It is a pivotal time for astrophysicists, cosmologists, and philosophers alike. In the coming years, next-generation space and ground-based telescopes will come online that will use cutting-edge technology and machine learning to probe the deepest depths of the cosmos. What they find there, with any luck, will allow scientists to address some of the most enduring questions about the origins of life and the Universe itself.
Alas, one question that we may never be able to answer is the most pressing of all: if the Universe was conceived in a Big Bang, what was here before that? According to a new op-ed by Prof. Abraham Loeb (which recently appeared in Scientific American), the answer may be stranger than even the most “exotic” explanations. As he argued, the cosmos as we know it may be a “baby Universe” that was created by an advanced technological civilization in a lab!
As the former chair (2011-2020) of the astronomy department at Harvard University, the founding director of Harvard’s Black Hole Initiative (BHI), the director of the Institute for Theory and Computation (ITC) at the Harvard-Smithsonian Center for Astrophysics (CfA), and one of the chief researchers with the Galileo Project, Loeb is no stranger to “exotic” theories about advanced intelligence and cosmic origins.
His credentials also include chairing the National Academies’ Board on Physics and Astronomy, the advisory board for Breakthrough Starshot, and being a member of the President’s Council of Advisors on Science and Technology. He is also the author of the bestselling book “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth,” which addressed the possibility that the interstellar object ‘Oumuamua was an artificial probe.
This time around, it’s the foundations of the Universe itself (and whether or not aliens may have been involved) that have attracted Loeb’s interest. For starters, there have been many conjectures as to what might have existed before the Big Bang. Some of the more well-known examples include that the Universe emerged from a vacuum fluctuation or that it is a cyclic process with repeated periods of contraction and expansion – Big Bang, Big Crunch, repeat.
There is even the notion that the Universe was born from matter collapsing inside a black hole in another Universe, which then rebounded to form the other side of the Einstein–Rosen bridge (a “wormhole”) where our Universe was conceived. A similar version of this argument states that the Big Bang could have been a supermassive “white hole” that formed from a supermassive black hole (SMBH) in our parent universe.
Yet another theory is that our Universe is a consequence of the string theory interpretation of the multiverse, where infinite Universes coexist, and every possibility plays out an infinite number of times. According to Loeb, this could take the form of our Universe being created in a laboratory by an advanced civilization. “Since our universe has a flat geometry with a zero net energy, an advanced civilization could have developed a technology that created a baby universe out of nothing through quantum tunneling.”
In the context of quantum physics, tunneling refers to a phenomenon where a wave function can propagate through a potential barrier. This plays an essential role in physical phenomena, ranging from nuclear fusion and tunneling electron microscopes to quantum computing. Unfortunately, the Standard Model of particle physics models cannot resolve how quantum mechanics and gravity interact, hence why a Theory of Everything (ToE) is still lacking.
However, a sufficiently advanced species may have already developed a ToE and the technology for creating baby Universes. In essence, this theory offers a possible origin story that appeals to the religious notion of a creator and the secular notion of quantum gravity alike. It suggests that a Universe like our own – which hosts at least one civilization (i.e., us) – is like a biological system that reproduces over generations. As Loeb explained to Universe Today via email:
“It explains the Big Bang as an infinite series of baby universes born inside each other, just like chicks hatching out of eggs and laying new eggs later in their life. If something predated this series of generations – it would have been something else, just as in the ‘chicken and egg dilemma.'”
This is reminiscent of the Kardashev Scale, which characterizes civilizations by Type (I, II, and III) based on the amount of energy they can harness. Whereas Type Is are able to harness the energy of their entire planet, Type II civilizations can harness the energy of their whole star systems, and Type IIIs can harness the energy of their entire galaxy. In this case, says Loeb, the metric is a civilization’s ability to reproduce the astrophysical conditions that led to their existence.
The Big Bang Theory: A history of the Universe starting from a singularity and expanding ever since. Credit: grandunificationtheory.com
For some, this whole Baby Universe theory might sound similar to the Zoo Hypothesis – a proposed resolution to the Fermi Paradox. But as Loeb explained, there’s a fundamental difference between the two:
“The Zoo is a place where you watch the animals, but a baby universe cannot be observed from the outside according to General Relativity, Einstein’s theory of gravity. The interior of the baby universe disappears from view of the creator and snaps out of the creator’s spacetime. The situation is analogous to the formation of a black hole, where all the matter that falls into it cannot be observed once it enters the black hole horizon.
“As a result the creator of the baby universe will never know which type of civilization formed in it and will also not be able to intervene. Creating a baby universe might not consume energy because the negative gravitational energy cancels out the positive energy of matter and radiation in our universe, which is characterized by a flat geometry.
“The fate of our Universe is completely independent of the baby universe, just as the history of a person that enters the event horizon of a black hole has no influence on us. Based on everything we know, our own universe will expand forever.”
Another appealing feature of this theory is the way it’s free of anthropic reasoning, which essentially states that the Universe was selected for us to exist in. Formally known as the Anthropic Principle, this stands in opposition to the Copernican Principle (or Cosmological Principle) that asserts that there is nothing special or unique about humanity or the space we occupy in the Universe. However, the mere fact that slight variations in the laws of physics would rule out life would seem to suggest that we are fortunate.
Artist view of an active supermassive black hole. Credit: ESO/L. Calçada
In recent years, it has been suggested that multiverse theory is a possible resolution for the Anthropic Principle. The Baby Universe theory is consistent with this idea, as it theorizes that the Universe gives rise to advanced civilizations that are drivers of a cosmic Darwinian selection process. At present, humanity is not advanced enough to replicate the cosmic conditions that led to our existence.
Whereas a civilization that could recreate these cosmic conditions (i.e., produce a “baby Universe” in a laboratory) would fall into class A on this proposed cosmic scale, a class B civilization could adjust the conditions in its immediate environment to be independent of its host star. Given our present situation, humanity is currently a class C or D since we cannot recreate the habitable conditions on our planet (when our Sun dies) and are carelessly destroying planet Earth through climate change.
But eventually, humanity may reach the point where we become a class A civilization and can partake in the hypothesized process of cosmic reproduction. Who knows? Maybe we will even be able to create a baby Universe that is an improvement over our own. Loeb contends that such hopes may be a tad optimistic but that the prospect for cosmic procreation presents some very inspiring possibilities:
“We are getting close to producing synthetic life in our laboratories. Once we will understand how to unify quantum mechanics and gravity, we might know how to make a baby universe in the laboratory. The ethics of making another universe would be similar to making another human being...
“But ultimately, it would be flattering to our species if the abilities that past generations assigned to God, namely creating a universe and creating life in it, will be at our disposal as an advanced scientific civilization. If another civilization that predated us by a billion years had reached that goal already and we will encounter it one day, then that civilization will be a good approximation to what our past religions regarded as God.”
Further Reading: Scientific American