The Universe
In the beginning there was nothing - no galaxies, no stars, no planets, and no life. There was no matter at all, not even tiny particles existed. So how was something as huge and complex as the Universe created out of nothing?
What is the Universe? How big is the Universe? Is the Universe moving? What's in the Universe? Is the Universe open, closed or flat?
All the above questions can be answered very simply, WE'RE NOT QUITE SURE! One thing we do know is that the universe is about 14 billion years old, and humans are only 35,000 years old, so it's not surprising that we don't understand everything. There is a lot more we don't know about the Universe than that we do know, but there is still an awful lot we do know, and here it is.
The Big Bang
The universe is about 14 billion years old, and is believed to have began it's life in the well known theory of the beginning of everything, THE BIG BANG. As contradictory as it may seem, it wasn't really a bang at all, but more of a very very fast inflation. "How fast"? Well some cosmologists believe that the infant universe more than likely started out as a singularity. Just like the singularity inside a black hole, this point would have been infitesimaly small and dense. This singularity though would not contain the mass of a few stars, but possibly the whole universe. Starting out from a point 0.00000000000000000000000000000001.6cm in size, It grew to the size of a base ball in 10-43seconds (Ten million trillion trillion trillionths of a second). This equates to an expansion rate faster than light. How is this possible if nothing can travel faster than light? Nothing can travel faster than light through space-time (today's universe). Back 14 billion years ago, it was space-time itself expanded into nothing, hence the reason this is possible. If the universe is still expanding at the speed of light as most cosmologists believe, then nothing inside it can travel faster than itself, Einstein's special theory of relativity explains the reasons why. There are still scientists who believe in the steady state theory. This says that the universe has always been here and will always be here. But surely the universe must have come from something or somewhere?
Obviously we do not know for certain how the universe began, and chances are we never will. From what we can gather, around 14 billion years ago there was absolutely NOTHING. As the small sentence at the top of this page suggests there were no galaxies-stars-planets-gas & dust particles-atoms-quarks-leptons etc. There was obviously a void infinitely big but containing nothing at all. Somewhere and somehow a huge serge of energy just appeared, and began to expand at unbelievable speeds. Within the first trillionth of a second every piece of matter in the universe had already been created. They were constantly annihilating each other, changing from one piece of matter to another. When the Universe was only around 10-43 seconds old it was filled with around 50% matter & 50% antimatter. Whenever a particle of matter & antimatter meet, they destroy each other & release energy. Although it is thought that there was around 50% of each, Matter won the battle & now dominates the Universe, the rest is history. There are a few people who do not believe in the theory of the big bang, and understandably so. Based on observational evidence from the Cosmic Microwave Background Radiation (CMBR) it is the best theory we have.
The theory of the Big Bang has successfully predicted a lot of facts that we know about the Universe, far above any other theory known. A few of these include the "background microwave radiation" mentioned above, which looks very much like the echoes from a large explosion. However, the biggest evidence comes from the known fact that every galaxy we know of appears to be moving away from every other galaxy at huge speed. In fact it is now known that the universe is accelerating and expanding faster than it ever has done.
What does this mean? Well it means that if the Universe is expanding as time is increasing, then in the past the Universe was much smaller and denser. If we run the clock back 14 billion years, then all the matter in the Universe must have co-existed at a single point. Hence a Big Bang like event must be responsible for triggering the expansion of the Universe.
What is in the universe?
The universe contains everything. But put simply it can be split into categories.
| UNIVERSE | |||||
| Radiation | Quasars | Dark Matter | Galaxies | Hydrogen | Time |
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The primary form of radiation in the Universe comes in the form of electromagnetic radiation i.e. photons. Stars produce vast quantities of photons covering a wealth of energy levels, Infra-red, Ultra Violet, Gamma ray, and X-ray. The Universe is also filled with microwave radiation from the Big Bang. Many believe that microwave radiation in this form fills all of observable space, and that most of the radiation energy in the universe is in the cosmic microwave background. |
Short for QUASi-stellAR radio source. A quasar is a huge sources of radio and optical energy at the edge of the known Universe, fuelled by enormous black holes. They are classed as very young galaxies that formed when the universe was only a few hundred million years old. The energy output of Quasars dwarfs that of any known astronomical phenomena. | Invisible matter that fills over 90% of the Universe. If this dark matter does not exist, then the Universe is destined to expand forever. The dark matter component of the Universe contains significantly more mass than the visible part of the Universe. Dark matter is thought to contribute to approximately 22% of the total energy density of the Universe, while over 70% is thought to be dark energy. | Stars, Planets, all known elements, gas and dust, comets, meteors, black holes. Containing pretty much everything in the Universe, galaxies are gravitationally bound system of stars. They are in effect "the cities of the Universe". They are believed to be made up of almost 90% dark matter. |
Hydrogen is the most abundant element in the Universe, primarily because it is the simplest. One proton at its centre and one electron. It is a colourless, odourless, non-metallic, tasteless, highly flammable diatomic gas. |
Time is something that effects everything in the universe. Although very hard to explain, it is something that came into existence along with the universe itself |
What does the universe look like?
This photograph is called the "Hubble Ultra Deep Field". It is a image observed with the HST with an accumulated exposure captured between Sept 3rd 2003, and Jan 16th 2004. It was imaged after the very successful Hubble deep field taken in 1995.
