Yep I reckon you summed it all up quite nicely.

I always say god is to religious people what the square root of minus one is to mathematicians.
A concept that is impossible in reality, yet is useful in visualising real problems.

I think you're exactly right and said it very well -- 'humans lose the need to have a god to explain it'.

One of my favorite sources is a blogger/author named Greta Christina. She goes into more depth but says essentially the same thing.

When you look at the history of what we know about the world, you see a noticeable pattern. Natural explanations of things have been replacing supernatural explanations of them. Like a steamroller. Why the Sun rises and sets. Where thunder and lightning come from. Why people get sick. Why people look like their parents. How the complexity of life came into being. I could go on and on.

All these things were once explained by religion. But as we understood the world better, and learned to observe it more carefully, the explanations based on religion were replaced by ones based on physical cause and effect. Consistently. Thoroughly. Like a steamroller. The number of times that a supernatural explanation of a phenomenon has been replaced by a natural explanation? Thousands upon thousands upon thousands.

Now. The number of times that a natural explanation of a phenomenon has been replaced by a supernatural one? The number of times humankind has said, “We used to think ( X ) was caused by physical cause and effect, but now we understand that it’s caused by God, or spirits, or demons, or the soul”?

Exactly zero.

It is also the rejection of authority. I think I read somewhere that you are more likely to believe in god if you had a strong grandparental influence in your childhood. That makes sense as your parents would have a higher power too.
Someone like myself who hates being told what to do would automatically balk at a book of rules that tried to govern my actions and thoughts.

Requiring your believe be grounded in evidence instead of faith brings you to more truths. Having more truths gives you more informed decisions for your life. The better your decisions are the less mistakes you make. Question everything and follow the evidence instead of blind faith. That is Atheism to me.

Mine is even shorter... (But I really like the way you did it also.)

Religion is for those that are taught what to think.

Atheism is for those that are taught to think.

The more we know, the more science advances, the less dependent we become for quick answers to unknowns.

Eh...don't be so quick to judge a private Christian college unless you do actually know it to be a rather conservative one. I went to a Christian liberal arts college once upon a time and though I dropped out, I was there for a time and really, during that time, only took one religion class and classes for the most part didn't get heavily Christian handed.

That said, I agree, atheism in and of itself doesn't have much to attract people compared to religion but religion has a lot of issues that I think is causing the current generation to balk: current sexual abuse scandals, lack of inclusiveness, inability to really answer the questions that science is more able to answer, and so on. And unless that atheist finds a group, he or she is pretty alone but there can be a certain freedom in not being trapped by religious dogma too.

Atheism is no more attractive than a non-belief in unicorns.

Welcome back!!!

I definitely think the God of the Gaps and the rise in rationality is party of it. Science produces miracles that religion can't even dream of.
I think another important factor is social change. People are much more mobile in their lifestyle now, less dependant on the fixed social structure of work/family/church than they used to be.

The more science progresses and explains the unknown, the more humans lose the need to have a god to explain it.

Using your own words here explains it very well. God and the bible are static and never changing. Science is progressive and ever changing. That works for me because a flat earth and weird ideas about a firmament, worldwide floods, and talking snakes are a bit much. The biblical god is much like Zeus and about as credible.

The one thing I like most about the god of the gaps, is that it has kept on getting smaller and smaller all the time, till it perhaps fades away.

“I don't want to believe. I want to know.”

“For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring.”

― Carl Sagan

Give your friend credit. Answering your challenges will strengthen her faith. Most religions discourage critical thought or variations of belief. If she has asked these questions to herself she may be prepared. This may be a homework assignment preparing her for evangelizing.