiverse or have no end with any cosmic certainty.
How will the universe end? We have many people guessing at it. Can you re-boot the universe? As in, end it and begin it again? Now that is a real question. Good luck figuring that out. Everything else is, but, of course, elementary.