I have heard of a few scientific theories that aim to explain the origin of our universe that I think are interesting. There is String Theory, for example.. Or the theory where the universe started from different, smaller explosions... Or a multiverse theory where our universe may be one of many universes out there that formed in the same way galaxies are born but on a bigger scale. There's even Simulation Theory that people like Elon Musk find possible. Do any of you subscribe to other theories aside from the mainstream Big Bang Theory as an explanation for the origins of our universe? Let me know what you think
Gonna be a little nitpicky but please bear with me.
I think most of the theories you listed are complimentary rather than being in opposition to one another.
Technically Big Bang Theory applies to what happened immediately after the universe already existed. The multiverse is one explanation of what preceded (and caused) the local big bang, and it also links to cosmic inflation (also the leading theory for the expansion of the early universe). Some inflation models still require a "big bang" of sorts to kick-start the process while others are eternal in both past and future directions.
String theory is separate from all of this and could conceivably explain any and all of the above, albeit at very tiny scales.
None of this rules out the universe being a simulation, because that hypothesis could theoretically apply to any theory, as far as I am aware. The only requirement I can think of for simulation theory is that the parent universe (and even the simulator machine) must contain more energy than the child universe (ours). Otherwise the simulation would not run at "real time" (which may or may not be the case).
Probably my favourite scenario is that of the universe coming from a white hole, effectively we are the other side of a black hole in a parent universe. One feature I like about this idea is that it suggests a kind of cosmic natural selection where the laws of physics are optimised over time to produce more black holes. It turns out this laws are also good for life. It's just an idea and not one I put much belief in. I'm agnostic until evidence presents itself.
To clear up some misconception: neither string theory nor multiverse are alternatives to big bang. Neither is the simulation hypothesis since the big bang could still be simulated.
One of my favorite alternatives however is Roger Penrose's Confromal Cyclic Universe. This is the latest in a brand of theories that say that Universe doesn't "bang" or doesn't "bang" just once but rather expands and contracts as a lung would. It doesn't require a singularity; only that when matter is dense enough it starts repealing in an outwards cycle and when matter is rarefied enough, it starts to contract.
I wonder if it's a cycle. It's hypothesised the universe will keep expanding, leading to cosmological event horizon and possibly heat death and this will cause a rip or a tear to occur.
This plants the seed in my mind that the tear could create a singularity, like the posited big bang. So I wonder if our observable universe is expanding within the remnants of a previous universe.
Multiverse hypothesis = Big Bang still happened
Smaller explosions = Big Bang still happeneed
Simulaton hypothesis = Big Bang still happened
String Theory isn't an origin theory, it's just theory of trying to understand particles and how they interact in our universe.
The big bang is the only theory we have at the moment that is demonstrable true. Anything more than that is just a hypothesis.
I like the Silva Neves theory that the universe has always existed, and keeps expanding and contracting in cycles
Since there is no direct evidence of the original singularity, (Collecting information from that first moment of expansion is impossible with current methods.) Brazilian physicist Juliano Cesar Silva Neves claims it may never have existed.
Silva says, "there are many observations in cosmology" that support the hypothesis that the universe went through a period of rapid expansion, but no direct evidence that this expansion started with a singularity."
Instead, the universe is eternally undergoing a cycle of contraction and expansion. These alternating phases smoothly follow each other like the phases of the tide.
Similar to the original singularity from which the universe emerged, black holes are believed to have a point of infinite density in their center. But while a point of "infinite" mass can exist easily on paper, scientists have always struggled with how such a thing could exist in reality.
And general relativity suggests that the normal laws of physics break down inside a singularity, and thus it offers little guidance to resolve this conundrum.
What If the Big Bang Wasn't the Beginning? New Study Proposes Alternative [shar.es] via @SPACEdotcom
The thing that bothers me is, what's done with knowledge gained from the past? I agree it is fascinating, but in the end, what do we do with the information? I hope we don't try to create any other worlds or universes because we have already littered up this one.
The big bang has the only evidence we can directly observe due to redshift. The further an object is from us the faster it’s racing away from us. All other theories are based in some abstract mathematical modeling that’s in most cases unverifiable.
Still, we haven't resolved many things in this model like how relativity is a factor. Since we know universal expansion is accelerating it follows that in the distant past it was much slower, which skews everything we know, from the age of the universe to the factors associated with the accepted ”facts” about the state of the universe when it was the size of a basketball or a planet or a modern galaxy. But this is science and we are constantly learning more.
While our ignorance in the past has been well established, our ignorance in the present just keeps being a revelation that many find hard to accept.
Our minds are limited to the space/time/matter model, which is nothing but illusion. Questions about when and how the universe sprang into existence can not be answered with that model, and from a higher perspective the questions are simply not meaningful.
I am just reading “Reality is not What it Seems”, by Carlo Rovelli, a physicist who is working on the theories of quantum gravity. According to Rovelli, time does not exist.
The experience of reality is truly awesome and thrilling and joyous, but the implications are baffling in the extreme.
The "beginning" of the universe is the most mind boggling concept to me. On one hand, how could it have been here "forever"? On the other hand, how could something spontaneously "arise" from nothing--or evolve from nothing? How did the elements of its creation exist as they, too, would have arisen from "nothing"? Multiverses do not explain these issues. Perhaps there was a big bang, but that leads back to the original issues of something from nothing.
I sometimes lie awake at night, pondering these questions.
I'll stick with the inflationary model of the Big Bang as long as the evidence continues to support it over anything else. The rest are pretty much speculation and, as much as I love speculation, that's where they'll remain until further evidence suggests otherwise. Emergence is interesting and I look for more along this line to explain anti-entropic development, but it's not about cosmological origin. String theory remains that and evidence to support it is a major issue. It's also not an origin theory. Simulation is still SF. Here's a recent article that provides a brief history of our understanding of cosmological origin:://www.space.com/16042-cosmology.html I am particularly interested in dark matter/energy which apparently make up about 95% of the total mass and energy (in other words, everything) in our universe, according to current evidence--and we can't understand determine what it really is. Another way of looking at it is to took around the room you are in and realize that 95% of what's there right now is totally "invisible" to you--and you're full of it. (Some will probably say I am that, too.)
I'm something of a fan of version of the anthropic principle based upon the Heisenberg uncertainty principle and Niels Bohr, conception that physical existence is reliant on measurement and observation, therefore physical existence and consciousness are reliant on each other.
That which is observed requires an observer in order to be observed and therefore exist, the observer requires an observer in order to exist and observe.
Therefore self awareness of being is the root of everything,
Awareness is observation
Observation is measurement
Measurement brings about existence (including time and space)
Existence becomes aware
The circle is complete.
The most efficient way to achieve this is Sentient Life.
I got my own theory i can share but its nothing more than my thoughts. i think its possible that just because everything is flying away from everything doesnt in fact denote a singularity. it is possible that somewhere out there is a place that new matter is constantly formed and as process occurs things are sent hurling through space. we are very limited in our view of things if u just look at the truth of all w really can prove 100% without question. im probable 100% wrong but its just something i been toying with for a while and i might develop it more as new things are learned. i just can't see all the matter of the universe being all packed in to one singularity but im not a physicist or astronomer, just a hobbiest that ponders these things. i know as a kid i had my own version of the goldilocks theory that wasnt exact but still was correct somewhat and this was long before i heard of the actual theory. i explained it as heat from a star meets cold from space and at a certain point and u can have the creation of the ozone in some way hot and cold make steam and such. therefore making life only possible at certain spots around stars. felt good to finally see it actually in a real science journal even tho i had some things wrong.