A few questions

[Dotard]

Oh what the hell, I'll jump in on this bandwagon also.

1. Do you think it is possible to know why the universe exists?

It exists for my pleasure. That's my opinion of 'why'. Beyond that, there is no 'why'.

2. How do you think morality can exist without objective authority or verification?

Who's morality? Mine, yours or the prevalent morality of the U.S. in the 1700-1800s?

3. If there is no afterlife, what motivation would/should anyone have for living any particular way, such as trying to live ethically, civilly, healthily, or any specific way?

Damn, you're right! Gosh, I got a lot of murdering, raping and plundering to catch up on. Can someone please put that carrot back on a stick so I won't wander in random directions? Or maybe I could become a christian and just proclaim Jesus as my savior thus assuring a place in heaven and insto forgiveness and then I can continue in a life of murdering, raping and plundering without fear because, well, you know, all sins are forgiven right? Long as I don't smack-talk that Holy Ghost.

4. If there is no afterlife and no essential or ultimate meaning to existence, why should an atheist care if someone believes in a religion and, indeed, if believing in a religion would make their life easier, would that bother you as an atheist?

I don't and no it doesn't bother me anymore than that 4 year old child believing Santa Claus exists.

5. Can you be absolutely certain, without a doubt, that God or something supernatural does not exist?

Yes I am absolutely certain with out a doubt that God or something supernatural does not exist.
This does not negate the possibility that I could be wrong.