Experts! Help me out please. I know both the programming languages are extremely popular and have their own advantages. But if you have to suggest one of them which one would it be and why?
Or is it too late to learn any one of them in the era of Dart and Go?
Nash
Scientific image processing
Depends what you want to do - if you are doing anything remotely related to scientific computing, Python is the way to go. If you want to deploy client-side applications, Python is the way to go.
If you want to develop web services, Javascript platforms like Node.js are currently the 'in' thing. You can also in principle build client-side deployable applications with Javascript through ElectronJS.
Go seems to be getting popular for "native" speeds, but then there are more mature languages out there for the same like C++, D etc.
Dart is pretty much for internal Google use these days, and eventually compiles to Javascript anyway.
Frankly, there is very little reason to use Ruby the way I see it. Ruby is focused on web service development. Python is a lot more versatile. If you want a specific comparison between Python and Ruby here is a quick cheat sheet : http://learn.onemonth.com/ruby-vs-python