Astrophysics Part IV: Redshift and the Expanding Universe

Nowadays the universe is believed to have began with the big bang. The universe began from a singularity, a spot of infinite density where the four fundamental forces, gravity, the strong and weak nuclear forces, and the electromagnetic force were united. Before this explosion, time and space did not exist.

However, for many years, it was thought that the universe was static, stationary and infinite.  In fact the great physicist and mathematician, Isaac Newton believed this as well, arguing that unless this was correct, the universe would become a spherical mass, as all the stars would have been attracted together, by gravitation.  But it was a German amateur astronomer, Henrich Olber, who disproved Newton’s theory.  The famous Olber’s paradox states that if the universe was infinite and stationary, then the whole sky would be bright.  If one was to look at any direction the night sky would be bright because, there would be an infinite number of stars in any given direction. This can be mathematically shown by a simple proof.

Imagine the stars are distributed in a layer with a density of ρ, thus the number of a stars would seem to be the density, ρ, multiplied by the thickness of the layer, d, multiplied by the surface area of the layer, which is that of a sphere, 4πR². Thus the number of stars that would be visible would be 4πR²ρd.  The volume of visible stars would increase by R², however, luminosity would decrease by 1/R².  Thus luminosity would be equal anywhere. The distance of R² would cancel out, leaving the luminosity to be 4πρd, which would only depend on the thickness d, and the density ρ, not on the location of the observer.

The night sky however, is dark and thus we can conclude that the universe is not infinite or static, but changes with time. The big bang model states that the universe is constantly expanding, and that the distribution of stars is not uniform, resolving Olber’s paradox. However there are many other factors which support the big bang. The first is redshift. This is a phenomena which occurs with radiation emitted from stars that are moving away from us. This is similar to the Doppler Effect.

The Doppler Effect: The changing of frequency which arises from the relative motion between a source and observer

However, the rarefaction or stretching of light waves is actually not due to the Doppler Effect, instead it is due to the fabric of spacetime itself increasing.  Since the big bang, the universe has been increasing in size.  If a photon leaves a nearby galaxy, it spends a considerable time in space. But the space where it is moving is actually being increased in size, thus the longer a particle spends travelling in space, the more the light is rarefacted. As electromagnetic radiation travels at a constant speed, the amount of redshift can be use to determine how far away an object is, and also suggests to us that the universe is expanding. When the particle reaches us, it will have been redshifted, showing us how the universe is expanding, from a central point, suggesting the big bang model is correct.

This relationship can be expressed mathematically by the formula,

Δλ/λ=v/c

Where Δλ = λ’- λ, where λ is the wavelength from a stationary source, and λ’ is the wavelength measured from the source that is moving at speed v , and c is the speed of light

The third factor which supports the big bang is to do with the amount of helium in the universe. In fact 24% of the universe is helium, but the percentage is too high to be solely produced by fusion in stars, suggesting that the helium was made elsewhere. Two physicists, Dicke and Peebles, suggested that this helium was formed in the early universe, when temperatures were large enough to allow hydrogen fusion. In these reactions, high energy photons would have also been produced.  But when later, two physicists Penzias and Wilson positioned an aerial facing space, they encountered constant cosmic background radiation that seemed to have been emitted from a black body of only 2.726K.  (Click this link for information about Wien’s Law) However, the temperatures for hydrogen fusion would have been much larger than this.  The wavelength of this radiation must have increased, supporting the idea of an expanding universe once more, and the big bang.

There are numerous other factors which support the big bang, such as the existence of quasars, and large gas clouds. To summarise we will list the three factors which support the big bang model, which you may have to list in an exam paper.

The three factors which support the Big Bang model

• Olber’s Paradox
• Redshift / The Expanding Universe
• Amount of Helium / Cosmic Background Radiation

Arguments for Trade Protection

Trade protection occurs when a country’s government intervenes in international trade, imposing trade restrictions to prevent the free flow of imports into the country and protect the domestic economy from foreign competition

There are 4 main types of protectionist methods:

1. tariffs
2. quotas
3. production subsidies
4. administrative barriers

Although their methods vary, they all share the same effect of decreasing the number of imports, and increasing the quantity of goods and services domestically produced. However, one must consider the arguments for and against trade protection, to evaluate whether these measures can really be justified.  To start, we will look at the arguments for trade protection.

