Where did this single self replicating cell come from? Whether or not any of the proposed origin of life hypothesis by scientists are plausible is a matter of opinion. In my opinion not only are they not plausible but rather impossible. Consider the big bang theory, what created the matter that exploded in the first place. It doesn't take a scientist to know that if you take a whole bunch of nothing, it can not be expected that you end up with a whole lot of something, densely compressed until it explodes. Another implausible hypothesis or theory.
I can't believe I have to explain this to people, Big bang was the expansion of space time, no thing exploded space it self just expanded very rapidly, atoms that make up our universe came from the energy stored in the very high vacuum potential energy of the inflation field that filled all space and caused the inflationary period after the big bang. According to the inflationary ΛCDM model of cosmology the way atoms were created was through this process:
The Big Bang and Grand unification epoch - from T=0 to 10^−36sec
During the immediate expansion of the universe after of the big bang up to the beginning of the inflationary period, the
Grand unification epoch would have create all kinds of particles, including
Magnetic monopoles.
Inflationary epoch from T=10^−36sec to 10^−31sec,
During the inflationary epoch the universe would have increased in volume by a factor of 10781078 or more. This would dilute whatever particles were created in the grand unification epoch. This means that it is extremely unlikely that even one magnetic monopole (or any other particle) from that epoch would be present in our current Hubble volume (our observable universe). In fact getting rid of the magnetic monopoles was the original motivation when
Alan Guth invented inflationary theory. This rapid inflation would have been driven by a very high vacuum energy density that would have slowly rolled down a shallow slope (slow-roll inflation):
(image from
http://scienceblogs.com/startswithabang/2011/10/28/why-we-think-theres-a-multiver/)
At the end of inflation, the inflaton field will rapidly roll down the steep part of the potential to the minimum at 0 potential energy (labelled True vacuum). Before this rapid rolling phase, the part of the universe that became our observable universe would be empty of all particles, but it would be filled with the high energy density inflaton field potential energy. During the rapid roll to zero potential (called reheating), all that high energy vacuum inflaton potential energy would have been converted into the particles that would eventually decay or become the particles in our current universe.
At the end of reheating the universe would be filled with a high energy, high temperature quark gluon plasma and all of this plasma was generated by the energy in the potential energy of the inflaton field. This quark gluon plasma would have equal numbers of quarks and anti-quarks.
Supersymmetry breaking (speculative)
If
supersymmetry is a property of our universe, then it must be broken at an energy that is no lower than 1
TeV, the electroweak symmetry scale. The masses of particles and their
superpartners would then no longer be equal, which could explain why no superpartners of known particles have ever been observed.
To explain why the universe does not have equal amounts of matter and antimatter today, at this point in time there must have been some slight asymmetry between matter and antimatter that allowed 1 out of a billion matter particles to survive in this period. The exact mechanism of this asymmetry is not currently known - this is one of the unsolved problems in physics. See
Baryon asymmetry.
From this point on, the physics is very well understood and is far less speculative. For this, I will just reproduce the relevant sections from Wikipedia (
Chronology of the universe - with slight edits):
Electroweak symmetry breaking and the quark epoch - 10^−12
sec to 10^−6
sec after the Big Bang
As the universe's temperature falls below a certain very high energy level, it is believed that the
Higgs field spontaneously acquires a
vacuum expectation value, which
breaks electroweak gauge symmetry. This has two related effects:
- The weak force and electromagnetic force, and their respective bosons (the W and Z bosons and photon) manifest differently in the present universe, with different ranges;
- Via the Higgs mechanism, all elementary particles interacting with the Higgs field become massive, having been massless at higher energy levels.
At the end of this epoch, the
fundamental interactions of
gravitation,
electromagnetism, the
strong interaction and the
weak interaction have now taken their present forms, and fundamental particles have mass, but the temperature of the universe is still too high to allow quarks to bind together to form hadrons.
Hadron epoch - Between 10^−6
sec and 1 sec after the Big Bang
The quark-gluon plasma that composes the universe cools until
hadrons, including baryons such as
protons and
neutrons, can form. At approximately 1 second after the Big Bang
neutrinos decouple and begin traveling freely through space. This
cosmic neutrino background, while unlikely to ever be observed in detail since the neutrino energies are very low, is analogous to the
cosmic microwave background that was emitted much later. However, there is strong indirect evidence that the cosmic neutrino background exists, both from
Big Bang nucleosynthesis predictions of the helium abundance, and from anisotropies in the
cosmic microwave background
Lepton epoch - Between 1 second and 10 seconds after the Big Bang
The majority of hadrons and anti-hadrons annihilate each other at the end of the hadron epoch, leaving
leptons and anti-leptons dominating the mass of the universe. Approximately 10 seconds after the Big Bang the temperature of the universe falls to the point at which new lepton/anti-lepton pairs are no longer created and most leptons and anti-leptons are eliminated in
annihilation reactions, leaving a small residue of leptons.
[4]
Photon epoch - Between 10 seconds and 380,000 years after the Big Bang
After most leptons and anti-leptons are annihilated at the end of the lepton epoch the energy of the universe is dominated by
photons. These photons are still interacting frequently with charged protons, electrons and (eventually)
nuclei, and continue to do so for the next 380,000 years.
Nucleosynthesis - Between 3 minutes and 20 minutes after the Big Bang
During the photon epoch the temperature of the universe falls to the point where atomic nuclei can begin to form. Protons (hydrogen ions) and neutrons begin to combine into atomic nuclei in the process of
nuclear fusion. Free neutrons combine with protons to form deuterium. Deuterium rapidly fuses into helium-4.
Nucleosynthesis only lasts for about seventeen minutes, since the temperature and density of the universe has fallen to the point where nuclear fusion cannot continue. By this time, all neutrons have been incorporated into helium nuclei. This leaves about three times more hydrogen than helium-4 (by mass) and only trace quantities of other nuclei.