Perhaps the most important scientific debate is the one over whether or not we are alone in the universe. The possibility of alien life has been argued about for hundreds of years because of its significance in our place in the universe as a species. Unfortunately, there is virtually no way of determining the answer to this question without going out and searching every corner of the universe for aliens. In this paper, a model of the big bang is built which is incompatible with alien life and is, therefore, either valuable for offering an answer to whether sentient aliens exist, or valuable for being falsifiable in the case that sentient alien life is discovered.
Assume there are infinite bubble universes, and that the probability of each unit of mass forming in a big bang is a constant independent value in all universes. These two intuitive assumptions create a model of the origin of the universe that is falsifiable because it directly contradicts the existence of sentient extraterrestrial life, therefore, if sentient beings from another planet are contacted, the two assumptions upon which this model is based can't coexist. Through this method of using falsifiable models to find which assumptions can coexist and which can't, a complete model of the origin of our universe might be made out.
If there is a bubble multiverse, and the mass of each universe at its formation is a random amount determined by the exponential probability P^Ω, P being the individual probability of a given unit of mass exploding into existence and Ω being the mass of the universe in mass units corresponding with P, then universes with greater masses become exponentially less likely. If a single electron mass has a P value of 0.5, for example, then a universe with our mass is twice as likely to form as a universe with our mass plus a single electron. If a universe has a mass equivalent to 10¹⁵ mass units, it has a P^(10¹⁵) probability of forming. If the P-value for a given mass unit is 0.9, that is, a single mass unit has a 90% chance of existing at a universe's big bang, then the probability of a randomly selected universe out of the infinite multiverse having that mass is 7.4918669 × 10^-45,757,490,560,676. There is nothing, on neither the atomic nor the cosmic scale, that can be used to put in perspective how astronomically tiny that value is. Approximately 1 in every 1.3347808 × 10^45,757,490,560,675 randomly selected universes will have the mass 10¹⁵ units when P is equal to 0.9.
Using this logic, smaller universes are many times more likely to form than larger ones, though all possible Ω values will exist in an infinite multiverse. For every universe with a mass of 2 units, there are 1/P with a mass of 1. If P in this example is 1/10¹⁵, there will be 1,000,000,000,000,000 universes with a mass of 1 unit for every single universe with a mass of 2 units. This means that any universe with a specific trait is almost certainly the minimum size a universe can be while still containing that trait.
This brings the discussion to the Weak Anthropic Principle, which states that sentient life will always find itself in a universe seemingly finely tuned for its existence, even if the conditions for its existence are extremely unlikely because life can never find itself in a universe that isn't perfectly balanced for its existence, even if that type of universe is infinitely more likely. This logic can be adapted to the model of the universe proposed by this paper. If life will inevitably find itself in a universe that can support it, regardless of how unlikely the conditions of that universe are, and that sentient life is a trait which will nearly always occur in as small a universe as possible, then we can assume that our universe, despite its incredible mass, must be the minimum size a universe with sentient life can be. The universe, under this model, must be as small as possible right down to the electron for sentient life to occur. Different instances of sentient life would tend to be alone in their universes, surrounded by the minimum amount of mass needed to form enough solar systems to make the probability of life emerging higher than the probability of every universe with a higher mass, rather than be contained in the same universe. The expression P(Ω)^x determines the probability of a given universe having x occurrences of a trait, with P(Ω) representing the probability of a universe with the minimum mass needed for a single occurrence of said trait.
In a given universe, the emergence of sentient life relies on a balance between how accommodating the universe is for life (that is, how many planets on which life could potentially emerge there are) and how likely the universe itself is to form, or P^Ω. If the universe is more accommodating then it stands to reason that it is less likely to form, because more mass is needed in a universe that has more star systems with planets that could potentially develop life. Life will more often find itself in internally unaccommodating circumstances than a universe large enough to be internally accommodating. That is to say, relating to the last paragraph, if 1 in 10 Earth-like planets bear sentient life, then those 10 planets will be spread across 10 universes rather than be contained in just one. One of the universes they are spread across will have sentient life which could look at every planet in its universe and conclude that, since no other planet besides theirs is earth-like, 100% of Earth-like planets will harbor life. In reality, only 10% would, but life will usually occur in a small universe where it is unlikely (one where there is only one earth-like planet), rather than a large universe where it is likely (one where there are 10 earth-like planets). The balance between the accommodability of the universe and the probability of the universe will nearly always be struck where there is only one occurrence of a planet with sentient life. Therefore, under this model, we can conclude that earth is almost certainly the only planet that bears sentient life in the universe.
But how certain can we be? What is the probability of a universe with two Earth-like planets that bear sentient life versus a universe with just one? This is a difficult question to answer because the exact value for both P and Ω are unknown, but we can make estimates. Our universe's minimum possible mass, or the mass of the observable universe, is roughly 10⁵³ kg, or about 5.586592 × 10⁸² MeV/c². If we assume that the probability of one MeV/c² of mass forming at the big bang is 1%, then the calculation for our universe's probability is 0.01^(5.586592 × 10⁸²). This value is equal to the number of universes with twice our universe's mass for every universe with a mass equal to ours, and presumably the number of universes bearing two instances of sentient life for every universe with just one instance, because the number of occurrences x (in this case the number of times a planet with sentient life emerges) is the exponent of P(Ω). In this example x = 2, therefore there are P(Ω)² universes with 2 instances of a sentient life-bearing planet for every P(Ω) with just one. P(Ω)² ÷ P(Ω) = P(Ω), therefore for every single universe with one planet that bears sentient life, there are P(Ω) universes with two. P(Ω) in this example is a fraction so impossibly tiny that it can not be put in terms of even the astronomically tiny example in paragraph 2. With the assumptions made, there are 10^(-1.1173184 × 10⁸³) universes with 2 instances of sentient life for every universe with a single instance. With this calculation, with the assumptions made, there would be 10^(1.1173184 × 10⁸³) universes like ours, where there is only one earth-like planet bearing life, for every universe with 2. The value 10^(1.1173184 × 10⁸³), made with forgivingly conservative estimates, is so large that it could not be written out in the base-10 format if every atom in the universe were converted into enough ink to write a single digit because you would run out of ink by the time you had completed 0.1% of the task. Of course, this value is just an estimate, but it does justice to the main thesis which is that we are almost certainly alone in the universe under the model described. If sentient alien life were to be contacted, it would prove that the assumptions made in this model can not be simultaneously true.