And by that, I don't mean "will an apple fall if I let go of it" or "do the laws of gravitation as we know them really work?" I want to know if the messenger particle for gravity, the graviton, has been irrefutably proven to exist through observation, not just inference.
My understanding (I am not professional, nor even remotely on the cutting edge of physics - I just pay attention to concepts and like thinking about them) has been that gravitons were assumed to exist, down to having a certain mass and spin and whatever, but have never been detected. The explanation I heard was that they might be so tiny and near-massless that they don't exist in our universe for very long, and disappear instantly after doing their job here.
That's all well and good, and I certainly accept that as probably true, but it's not irrefutable in that just because something SHOULD be there based on what we've found out about physics, that doesn't mean it definitely is. And it does seem a bit weak to assume something exists, to the point of mocking alternative theories, and explain away the lack of direct proof just by saying "well, it fits the model so conveniently well, and we can't find them because... um... they're `unfindable!' Yeah, that's the ticket!" Indirect evidence is all well and good, and it's how we know tons of stuff about the universe, but I don't think it quite qualifies as "irrefutable." Otherwise, I could claim that tiny undetectable elves with pointy hats move objects toward each other and sit back and smugly cross my arms.
While there are lots of seemingly kooky "alternate theories" that degenerate into equally unproveable pseudo-science, it doesn't seem prudent to dismiss the possibility. I recall reading Everett's Many Worlds paper and thinking that some implications of that could eliminate the need for gravitons to exist to remain consistent with observations, even though the existence of gravitons is assumed in the paper anyway. I often think that what appears to be "gravity" could just be a consequence of massive objects "denting" spacetime and allowing that all objects move along that curvature, which is "steeper" near more massive bodies - it seems to me that that would allow for behavior consistent with the math behind gravity but preclude the need for an actual particle to be part of the mechanism.
Some science teacher at my school said that this was wrong, and that gravitons HAVE been reliably and irrefutable observed. Is this true? Where, when, and how was this done? If so, was I completely and utterly mislead or is it recent enough that my impression WAS valid in the past, but has since been rendered moot?
I'm trying to recall other "alternative" theories that still fit the math, however seemingly fanciful - like the one that had all matter "growing" at a constant rate. Just as unverifiable as "unobservable mystery particles that fit conveniently," but assuming I wasn't completely misinformed, certainly not dismissable in favor of something else based on that criteria alone.
I'll save wondering if time and motion are also illusions for another time... :P
EDIT: Why did some dumb fucker change the title of this thread, especially considering how obvious it is from the discussion in this thread that the original was a much more valid title? :rolleyes: