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22. The four fundamental forces

So during the early history of the universe you have seen the main events as being inflation, as well as the division into the four fundamental forces in physics.

But what are those four fundamental forces?  

The weakest force is gravity, which might at first seem counter intuitive as we’ve seen the influence of enormous quantities of mass holding planets and stars in place, however if you think of how an ant is much stronger than a human compared to its body weight, this is how you might consider gravity.  Mass tends to gather in huge amounts, where as electricity for example does not, so this is why gravity seems to have more power.

The second most powerful force is the nuclear weak force, which is about 10^25 times the strength of gravity.  This type of force is found in actions such as radioactive decay.  The third most powerful is the electromagnetic force which is 10^ 36 times the force of gravity, and finally the fourth most powerful is nuclear strong force which is 10^38 times stronger than gravity and manages to hold protons and neutrons together.

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21. The Quark Era

After the electroweak era, the final two of the four fundamental forces separated into the electromagnetic force and the nuclear weak force.  Remember that gravity was the first force to break away, then the nuclear strong force, and then finally during what we call The Quark Era, the weak force separated from the electromagnetic force.  The Quark Era lasted from 10^-12 seconds after the Big Bang to 10^-6 seconds.  These are still incredibly tiny units of time from the human perspective but at least now we can finally begin to grasp these numbers.  The temperature cooled from about 10^15 to 10^13 Kelvin.

The Quark Era is named as such because the universe still resembled a soup of quarks and other basic particles, and were not yet able to form hadrons.  Scientists however believe they now have acquired mass from interaction with the Higgs field.

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20. The inflationary period

During the Electroweak Epoch, a concurrent event occurred that had even a more profound effect on the future of the universe.  Some scientists hypothesized that in order for matter to exist, from about 10^-36 seconds to 10^-32 seconds, an inflationary period must have happened where the universe expanded on the order 10^50 times its current size.  Particles and anti-particles in close proximity normally will annihilate each other, however, in a volatile environment where matter was being produced in enormous quantities while expanding at an incredible rate, perhaps it would be possible for matter to form in a such a state.  So the Big Bang Theory could explain the conditions where matter might form at high enough temperatures if the energy was combined with inflation.  Once again, the Cosmic Microwave Radiation Background seems to provide confirmation of such an event as the perfectly uniform wave signature at every direction of the universe would be consistent of a universe deriving from a single point.  There are some ripples in the CMB, however scientists have explained these as the product of quantum fluctuations during the early universe.

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19. The Electroweak era

From about 10^-36 seconds to 10^-12 seconds after the Big Bang was the Electroweak Era.  At this point the nuclear strong force separated from the electromagnetic and nuclear weak force which stayed combined as the Electroweak force.  This was a significant development as the strong force could hold particles together and were now able to form matter.

Also it is believed the inflationary era happened concurrently during this period where the universe grew enormously from a subatomic size to perhaps the size of a grapefruit.

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18. What are fermions and bosons?

During the Grand Unification Era, the only particles currently known to exist during that time were the basic building blocks called fermions and bosons.  Fermions are the materials from which traditional matter is made and they are characterized by having a half integer spin and also for following the Fermi-Dirac statistics which means each fermion can only occupy a unique space in the universe, in other words they cannot share the same spot with another fermion.  Examples of fermions are quarks and electrons.

On the other hand, bosons have a whole integer spin and they follow the Bose-Einstein statistics which means any number of bosons can occupy the same exact location.  Some examples include photons, gluons, and of course bosons.

The difference between the two particles explains why in the case of fermions, we don’t fall through the floor... or in the case of a boson, why a radio wave can travel through a wall.

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17. The Grand Unification Era

After the Planck era ended 10^-43 seconds after the Big Bang, and time began to exist, the next era ended only 10^-36 seconds from the beginning and is known as the Grand Unification Era.  Again, these units of time are ridiculously small in human terms but in an accelerated early universe where enormous changes were happening with incredible speed, they make perfect sense.

This era was marked by the separation of Gravity from the combined super force and the other three forces, the Strong, the Weak, and the Electromagnetic force were known briefly as the GUT force or the Grand Unified Theory force.  The temperatures cooled from 10^32 Kelvin to 10^27 Kelvin, but the energy levels were so high that one photon could produce 100 trillion particles.

The only particles that existed during the GUT era were fermions and bosons

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16.  The Planck era and the beginning of time.

The first era in the history of the universe is known as the Planck era.  It lasted the length of the shortest possible unit of time which is 10^-43 seconds.  The temperature was greater than 10^32 degrees Kelvin, and all the four known forces in Physics were unified into one super force.  The Nuclear Strong Force, the Electromagnetic Force, the Nuclear Weak Force, and Gravity.

These units of time seem absurdly short, incomprehensible to the human mind, but remember that in a universe without humans, a Planck unit could seem as long as a century.  Everything is relative and in this early human universe, our perspective would be irrelevant.

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15.  There is no “center” of the universe.

If you stare out into space, you may notice that the universe is very homogeneous.  This means that no matter which direction you look, the stars and distant bodies look fairly evenly distributed.  Sure you might see certain clusters of stars or galaxies here and there but all in all, everything looks pretty even in all directions.  

If you think of the loaf of raisin bread, we are not in the center as space continues to expand between all bodies equally.   There is no center as no matter where you are situated in the universe, it will essentially look the same

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14. Einstein’s biggest blunder

Einstein, as did virtually every scientist of his era, originally believed the universe was static.  Because there were no satellites or even telescopes during the early 20th century that could properly observe distant bodies such as galaxies and discern them from stars, it was difficult for them to imagine a universe beyond our own Milky Way.  Therefore, when he developed some of his equations on relativity, he devised what he designated as a cosmological constant that would fit them within the accepted narrative of the community, essentially shoehorning them into the static theory.