Infant industry argument

An infant industry is a new domestic industry that has only just established itself, not having the time to grow larger, and achieve economies of scale. Thus, the firms will have relatively low efficiencies, and be unable to compete with ‘efficient’ foreign firms. Without any type of production, the new infant industries would probably shut down, unable to compete and grow amongst much more efficient firms.  Arguably, trade protection should be utilised until the firm is large enough to achieve economies of scale. After first being introduced as an argument in 1791, the argument is primarily used now by developing countries trying to expand production. Economists consider this theory to be one of the strongest justifications for trade protection, possibly because it obeys the theory of comparative advantage,

The theory of comparative advantage states that along as opportunity costs in two (or more) countries differ, it is possible for all countries to gain from specialization and trade according to their comparative advantage; this results in an improvement in the global allocation of resources, resulting in greater global output and consumption.

The country in question may have a comparative advantage compared to another country, but first must receive protection. This can only be justified if the production is limited to a temporary period.  As soon as the infant industry can compete, the protection should be eliminated. However, this theory can also be misused and wrongly implemented.  Governments can misjudge different firms; wrongly deciding which firms could become low-cost producers. This also presents the opportunity for corruption and possible favouritism from governments.  Furthermore, once a firm is protected, it may not see the need to become efficient, forever existing as an ‘infant industry’. Similarly, a firm could protect an ‘infant industry’ long after it has achieved economies of scale.  The infant industry argument here has been purely reduced to a subsidy.

Strategic trade policy

This is similar to the infant industry argument, but the firms protected are slightly different.  High-technology firms are protected, as their presence is deemed important to the future growth of an economy.  There growth is assisted until they are large enough to compete for themselves.  This argument also applies to more developed countries, who may also aspire to increase their high technology industries. Here though the trade protection is not only limited to the traditional methods, but can also take the form of various supply-side policies, such as lower taxes, low-interest loans, and even government financing of research and developing.  However, along with the infant industry argument, there are also difficulties about who to protect, and also selecting appropriate protectionist measures.  Also, if many firms use this kind of protection at the same time, the idea of comparative advantage is made redundant. The protection could also last much longer than necessary, the government, continuing their protection for too long.

National Security

Some industries, such as aircraft, weaponry, chemical substances  and ores and minerals are believed to be beneficial for national defence, and thus are deemed necessary for protection, in the event of an attack.  In war, a country may have to rely on its own industries for defence, and thus industries which benefit national security should be protected.  Furthermore, in this sector, specialisation is discouraged.  For example, if a volatile or dangerous country specialises in weaponry, or a country is relied upon for aircraft, but then ends ties with other countries, the situation could be become dangerous. However, of course this theory for trade protection is subjective to each country.  Governments will differ in what they deem to be important to national security, however countries could also use this argument a façade, purely to subsidise products and employ trade protection.  For example, the United States protects goods such as candles, gloves and umbrellas, all in the name of national defence.

Health, safety and environmental standards

Countries have health, safety and environmental standards, that imported goods and services must meet before they can enter a country. Although each country can set its own standards, sometimes these standards can be used as a type of ‘hidden protection’, to keep some goods out, so they cannot compete with locally-produced goods.

Efforts of a developing country to diversify

Countries may employ trade protection on certain goods in order to diversify

Diversification: Generally refers to change involving greater variety, and is used to refer to increasing the variety of goods and services produced and/or exported by a country; it is the opposite of specialization.

In the past, the world has seen developing countries specialise in particular products, for example, Cuba in sugar and Ecuador in bananas. However, although this can yield both high quality and quantity of a good, arguments exist in favour of diversification. Listed below are some of the arguments for diversification.

• These goods which we have seen developing countries specialize in are generally primary sector goods.  However, as countries grow, manufacturing and services become progressively more important.  In developing countries, this is made possible by diversifying its range of goods and services into other sectors.

• Another reason for diversifying into manufacturing industry is that each step in production adds value to the good.  For example, in the extraction of metal ores, we see processes such as refining add value to the good, if developing countries not only manufacture but also extract, they can sell their products for higher prices and receive more revenue, resulting in economic growth.

• Primary goods also have much higher price volatilities than manufactured goods, and services, due the low price elasticities of demand and supply of such goods.  This can result in fluctuating wages for farmers, due to the low price stability of such goods. This is another factor supporting the diversification of goods.