Welcome to OT! You're going to find pretty strange specimens and hear lots of new words being thrown around here. Do look around, don't be scared by funny long words, and devote a bit of time to reading up on the issues.
Your brother-in-law has raised a very good point. The Bible seems to have been written to some people who had no problem thinking that the Earth was pretty recently created. They appear to talk about the sun running across the sky or stopping still in the sky, or about the Earth resting on pillars, or other such things. How is this supposed to make sense to us? We can't jolly well believe that the Earth isn't billions of years old, can we, or that evolution didn't happen? If the Bible tells us that the earth is just 6,000 years old, isn't it getting a little primitive?
There are three basic ways to approach the issue. The first is to chuck the Bible out altogether. Many people do just that upon first thought. But that's not an option for us.
The second is to say that "Yes, we
can believe that the earth is only about 6,000 years old, that man was not evolved but was supernaturally created, and that the evolutionists are all wrong when it comes to the question of where we came from. Therefore we can believe the Bible on everything, including when it says that the Earth is young." These people are known here as Young Earth Creationists (YECs), with other variations being OEC (Old Earth Creationists) and Gap Theorists. The problem is that the scientific evidence they cite may not be very convincing, especially when compared to what experts in the field say, and thus it will earn you instant skepticism especially from more scientifically-inclined people. However, their position is quite easy to grasp, even though I find it scientifically inaccurate.
The third option is to dig deep and ask "What
is the Bible
really trying to say when it talks about a young earth and a supernatural creation? Is it really describing events that actually occurred - or is it trying to make a theological point to people who didn't know enough science to grasp the full picture?" Most of the people here are labeled Theistic Evolutionists (TEs), which really means that they are quite sure that evolution really happened, but at the same time don't think that it poses a problem for God and the Bible. At first glance it seems like we've compromised what the Bible is actually saying in favour of science. (You can tell what I hold to
) But we do have sound theological reasons for believing what we believe. It can be a bit difficult to grasp but I would say that it's worth the effort.
Anyways, continue to hold fast to your faith as you explore the issue of origins theology ... and remember that we don't bite! Feel free to PM if there's anything you feel too afraid to ask in public. God bless!