Before anyone comes for me, I grew up southern baptist – went to a private christian school & was homeschooled for a few years. The extent of my “science” education when it came to evolution & the origin of the universe was “if we came from monkeys why do monkeys still exist?” and “look at this galaxy that’s shaped like a cross, isn’t god amazing!!” I’m an atheist now and would like to have some sort of understanding of how our world came to be, but trying to figure it out as an adult with no real foundation has been incredibly difficult, and none of it’s making sense. I also know I’m asking a lot as all 3 of those subjects are pretty extensive, so if you know any good videos or books I’d love some recommendations!
In: Biology
We need to dispel one myth right now.
Evolution, Big Bang, and Abiogenesis are 3 separate things. The way the question is written suggests you think of them as all the same thing. Despite what Christians say, they are not. They are separate and have to be discussed separately.
Evolution:
This is the one of the 3 that we know the most about. It’s the phenomenon whereby populations of organisms adapt to their environments over time. Crucially, the environments change too. And sometimes, populations get separated from one another, and get stuck in different environments, where the environments they have to adapt to are not the same.
The way it generally goes is like this:
– when an organism reproduces, the offspring will usually have the genetic material of the parent or parents
– however, some gets changed by mutation (random copying errors)
– normally this does very little, or is harmful. But on occasion, it can be helpful.
– the individual with the helpful mutation has more offspring than others of the species, causing the helpful mutation to become more common over time.
Of course, there’s a lot more that does and can happen. You could spend your whole career just learning about evolution, and youtuber [Forrest Valkai](https://youtu.be/1GMBXc4ocss?si=XAGjJITDKCYcLnOB) has. I recommend his content for this, he knows more than me about this and explains better than I do.
Abiogenesis:
Less well understood, but this is the event that would have been the beginning of life on earth.
As far as we can tell, RNA can and often does form spontaneously (ie just from random interactions of simple chemicals). All you’d need is a sequence to form that catalyzes its own replication, and you can get simple RNA-based life (well, “life”).
What I’ve just described is the RNA World Hypothesis. It’s not the only idea in town, and probably isn’t the whole story. But here’s [a video on the topic](https://youtu.be/K1xnYFCZ9Yg?si=PD3t8YB5qaxaGQiZ)
There’s some missing bits. Cell membranes would likely have come about independently; though they actually have the same chemistry as soap bubbles and aren’t hard to form spontaneously.
Big Bang:
This one, funny enough, was named by a detractor.
What we have here, is that the universe is expanding. This much is clear from measuring the light from other galaxies. The universe is getting colder and sparser.
So when we run the clock backwards, we get the universe in a hotter and denser state. If we run it far back enough, we get infinite density, about 14 billion years ago.
At least, that’s the prediction we get from relativity. That point of infinite energy density followed by density that’s finite and shrinking is what we call the Big Bang.
We know it accurately describes the universe pretty far back. It correctly predicted that at a few hundred thousand years old, the particles that were beginning to exist would emit light that would subsequently be ubiquitous. We’ve found that and subsequently called that the Cosmic Microwave Background.
But there are some known unknowns. We don’t actually know if the universe behaves the way we think it does when the energy density gets that high. We also have no idea what (if anything) caused it to occur, or if that question is even a meaningful one. We don’t know if we can unify gravity with the other 3 forces (electromagnetic, weak, strong) like we did with the first 3, and that would change what the early universe was.
The Big Bang model is pretty good for slightly later times, we just don’t know how well it does for really early times, or even t=0.
Latest Answers