That's because the day/night cycle was the first thing created. The "myth" specifically refers to each day of creation as a "day and a night, one day".
Day is, by definition and empirical observation, when the sun is shining, driven mostly by the rotation of the Earth. If that mechanism is not driving the day-night cycle, there is no reason to assume any sort of 24 hour period.
Given the probability of evolutionary theory as so far past impossible (try 1 in 10^50), I'll stick with the other side.
Whoever told you this lied to you. That argument was created to attack abiogenesis, not evolution. The theory of evolution is about The Origin of Species
, not the origin of life.
It's not even true in the first place, but abiogenesis is a separate topic of discussion. Start a new thread if you want to argue that.
But feel free to pick the side you want as we no more know for sure how the universe came into being then we do how the Egyptians built the pyramids.
Evolution is completely separate as a theory from the Big Bang. They are not related, although they occasionally borrow terms from each other, which confuses people, but they are not the same.
Again, separate thread (though I owe a post on relativity and that too, oi).
If you are going to argue for creationism, you will find yourself much better received if you work to understand the subject matter - most of it really is not that difficult.
If you have a question, ask.
There is no such thing as a scientific "fact".
A fact is a piece of data. Observations of mutations, speciation, and so on are empirically observable, are not particularly difficult to observe, and have been observed in such immense quantities that yes, they are facts.
The most basic definition of evolution is the change in allele frequency in a population over time. The alleles governing eye and hair color, for example, have a slightly different frequency (1/3rd for brown eyes, 2/3rds for blue eyes) than my parents (1/4th brown, 3/4ths blue). That's an oversimplification, of course - there are multiple genes covering eye melanin. But saying that it did not drift between generations would require that those frequencies somehow be the same - which for my particular situation is actually mathematically impossible
It's actually impossible for evolution not to take place between my parents and their children, unless they somehow, by social and medical miracle, have another child. You cannot construct an alternate scenario.
Nature never says yes, only 'no' or 'maybe', but you can get enough 'no' answers to lock parts down pretty thoroughly. : )
Gravity is still a theory.
No, gravity as it is commonly described is a law, which is simply a rule by which observations (facts) seem to follow in every observable instance. There's no explanation for why gravity is what it is.
You may be thinking of Einstein's general theory of relativity, which is a theory, albeit a very well supported one, which proposes that gravity's mechanism is actually a sort of curvature in spacetime.
The sun rising in the morning is still a theory.
That the sun rose yesterday is a fact. That the sun will rise tomorrow is simply a prediction - a reasonable guess that precludes say, a rogue black hole slamming into Earth or the Sun at a high fraction of c before it rises.
There is no way to prove that gravity has always existed, and will always exist.
That's why it's called a law, in general, and not a theory. We can't really explain why gravity 'is'. We see it quite often, and make incredibly precise measurements about it, but its exact mechanism is still hidden from us. Actually figuring it out for sure would require a particle accelerator the size of a small globular cluster - not particularly likely any time soon!
Especially with this economy, to paraphrase Hawking.
Einstein's GTR shifts this into saying that concentrations of mass-energy warp spacetime around themselves. It still doesn't explain why that happens.
The same applies to evolution. This coming from someone who believes in Evolution, but not in biblical theory. It just cannot be proven.
As I mentioned, things that are observed are still a part of the factual record. The only part of evolution that is impossible to observe is common descent. Common descent is, for the most part, what creationists are arguing against, anyway.