Later, as Hubble and others identified the galaxies and noticed their redshift, astronomers gradually began to accept the idea that the universe was expanding.  Thus, the cosmological constant eventually became known as one of the rare blunders in an otherwise brilliant career.

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13.  Olbers’ paradox: How early scientists hacked the question of an infinite universe

Years before Hubble and others came up with the idea of the Big Bang Theory, a German astronomer in the early 19th century named Heinrich Olbers proposed the argument that had the universe been infinite, the night sky would be as bright as the day because the light from even increasingly distant stars would still eventually fill the entire field.

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12. How E=MC^2 can be used to explain the formation of the universe

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Einstein’s famous formula, E=MC^2, expresses how energy might be converted into mass, and how mass can become energy.  For example, a photon which is a unit of pure energy can become mass such as a proton and an antiproton, or an electron and antielectron (as these units usually come in pairs), if the photon is exposed to enough energy.  By knowing the mass of a proton/anti proton pair, one can use the formula to calculate how much energy would be needed to make a proton or a smaller electron.

So by extrapolating the wavelength of the current cold universe near absolute zero and calculating the short wavelengths that would correspond with the temperatures necessary to produce matter, scientists could build a timeline of the early universe when it could no longer produce the larger protons and eventually the smaller electrons which required lower temperatures.

They calculated that the universe must have been at least 4.4 trillion Kelvin to make proton pairs and 2.4 billion K to make electron pairs.  When the the universe cooled below this point, it no longer made matter and slowly cooled to the state it is today.

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11.  Calculating the Earth’s relative motion.

COBE was also able to calculate very subtle differences in the redshifts and blueshifts of local constellations.  Unlike the shifts from more distant bodies, by taking the difference of warmer bodies such as the constellation Leo, or the cooler wavelengths from the constellation Aquarius and comparing it to the standard of the CMB, scientists were able to approximate its speed moving through space, which was about 371 km/second.

Once again this measurement corresponds to movement towards or away from local bodies versus the general expansion of space relative to more distant galaxies.

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10. The importance of the Cobe satellite of 1989

Even though the Earth’s atmosphere to the human eye seems relatively transparent, it filters out most radiation with wavelengths between 1 and 10 mm long.  In order to more accurately observe the the Cosmic Microwave Background Radiation, the COBE satellite was launched on November 18, 1989 to more accurately measure the wavelength emitted by the CMB outside this interference .  The scientists discovered that the length was very uniform throughout the universe at about 1.064 mm.  By using Wien’s Law, they were also able to estimate it’s temperature at about 2.74 Kelvin.

By using the temperature when the universe was capable of fusing hydrogen into helium (10 million Kelvin), scientists could also extrapolate the amount it had expanded from when it was 10,000,000 degrees to its current 2.74.

This calculation would mean the universe was about 3.7 million times larger than when it was processing hydrogen into helium.

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9. Discovery of the Cosmic Background Radiation

In the early sixties, two engineers for Bell Laboratories were working on calibrating a microwave horn antenna to communicate with satellites.  At the time this was very early experimental technology, but of course, nowadays we use it all the time for communications, surveillance, many essential functions.

These engineers, Arno Penzias and Robert Wilson, accidentally came upon an important discovery while trying to get their antenna to communicate properly.  It turned out, no matter how much they cleaned and adjusted their instruments, a type of white noise was always present.  After about a year, they finally managed to correlate this noise with the concept that Dicke, Peebles, Gamow, Alpher, Herman, and Hubble had proposed of an early event in the universe’s history where everything had once been close together.

This “noise” later known as the Cosmic Background Radiation was found to exist no matter where they pointed their instruments and the wavelength detected was about 1mm in length and converted to about 3 degrees Kelvin.  They reasoned the only way this type of uniformity could exist, was if everything had all originated from one point.

Later Penzias and Wilson would win a Nobel Prize for this discovery.

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8. What is inflation theory?

Before we explore the implications of the discovery of the cosmic microwave background radiation, which came about 379,000 years after the Big Bang, when photons were first able to travel freely through space, scientists have come up with the idea of inflation theory, which uses quantum theory to explain some of the anomalies found in the background.

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7. Radiation and temperature

In the early 1960s, Robert Dicke and PJ Peebles reasoned that if the theory of the early, hot universe was true, that there should be evidence of this era where the average temperature of the universe was hot enough to turn hydrogen into helium.  Because there is an inverse relationship between temperature and the amplitude of a light wave, they thought shorter waves which corresponded to higher temperature might be discovered that could be correlated to longer waves and lower temperature of the current universe using Wien’s Law.  

Soon after, evidence was accidentally discovered by a nearby laboratory that confirmed the idea of a “cosmic background radiation” that previously had also been predicted by George Gamow, Ralph Alpher, and Robert Herman.

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6. The hot, early universe

The next important concept in formulating the Big Bang Theory was Ralph Alpher and Robert Herman’s proposal in the 1940s that because the universe was roughly composed of 75% hydrogen and 25% helium with the rest of the elements comprising only a tiny fraction of the rest of known matter, the universe at some point must have been very dense and hot to facilitate the nuclear fusion that might explain that volume of helium.  This process can still be found in the center of stars like our Sun.

They reasoned that because this type of fusion requires temperatures of over 10,000,000 degrees Kelvin, that the early universe must have been very dense and hot to produce helium in such enormous quantities.  They also believed there might be some residual evidence of this radiation in the skies.  Unfortunately, at the time their ideas were met with resistance and their theory wouldn’t be confirmed until the sixties.