# Reflected light from pulsars

If I point one telescope at a pulsar and record the image and then I point a second telescope at a mirror that has the image of the pulsar on it and record it, will the two recordings be different? It seems to me that according to the theory posted in the link below they should.

Thought experiment regarding an object approaching a mirror

-
It's not clear how they should be different. Also, what makes pulsars special? It's good to remember that most all astronomical images are reflected off various mirrors before being captured, and that the number of such mirrors varies among telescopes. –  Chris White Feb 6 '13 at 16:58

## 1 Answer

I think you're confused about what to consider relativistically here.

The pulsar itself isn't spinning at relativistic speeds. The fastest we've observed has a period of about $2$ $ms$. Even though light is relativistic by definition, the information isn't arriving at relativistic speeds, i.e., the intensity of the light as a function of time doesn't change relativistically. Therefore, if you looked at a pulsar in a mirror, you'd see exactly the same thing as looking at the real pulsar (if you've got a really good mirror), except perhaps delayed by the extra light travel time between the mirror and the lens of the telescope.

-
From what I've read is that the surface does travel at reletivistic speeds and that is why they produce syncrotron radiation. Therefore I assume the right angle would produce a surface traveling towards the mirror at close to light speed. abyss.uoregon.edu/~js/glossary/pulsar.html –  Jitter Feb 27 '13 at 12:06
No, the particles trapped in the pulsar's magnetic field are the one's producing synchrotron radiation. The particle velocity is independent of the surface velocity. If the surface was rotating at that speed, it wouldn't be gravitationally bound. Have a look at breakup velocity –  Kitchi Feb 27 '13 at 13:52