Background+Information

Find below the chapters of Science Focus 3 by Whalley K, Roberson P, Rickard G and Isabella B with a full summary on each chapter and its components: =Chapter 3: Origins of the Universe=

**The Doppler Effect**
The Doppler Effect happens with light and sound. It was invented by an Austrian Physicist, Chirstian Doppler. To take as an example, we can take an ambulance. When the ambulance's siren goes on, it makes wavelengths going in different directions. However, when the ambulance moves forward, another thing happens. As it goes forward, it 'catches up' a little on the wavelengths which make them shorter, resulting in a high-pitched sound. However, the wavelengths behind it have more gap between each individual wavelength because as the ambulance goes forward it 'runs away' a little from each wavelength, resulting in a low-pitched sound.

Similarly, the doppler effect works on light. When this happens, there is a change of colour in what we call spectrum. To fully observe all the colours of the white light, you would need to refract light through a triangular prism. You can use a spectrometer to observe these colours. Using this theory Edwin Hubble discovered that stars moving away from us are red-shifted, moving to the red side of the spectrum and that stars coming towards us are blue-shifted, moving towards the blue end of the spectrum. This is only noticeable in fastly moving stars. This theory has proveded that the universe is expanding more and more rapidly.

**Backwards in time**
Scientists observe videos of stars over a long period of time to deduce where the stars were when they started. This is similar to taking a bird's eye-view of people going home from a club and rewinding it to find out where they started from. Scientists have used this method to observe that at the beginning of time, all stars were in a single point, called a singularity, before exploding in what is called the big bang. Before the big bang, neither time nor space existed. This will be further investigated in the next unit.

**The First Few Minutes**
What happened at the beginning of the universe is called the **Big Bang Theory**. The theory is explained in the paragraph below.

The universe exploded from a single point or dot called a singularity in all directions. Like many bombs, at the moment of creation, the temperatures were beyond the law of physics, and it was very very hot. Einstein's theory of E=MC2 explains that energy can be converted into mass (kilograms) times the speed of light squared. This was exactly what happened. During this intense period, energy was being converted into mass, or more specifically, matter and antimatter.



Matter and antimatter can be explained in a hydrogen atom. If matter were a hydrogen atom, then an electron would circulate around a proton. However, antimatter in a hydrogen atom would be a proton circulating around an electron.

That was the first fraction of a second after the big bang.

Then, the universe back then inflated to become 1*10^26 (100 million billion billion) times bigger and 1*10^26 (100 trillion trillion) times hotter. When metals grows hot, it goes red. When it undergoes intense heat, it glows white and emits radiation. Therefore, when the universe became this hot, it was a foggy place full of radiation, X-Rays and light.

When matter and antimatter collided, they gave off immense bursts of light energy called photons and then annihilate each other. To compare this, 1 millionth of a gram of antimatter colliding with the equivalent of matter can power a rocket to Mars. When the war between matter and antimatter began, there was doubt about the fate of the universe. Luckily, there were more matter particles than that of antimatter and these matter particles drifted in space.



After a second, the universe cooled to 'only' 1*10^10 (ten billion) degrees celsius. After three minutes, it had further cooled down to 1*10^9 (one billion) degrees celsius. As earlier compared to a bomb, after it explodes, it eventually cools down the more time passes. This is what happened in the Big Bang.

Because the temperature was now low enough for particles to start to clump together, reactions began. Protons and Neutrons were formed from quarks that were made during the Big Bang. Since a proton makes up the simplest atom there is, hydrogen, the first atoms were formed. Another atom that was formed simply was deuterium. These put together formed helium. Because hyrdrogen was the simplest atom, followed by helium, it is estimated that 77% hydrogen and 23% helium existed during that period.

**The Fog Clears**
As described earlier, X-rays, radiations and light made the early universe a very foggy place. 300,000 years after the big bang, temperatures had cooled down to 3000 degrees celsius. This was a low enough temperature for reactions to start taking place. Atoms and elements were formed at this stage and the radiation took the form of heat, radio waves and microwaves.



**Afterglow**
As previously mentioned, radiation was left over from the beginning of the universe. In 1965, two physicists called Arno Penzias and Robert Wilson were trying to detect radiation sources from various places. Instead they found that no matter what the time was or no matter where they aimed the instrument, background radiation was being picked up. What they later realized was that the background radiation was the radiation left over from the beginning of the universe. This was an important step towards understanding the Big Bang theory.

**Galaxies, stars and planets**
It was previously mentioned in this summary that matter had won the battle against antimatter because of their sheer numbers. This matter now formed clouds of gas which then started to make the first galaxies. They had their own gravity which made them pull together large amounts of gas and dust to form stars. These in turn formed young planets or planetismals which pulled together other celestial bodies.

**The Future**
There are many theories about the future of the universe but there are four main ones:
 * **Open Universe**- This universe states that is the universe has a low enough mass, then it is possible that the universe will keep on expanding, but at a decreasing rate. Eventually the light will be sucked out of the world along with the heat.
 * **Closed Universe**- If the universe has a high enough mass, then the gravity of the planets, stars and galaxies will eventually pull each other together and they will stop before starting to come back together. Black holes will form one massive hole and they will suck all the planets into on tiny space called the 'Big Crunch', the opposite of the Big Bang.
 * **Flat Universe**- The universe will eventually stop expanding but it will never start to reverse.
 * **Accelerating Universe**- Recent research has proved that the universe is instead expanding at a faster and faster rate. This is because of energy called 'dark energy'. It is named so because we cannot see it, feel it and we do not even know what it is.