To see exactly what lay out in space in the darkest depths of the sky, astronomers pointed the world's most powerful telescope to a region of sky in the constellation of Fornax. The area of sky covers just 1/10th the size of the full moon (the size of a grain of sand when held at arms length) and appears completely void of any foreground stars or radiation sources from within our own galaxy. Comprising of 800 exposures taken over the course of 400 orbits of Earth the final picture shows over 10,000 galaxies. In a patch of sky just 3arcmin2, it shows how many galaxies there must be covering the entire sky.
How big is the Universe?
It is worth remembering that the universe has been expanding at close to the speed of light for almost 14 billion years, and by the time you have read this sentence, the Universe has expanded by almost 2million miles in all directions. Even travelling at 671,367,300 Mph, it would take over 4 years to get to the NEAREST star in our galaxy. It would take about 30,000 years to get to the centre of our galaxy. Even travelling to the closest edge of the Milky Way would take close to 10,000 years. Due to this fact, it is known that even if we could somehow travel at the speed of light, chances are we will not be able to see what the true shape of the Milkyway is for thousands of years. As we cannot travel this fast, the human race will probably never know what our gorgeous and somewhat special galaxy will ever look like. It would take over 2.2 million years to get to the NEAREST galaxy in the Universe. We now that there are at least two hundred billion galaxies in the Universe, and using the HST we know believe that the Universe is in excess of 30 billion light years in diameter (100 billion trillion miles).
Big Crunch?
We know how the Universe began, and we know what it is doing now, but what will happen to the Universe? The majority of people did and still do believe that because of the amount of matter and therefore gravity in the universe, it will stop expanding and then begin to collapse into an enormous black hole only to expand again and form another Universe. Although this theory known as "the big crunch" is valid, there is one problem. There does not appear to be enough gravity. Over 90% of matter in the universe seems to be missing. This is why cosmologist believe it to be filled with "dark matter and primarily "dark energy". Scientific instrumentation designed to find dark matter has almost concluded that there is not enough to prevent the Universe from expanding. However, we do know that the Universe is accelerating, and therefore must be driven by some unknown force. What this force is, is unknown, but Einstein's elusive cosmological constant, may just come back to haunt him.
The Universe is a very large & violent place at present, but not forever. One by one all the stars we can see in the night sky will slowly burn out producing either beautiful planetary nebulae, supernova remnants or black holes. Although these will carry on giving out light for many millions of years after the last stars have extinguished, the last objects to disappear will be the Black holes. It is estimated that supermassive black holes at the centre of galaxies that have formed in the last few billion years, will not evaporate through "Hawking radiation" for another 200, billion, billion, billion, billion, billion, billion years. This number represents the end of the Universe. Although this may seem like a long way off yet, it is inevitable that it will at one point happen. It will be the end of everthing that has ever existed.
The Universe is 14 billion years old, and if it does not perform another miracle in sprouting life in the next 50 or so billion years (if it hasn't already) it will be to late. We will be the most important thing to have ever happened in the history of everything ever. One day the Universe will be as black as black can be. There will be no light anywhere, spanning an area trillions of trillions of trillions of light years in all directions. There will still be all the energy present in today's Universe, but only in the form of radiation. Time as we know it will vanish, with no use for it anymore. At the top of this page reads "In the beginning there was nothing - no galaxies, no stars, no planets, and no life. There was no matter at all, not even tiny particles existed. So how was something as huge and complex as the Universe created out of nothing?" In many trillions of years this will be repeated. There will be no stars, no galaxies and most of all, no life. At one point there was nothing, so there is no doubt that there will again at some point be nothing. The Universe is destined to die just like you and me. Just think that one day the atoms that make up your body right now, the atoms in the air that you breath, the food that you eat and the water you drink, will all at some point in the future be a part of this never ending vastness of space larger than your imagination could ever comprehend. It will continue to expand forever, never stopping for anything. Next time you go outside on a clear night, look up at the stars and try to imagine how big the Universe really is (good luck) it will not be there forever. You are the universe literally, the clock is ticking, so make the most of it!
What if there is enough matter to stop the Universe expanding?
If in the next 100+ years scientists do find that there is enough dark matter, then things will be a little different. In this case the Universe is known as CLOSED. Again, there is nothing for us to worry about as nothing noticeable will happen for around 30-50 billion years. Like anything elastic, the Universe will very slowly stop expanding. For just a split second the whole universe and all of it's contents will be completely stationary. Very slowly it will begin to collapse gaining speed as it does so. After approximately 35-50 billion years (or however old it was when it stopped expanding), it will have accelerated to above the speed of light quickly converging into a single point. The whole universe & all of it's possessions, that is - 100 billion + galaxies, 200 billion trillion stars, all planets, you, me and basically everything that exists in the Universe will be condensed into unimaginable temperatures and pressures, converging to a point many millions of times smaller than an atom.
From here? Nobody knows, perhaps it may just vanish back into nothingness never to occur ever again, or, perhaps it may again go bang to form Universe no:2. Unfortunately for us we do not know where our own Universe came from, so maybe this process may have happened before. We may at present live in Universe no:1, no:2 or for all we know we may live in Universe no:1,000,000,000,000. Maybe it's a physical process that started an infinitely long time ago and has occurred many billions or even trillion of times, it may even be a one off. What ever happens to the Universe it makes no difference, we will never know.
We may be here now, but we will not always be here. One day the time will come when days and time do not matter, there will be nothing here to appreciate the Universe that has been and gone. If we do end up being the only forms of life in the universe ever to exist (although we will probably never know), it will make no difference, we have not contributed anything to the Universe, so what's the point in all of this? An experiment? But by who? Maybe the universe is the brains in all off this, telling us to find out what it wants to know.
