How much money does a person with a PHD earn?
It depends on where they work.
That totally depends on what you do with it. If you want to stay in academia, you face years of postdoc and possibly non-tenure track positions. In that case, you will earn very little for a very long time. If you want to go into industry, then you have postdoc time and hopefully a job, where you will earn more. If you quit science and can get a management consulting job, you make what a…
How much money do environmental consultants make and where should you look for salary information about this field?
The two postgraduate degrees are a master's degree and a doctorate degree (PhD). It would take 2-3 years to earn a master's degree. After you earn a master's degree, it would take about 4-5 years to earn a PhD. There are some PhD programs that incorporate master's degree work though so you don't have to do a separate degree.
In the US, a PhD physicist in academia who teaches and does research might earn $40-$80k (depending on the university) at the assistant professor level. Associate and full professors can earn much more, up to six figures at prestigious institutions. A research physicist at the National Laboratories might start at $60-$80k and, after 5-10 years with high productivity, make $120k or more. I don't know about industry.
You can't get a phD in Autism - Autism is a neurological difference and/or identity. You may be able to get qualifications specializing in Autism, how much you could earn depends on your qualifications, experience, and how good you are at your job (remember the real autism experts are Autistic people - if you want to work with Autistic people learn about them from them).