Who Am I said:
Yeah, I'd be happy making a low wage working at an observatory, working on finding a way to increase the energy density of batteries or answering problems that would lead to more effective energy sources, just to name a few of my research ideas.
It's just that being a professor would be beyond amazing for me and I would love to have the advantages that come with it, not just for me but for my future family.
Of course - I'm not talking about changing your dream to become a professor. What I mean is that you have to be flexible with your academic choices, and that chance will also play a role in becoming what you desire. Like I said, the most important thing is to keep your goal and stick with it.
For example, if there are more graduate opportunities in acoustics than optics, it would make sense to pursue acoustics. This will lead you closer to your goal. What I mean is that you shouldn't have a one-track mind for one subject area or interest. You need to look for opportunities, and you also need a little bit of luck. The most important thing, however, is that you need to love what you do.
I also like the analogy given by jgm340. I think the reason why some of the posts given here in this thread are so vague is due to the unknown aspects of the journey that many of us took down the path that you desire.
Here's my attempt to answer some of your questions. I am certain that these are not the best answers, but here goes.
"How did those professors get to the other side of the glass?
Often, to become a professor you need to first complete an undergraduate degree, usually a BSc. This bachelor's degree is the base requirement, and fulfills society's expectation that you should have some knowledge in your field. Most good graduate schools (if not all) require a BSc (Honors) degree before you enroll. To obtain an Honors degree, you need to have an average that is generally higher than average, and you may also need to complete some additional classes. There is usually (but not always) a project requirement in your last year of studies (typically your 4th year). Sometimes, you can work for a professor or other researcher during the summer of your 2nd and 3rd years, and this work experience (highly recommended!) may help you select a final project.
Your most important years in the program are: the first year, and the last two years. How well you do in your first year may influence if you can enter a certain degree program. Your last two years of your degree program will influence if you can receive an Honors degree. If you don't receive an Honors degree, then you may be forced to upgrade (and take additional classes) before entering graduate school.
If you are interested in doing graduate work in optics, then I would strongly suggest taking undergraduate work in optics. The same applies to any other field. If you don't take undergraduate courses in the area which you would like to do graduate work, I can almost guarantee that you will be forced to take these undergraduate classes in graduate school. Your GPA should be high in these undergraduate classes, although it is possible that some professors have indeed upgraded by taking additional in graduate school. Remember that most professors are just ordinary average people - some were good students, and some were not.
I would also recommend that you keep extra-curricular activities to a minimum when working on your degree. Yes, it is good to network with other people, but make sure that you effectively schedule your time. Scheduling is everything, and I would go as far to say that many people became professors because they knew how to use time wisely.
Once you are through the BSc, then you should enroll in graduate school. Most job offers for a professor will insist that you have a graduate degree. The next step up from a BSc is usually a MSc, which is a Master of Science. The MSc could be project-based, or it could be research-based. It is my opinion that you should take the research-based degree, since it demonstrates that you can do a research project.
You may find that not all professors are willing to give you recommendations. To obtain the required recommendations, you should approach only those professors whom you know. Approach the professors that you have worked with or have taken classes from. It can help to have a professor who is well-known in the field write a recommendation for you, but don't discount the opinion of less well-known professors. Sometimes it can be the less well-known professors who will write better recommendations for you.
After completing your MSc, you should then enroll in a PhD. Although some universities will hire professors with only an MSc degree, you will find that there may be limited opportunities. I would strongly suggest that the next step to becoming a professor is to enroll in a PhD program. The PhD is generally required for being hired by top-tier schools.
To get this far, I would strongly suggest that you have become an independent learner. Don't just study the textbook, study outside of it.
The PhD is going to be more theoretically-based, but your thesis will be the document which will establish you as a researcher in a field. Try to find a niche that you can comfortably occupy - this will increase your changes of getting hired by a top-name school. Also try to find a topic that is unique. This will help you to attract attention in the field. Also ensure that you are publishing papers and attending conferences. You should present your research findings at these conferences, and make sure that you talk with other researchers in the field.
Although working under a "big name" professor at a "big name" school can help you obtain a job, it is often not as cut-and-dried as you may imagine. Luck and serendipity can play a large role in obtaining a position. Most professors who have obtained a position at a top-name school did so only after occupying a number of positions at smaller universities. Some (but not all) had degrees at top name fields. If you look at the CVs of many well-known professors, you will find that most of them had to have some experience before applying to the "big name" school. Why? It's because the "big name" school asked for applicants with "x years of teaching" or "x years of industry experience." In the above, "x" can be any number. There's a chance that you might get hired at a "big name" school straight out of graduate school, but then again, this is totally dependent on serendipity and luck. I can't advise you on this aspect.
Once you get hired at a university, you usually don't start out as a "Full professor." There is usually a ranking hierarchy, with promotion and tenure being awarded only after successful publication of a few papers, and usually a monograph or book chapters. In addition, you may have to show that you can train graduate students and attract research grants. There is no set number of books or papers that you have to publish. Usually what will happen is that a committee (composed of other professors) will evaluate your work. If the committee is happy with your work, you will receive tenure. Tenure at a smaller university is often the first step on the path to obtaining tenure at a larger "big name" university.
In short, there are many unknowns in this process, and that is why I say that chance has a large role to play in becoming hired at a "top name" school. In addition, you need to look for opportunities while you are an undergraduate and graduate student, since there are no hard-and-fast rules to becoming a professor.
I believe that perhaps the best thing to do is to try and be a good student, and try to be a good professor who teaches well and loves the world. Obtain a job at a university, and be happy with what you have. Chance and future opportunities may help you achieve a job at a "top-name" school, but you need to first focus on being happy with your research and with your life. This is the key to all other things.
Remember that even the venerable Einstein was once a lowly patent clerk. Everyone starts somewhere.
