B Doppler effect for stationary observer?

If I and the light source are both moving toward one another, I see light blueshifted. What if I'm at rest and the source moving towards me?
 

Orodruin

Staff Emeritus
Science Advisor
Homework Helper
Insights Author
Gold Member
2018 Award
15,598
5,622
At rest relative to what? You have asked enough questions in the relativity forums to know that there is no absolute rest and that being precise in formulations is important. You should also post your own work, not just say that you "seem to get" something.
 

Vanadium 50

Staff Emeritus
Science Advisor
Education Advisor
22,811
5,054
I've worked out the equations
Not correctly. If you did it correctly, a source moving towards you would be blueshifted.
 
At rest relative to what?
Self evident. I do not believe I would have to make that explicit to a experienced physicist like you.
a source moving towards you would be blueshifted.
Indeed, as soon as I posted this question, I realised where I was going wrong, and got the correct result.
 

Nugatory

Mentor
12,111
4,587
At rest relative to what?
Self evident. I do not believe I would have to make that explicit to a experienced physicist like you.
Not only is the answer not self-evident, but I am unable to imagine any possible answer. As you posed the problem, there are only two things to consider: you and the light source, and these certainly are not at rest relative to one another.
 

Nugatory

Mentor
12,111
4,587
The original poster says they've found their error so this thread is closed.
The key point here is that it is the exact same physical situation whether we think in terms of the light source approaching the observer or the observer approaching the light source; neither is more "at rest" than the other.
As always, if you have more to say on the topic, PM me or any other mentor.
 

Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving

Hot Threads

Top