My question is about the ethics of working in applied vs. pure research. I'm a student in a technical field. I am now trying to choose between a few subfields, some of which contribute more to practical technology than others. Say I'm a physics student with a choice between black-hole research, or designing a better solar cell. What, if any, are my ethical responsibilities in making this decision? Is it ethically wrong to devote my time to what amounts to a very expensive hobby, and at taxpayer or university expense? Is it better to use my education and skills to work for solutions to urgent problems? In short, what is the ethical difference between a career in pure and applied scientific research? Thank you for any response.