An idea has been nagging me for over a year now but its not within my expertise. What can I do ?Learn about this field or just try to make it happen?

Start by interviewing people who do have experience in the field and determining to what extent they feel the pain for the problem you're solving. Your biggest risk with an idea where you don't have domain expertise in is that you're solving a problem that doesn't need solving.

If after speaking with a number of people in that field, there is a strong sense of validation, then you might consider moving forward on attempting to execute the idea but before doing so, I'd recommend you talk to me or another well-reviewed Clarity advisor to ensure you are well equipped to move forward on the idea.

I fully agree with Tom regarding gathering some intel from those experienced in the field. My comments below are with the intention of further developing this idea.

You may discover that, as Tom mentioned, the "problem" (1) doesn't need solving OR (2) a solution already exists (that you may just not be aware of) OR (3) the idea / solution you have has already been tried and failed OR (4) though a "need" does in fact exist - the desire (by the market) to do anything about it doesn't.

You may also discover that your idea / solution, though perhaps far superior to the current solution (if one does indeed exist) would be rejected (again - by the market) due to the fact that the current solution is "good enough".

And I'd highly recommend you do your interviews face-to-face if at all possible. Prepare your questions in advance (to maintain focus and out of respect for their time). And record the audio of the sessions. (Just be sure to get the other party's consent before doing so - I'd get it in written form.)

If face-to-face isn't viable then skype (and record with camtasia) or do a google hangout.

Best of Luck!!

Explain the idea on Clarity and ask for feedback.

Great advise from Tom and David. After you have validated your idea using some of the suggestions listed above. you may want to identify an industry expert as a co-founder or
partner. The combination of an outside who can see an opportunity from a fresh perspective and an insider who knows the challenges and key levers of the industry has the potential of solving problems.
Good luck !

Until you feel confident that you know the topic or trust that others on your team do, skip the idea.

Options:

(1) Become an expert on the subject, and then reevaluate your idea.
(2) Pursue a conversation with an expert on the subject, and only continue with your idea if that expertise is represented in your team.
(3) Ignore the idea, since it probably won't pan out.