I am informed that gravitons are very expected by physicists. How would we ever get them to make some sort of electro/magnetic effect that our instruments could detect? All we ever detect are impacts and light, really, if you break it down. Even for smell and taste, you must have the impact of a particle, and the subsequent effect of its unique electron cloud and bonding.
I have no idea how one would detect a graviton (neither does anyone else, or they would do it!)…
As far as I know, the expected appearance of gravitons has nothing to do with empirical observations, but rather the current model of the atom.
Gravitons are the particles associated with gravity waves. Presumably efforts to detect gravity waves will precede efforts to detect an individual graviton.
There have been several experiments proposed to detect gravity waves, most involving large masses widely separated with the separation measured very precisely (using interferometers, IIRC). Few of these have been implemented since the waves are so feeble they put extreme demands on the precision and accuracy of the measurements required. Scientists are unwilling to spend a lot of money on an experiment with limited chance of success – success being defined as getting results, not necessarily the ones you expect. The gravity wave experiments are just not likely to get any results at all.
So until we know more about how to go about it or the technology advances significantly we’re not going to measure gravity waves.
Now consider how much easier it is to detect a light wave than it is to detect a single photon.
“I used to think the brain was the most important organ in the body, until I realized who was telling me that.”
Emo Phillips
Can you say Laser Interferometer Gravitational-Wave Observatory? I knew you could! 
It is too clear, and so it is hard to see.
It seems that there was an article in a fairly recent National Geographic which showed a picture of a series of lasers/detectors (very long, maybe miles) that were built to detect gravitons…I may be mistaken though.
Pluto wrote:
I strenuously disagree. Scientists are perfectly willing to spend huge amounts of money on scientific experiments. It’s the government (funding agencies) that puts the kibosh on such nonsense.
-k-
Karen Lingel, Physicist