**Birth of a Star**
When dust a gas come together in huge amounts, the raw ingredients of a star come together. They are given the name of nebula. When the gas and dust come closer further from a nebula, they form a protostar. Eventually, they become so packed that it gives off immense heat and is ready for nuclear reactions. At this stage, atoms of hydrogen form together to become helium and vast amounts of heat and light energy are given out. Then a main sequence star is formed.



**Death of a Star**
Stars like our sun do not die for at least 10 billion years. When they do use up all of their carbon, it starts to burn up its own supply of hydrogen. During this period, it expands upto 100 times its original size to become a red giant. When the supply of hydrogen runs out, it collapses under its own gravity to form a white dwarf. In comparison, a teaspoon from the white dwarf would weigh as 1.5 million times more than a teaspoon from the sun.

A different thing happens to stars with a mass ten times that much of the sun. It uses up its fuel supply in only 30 million years. It expands to become a blue supergiant, and then further to become a red supergiant. When it finally collapses under its own gravity, it will explode in less than a second to become a supernova. Leftover materials are blasted away into space, whose remains form a neutron star. It is from supernovae that elements such as gold, silver and iron are formed. In comparison, a teaspoon from a neutron star would weigh 500 billion times more than a teaspoon from the sun.



**Pulsars**
A rapidly rotating neutron star is a pulsar and has a strong magnetic field. As it sweeps across other matter, it emits radio waves which a special type of telescope called a radio scope can detect.



**Black Holes**
If a star has a high enough mass, it will collapse even more to form a black hole. Black holes have such a strong gravity that anything near it will be drawn to it and not be able to escape, even light! This is how scientists observe black holes: through mysterious patterns of X-Rays and the orbitting of nearby stars. Evidence has proved that a black hole with a mass 2.6 million times that of the sun is in the middle of the Milky Way, our galaxy.



**How to make contact?**
The quickest and easiest way to send messages to another planet is by sending electromagnetic radiation; physical contact would be impossible to think of, it would take 80000 years on the fastest rocket in the world to reach the nearest star! Lasers and radiowaves send and receive messages fairly quickly. They are continuously being sent from Earth in hope that intelligence might be found in the outer space. The main hope is to find a message from an intelligent race that have been sending it from a long time but we just couldn't recognise it ourselves.



**SETI**
This acronym stands for 'Search for Extra Terrestrial Intelligence'. Their headquarters are situated in Silicon Valley, California. The Project Phoenix is currently being operated upon in New South Wales. They constantly visit the Arechibo telescope in Puerto Rico, which is the largest telescope in the world, twice every year.

**For and Against**
Some people think of danger when they think about communicating with other planets in fear that they might wipe out our civilisation. However, SETI strongly opposes this saying they are more likely to have blown themselves up.

**Long-Distance Space Travel**
In simple words, with our current technology, it is impossible to go to other stars within the years of an average human's life. The closest star, Alpha Centauri, is 4.3 light years away from us and since light travels 300,000 kilometres pers second, it travels approximately 9.4608*10^12 (9,460,800,000,000) kilometres per year, which makes Alpha Centauri a //long// way away from us. Also expenditure gives another problem. It costs $50000 to throw one kilogram into space. And that is without the costs of humans and other luggage!

**New Rocket Technology**
There are several proposals that have popped up in the past, many of them very popular. Some of them are:
 * **Antimatter-** Antimatter are exactly the opposite of matter with a proton revolving around a electron instead! When they collide, both are destroyed and huge amounts of energy are released. One millionth of a gram of Antimatter is enough to power a rocket's journey to Mars. However, because they are so difficult to make, only 1 billionth of a gram of Antimatter has been made so far!
 * **Collect fuel as you go-** Because space contains various gas molecules and particles, less fuel would be needed if somehow, they could be converted into fuel so that they could use less fuel originally.
 * **Ion-drives-** Even though Ion-Drives can get higher speeds at less fuel and carry more mass, it takes a much longer time to accelerate into a speed fast enough to propel the rocket into space.
 * **Nuclear Bombs-** Scientists have proposed nuclear explosions taking place inside a rocket every second. If this happens, the rocket will have a speed of upto one-tenth that of the speed of light.
 * **Laser Drive-** Even though it is not noticeable, light pushes away an object when it hits something. If a big enough light and sail could be used, then the light could be used the propel the rocket.

**Change the rules**
Either by future technology or by changing the rules and reprogamming a law or device, new rules could be invented that could simlarly put the rocket in space. Some ideas include:
 * **Warp Engines**- A Mexican Physicist called Miguel Alcubierre proposed that we might be able to use warps to expand the distance behind the rocket whereas shrinking the distance in front of the rocket.
 * **Wormholes**- An American Pysicist called Kip Thorne proposed that there are wormholes in space that can act as portal from one place to another closer to the other star. This will enable us to get ther faster.
 * **Unlocking the mystery of gravity**- If we can control gravity and then change it around, we can revolutionise transport. We would be able to control how fast the rocket was going to go and maybe even solve many of the problems today!



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