No, at it's core it's a belief that something does not exist. It's very much a position, whereas a lack of belief would be equivalent to not thinking about it. There are weaker forms of atheism and agnosticism that describe those things.
Religion: "God exists!" (organized Religion and beliefs)
Atheism: "There is no god!" (conviction and belief)
Agnosticism: Meh... fuck it, I am going home" 
(lack of belief, "not thinking about it")
Wrong - both of you.
Agnosticism is the belief the the existence or non-existence of God
cannot be proven and therefore the question is scientifically irrelevant. There is a
huge difference between atheism and agnosticism - if you can't identify the distinction, you're an idiot, kindly step the fuck out.
And, for what it's worth, the 'feats' of the scientists mentioned are hardly noteworthy. Basically what they did is create RNA in a test tube. They created RNA the same way pharmaceutical companies create drugs - they created a process in which they could reliably create the chemical
they intended to create in a
repeatable fashion. What we atheists are looking for is to have a fish tank filled with simple chemicals, shine a bright UV light on it, zap it with some electricity, (aka lightening bolts) and end up with RNA at the end of the experiment. We've yet to accomplish that. This experiement does not prove shit.
