What authentication do I need to get a users friend and follower list if I am not their friend


I’m sorry if this is an obvious question but I have tried to go through all the web documentation. What I found is that I can’t access a user’s information like that if they haven’t approved my app. Which makes sense but in my context is quite debilitating. I have a list of tweets about climate change that I have wrote a learning program to do sentiment analysis on. I also have the names of the tweeters and I wanted to be able to put all of these people in a social graph with their opinions about climate change and try to determine any patterns on the spread of opinion. There seems to be no feasible way for me to get approval by all 6,000 or so people I have on this list (and I hope to later have more). I know people have done very similar things before but I just have been able to find what they did or what kind of authentication they had. My authentication currently allows me to read and write (which I though should be enough). I am undergraduate student at the University of Guelph and am doing this as a research project, any help would be greatly appreciated.