Do you have a need to worship/support a higher power?
The word Atheist means: a person who disbelieves or lacks belief in the existence of God or gods.
So I'd need to understand what you mean by "higher power". I mean, what we know as Mother Nature is something I believe in, and the general rule seems to be that nothing gets off this planet alive. It's a system of which we're part, but is it a "higher power"?
Do you replace god with something else?
See above.
Do you believe in spirituality?
Spirituality is defined as: the quality of being concerned with the human spirit or soul as opposed to material or physical things.
This is a more complex question. I think there's a lot of confusion and questions about what someone means by "spirit" or "soul". I tend to think of it in terms of the spark of life within us, the things that wakes up this mass of atoms that make up the human being. We don't have to try to live, we simply do. So much of what keeps us alive is done automagically within us, and that's truly amazing to me. Is that my soul?
This also delves in consciousness, what is it, where is it? A whole other minefield!
Can you be spiritual and not believe in god?
Should this have ended with "a God"? I mean, across the globe, not everyone believes in the same God. If you meant to infer the Christian God, then it stands to reason that the answer is "yes", because people do it all the time. If you mean generically, perhaps not. But then, to really be sure, you'd have to have a clear definition of what you mean by "spiritual".
Question - if we someday discover Earth was seeded by an alien race from another planet, would they be our Gods?
Do you have/attend a formal group for discussion and socialization?
For what, worship? What group meets to discuss non-belief?
For the record, I don't consider myself an atheist, though I have no God belief. I simply have not seen any evidence of a God, so have no reason to believe one exists. As such, I'm more an agnostic. If I were to be visited in the night by God, then I'd be a fool not to believe in him. I have been around religious folk, and in my teens dated a VERY religious girl with whom I attended church three nights a week. My own doubts were never appeased.